17-4PH钢安装座线切割加工过程炸裂原因分析  

Analysis on Splitting Crack of 17-4PH Steel Installation Base in the Process of Wire Electrical Discharge Machining

作　　者：刘松[1] 于淼[1] 谭盛斌 LIU Song;YU Miao;TAN Sheng-bin(AVIC Jincheng Nanjing Electrical and Hydraulic Engineering Research Center,Nanjing 211106,China)

机构地区：[1]航空工业金城南京机电液压工程研究中心,南京211106

出　　处：《失效分析与预防》2022年第1期50-53,72,共5页Failure Analysis and Prevention

摘　　要：同批17-4PH钢安装座在线切割加工过程中发生多起炸裂,炸裂起始位置基本相同。采用扫描电子显微镜、光学金相显微镜及工艺试验等手段,结合安装座的实际生产工艺流程,对其在线切割加工过程中发生炸裂的原因及性质进行判定和分析。结果表明:安装座在线切割加工过程中发生炸裂应与其内部残余应力较大有关;线切割破坏安装座残余应力的平衡状态,促使其内应力重新分配,致使在线切割割面尖端位置产生大于安装座的材料抗拉强度的附加拉应力,导致裂纹产生,迅速炸裂;安装座内部残余应力较大的原因是热处理产生的残余应力与机械切削加工产生的残余应力相互叠加;通过重新进行固溶处理能够改变或降低安装座原有的峰值残余应力的平衡状态分布,可以避免其在线切割加工过程中产生炸裂的现象。Many splitting cracks of 17-4PH steel installation base occurred in the process of wire electrical discharge machining(WEDM).The initial positions of the cracks were the same.The cause of 17-4PH steel installation base splitting cracks was analyzed by means of the scanning electron microscope,the optical microscope and the heat treatment experiment.In addition,the manufacturing processes of the installation base were also considered.The results show that the splitting crack is related to the large residual stress.The WEDM destroys the balance state of the residual internal stress and redistributes the internal stress.When the additional tensile stress produced at the front position of WEDM is greater than the tensile strength of the 17-4PH steel,the crack will be generated and rapidly expanded.The reason of the large residual internal stress in the installation base is that the residual internal stresses produced by heat treatment and machining are overlapped each other.The equilibrium distribution of residual internal stress in the installation base can be changed or reduced by resolution treatment.It can effectively prevent the splitting crack of 17-4PH steel installation base in the process of WEDM.

关 键 词：17-4PH钢 线切割加工 炸裂 安装座 残余应力 

分 类 号：TG142.71[一般工业技术—材料科学与工程]