THE CHLORIDE STRESS-CORROSION CRACKING BEHAVIOR OF STAINLESS-STEELS UNDER DIFFERENT TEST METHODS

Chloride-induced stress-corrosion cracking (SCC) is one of the failure modes of stainless steels, Highly alloyed austenitic stainless steels S32654, S31254, and N08028, and duplex grades S32750 and S31803 posse ss much improved resistance to SCC compared with S30400 and S31600 ste els, With the development of a database, SSData, experimental data col lected from calcium chloride tests, autoclave tests, and drop evaporat ion tests were evaluated, Stress-corrosion cracking data generated by autoclave tests agreed well with the practical service conditions and can be used to discriminate alloys for SCC resistance in sodium chlori de solution, Drop evaporation test data can be used in situations wher e evaporation may occur and cyclic loading may be involved. The SCC re sistance of alloys under each method increased with increasing molybde num equivalent Mo + 0.25Cr + 0.1Ni. For a given alloy, the testing res ult depends on the stress state and environment; different test method s can give different ranking orders concerning SCC resistance. The per formance of duplex stainless steels in a chloride containing environme nt at higher temperatures was not as good as expected when dynamic loa ding was involved,