A UNS S 32654 , A STAINLESS STEEL FOR CONDENSER TUBES
The new superaustenitic stainless steel UNS S32654 (Avesta Sheffield 654 SMO) is proposed for condenser tubes in desalination and power plants. A number of tests illustrating its corrosion resistance in a variety of chloride containing environments are being reviewed in terms of pitting, crevice corrosion and stress corrosion cracking. Relevant mechanical and physical properties are described. Health hazards and the impact on the environment are discussed as well as the cost benefits of using a stainless steel for this application.
Nickel migration from Cr—Ni stainless steel exposed to potable water
AbstractStudies of nickel migration from Cr–Ni stainless steel exposed to potable water indicate that there is a ‘stagnant water problem’, which is also known to occur with other pipe materials. The nickel levels can reach the EC recommended upper limit within a period of one week; depending on the surface condition and volume to surfacearea ratio. The fact that hardly any chromium is found in the water indicates that the presence of nickel is not attributable to corrosion of Cr–Ni stainless steel pipes but rather to leaching of nickel from the passive layer rich in chromium oxide. The leaching stops after afew weeks, indicating that nickel migration is only a matter of concern during commissioning. Unlike copper and hot dip galvanised steel pipes, stainless steel pipes do not undergo any general corrosion in potable waters. This is also true for waters that are highly acidic (pH 4) or contain strong complex forming species, e.g. cyanides and EDTA. From the point of view of health, therefore, stainless st...
AVESTA 654 SMO™ – A new nitrogen‐enhanced superaustenitic stainless steel
The properties of a new, very highly alloyed stainless steel, Avesta 654 SMO, are compared with those of other stainless steels and nickel-base alloys. The new steel has a very high strength but still possesses a high elongation. The corrosion properties have been investigated in accelerated laboratory tests and in environments representing the expected main application areas, sea water, pulp bleaching and flue gas cleaning. The tests clearly show that the new steel has appreciably better corrosion resistance than the superduplex and superaustenitic 6 Mo steels and that the resistance in many cases matches that of the best nickel-base alloys.