喷丸处理对304不锈钢焊接接头氯化钠应力腐蚀开裂的影响

Effects of Shot-peening Treatment on Stress Corrosion Crack of 304 Stainless Steel Welded Joints in NaCl Aqueous Solutions

对304不锈钢氩弧焊焊接接头表面作了喷丸处理,并在金相显微镜与扫描电镜下对处理后材料表面的微观组织进行了观察,用X射线应力衍射仪测试了喷丸处理后试样的残余应力分布,并进行了NaCl水溶液应力腐蚀试验。结果表明,304不锈钢焊缝在NaCl溶液中具有明显的应力腐蚀开裂敏感性,喷丸处理能够很好地提高焊接构件抗应力腐蚀开裂能力;应力腐蚀裂纹断口表现为脆性断裂,各区的应力腐蚀裂纹属于穿晶型裂纹。

The surface welded joint of 304 stainless steel was processed by shot-peening treatment. The microstructure of the material surface was observed by metallurgical microscope and scanning electron microscope. The residual stress of the sample by peening treatment was measured by X-ray stress tester, and the distribution of the residual stress was analyzed, and the stress corrosion experiment in NaC1 aqueous solution was processed. The results show that the welding line of 304 stainless steel has obvious crack sensitivity of stress corrosion in NaC1 aqueous solution, and the shot peening is an effective method for protecting weldments against SCC, which is an inverse to compressive residual stress. The crack is brittle rupture and the fracture of SCC shows a typical transgranular crack.