Study On Glow Plasma Nitriding And Vanadinizing On Cr12MoV Steel

Corrosion, fracture and wear are the main failure modes. The most common wear failure is leaded by the friction, which accounts for about70%of parts failure. Surface hardening technology which is an important means to improve the using performance and life of parts gets the extensive attention in domestic and overseas. The study of advanced surface hardening technology has a very important significance to improve the life, save cost and increase productivity. In the thesis, we used glow plasma technology to nitriding and vanadizing on the surface of Crl2MoV steel to produce vanadizing layer which had high-wearing feature.In the thesis, the ideal process of using glow plasma nitriding technology and double glow plasma vanadizing to handle the surface of Crl2MoV steel were explored. We used metallographic microscope, SEM, EDS, XRD to character the layer depth, morphology, chemical ingredients and phase composition, used micro hardness tester to measure the microhardness, and used friction-abrasion testing machine to measure the wear resistance of the sample which had been handled. The results showed that:1. Using the glow plasma nitriding technology to handle the surface of Crl2MoV could obtain ideal penetrating layer. The optimum parameters of this processing was showed following: the cathode voltage was600-700V, the nitrogen flow was80-100ml/min, the nitriding temperature was530℃, the pressure was500Pa, the soaking time was4h, and the hydrogen nitrogen ratio of nitriding gas was1:5.2. Using the glow plasma technology could obtain uniform nitride layer whose dept could reach150μm and whose compound layer depth was8～10μm.3. XRD analysis showed that the active ingredients of the nitride layer was composed by the s-Fe3N phase which had high-wear feature and the γ’-Fe4N phase which had high tenacity. The highest surface hardness could reach1400HV4. The optimum parameters of double glow plasma vanadizing was showed following:the source voltage was800-900V, the cathode voltage was400-500V, the vanadizing temperature was950℃, the pressure was30-35Pa, the Interelectrode distance was15-20mm, and the soaking time was4h.5. The sample that was handled by glow plasma nitriding before vanadizing could obtain more excellent vanadizing layer than that wasn’t nitride.6. The vanadizing layer depth was about10μm, and the vanadizing layer was composed by α’、VN、V2N and Fe3C which had high hardness and high-wear feature. The highest surface hardness could reach1900HV.7. The layer which was handled by glow plasma nitriding and vanadizing not only could obviously decrease the friction coefficient of friction pair, but had a very good abrasion resistance. The optimum processing conditions was followed:the soaking time of the glow plasma nitriding treatment was4h at530℃, and then the soaking time of the double glow plasma vanadizing was4h at950℃...