Research On Composite Hardening For Laser Hardening And Multi-elements Plasma Penetrating Process Of Alloy Steel Tool

As low alloy steel H13 steel, it has excellent mechanical properties such as the hardness and high wear resistance. It can be used to make knives cutting general hardness of metal materials with low-cost. In order to further improve H13 steel tool cutting performance, it can be modified on the surface treatment to extend its service life. About tool surface treatment at present, there are a lot of ways like laser hardening treatment or ion permeability. They are used to the tool surface strengthening treatment. Experiments show that these two kinds of technology can improve the cutting tool material surface hardness and wear resistance. But the combination of which two kinds of technologies has not been researched.Based on the study of laser phase transformation hardening as pretreatment with ionic multivariate composite reinforcement technology, this paper is studied to provide some technical parameters and experience for the later development of technology.Base on H13 steel was treated by the plasma multi-elements penetrating, laser hardening, laser hardening and Plasma Multi-elements Penetrating composite surface modification technology. Results are analyzed by the microscopic hardness tester,metallographic microscope, scanning electron microscopy(SEM), energy spectrometer, X-ray diffraction and friction wear testing machine to study the changing rules of the microstructure, composition and properties of the composite treatment layer along with changing of the technological parameter, at the same time laser hardening and Plasma Multi-elements Penetrating are carried to make contrast and analysis.Experimental research shows that:(1)when set inn the sot diameter of0.5mm,laser power control in 150 W,scanning speed is 200 mm/min, the surface after laser phase transformation hardening effect is better.(2)Treated by Laser hardening and Plasma Multi-elements Penetrating composite surface modification technology,the sample surface hardness was obviously higher than the front.(3)In the case of equal permeability layer thickness, composite treatment than the plasma multi-elements penetrating treatment are shorter processing time.(4)In the set of laser processing parameters, when H13 steel is in temperature of 500℃ time of 6 hours,its surface hardness and the layer thickness are impermeable by plasma multi-elements penetrating.(5)After laser hardening, surface grain becomes small, microstructuredefect density increases greatly, which can lead to increase of nitriding layer and nitrogen distribution uniformity, eventually make the hardness, wear resistance of composite layer was obviously higher than that of single nitrided case.(6)After composite processing of the laser phase transformation hardening and plasma multi-elements penetrating, the surface of sample H13 steel are mainly composed of ε,γ′and α-Fe phase, Of which the content of Fe2-3N and FeS in composite processing layer is more significantly than that in single permeability layer, while the residual austenite decreases.(7)After composite processing of the laser phase transformation hardening and plasma multi-elements penetrating samples’ wear resistance increased.In conclusion, due to the influence of grain refinement and the increase of surface nitrogen compounds, composite layer of hardness and wear resistance are significantly higher than the single nitriding layer and laser hardening layer.