Study On Microstructure And Properties Of Quasi-dry Electrospark Surface Reinforced 45 Steel

In the modern mechanical manufacturing process,most of the failure of the mold starts from the surface,such as wear,oxidation,corrosion,etc.How to improve the wear resistance,oxidation resistance,and corrosion resistance of the mold surface has caused us extensive attention.Through the powder-mixed quasi-dry electric spark surface strengthening technology,under the instantaneous high temperature and high pressure conditions generated by electric spark discharge,the enhanced powder and the reinforced electrode material react with the matrix material to form a multiphase reinforcement to form a surface strengthening layer.It is possible to use a smaller amount of special materials to achieve the effect that expensive whole materials are difficult to achieve,and to improve the overall performance of the materials.This paper adopts different electrodes and mixed powders to perform electric spark surface strengthening on 45 steel,and discusses the influence of process parameters on the microstructure and properties of the strengthening layer,and then performs surface enhancement of electric spark on H13 steel to obtain a better surface strengthening layer.The mechanism of strengthening was initially discussed.In this paper,CNC electric spark forming machine is used.First,titanium electrode mixed aluminum powder is used to strengthen 45 steel to determine the best discharge parameters.Under this optimal discharge parameter,titanium steel,carbon electrode and cemented carbide electrode were used for 45 steel under the conditions of mixed aluminum powder,boron carbide powder and mixed powder(aluminum powder and boron carbide powder were mixed in a ratio of 1:1).The surface is strengthened,and the influence of electrode material and mixed powder on the microstructure and properties of the reinforced layer is investigated.The addition of aluminum powder can significantly improve the surface morphology of the strengthening layer,making the surface smoother and smoother,reducing the surface roughness,the addition of boron carbide powder can significantly increase the microhardness of the strengthening layer,mixed powder(aluminum powder and boron carbide powder The addition of a 1:1 ratio of mixing improves the surface quality of the strengthening layer and also increases the thickness and hardness of the strengthening layer.The wear resistance of the strengthened layer was significantly higher than that of the matrix material,and it was 3 to 4 times that of the matrix.Among them,the microhardness and wear resistance of the strengthened layer obtained under the titanium electrode condition were the best,both superior to the carbon electrode and hard Alloy YG8 electrode reinforcement layer.On the basis of strengthening the 45 steel,the surface of the H13 steel was strengthened by electric spark in the conditions of quasi-dry working medium of kerosene,fog,and mixed aluminum powder.The overall microstructure of the reinforced layer was orange peel,and the hardness of the reinforced layer was relatively high.The hardness of the matrix H13 steel is greatly improved,and the average microhardness of the mixed Al powder in the quasi-dry working medium is significantly higher than that of the haze and kerosene.The composition and phase analysis of the strengthening layer show that the strengthening layer is not a simple coating of the strengthening material on the surface of the substrate,and the electrode material and the strengthening powder can both enter into the strengthening layer,and the substrate material occurs under high temperature and high pressure conditions.The spontaneous reaction produces a strengthening phase and plays a reinforcing role.