Exploring the effect of shot peening coverage on the stress corrosion cracking resistance of austenitic stainless steel
摘要
The following work assesses the effectiveness of shot peening (SP) to mitigate the stress corrosion cracking (SCC) in the austenetic stainless steel (ASS) weld joints. SP was performed with different coverages, varying from 100%, 500%, and 1000% on the gas tungsten arc welded ASS joints. The SCC experiment was conducted on ASS U-bend specimens in boiling MgCl2. The effect of SP on the ASS weld joint resulted in an austenite-to-martensite phase transformation, alongside the introduction of residual compressive stresses (RCS) and grain refinement. These effects were exacerbated as the amount of SP coverage increased. The SCC resistance of SP’ed U-bend specimens was remarkably enhanced for 100% coverage. However, at 1000% coverage, the SCC resistance of SP’ed U-bend specimens was lower because of the high fraction of the martensitephase, which outperformed the beneficial effect of RCS and grain refinement. Furthermore, the nature of the crack propagation changed from transgranular to intergranular after SP due to the dissolution of martensite-phase that further delayed the crack propagation due to the longer path.