图1为落料冲孔用冲头,原用W18Cr4V钢制造,按常规工艺热处理,1260℃整体加热,保温10s/mm后油淬,560℃回火三次。要求硬度为HRC63～65。被冲材料为厚度1.8mm的热轧高速钢带,HB211～239。使用中冲头寿命很低,每个冲头仅能冲2000个孔,有的甚至只冲几十个孔,一个班就要用4～5个冲头。失效形式几乎都是沿台阶处脆断。造成冲头脆断的原因,据分析主要是由冲头硬度过高、脆性大,韧性差,台阶处应力集中造成的。 Figure 1 punching punching blanks, the original W18Cr4V steel, according to conventional heat treatment, 1260 ℃ overall heating, insulation 10s / mm oil quenching, tempering at 560 ℃ three times. Requires a hardness of HRC63 ~ 65. Was punched materials for the thickness of 1.8mm hot-rolled high-speed steel, HB211 ~ 239. The use of punch life is very low, each punch can only punch 2000 holes, and some even punch dozens of holes, a class to use 4 to 5 punch. Failure forms are almost always fragile along the steps. Punch caused by brittle broken reason, according to the analysis is mainly caused by the punch too high hardness, brittleness, poor toughness, stress concentration caused by the step.