Metal-impregnated refractory product
This application is a continuation of application Ser. No. 07/721,557 filed Aug. 12, 1991 now ABN, which is the United States designated application of PCT/JP90/00066 filed Jan. 20, 1990. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a metal-impregnated refractory product for use in various types of molten metal treatment vessels such as a converter, a degassing furnace, and a ladle, and a method of manufacturing the same. 
     BACKGROUND INFORMATION 
     Refractory products used in a high-temperature furnace are brought into contact with a molten slag and a molten metal and subjected to various damages. In particular, lining bricks located in a slag line of a vessel can be corroded significantly by molten slag (slag attack) within a short period of time. In addition, the bricks spall after the repetition of a heating/cooling cycle. Graphite-containing refractory products such as magnesia-carbon (MgO-C) brick and a castable containing metal fibers having an improved spalling resistance have been recently put into practical use. 
     Conventional refractory products improve the slag attack resistance by adding carbon (graphite) in the refractory product or increasing the density of the refractory product, thereby suppressing penetration of the molten slag into the refractory product. 
     Japanese Patent Registration No. 1401778 discloses a product formed by adding a metal such as aluminum in a carbon-containing refractory product so that the metal, aluminum in the refractory product is preferentially oxidized to prevent high-temperature oxidation of carbon. 
     Published Unexamined Japanese Patent Application No. 57-500788 discloses a composite body formed by adding a powdered metal to an oxide-based ceramic in order to improve abrasion resistance and toughness of the oxide-based ceramic. 
     Published Unexamined Japanese Patent Application No. 49-99512 discloses a method of impregnating a metal in a sintered ceramic matrix. 
     The above conventional refractory products, however, have the following problems in terms of improvements in high-temperature characteristics. 
     1 When the density of a refractory brick is increased, the spalling resistance is generally decreased. Therefore, the brick easily cracks due to a thermal stress. 
     2 A carbon-containing refractory product is significantly damaged at high temperature because the oxide and the contained carbon in the product directly react. Even at low temperature, since the graphite easily oxides, depending on its use atmosphere and temperature are limited. 
     3 In a carbon-containing refractory product containing carbon and metal aluminum, the contained metal is oxidized within a short time period. Therefore, since oxidation of carbon cannot be sufficiently suppressed, a reduction in slag attack resistance occurs in an initial stage. In this case, the slag attack resistance means a resistance against damage caused by a molten slag which penetrates into the refractory product along open pores and dissolves the refractory product. 
     Use in a furnace is not contemplated for a conventional metal-impregnated ceramic product. An impregnated metal of the ceramic body flows out at a temperature higher than the melting point of the metal or the ceramic body consists of a composition having a low slag attack resistance, the ceramic body is therefore unsuitable for use in a high-temperature furnace. There are open pores and closed pores in refractory product. 
     Generally, properties (e.g., slag attack resistance and a spalling resistance) of refractory brick are largely affected by, e.g., amounts, shapes, sizes, and distributions of pores and voids. That is, when the porosity is increased, the brick becomes vulnerable to penetration of a molten slag. To the contrary, when a total amount of pores and voids is decreased to increase the density of a brick, spalling resistance is reduced. Therefore, to improve both the slag attack and Spalling resistances in conventional bricks, an amount of pores must be decreased while that of voids is increased. However, it is generally difficult to manufacture such a refractory product. 
     The present invention has been made in consideration of the above situation, and has as its object to provide a metal-impregnated refractory product excellent in various high-temperature characteristics, particularly, a slag attack resistance and a gas attack resistance and having a long life, and a method of manufacturing the same. 
     SUMMARY OF THE INVENTION 
     The present invention concerns a metal-impregnated refractory product used in direct or indirect contact with molten material and a method of making the same. The refractory product comprises a MgO-based or an Al 2  O 3  -based porous material impregnated with a metal or a metal alloy containing at least one metal selected from the group consisting of iron, chromium, and nickel, the porous material containing at least 4 vol % of open pores and more than 25 vol % of the open pores being impregnated with the metal or alloy. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-sectional view depicting an island-like (knot-like) pore. 
     FIG. 2 is a cross-sectional view depicting a tubular pore. 
     FIG. 3 is a cross-sectional view depicting a tubular pore. 
     FIG. 4 is a graph of average pore size vs. minimum particle size. 
     FIG. 5 is a graph of apparent porosity of a magnesia brick mixed with hemp vs. amount of hemp. 
     FIG. 6 is a graph of slag penetration depth vs. metal impregnation ratio with respect to pores. 
     FIG. 7 is a graph of slag corrosion rate vs. metal impregnation ratio with respect to pores. 
     FIG. 8 is a graph of metal penetration depth vs. pressurization time. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present inventors have made extensive studies on method of improving both a slag attack resistance and spalling resistance of a refractory brick and succeeded in impregnating various types of metals into various porous refractory product. A metal impregnation ratio, an impregnation depth, stability of an impregnated metal, and the like are affected by, e.g., a size, a cell shape, a degassing condition, a pressurization condition, and a preheating temperature of the porous material brick. Especially the shape of pores in the porous material brick is one of important factors having a large effect on the quality of a metal-impregnated refractory product. Therefore, pores contained in the porous material brick must have a shape which allows easy penetration of a molten metal and sufficiently holds the impregnated metal. 
     When a metal is impregnated into the pores of the porous material brick, penetration of a slag into the refractory product is suppressed, and a reaction between the refractory product and the slag is limited in a portion close to the operation surface. Therefore, a dissolving rate of the refractory product into the slag can be decreased, and no damage is caused by structural spalling generated by penetration of the molten slag. In addition, since the thermal conductivity and the fracture breaking energy of the refractory product are increased, the refractory product becomes stronger against thermal spalling than conventional oxide-based refractory products. 
     The properties of the metal-impregnated refractory product of the present invention are affected by factors described in items 1 to 5 below. 
     1. High-temperature characteristics of an impregnating metal. 
     2. Stability of an impregnated metal into pores. 
     3. An impregnation ratio of an impregnated metal. 
     4. Impregnation conditions. 
     5. The composition of a base refractory product. 
     The above factors having effects on the properties of the metal-impregnated refractory product will be described below. 
     1. High-Temperature Characteristics of Impregnating Metal 
     The effect of an impregnating metal is largely degraded during the use in a high-temperature furnace unless it is present in the form of a metal. For this reason, the metal must have a high oxidation resistance at high temperature. 
     Even if the metal has a high oxidation resistance, it is slightly oxidized in the vicinity of an operation surface. Therefore, this produced oxide (metal oxide made from an impregnated metal) preferably has a high melting point and does not produce a low-melting compound between said produced oxide and the base oxide (base refractory product). 
     In addition, since an impregnation treatment must be industrially performed, it is difficult to manufacture a metal-impregnated refractory product by using a metal having a melting point higher than 1,800° C. 
     For the above reasons, a metal to be used in the present invention was limited to a metal containing at least one of Fe, Ni, and Cr. 
     2. Stability of Impregnated Metal in Pores 
     The effect of the metal-impregnated refractory product is largely degraded if an impregnated metal flows out of the pores during the use of the refractory product. The shape of open pores of the brick has a large effect on preventing an outflow of the impregnated metal. A relationship between the pore shape and the stability of the impregnated metal and a method of controlling pores will be described below. 
     2.1. Relationship Between Pore Shape and Stability of Impregnated Metal 
     An effect of a pore size on a force of holding an impregnated metal will be described below. 
     An impregnated metal in a molten state is held in pores by a capillary force. When the molten metal moves out from the pores, the contact angle on the forward side differs from the contact angle on the backward side. A difference is produced in capillary pressures between the forward and backward sides due to this contact angle difference, and the produced pressure difference serves as a moving resistance of the molten metal. This moving resistive force can be a satisfactory holding force when the pore diameter range is 10 mm or less, due to wettability, between such refractory systems as Al 2  O 3 , MgO, and MgO-Cr 2  O 3  systems refractory and such metals as Fe, Cr, and Ni and the surface tension of each metal. 
     If the pore size is too small, however, a metal vapor and an atmospheric gas penetrate into pores containing the impregnated metal and replace the metal, and the metal flows out of the pores. According to an experiment, penetration and replacement of a gas occur when a pore size is 10 μm or less. When the pore size is large, i.e., 4 mm or more, a metal frequently outflows due to a force generated upon movement during the impregnation treatment. Therefore, the pore size was set at 10 μm to 3 mm. 
     The effect of a pore shape on the impregnated metal holding force will be described below. 
     FIGS. 1 to 3 are views showing models of a pore shape. A model 1 in FIG. 1 shows an island-like (knot-like) pore, in which a knot portion has a size of 10 μm to 3 mm. A model 2 in FIG. 2 shows a tubular pore having a pore size of 10 μm to 3 mm. A model 3 in FIG. 3 shows a tubular pore having a pore size of less than 10 μm. 
     When the models 1 to 3 are compared with one another, the models 1 and 2 do not easily cause gas penetration/replacement (degassing), while the model 3 easily causes the degassing. In addition, a refractory material 2 of the model 1 has a surface energy per unit mass of an impregnated metal 8 lower than that of the model 2 and moves less easily than the model 2 because the surface energy of a metal 8 is increased upon movement. Therefore, the refractory material 2 of the model 1 has an impregnated metal 8 holding force higher than that of the model 2. 
     2.2. Controlling Method for Forming Pores 
     Conventional refractory products generally have 7 to 20 vol % of pores, and many of them have an average pore size of 10 μm or less. Therefore, in order to use such a conventional refractory product as a porous material body for a metal-impregnated refractory product, pores having a pore size of 10 μm to 3 mm must be formed. 
     As an exception, there is a refractory product originally having an average pore size of 10 μm or more, such as a magnesia-chromium brick. Even in this case, however, pores having a pore size of 10 μm to 3 mm are preferably formed. A method of controlling pores of the porous material body will be described below. 
     1 Method for Obtaining Suitable Pores by Controlling the Size of Material Particles 
     Pore size can be increased by a particle size distribution obtained by removing fine particles from material particles of a porous material. FIG. 4 shows an average pore size as a function of minimum and maximum particle sizes of magnesia bricks burned at 1,750° C. using a sintered magnesia clinker having an MgO particle size of 95 wt % as a material. As is apparent from FIG. 4, when the minimum particle size is 44 μm or more, an average pore size of 8 μm or more, i.e., a pore size suitable for metal impregnation, is obtained. Therefore, the minimum particle size was set at 50 μm or more. As shown in FIG. 4, when the minimum particle size is 80 μm or more, an average pore size of 10 μm or more, i.e., a more preferable pore size, is obtained. 
     If the maximum particle size is too large, no sufficient strength is obtained in the porous material body, and a distribution of the impregnated metal becomes nonuniform. Therefore, the maximum particle size was set at 10,000 μm or less. 
     2 Method of Controlling Pores by Mixing Thermally Volume-Reducing Particles or Thermally Volume-Reducing Fibers 
     The pore amount and the pore shape of a brick can be controlled by adding thermally volume-reducing particles or thermally volume-reducing fibers, which cause thermal decomposition or reaction upon heating and are reduced in volume, to a raw material at a ratio of 5 to 50 vol %. 
     In this case, the diameter of the thermally volume-reducing particles or fibers is preferably set within the range of 80 to 10,000 μm. The lower limit of the diameter of the particles or fibers is set at 30 μm because pores having pore sizes large enough to stably hold the impregnated metal cannot be obtained if the diameter is smaller than that. On the other hand, the upper limit of the diameter of the particles or fibers is set at 10,000 μm because, if the diameter is larger than that, an average pore size is increased to reduce the compression strength of a formed product to make it difficult to impregnate a metal and to allow an outflow of the molten metal from the pores. In addition, the length of the mixed fibers is preferably set within the range of 1,000 to 30,000 μm (1 to 30 mm) in order to uniformly mix the fibers into the powder material. 
     various types of organic fibers can be used as the above fibers. However, it is preferred to use a synthetic fiber or a natural fiber which can cause thermal decomposition even at a baking temperature or a drying temperature as comparatively low temperature as well as a burning temperature as high temperature. Examples of these synthetic or natural fibers are hemp, a vinyl fiber, an acrylic fiber, pulp, and a cotton yarn. 
     FIG. 5 shows the porosity of a magnesia brick mixed with hemp having a diameter of 500 μm and a length of 3 mm as an example. As is apparent from FIG. 5, the porosity was increased upon mixing of the hemp, and an average pore size was also increased as the mixing amount was increased. 
     3 Method of Adding Metal Particles 
     In addition to the control of pores of the brick, the metal diameter obtained after impregnation of a metal can be controlled by mixing 5 to 20 vol % of metal particles having a particle size of 30 to 1,000 μm into the raw material. 
     The lower limit of the particle size of the metal particles is set at 30 μm because, if metal particles having a particle size smaller than that are mixed, the particle size is decreased to be 10 μm or less due to deformation of the metal particles during forming and burning of the brick, resulting in an insufficient force for holding metal particle in pores. On the other hand, the upper limit of the particle size of the metal particles is set at 10,000 because, if the particle size is larger than that, only the metal particles are sometimes removed from the matrix, therefore a slag attack rate of the matrix accelerates when a slag attack proceeds to expose the metal particles. 
     In addition, the amount of the metal particles is set at 5 to 20 vol % because no satisfactory addition effect can be obtained if the amount is 5 vol % or less and a formed brick cannot acquire satisfactory sintering strength to make it impossible to perform the metal impregnation treatment if the amount exceeds 20 vol %. 
     3. Impregnation Ratio of Impregnated Metal 
     An impregnated metal is preferably, uniformly distributed in a portion of the refractory product brick to be damaged during the use. 
     FIGS. 6 and 7 show a slag penetration depth and a slag attack rate, respectively, obtained by a rotational erosion test for metal-impregnated refractory products fromed by impregnating SUS 304 in magnesia bricks (MgO; 95 wt %) having different porosities and metal impregnation ratios. Both the slag penetration depth and the corrosion speed are reduced upon impregnation of 25 vol % of the SUS 304. As is apparent from FIGS. 6 and 7, as the metal impregnation ratio is increased, the slag penetration depth and the corrosion speed are decreased. Therefore, the metal impregnation ratio is preferably increased. 
     4. Metal Impregnation Conditions 
     A method of impregnating a metal in a brick has the following steps (a) to (f). 
     (a) A heating step for heating a brick up to a temperature of the melting point or higher than a metal to be impregnated. 
     (b) A degassing step for degassing an internal gas of the brick to 100 Torr or less. 
     (c) A dipping step for dipping the brick in a molten metal bath at a temperature of 1,500° C. or higher. 
     (d) A pressurizing step for pressurizing the brick in the molten metal bath up to a predetermined pressure within the range of an absolute pressure of 1 to 100 kg/cm 2 . 
     (e) A removing step for removing the brick impregnated with the metal from the molten metal bath. 
     (f) A slow cooling step for slowly cooling the removed brick. 
     The vacuum degree of the above degassing step is set at 100 Torr because degassing becomes insufficient at a low vacuum degree exceeding 100 Torr and the molten metal is pushed back by an internal residual gas pressure when the applied pressure is released. 
     The applied pressure is set at an absolute pressure of 1 to 100 kg/cm 2  because at least 1 kg/cm 2  is required to impregnate the metal in 25 vol % or more of pores. On the other hand, if the applied pressure 100 kg/cm 2 , almost no increase is found in the metal impregnation amount. 
     FIG. 8 is a graph showing check results of a metal penetration depth obtained by variously changing degassing and pressurization conditions, in which the abscissa indicates a pressurization time and the ordinate indicates the metal penetration depth. Referring to FIG. 8, a curve G indicates a result obtained when a brick was degassed in a furnace at a vacuum degree of 120 Torr and dipped in a molten metal bath at an atmospheric pressure of 10 kg/cm 2 . A curve H indicates a result obtained when a brick was degassed in a furnace at a vacuum degree of 0.1 Torr and dipped in a molten metal bath at an atmospheric pressure of 10 kg/cm 2 . Note that the temperature of the molten metal bath was about 1,600° C., and a brick of 200-mm cube was dipped in the bath. As is apparent from FIG. 8, when the degassing condition is set at a vacuum degree of 0.1 Torr, the metal penetration depth reaches a depth of 100 mm or an core after about 10 minutes of a pressurization/dipping treatment. On the contrary, when the degassing condition is set at a vacuum degree of 120 Torr, only a penetration depth of about 85 mm can be obtained, and an internal residual gas amount after the degassing treatment is left non-impregnated. Therefore, the vacuum degree during the degassing treatment is preferably increased up to 0.1 Torr or more. 
     5. Composition of the Brick 
     The metal-impregnated refractory product according to the present invention is used in a member which is brought into contact directly or indirectly with a molten product or a dry gas. This metal-impregnated refractory product is characterized by impregnating a metal mainly consisting of iron, chromium, nickel in a brick, which is formed of a refractory substance mainly composed of MgO or Al 2  O 3  and contains at least 4 vol % of open pores (pores communicating with the surface), at a ratio of 25 vol % or more of the pores. 
     The content of MgO or Al 2  O 3  as the main component is preferably 40 wt % or more with respect to the brick before impregnation of the metal. A magnesia system refractory product preferably contains 40 wt % or more of MgO and contains Al 2  O 3 , Cr 2  O 3 , ZrO 2 , and SiO 2  as other components. An alumina system refractory product preferably contains 60 wt % or more of Al 2  O 3  and contains MgO, ZrO 2 , and SiO 2  as other components. The brick contains a binder agent or a pore controlling agent (e.g., an organic fiber) in addition to the above components. 
     The atmosphere, the slag component, and the like change in accordance with the type of high-temperature furnace in which the metal-impregnated refractory product is used in the present invention. Therefore, the composition of the brick is important as in-the case of conventional refractory products. 
     Some of the experiments which lead to the present invention and examples and comparative examples of the present invention will be described below. 
     Manufacture and Properties of Brick 
     Tables 1(1) and 1(2) show manufacture examples of a brick of magnesia system, metal impregnation examples, and results of an outflow test of impregnated metal. A sintered magnesia clinker containing 98% of MgO was used as a magnesia material, and a bittern was used as a molding binder. A pressure was set at 1 ton/cm 2 , and the size of the formed block was 150 mm×100 mm×300 mm. As a result, pores having a pore size of 10 μm or more could be formed by any of particle size control of removing fine particles having a particle size of 44 μm or less mixing of thermally volume-reducing particles or fibers, and mixing of metal particles. In addition, as the ratio of pores having a pore size of 10 μm or more was increased, an outflow ratio of an impregnated metal in the outflow test at high temperature was decreased. As a result, a slag resistance and an oxidation resistance of the impregnated metal were improved to realize a large metal impregnating effect. 
     The same effects as those of the sintered brick were obtained by a non-sintered brick (Example 12) and a cast-molded brick (Example 13). In the molding of Example 12, a binder or a novolak phenol resin was mixed in raw material. 
     Note that in the erosion test shown in Tables 1(1) and 1(2), a temperature was held at 1,700° C. for four hours, and an eroding agent was replaced every 30 minutes. The eroding agent had a composition of 27 wt % of silica sand, 53 wt % of lime, and 20 wt % of mill scale and was replaced in an amount of 1 kg at a time. 
     Tables 2(1) and 2(2) show manufacture examples of a brick of alumina system containing 96% of Al 2  O 3  and a brick of magnesia/chromium system containing 55% of MgO and 32% of Cr 2  O 3 , and metal impregnation examples. 
     As is the case with the brick of magnesia system porous material body, the metal impregnating effect was enhanced as the ratio of pores having a pore size of 10 μm or more was increased. 
     The porous material brick of magnesia/chromia system provided a high ratio of pores having a pore size of 10 μm or more and good results even in Example 18 in which the porous material body was manufactured by the same method as that of a conventional refractory product. 
     Note that in the erosion test shown in Tables 2(1) and 2(2), a temperature was held at 1,700° C. for four hours, and an eroding agent was replaced every 30 minutes. The eroding agent had a composition of 32 wt % of silica sand, 48 wt % of lime, and 20 wt % of mill scale and was replaced in an amount of 1 kg at a time. 
     Tables 3(1) and 3(2) show a change in impregnation amount obtained in accordance with a vacuum degree and an applied pressure when Fe-18Cr was impregnated in a brick of magnesia system similar to that in said Example 3. 
     When the vacuum degree was 100 Torr or less, the metal could be impregnated to the core of a porous material body. To obtain a better impregnated refractory product, the vacuum degree is preferably 1 Torr or less. 
     Even when the applied pressure was increased up to 100 kg/cm 2  or more, no large increase is found in the impregnation amount. 
     Tables 4(1), 4(2), and 4(3) show results obtained by manufacturing metal-impregnated refractory products consisting of magnesia, spinel, magnesia/chromium, magnesia/dolomite and performing tests using a actual converter and a stainless smelting furnace. Better results than those obtained using conventional MgO-C bricks could be obtained in any of the wall and the tapping member of the converter and the wall of the stainless smelting furnace. 
     Tables 5(1) and 5(2) and Tables 6(1) and 6(2) show results of actual tests using a molten iron ladle, a molten steel ladle, and an RH degassing smelting furnace. A large effect was found since the corrosion speed of the metal-impregnated refractory product was small. 
     Commercial Applicability of the Present Invention 
     According to the metal-impregnated refractory product of the present invention, since pores contained in the refractory product are filled with a metal, high slag attack resistance, gas attack resistance, spalling resistance, and corrosion resistance can be obtained. Therefore, when this metal-impregnated refractory product is used in slag lines and the like of various types of metal smelting furnaces and molten metal vessels, the life of the furnace or vessel can be largely prolonged as a whole. In addition, maintenance cost can be largely reduced by using the metal-impregnated refractory product of the present invention, which would be subjected to possible significant damage by a stream of molten steel, such when used to form the tapping hole of a converter. 
     Especially when a porous material brick is formed by adding various types of cell controlling agent in a material body so as to control pores contained in the brick in a desired state, a metal can be impregnated more easily. By controlling pores in a desired state in this manner, a metal can be impregnated in a central portion of a large porous molded body to enable manufacture of a large metal-impregnated brick. Large metal-impregnated bricks can be used as linings in, e.g., a converter and a degassing furnace. In addition, large bricks can be used as a molten metal contact block of a ladle and the inner wall of a slag line. Furthermore, large bricks can be used in a portion of an apparatus subjected to a high-temperature atmosphere, such as a coal liquefying gas pipe. 
     By arbitrarily selecting pore control conditions and molten metal impregnation conditions (e.g., an applied pressure and a heating temperature), a metal-impregnated brick having a high impregnation amount can be obtained. Since the metal-impregnated brick having a high impregnation amount has various characteristics not found in conventional bricks, various types of structures can be constructed using good mechanical properties and workability. In addition, the metal-impregnated brick having a high impregnation amount can be used as a functional material as well as a structural material. For example, the brick can be used as an ultrasonic medium for transmitting an ultrasonic wave directly to a high-temperature molten product. 
     
                                           TABLE 1 (1)                             
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                  Examples                                                
                                                6                         
                                                Mixed                     
                        2     3     4     5     with                      
                  1     Particle size control   sawdust                   
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(1)      1 to 6 mm                                                        
                  30    30    35    35    30    30                        
Particle 1 to 0.15 mm                                                     
                  30    35    35    40    30    30                        
size dis-                                                                 
         0.15 to 0.44 mm                                                  
                  20    25    30    25    40    20                        
tribution                                                                 
         0.44 mm or less                                                  
                  20    10    0     0     0     20                        
(vol %)                                                                   
(2)               --    --    --    --    --    5                         
Thermally volume-reducing                                                 
particle amount (vol %)                                                   
(3)               --    --    --    --    --    0.1                       
Diameter (mm)                                                             
(4)               1750  1750  1750  1750  1750  1750                      
Burning or heat treatment                                                 
temperature (°C.)                                                  
(5)               13.5  15.8  29.6  22.3  19.5  19.4                      
Apparent porosity (wt %)                                                  
of base brick                                                             
(6)               6     20    40    70    35    43                        
Ratio (%) of cells having                                                 
cell size of 10 to 3,000 μm                                            
(7)               4     7     19    54    28    39                        
Average cell size (μm)                                                 
(8)               Fe--18Cr                                                
                        Fe-- 18Cr                                         
                              Fe--18Cr                                    
                                    Fe--18Cr                              
                                          Fe--18Cr                        
                                                Fe--18Cr                  
Impregnated metal                                                         
(9)               1670  1670  1670  1670  1670  1670                      
Molten metal temperature (C.°)                                     
(10)              8     8     8     8     8     8                         
Impregnation pressure                                                     
(gauge pressure kg/cm.sup.2)                                              
(11)              1     1     1     1     1     1                         
Degassing vacuum degree (Torr)                                            
(12)              9.3   11.9  27.1  19.6  15.7  15.6                      
Impregnated amount (vol %)                                                
(13)              4.2   3.9   2.5   2.7   3.8   3.8                       
Apparent porosity (vol %)                                                 
(14)              69    75    92    88    81    80                        
Filling ratio (%)                                                         
(15)              11.9  12.2  15.2  5.8   11.8  11.0                      
Porosity (vol %) after metal cut                                          
flow test (Held in argon gas                                              
atmosphere at 1,650° C. for                                        
four hours)                                                               
(16)              12    23    49    74    39    43                        
Filling ratio (%) after outflow                                           
(17)     (18)     100   98    73    42    61    54                        
Erosion test                                                              
         Corrosion ratio                                                  
results  (19)     100   102   95    20    70    43                        
         Penetration ratio                                                
(20)              800  800  900  850  850  850                            
Critical radiation temperature                                            
(C.°) of radiation rapid heating                                   
test                                                                      
(21)              2.5  2.1  1.4  0.7  1.1  1.1                            
oxidation rate (mm/hr) of im-                                             
pregnaed metal 1,400°  C. × 20 hours                         
in atmosphere                                                             
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                                           TABLE 1(2)                              
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Examples                                                                  
7          8    9     10     11     12    13    Comparative               
Mixed with            Mixed with Fe--18Cr                                 
                                    Mixed with                            
                                          Mixed with                      
                                                Example                   
sawdust               Metal Particles                                     
                                    Hemp  vinyl 1                         
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      30   30   30    30     30     30    30    30                        
      30   30   30    30     30     30    20    30                        
      20   20   20    30     20     20    20    20                        
 (1)  20   20   20    20     20     20    30    20                        
                                          (Containing                     
                                          4% of                           
                                          cement)                         
 (2)  30   50   60    10     20     20    20    --                        
 (3)  0.1  0.1  0.1   1      1      0.1 mm                                
                                          0.02 mm                         
                                                --                        
                                    (Diameter)                            
                                          (Diameter)                      
                                                --                        
                                    5 mm  10 mm                           
                                    (Length)                              
                                          (Length)                        
 (4)  1750 1750 1750  1750   1750   350   600   1750                      
                      (Reducted                                           
                             (Reducted                                    
                      atmosphere)                                         
                             atmosphere)                                  
 (5)  36.2 69.3 78.5  14.3   15.6   39.4  36.2  13.5                      
 (6)  84   91   95    15     40     69    59    --                        
 (7)  70   83   95    7      9      250   43                              
 (8)  Fe--18Cr                                                            
           Fe--18Cr                                                       
                The exper-                                                
                      Fe--18Cr                                            
                             Fe--18Cr                                     
                                    Fe--18Cr                              
                                          Fe--18Cr                        
                                                --                        
 (9)  1670 1670 iment was                                                 
                      1670   1670   1670  1670                            
(10)  8    8    impos-                                                    
                      8      8      8     8     --                        
(11)  1    1    sible due                                                 
                      1      1      1     1     --                        
(12)  32.8 66.4 to low                                                    
                      20.4   31.5   36.9  32.8  --                        
(13)  3.4  2.9  strength                                                  
                      3.9    4.1    2.5   3.4   --                        
(14)  91   96         84     88     94    91    --                        
(15)  8.2  6.3        11.0   8.4    13.2  12.7  --                        
(16)  83   91         55     76     66    65    --                        
(17)                                                                      
   (18)                                                                   
      38   69         72     49     79    83    143                       
   (19)                                                                   
      15   13         64     32     62    85    341                       
(20)  1300 &gt;1400      1200   1300   1350  1350  500                       
(21)  0.7  0.5        1.0    0.8    1.2   1.2   --                        
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                                           TABLE 2 (1)                             
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                Alumina system material                                   
                                        Comparative                       
                Examples                Example                           
                14    15    16    17    2                                 
__________________________________________________________________________
(1)    1 to 6 mm                                                          
                30    35    30    30    30                                
Particle                                                                  
       1 to 0.15 mm                                                       
                30    35    30    30    30                                
size dis-                                                                 
       0.15 to 0.44 mm                                                    
                20    30    20    20    20                                
tribution                                                                 
       0.44 mm or less                                                    
                20    --    20    20    20                                
(vol %)                                                                   
(2)             --    --    30    10    --                                
thermally volume-reducing   (saw- (Fe--18Cr)                              
particle amount (apparent vol %)                                          
                            dust)                                         
(3)             --    --    0.1   1     --                                
Diameter (mm)                                                             
(4)             1700  1700  1700  1700  1700                              
Burning or heat treatment         (Reduc-                                 
temperature (°C.)          tion                                    
                                  atmos-                                  
                                  phere)                                  
(5)             14.2  32.4  37.9  17.5  14.2                              
Apparent porosity (wt %)                                                  
of matrix                                                                 
(6)             13    64    82    30    --                                
Ratio (%) of cells having                                                 
cell size of 10 to 3,000 μm                                            
(7)             6     32    48    7     --                                
Average cell size (μm)                                                 
(8)             Fe--18Cr                                                  
                      Fe--18Cr                                            
                            Fe--18Cr                                      
                                  Fe--18Cr                                
                                        --                                
Impregnated metal                                                         
(9)             1670  1670  1670  1670  --                                
molten metal temperature (C.°)                                     
(10)            8     8     8     8     --                                
Impregnation pressure                                                     
(gauge pressure kg/cm.sup.2)                                              
(11)            1     1     1     1     --                                
Degassing vacuum degree (Torr)                                            
(12)            10.3  29.3  35.6  24.1  --                                
Impregnation amount (vol %)                                               
(13)            3.9   3.1   2.3   3.4   --                                
Apparent porosity (vol %)                                                 
(14)            725   90    94    88    --                                
Filling ratio (%)                                                         
(15)            9.5   7.3   4.7   7.2   --                                
Porosity (vol %) after test of                                            
metal outflow (Held in argon gas                                          
atmosphere at 1,650° C. for                                        
four hours)                                                               
(16)            33    77    87    59    --                                
Filling ratio after test                                                  
of metal outflow                                                          
(17)   (18)     100  64   45   78    135                                  
Erosion test                                                              
       Corrosion ratio                                                    
results                                                                   
       (19)     100  86   63   74    245                                  
       Penetration ratio                                                  
(20)            1150  &gt;1400 &gt;1400 1300  950                               
Critical radiation temperature                                            
(C.°) of radiation rapid heating                                   
test                                                                      
(21)            2.7   1.0   0.6   1.2                                     
Oxidation rate (mm/h) of impreg-                                          
nated metal 1,400° C. × 20 hours                             
in atmosphere                                                             
__________________________________________________________________________
 
    
     
                                           TABLE 2 (2)                             
__________________________________________________________________________
Magnesia/chromia system material                                          
                                  Comparative                             
Examples                          Example                                 
18           19     20     21     3                                       
      Cr.sub.2 O.sub.3                                                    
          MgO                                                             
             Cr.sub.2 O.sub.3                                             
                 MgO                                                      
                    Cr.sub.2 O.sub.3                                      
                        MgO                                               
                           Cr.sub.2 O.sub.3                               
                               MgO                                        
                                  Cr.sub.2 O.sub.3                        
                                      MgO                                 
__________________________________________________________________________
 (1)  5   25 16  25 5   25 5   25 5   25                                  
      15  15 20  15 15  15 15  15 15  15                                  
      15  5  25  5  15  5  15  5  15  5                                   
      20  -- --  -- 20  -- 20  -- 20  --                                  
 (2)  --     --     30     10     --                                      
                    (Sawdust)                                             
                           (Fr--18Cr)                                     
                                  --                                      
 (3)  --     --     0.1    1      --                                      
 (4)  1850   1850   1850   1700   1850                                    
                           (Argon                                         
                           atomoshere)                                    
 (5)  16.5   23.5   39.6   18.1   16.5                                    
 (6)  40     53     88     43     --                                      
 (7)  8      12     40     9      --                                      
 (8)  Fe--18Cr                                                            
             Fe--18Cr                                                     
                    Fe--18Cr                                              
                           Fe--18Cr                                       
                                  --                                      
 (9)  1670   1670   1670   1670   --                                      
(10)  8      8      8      8      --                                      
(11)  1      1      1      1      --                                      
(12)  14.7   22.2   38.9   26.9   --                                      
(13)  1.8    1.3    0.7    1.2    --                                      
(14)  89     94     98     96     --                                      
(15)  7.8    8.9    3.1    6.3    --                                      
(16)  53     62     92     77     --                                      
(17)                                                                      
   (18)                                                                   
      100    68     35     62     183                                     
   (19)                                                                   
      100    83     56     71     329                                     
(20)  800    1350   &gt;1400  1400   700                                     
(21)  0.8    0.9    0.3    0.4                                            
__________________________________________________________________________
 
    
     
                                           TABLE 3 (1)                             
__________________________________________________________________________
                Examples                                                  
                26     27  28  29  30  31                                 
__________________________________________________________________________
(1)    1 to 6 mm                                                          
                35     35  35  35  35  35                                 
Particle                                                                  
       1 to 0.15 mm                                                       
                35     35  35  35  35  35                                 
size dis-                                                                 
       0.15 to 0.44 mm                                                    
                30     30  30  30  30  30                                 
tribution                                                                 
       0.44 mm or less                                                    
                --     --  --  --  --  --                                 
(vol %)                                                                   
(2)             --                                                        
Thermally volume-reducing                                                 
particle amount (vol %)                                                   
(3)             --                                                        
Diameter (mm)                                                             
(4)             1750   1750                                               
                           1750                                           
                               1750                                       
                                   1750                                   
                                       1750                               
Burning or heat treatment                                                 
temperature (°C.)                                                  
(5)             29.6   29.6                                               
                           29.6                                           
                               29.6                                       
                                   29.6                                   
                                       29.6                               
Apparent porosity (wt %)                                                  
of matrix                                                                 
(6)             40     40  40  40  40  40                                 
Ratio (%) of cells having                                                 
cell size of 10 to 3,000 μm                                            
(7)             9      9   9   9   9   9                                  
Average cell size (μm)                                                 
(8)             Fe--18Cr                                                  
Impregnated metal                                                         
(9)             1670                                                      
Molten metal temperature (C.°)                                     
(10)            1      10  100 200 1   10                                 
Impregnation pressure                                                     
(gauge pressure kg/cm.sup.2)                                              
(11)            100    100 100 100 1   1                                  
Degassing vacuum degree (Torr)                                            
(12)            (Non-                                                     
Impregnation amount (vol %)                                               
                impregnated                                               
(13)            portion is                                                
Apparent porosity (vol %)                                                 
                present in                                                
                central                                                   
                portion)                                                  
(14)            35     72  86  86  40  94                                 
Filling ratio (%)                                                         
__________________________________________________________________________
 
    
     
                                           TABLE 3 (2)                             
__________________________________________________________________________
Examples                   Comparative Example                            
32     33  34  35  36  37  5                                              
__________________________________________________________________________
(1)                                                                       
   35  35  35  35  35  35  35                                             
   35  35  35  35  35  35  35                                             
   30  30  30  30  30  30  30                                             
   --  --  --  --  --  --  --                                             
(2)                                                                       
(3)                                                                       
(4)                                                                       
   1750                                                                   
       1750                                                               
           1750                                                           
               1750                                                       
                   1750                                                   
                       1750                                               
                           1750                                           
(5)                                                                       
   29.6                                                                   
       29.6                                                               
           29.6                                                           
               29.6                                                       
                   29.6                                                   
                       29.6                                               
                           29.6                                           
(6)                                                                       
   40  40  40  40  40  40  40                                             
(7)                                                                       
   9       9   9   9   9   9                                              
(8)                                                                       
(9)                                                                       
(10)                                                                      
   100 200 1   10  100 200 100                                            
(11)   1   0.1 0.1 0.1 0.1 200                                            
(12)                       (Non-impregnated portion                       
(13)                       is present in central                          
                           portion)                                       
(14)                                                                      
   99  99  40  94  99  99  30                                             
__________________________________________________________________________
 
    
     
                                           TABLE 4 (1)                             
__________________________________________________________________________
(Converter)                                                               
                 Magnesia system material                                 
                 Examples                                                 
                 38      39      40                                       
__________________________________________________________________________
(1)  1 to 6 mm   35      25      25                                       
Particle                                                                  
     1 to 0.15 mm                                                         
                 35      30      30                                       
size dis-                                                                 
     0.15 to 0.44 mm                                                      
                 30      40      40                                       
tribution                                                                 
     0.44 mm or less     5       5                                        
(vol %)                                                                   
(2)                      15      25                                       
Thermal volume-reducing                                                   
particle amount (vol %)                                                   
(3)                      0.5     0.5                                      
Diameter (mm)                                                             
(4)              1800    1800    1800                                     
Burning or heat treatment                                                 
temperature (°C.)                                                  
(5)              27.3    36.2    47.8                                     
Apparent porosity (wt %)                                                  
of base brick                                                             
(6)              35      63      79                                       
Ratio (%) of cells having                                                 
cell size of 10 to 3,000 μm                                            
(7)              7       27      44                                       
Average cell size (μm)                                                 
(8)              Fe--18Cr--8Ni                                            
                         50Ni--50Cr                                       
                                 50Ni--50Cr                               
Impregnated metal                                                         
(9)              1500    1500    1500                                     
Molten metal temperature (C.°)                                     
(10)             9       9       9                                        
Impregnation pressure                                                     
(gauge pressure kg/cm.sup.2)                                              
(11)             1       1       1                                        
Degassing vacuum degree (Torr)                                            
(12)             26.6    35.6    46.6                                     
Impregnation amount (vol %)                                               
(13)             0.7     0.6     1.2                                      
Apparent porosity (vol %)                                                 
(14)             97      98      97                                       
Filling ratio (%)                                                         
(22) (23)         0.4    0.2                                              
Actual                                                                    
     Converter wall (mm/h)                                                
machine                                                                   
     (24)                        92                                       
test Converter tap hole (the                                              
     number of charge times)                                              
     (25)                1.1                                              
     Stainless smelting                                                   
     furnace wall (mm/h)                                                  
(26) Mgo         96      96      96                                       
Chemical                                                                  
     Cr.sub.2 O.sub.3                                                     
com- SiO.sub.2   3       3       3                                        
position                                                                  
     Al.sub.2 O.sub.3                                                     
     CaO         1       1       1                                        
__________________________________________________________________________
 
    
     
                                           TABLE 4 (2)                             
__________________________________________________________________________
(Converter)                                                               
Spinel system Material        Magnesia/chromia system material            
Examples                                                                  
41            42      43      44      45      46                          
__________________________________________________________________________
(1)   35      25      25      30      20      20                          
      35      30      30      30      30      30                          
      30      40      40      20      30      30                          
              5       5       10      20      20                          
(2)           15      25              15      20                          
(3)           0.5     0.5             0.5     0.5                         
(4)   1800    1800    1800    1850    1850    1850                        
(5)   28.2    38.3    49.2    21.3    34.6    42.1                        
(6)   42      70      88      63      84      92                          
(7)   9       39      64      23      79      126                         
(8)   Fe--18Cr--8Ni                                                       
              Fe--18Cr--8Ni                                               
                      Fe--18Cr--8Ni                                       
                              Fe--18Cr--8Ni                               
                                      Fe--18Cr--8Ni                       
                                              Fe--18Cr--8Ni               
(9)   1550    1550    1550    1550    1550    1550                        
(10)  7       7       7       9       9       9                           
(11)  0.1     0.1     0.1     0.1     0.1     0.1                         
(12)  27.7    37.7    48.3    20.6    33.5    41.2                        
(13)  0.5     0.6     0.9     0.7     1.1     0.9                         
(14)  98      98      98      97      97      98                          
(22)                                                                      
   (23)                                                                   
      0.4     0.3             0.5     0.4                                 
   (24)               56                      88                          
   (25)       0.4                     0.3                                 
(26)  29      29      29      53      53      53                          
                              32      32      32                          
      1       1       1       3       3       3                           
      68      68      68      5       5       5                           
__________________________________________________________________________
 
    
     
                                           TABLE 4 (3)                             
__________________________________________________________________________
(Converter)                                                               
                        Comparative Examples                              
Magnesia/dolomite material                                                
                        6     7                                           
Examples                MgO--C                                            
                              MgO--C                                      
47          48    49    brick brick                                       
__________________________________________________________________________
(1)   35    25    25    MgO 76%                                           
                              MgO 76%                                     
      35    30    30    C 19.6%                                           
                              C 19.1%                                     
      30    40    40                                                      
            5     5                                                       
(2)         15    25                                                      
(3)         0.5   0.5                                                     
(4)   1800  1800  1800  300   1200                                        
                              (Reduction                                  
                              atmosphere)                                 
(5)   26.5  34.8  45.3  3.5   6.9                                         
(6)   32    59    72                                                      
(7)   7     19    29                                                      
(8)   50Ni--50Cr                                                          
            50Ni--50Cr                                                    
                  50Ni--50Cr                                              
(9)   1500  1500  1500                                                    
(10)  25    25    25                                                      
(11)  0.1   0.1   0.1                                                     
(12)  26.2  34.7  45.0                                                    
(13)  0.3   0.2   0.3                                                     
(14)  99    99    99                                                      
(22)                                                                      
   (23)                                                                   
      0.3   0.2         0.6                                               
   (24)           121         40                                          
   (25)     0.8         1.4                                               
(26)  78    78    78    76    76                                          
                        (C 19.6)                                          
                              (C 19.1)                                    
      3     3     3                                                       
      14    14    14                                                      
__________________________________________________________________________
 
    
     
                                           TABLE 5 (1)                             
__________________________________________________________________________
                Alumina system material A                                 
                               Alumina system material B                  
                Examples                                                  
                50   51   52   53   54   55                               
__________________________________________________________________________
(1)     1 to 6 mm                                                         
                30   30   30   30   10   10                               
Particle                                                                  
        1 to 0.15 mm                                                      
                35   20   20   30   20   20                               
size dis-                                                                 
        0.15 to 0.44 mm                                                   
                30   30   30   40   40   40                               
tribution                                                                 
        0.44 mm or less                                                   
                5    20   20        20   20                               
(vol %)                                                                   
(2)                  5    10        10   15                               
Thermally volume-reducing                                                 
particle amount (vol %)                                                   
(3)                  0.5  0.5       0.5  0.5                              
Diameter (mm)                                                             
(4)             1700 1700 1700 1650 1650 1650                             
Burning or heat treatment                                                 
temperature (°C.)                                                  
(5)             23.1 19.5 24.6 19.3 21.6 27.8                             
Apparent porosity (wt %)                                                  
of matrix                                                                 
(6)             60   55   74   72   59   83                               
Ratio (%) of cells having                                                 
cell size of 10 to 3,000 μm                                            
(7)             15   13   21   20   12   30                               
Average cell size (μm)                                                 
(8)             Fe-18Cr                                                   
                     Fe-18Cr                                              
                          Fe-18Cr                                         
                               Fe-18Cr                                    
                                    Fe-18Cr                               
                                         Fe-18Cr                          
Impregnated metal                                                         
(9)             1600 1600 1600 1600  1600                                 
                                         1600                             
Molten metal temperature (C.°)                                     
(10)            10   10   10   10   10   10                               
Impregnation pressure                                                     
(gauge pressure kg/cm.sup.2)                                              
(11)            0.1  0.1  0.1  0.1  0.1  0.1                              
Degassing vacuum degree (Torr)                                            
(12)            22.8 18.9 24.1 18.4 21.3 27.4                             
Impregnation amount (vol %)                                               
(13)            0.3  0.6  0.5  0.8  0.3  0.4                              
Apparent porosity (vol %)                                                 
(14)            99   97   98   95   99   99                               
Filling ratio (%)                                                         
(15)            0.3  0.2  0.2  0.4  0.4  0.3                              
Actual machine test Molten iron                                           
ladle wall (mm/h)                                                         
(16)            1.6  1.4  1.4                                             
Molten steel ladle slag line                                              
(17)            1.1  0.6  0.5                                             
Molten steel ladle wall                                                   
(18)            1.4  0.8  0.7                                             
Molten steel ladel metal contact                                          
portion                                                                   
(19)    Al.sub.2 O.sub.3 (vol %)                                          
                95   95   95   78   78   78                               
Chemical                                                                  
        Mgo                                                               
com-    SiO.sub.2                                                         
                2    2    2    18   18   18                               
position                                                                  
__________________________________________________________________________
 
    
     
                                           TABLE 5 (2)                             
__________________________________________________________________________
                                    Comparative                           
Magnesia system material                                                  
                     Spinel system material                               
                                    Example 8                             
Examples                            Alumina                               
56         57   58   59   60   61   brick                                 
                                         MgO--C                           
__________________________________________________________________________
(1)   30   20   30   30   20   20                                         
      30   30   30   30   30   30                                         
      30   30   30   30   30   30                                         
      10   20   20   10   20   20                                         
(2)        5    10        5    10                                         
(3)        0.5  0.5       0.5  0.5                                        
(4)   1800 1800 1800 1800 1800 1800 1700 300                              
(5)   22.4 21.5 27.3 21.2 20.8 25.8 13.0 4.1                              
(6)   29   55   82   38   60   82                                         
(7)   18   10   120  18   23   211                                        
(8)   Fe-18Cr                                                             
           Fe-18Cr                                                        
                Fe-18Cr                                                   
                     Fe-18Cr                                              
                          Fe-18Cr                                         
                               Ni                                         
(9)   1600 1600 1600 1600 1600 1550                                       
(10)  10   10   10   10   10   15                                         
(11)  0.1  0.1  0.1  0.1  0.1  0.1                                        
(12)  21.9 20.9 26.9 20.5 20.5 25.1                                       
(13)  0.5  0.6  0.4  0.7  0.3  0.7                                        
(14)  98   97   99   97   99   99                                         
(22)                                                                      
   (23)                                                                   
                     0.3  0.2  0.1  0.6                                   
   (24)                                                                   
      1.2  1.1  0.8  0.8  0.7  0.4       2.2                              
   (25)                                                                   
      0.8  0.8  0.6  0.4  0.3  0.2  0.9                                   
(26)  7.0  1.0  0.7  0.5  0.4  0.3  1.3                                   
                          70   70   90   93                               
      92   92   92   24   24   24        72                               
      3    3    3    2    2    2    5                                     
__________________________________________________________________________
 
    
     
                                           TABLE 6 (1)                             
__________________________________________________________________________
                Magnesia system material                                  
                Examples                                                  
                62     63      64                                         
__________________________________________________________________________
(1)     1 to 6 mm                                                         
                30     20     20                                          
Particle                                                                  
        1 to 0.15 mm                                                      
                30     30     30                                          
size dis-                                                                 
        0.15 to 0.44 mm                                                   
                30     30     30                                          
tribution                                                                 
        0.44 mm or less                                                   
                10     20     20                                          
(vol %)                                                                   
(2)                    5      10                                          
Thermally volume-reducing                                                 
particle amount (vol %)                                                   
(3)                    0.5    0.5                                         
Diameter (mm)                                                             
(4)             1800   1800   1800                                        
Burning or heat treatment                                                 
temperature (°C.)                                                  
(5)             22.4   21.5   27.3                                        
Apparent porosity (wt %)                                                  
of matrix                                                                 
(6)             29     55     82                                          
Ratio (%) of cells having                                                 
cell size of 10 to 3,000 μm                                            
(7)             8      10     120                                         
Average cell size (μm)                                                 
(8)             Fe-18Cr-8Ni                                               
                       Fe-18Cr-8Ni                                        
                              Fe-18Cr-8Ni                                 
Impregnated metal                                                         
(9)             1100   1100   1100                                        
Molten metal temperature (C.°)                                     
(10)            10     10     10                                          
Impregnation pressure                                                     
(gauge pressure kg/cm.sup.2)                                              
(11)            0.1    0.1    0.1                                         
Degassing vacuum degree (Torr)                                            
(12)            21.9   20.9   26.9                                        
Impregnation amount (vol %)                                               
(13)            0.5    0.6    0.9                                         
Apparent porosity (vol %)                                                 
(14)            98     97     99                                          
Filling ratio (%)                                                         
(15)            0.6    0.5    0.5                                         
Actual machine test                                                       
RH dipp tube (mm/n)                                                       
(26)    Mgo     92     92     92                                          
Chemical                                                                  
        Cr.sub.2 O.sub.3                                                  
com-    SiO.sub.2                                                         
                3      3      3                                           
position                                                                  
        Al.sub.2 O.sub.3                                                  
__________________________________________________________________________
 
    
     
                                           TABLE 6 (2)                             
__________________________________________________________________________
                                                       Comparative        
                                                       Example 9          
Spinel system material      Magnesia/chromia-system material              
                                                       Magnesia/          
Examples                                               chromia            
65          66      67      68       69       70       material           
__________________________________________________________________________
(1) 30      20      20      5    25  5    25  5    25                     
    30      30      30      15   15  15   15  15   15                     
    30      30      30      15   5   15   5   15   5                      
    10      20      20      20   20       20                              
(2)         5       10      --       10       15                          
(3)         0.5     0.5              0.5      0.5                         
(4) 1800    1800    1800    1850     1850     1850                        
(5) 21.2    20.8    25.8    23.5     34.9     39.8     15.3               
(6) 38      60      82      53       192      258                         
(7) 8       23      211     12       91       94                          
(8) Fe--18Cr--8Ni                                                         
            Fe--18Cr--8Ni                                                 
                    Fe--18Cr--8Ni                                         
                            Fe--18Cr--8Ni                                 
                                     Fe--18Cr--8Ni                        
                                              Fe--18Cr--8Ni               
(9) 1100    1100    1100    1550     1550     1550                        
(10)                                                                      
    10      10      10      9        9        9                           
(11)                                                                      
    0.1     0.1     0.1     1        1        1                           
(12)                                                                      
    20.5    20.5    25.1    22.2     34.0     39.1                        
(13)                                                                      
    0.7     0.3     0.7     1.3      0.9      0.7                         
(14)                                                                      
    97      99      97      94       97       98                          
(31)                                                                      
    0.4     0.3     0.4     0.3      0.2      0.3      0.7                
(26)                                                                      
    70      70      70      53.2     53.2     53.2     53.2               
                            28.6     28.6     28.6     28.6               
    2       2       2       3.2      3.2      3.2      3.2                
    24      24      24      8.4      8.4      8.4      8.4                
__________________________________________________________________________