A Study On Deep-Layer QPQ Treatment Process For 45 Steel

Since the conventional workpiece compound layer QPQ treatment techniques only about 15μm, can not meet the higher requirements of the workpiece abrasion and corrosion resistance aspect, while the thickness of the compound layer reaches the deep processing technique QPQ 30μm or more, it is possible to handle the higher demands parts; 45 steel as widely used in the steel, the study further application of the underlying QPQ treatment process to promote the technology has important significance.In this paper, deep-layer QPQ treatment process were 45 steel process were studied cyanate, temperature and time of infiltration nitride layer; and using optical microscopy, scanning electron microscopy, X-ray diffraction analysis of the permeation layer and morphology; discusses the differences QPQ treatment process 45 steel in mechanical properties, wear resistance, corrosion resistance and the like.The results showed that:After deep-layer QPQ treatment steel nitrided layer of an oxide film 45, loose layer (compound layer is not dense part), the compound layer, an intermediate layer and the diffusion layers; layer depth compounds reach more than 35μm, loose layer less than 10μm, surface hardness HV0.1≥600; nitrogen distributed throughout the compound layer is relatively flat, the highest nitrogen concentration is not located at the surface of the nitrided layer; seepage layer compound layer is mainly composed of Fe3O4, Fe3N, Fe4N phase, an intermediate layer Fe4N and a composition, with the intermediate layer obtained in different ways in different cooling; QPQ process compared to conventional, deep QPQ treatment can improve toughness, elongation and reduction of area, but also allows the yield strength, tensile strength decreased; and After 45 QPQ treated steel as compared to conventional QPQ treated by deep, rolling wear properties of 45 steel up 2.8 times, sliding wear performance four times; 45 steel corrosion weight loss of 13.3 times that of conventional QPQ treated; 45 QPQ steel deep processing Rusty time of sample salt spray test is 1.78 times that of conventional QPQ processing; deep processing+rust QPQ time sealant salt spray test specimen is 5.1 times that of conventional QPQ treatment, and 45 samples were deep QPQ treated steel+After the sealant treatment, anti-salt spray corrosion resistance greater than 300h.