Study On Laser Surface Modification Process Of Die Cutting Edge

With the rapid development of China's automotive industry,the automotive mold industry has also achieved rapid growth.A large number of automobile stamping dies fail due to local wear in practical application.The most easily worn part is the edge of the die,so the die should be trimmed after working for a certain period of time.Wear and tear,as one of the main failure forms of stamping die edge,is a difficult problem to restrict die life.Practice has shown that the wear failure of the stamping die edge is closely related to the surface properties of the material.Therefore,in order to improve the wear resistance of the die edge to increase its service life,the surface of the die is surface strengthened.In this paper,the stamping die of automobile panel of Cr12 MoV steel is taken as the research object.The edge of Cr12 MoV steel plate is taken to simulate the edge of die,and the surface hardening of the die is carried out by laser surface quenching.In this paper,a three-dimensional transient temperature field model for laser surface quenching of die edge is established on the finite element analysis software ANSYS.The temperature field of single-channel laser surface quenching at die edge was numerically simulated.According to the critical phase transition temperature,the depth of quenching layer was predicted,and the pre-selection range of single-channel scanning laser surface quenching process parameters was determined.Based on the range of preconcentration parameters determined by finite element simulation and the results of single factor experiment of laser quenching,the orthogonal experiment of single channel scanning laser quenching is designed,and the optimum technological parameters of single channel scanning laser quenching are obtained,and the hardness of the quenched layer is obtained.The microstructure and wear resistance were studied.On the basis of this,the multi-channel scanning laser quenching test on die edge was carried out by changing the lap ratio.The optimum parameters of multi-channel scanning laser quenching were determined by metallographic microscope,surface hardness test and wear resistance test.The single channel laser quenching test of die edge shows that the hardening effect is the best when the laser power is 1400 W,the scanning speed is 12 mm / s,and the spot size is 3mm × 8mm.The depth of the quenched layer is about 0.59 mm,the surface hardness is up to 61 HRC,significantly increased hardness,and the wear volume is reduced by 65.6%,that is,the wear resistance is about 2 times higher than that of the substrate.The optimum parameters of multi-channel laser quenching for die edge are: laser power 1 400 W,scanning speed 12 mm,spot size 3mm × 8 mm,lap ratio 20%.After test,the microstructure of hardened layer is mainly fine acicular martensite and dispersed eutectic carbide.The hardness and wear resistance of the hardened layer are improved obviously.