Effect of pre-strain on microstructure and hydrogen embrittlement of K-TIG welded austenitic stainless steel

摘要

The effects of pre-strain on hydrogen embrittlement of 304L K-TIG welded joint were investigated. As pre-strain of joint increased, fracture location of hydrogen-charged joint changed from weld metal to base metal. In low prestrained joints, fracture may be initiated at the sites of clustered dislocations due to hydrogen in weld metal with a high density of pre-existing dislocations. In high prestrained joints, some regions in base metal suffered severe strain-induced alpha' martensitic transformation due to Ni depletion bands and cracking occurred at phase boundaries where may provide more sites for the accumulation of hydrogen atoms and dislocations.