Stress Corrosion Crack Growth Bihavior of Austenitic Stainless Steel Composite Material in 35% MgCl<SUB>2</SUB> Solution

Stress Corrosion Cracking(SCC)in 35%MgCl2 aqueous solution was investigated at 363K for a sheathcore type composite material comprising two types of stainless steel :SUS316L in the core and SUS304 in the sheath. Followings are main points of the obtained information.a)The value of the KISCC for the composite was lower than those of the component steels.b)The rate of the crack propagation, which was initially identical with that of SUS304, suddenly decreased at the SUS304/316L interface to a value which was lower than that of either component.c)After the crack arrived at the SUS304/316L interface, it propagated through SUS304 as Well as through SUS316L, although the rate of propagation was much slower in the latter.d)The slow rate of propagation in SUS316L in the composite was explained from Evans diagram taking account of a shift of the potential by applied stress.