喷砂处理对Al-Zn-Mg合金焊接接头应力腐蚀性能的影响

采用慢应变速率应力腐蚀方法研究喷砂处理对高速列车车体材料A7N01铝合金焊接接头应力腐蚀性能的影响。试验结果表明,经喷砂处理后,A7N01铝合金焊缝的残余拉应力转变为压应力,同时接头整体应力降低,趋于均匀分布。经喷砂处理后,A7N01铝合金焊接接头在3.5%NaCl中的应力腐蚀敏感指数降低,断口未呈现脆性断裂特征,表明喷砂处理增强了其抗应力腐蚀能力。喷砂试样表面均匀分布的压应力,降低了在外加载荷作用下焊缝所承受的拉应力,增加了焊接接头的强度。同时,表面压应力层的存在抑制了接头在腐蚀环境中裂纹的萌生,从而减少腐蚀介质向内部的扩散和作用,增强了焊接接头的抗应力腐蚀能力。

Influence of sand blasting treatment on stress cracking corrosion of A7N01 aluminum alloy welding joint

In this paper,the influence of sand blasting treatment on stress cracking corrosion of A7N01 aluminum alloy joint was studied through slow strain rate test.The results showed that after sand blasting treatment,the tensile residual stress in welding seam of A7N01 joint transferred to compressed stress,and the residual stress distributed more evenly in the treated joint.The stress corrosion sensitive factor (ISSRT) of treated welding joint in 3.5％NaC1 solution was lower than that of untreated joint,and no brittle fracture morphology was seen in the treated joint.The evenly distribution of compressed residual stress on the surface of treated joint decreased the tensile stress loading on the welding seam,which increased the strength of A7N01 welding joint.Furthermore,the compressed residual stress could inhibit the development of crack in corrosion solution,thus improved the anti-corrosion ability of A7N01 welding joint.