7A19-T652铝合金零件表面裂纹产生的原因分析

Cause analysis of surface crack of 7A19-T652 aluminum alloy part

某大型机械的7A19-T652铝合金零件制造过程经过开坯、模锻、热处理、机加工和阳极氧化等多道工序,在成品检验时零件表面发现裂纹,造成较大的经济损失。为了查明7A19-T652铝合金零件表面裂纹缺陷的本质及形成原因,在带有表面裂纹的零件上取样分析。采用扫描电子显微镜(Scanning Electron Microscope,SEM)、光学显微镜(Optical Microscope,OM)、能谱仪(Energy Dispersive Spectrometer,EDS)对裂纹组织形貌进行观察分析。结果表明:零件表面裂纹是锻造公司生产过程中外来异物压入所致,压入的块状物质是Ti的氧化物。

Surface cracks were found on the 7A19-T652 aluminum alloy parts made for a large-scale machinery in the process of finish product inspection after breakdown forging,die forging,heat treatment,machining and anodizing,which have caused great economic losses.In order to find out the nature and causes of surface crack defects of 7A19-T652 aluminum alloy parts,samples were taken from the surface of parts with cracks.Scanning electron microscope(SEM),optical microscope(OM)and energy dispersive spectrometer(ED S)were used to observe and analyze the crack microstructure.The results show that the surface cracks of the parts are caused by foreign matters,which are pressed in during production of the forging company,and the pressed massive material is Ti oxide.