The present invention relates to methods for obtaining metal hollow ingots by electroslag remelting, and to devices for effecting same. The invention may be made use of for obtaining hollow ingots of pipe stock from steels, alloys and metals (ball-bearing, highly alloyed, heat-resistant, anticorrosive, high-strength structural, and the like including those difficult to work), intended for subsequently processing into pipes and other articles by pressing, rolling out, rolling, etc.
Known in the prior art is a method for obtaining hollow metal ingots by the electroslag remelting of a hollow (in the tubular form) consumable electrode in a cooled annular ingot mold composed of a cooled mold and a cooled bottom plate together with a cooled core being made stationary in relation therewith.
In this case, a consumable electrode is remelted in an annular gap between the mold and core. During the entire remelting process of a hollow ingot, the slag bath is given an annular form. Its cross section is almost equal to that of a hollow ingot to be made.
A disadvantage of the prior-art method consists first of all in that for making ingots there are employed expensive hollow (in the tubular form) consumable electrodes. Moreover, the hollow ingot to be built-up squeezes the core during shrinkage, which may cause cracking in the ingot, and as a result the core will have to be removed from each ingot by mechanical means.
A primary object of the present invention is to provide such apparatus using electroslag remelting to make ingots, particularly hollow ingots, which would permit using cheap consumable electrodes of a solid section (both deformed or cast), precluding the formation of cracks in the ingot making ingots, particularly hollow ingots possessing a good internal surface, to be directly used for further processing.
In conformity with these and other objects of the invention, the proposed device or apparatus for making hollow ingots by the electroslag remelting of a consumable electrode in a cooled mold having a core disposed therein, the core forming the internal cavity of the ingot being built up on a cooled bottom plate, features, according to the invention, a mold, a core and a bottom plate together with an ingot secured thereon in the process of remelting the consumable electrode, which are given longitudinal motion in relation to each other so that the upper end face of the core is constantly immersed in the molten slag bath.
The mutual motion of the mold, core and bottom plate may be carried into effect either by moving the cooled core upwardly in relation to the stationary mold and bottom plate, or by moving the bottom plate together with the ingot secured thereon downwardly in relation to the core and stationary mold, or, finaly, by moving the mold together with the bottom plate and the ingot secured thereon and being built-up downwardly in relation to the core.
To improve the internal surface of the hollow ingot being made, the core during the remelting process should be given rocking motion.
The device for carrying into effect the proposed method, comprising a cooled mold, a bottom plate and a core for shaping a cavity in the ingot being built-up, according to the invention, is provided with mechanisms for effecting mutual motion of the mold, bottom plate and core in the process of remelting a consumable electrode.
The device is preferably provided with a mechanism for imparting to the cooled core a rocking motion in a longitudinal direction, and a mechanism for imparting to the core reciprocal rotary motion.
The nature of the present invention will further be made more fully apparent from a consideration of the following description of its exemplary embodiments, taken in conjunction with the accompanying drawings .