镦粗是塑性成形加工中最基本的变形方法。由于在镦粗过程中,被镦粗的金属和模具接触表面之间存在着摩擦力的影响,金属的流动是不均匀的。这种摩擦力的影响,改变了工件与模具之间的接触正应力分布状态。因此,研究镦粗过程中接触正应力的分布规律,对研究工件镦粗过程中的变形规律有着重要的意义。对接触正应力分布的测量,一般采用模拟实验的方法,使用铅或铝材料,在常温下进行。测量方法之一即所谓缝隙法,即在模具上加工一条垂直于镦粗平面的细缝,镦粗时,金属流进缝隙内形成一个特殊的峰脊,峰脊的高低与接触正应力成正比。这种方法是一种定性测量方法,不能准确地反应出正应力的量的大小。近几年 Upsetting is the most basic deformation in plastic forming. Due to the frictional forces between upsetting metal and the mold contact surface during upsetting, the flow of metal is not uniform. This frictional effect, changing the contact between the workpiece and the mold is the normal stress distribution. Therefore, to study the distribution law of normal contact stress during upsetting is of great significance to study the deformation law during upsetting of workpieces. The measurement of the contact normal stress distribution generally adopts the method of simulation experiment, and uses lead or aluminum material at normal temperature. One of the measurement methods is the so-called slit method, that is, a vertical slit is formed on the die. When upsetting, the metal flows into the slit to form a special peak ridge. The height of the peak ridge is directly proportional to the contact normal stress . This method is a qualitative measurement method that does not accurately reflect the amount of normal stress. recent years