Cr12MoV steel has high carbon content and chromium content, can form a large number of carbides and high-alloy martensite, so that the steel has high hardness and high wear resistance. At the same time, chromium also makes steel have high hardenability and tempering stability. Molybdenum increases the hardenability of steel and refines the grains. Vanadium can refine the grains and increase the toughness of the material, and it can also form high Hardness of VC, in order to further increase the wear resistance of steel, so Cr12MoV steel is a widely used material for manufacturing cold work molds. Take Cr12MoV steel silicon steel sheet punch as an example: The manufacturing process is: blanking→forging→spheroidizing annealing→machine Machining→final heat treatment→grinding. The final heat treatment process is: quenching heating temperature 1030℃, tempering 220℃. Although the blank is forged before machining, the service life of the die is not high after heat treatment. Punch failure analysis Through the analysis of 26 failed punches, it is found that the cause of the mold failure is splitting and breaking. The fracture position is basically in the middle of the length of the punch, and the split positions are all at the bottom of the tough mouth, and the punch is broken. There was no change in the size and shape before and after, no plastic deformation was found in the fracture process, all brittle fracture. The chemical composition of the failed punch: 1.65C, 0.36Si, 0.30Mn, 12.1Cr, 0.46Mo 0.23V, 0.027S, 0.026P.