Effect of test method on SSC performance of modified 13Cr steel

Effect of test method on SSC performance of modified 13Cr martensitic stainless steel (0.025C-13Cr-Ni-Mo) are investigated. The SSC for martensitic stainless steel initiates at the pitting and propagates by hydrogen embrittlement. The pH stability of the test solution affects the test results. SSC threshold stress for modified 13Cr steel in the stable solution is higher than that in the unstable solution. This difference seems to depend on the pH value in the pitting, since a great volume of hydrogen enters into steel at low pH condition and causes SSC. The SSC susceptibility for subsize specimens is higher than that for full size specimens. The oxygen in the test solution causes pitting. The deaeration procedure affects the SSC test result. The deaerated test solution should be transferred to test vessel. The SSC performance for martensitic stainless steel should be evaluated by full size test specimens under stable pH condition.