我厂的方孔冷冲模是用T8钢制造,如图1,生产中常发生脆断,端面深层掉块和浅层剥落,使用寿命很短。为了提高冷冲模的断裂韧性和强度,我们参照文献对T8钢方孔冷冲模进行了强韧化处理,对延长冲头使用寿命取得一定效果。T8钢冲模原工艺流程为:锻造→球化→机械加工→热处理→成品。原热处理工艺如图2,回火后硬度为HRC56～58,金相组织为片状马氏体,硬而脆。后来我们改用调 My factory square hole cold die is made of T8 steel, as shown in Figure 1, the production of brittle fracture often occur, the end of the deep block off and shallow peel off, the service life is very short. In order to improve the fracture toughness and strength of cold die, we refer to the literature on the T8 steel square hole cold die toughening treatment, to extend the service life of the punch to achieve some results. T8 steel die of the original process: forging → ball → machining → heat treatment → finished product. The original heat treatment process shown in Figure 2, after tempering hardness HRC56 ~ 58, the microstructure of sheet martensite, hard and brittle. Later, we use to transfer