脉冲磁场处理对SKD11模具钢残余拉应力的影响机理分析  

Influence Mechanism of Residual Tensile Stress in SKD11 Steel Caused by Pulse Magnetic Field Treatment

作　　者：罗丞[1] 李正龙[1] 曹洪志[1] 张祥林[1] 

机构地区：[1]华中科技大学材料成形与模具技术国家重点实验室,武汉430074

出　　处：《中国机械工程》2016年第11期1535-1540,共6页China Mechanical Engineering

基　　金：湖北省重大专项(2015BAA015);国家科技重大专项(2009ZX04014-073-04)

摘　　要：为了探究脉冲磁场处理对SKD11钢残余应力的影响机理,设计了单因素试验并得到了磁场强度、磁场频率、磁场方向以及磁处理时间等参数单独变化时试样残余拉应力的变化结果。同时从应力的本质入手,将磁处理过程划分为位错塞积开动和位错增殖两个阶段来分析,对试验现象做出了全面解释,推导出了在第一阶段中使位错塞积群克服点阵阻力所需的临界磁场强度H_p的公式,以及在第二阶段中使单个弗兰克-瑞德位错源增殖所需的临界磁场强度H_c的公式和使单个位错克服点阵阻力所需的临界磁场强度H′_p的公式。最后,以试验结果和理论推导为依据,建立了脉冲磁场处理在冲压模具的应用中需要遵循的原则。Sevel single factor experiments were designed to explore the influence mechanism of residual tensile stress in the SKD11 steel by PMT.When the magnetic field strength,the magnetic field frequency,magnetic field direction and the processing time were varied individually,the changes of residual tensile stress in the sample were obtained.All experimental phenomena were explained from the angle of dislocation-nature of the stress.Process of PMT was divided into two stages in the explanation.The first stage was un-piling of the dislocation pile-up group and the second was multiplication of dislocation.Formula of H_p was deduced and H_p was the critical magnetic field strength which started the un-piling of dislocation pile-up group in the first stage.Formula of Hcand H′_pwere deduced.In the second stage,H_c was the critical magnetic field strength which started multiplication of a single Frank-Read dislocation source and H′_pwas the critical magnetic field strength which made a single dislocation overcome the lattice resistance.The principals of PMT in the applications to stamping die were established based on the experiments and the theory.

关 键 词：SKD11钢 脉冲磁场处理 残余拉应力 位错 冲压模具 

分 类 号：TG76[金属学及工艺—刀具与模具]