Metallographic Essence of Hydrogen-induced Disbonding of Stainless Weld Overlay

The factors influencing hydrogen-induced disbonding were studied through a series of electrolytic hydrogen charging tests.The essence of metallography concerning the cracking was analyzed thoroughly.The results showed that there is a migration of carbon and chromium after PWHT.There are abrupt changes in the distribution of carbon and alloy elements in the region of initiation of hydrogen-induced disbonding.The studies showed that the initiation and growth of cracks might be caused primarily by the deposited carbide and transformation production as well as the action between these and dislocations, stress and hydrogen in the material.