Alloy desensitisation to stress corrosion - by shot peening to destroy surface grain structure

摘要

Before exposure to a sensitising temp. the alloy surface is severely shot peened to break up the existing grain structure, pref. to = mils below the surface. The treatment is applied partic. to an 18-8 steel using ceramic beads, the degree of peening necessary being determined by non-destructive testing which has been calibrated against corrosion tested samples. The testing may be carried out by an eddy current method or one dependent on measurement of transformation to ferrite.