Study On Optimizing The Tecnics Of The Super Saturation Carburization On 20Cr Steel And A New Stype Super Saturation Carberization Steel

With the development of the society,the mechanicalequipment became smaller and with more functions. So it is necessary for the machine part to be credible and with excellent mechanical properties. The surface of the normal cementation steel contains 0.8-1.0% carbon after the heat treatments, carbide distributes on the martensite and austenite. The amount, distribution, size and form have something important to the hardness, strength and abrasion resistance of the surface. In order to enhance the mechanical properties, the amount of the carbon should be increased with carburization, but the netted carbide would precipitate from the grain boundary of the austenite, and it is detrimental for the mechanical properties.In this dissertation, from the carburization process and cementation steel, the super carburization process especial designed for the alloy cementation steel is developed. The super saturation cementation steel 35Cr3SiMnMoV is designed according to the molectronic. The amount of the carbon in the carburization layers is 2% according to the chemical analysis. From the metallographic microscope, it can be known that there are some small alloy carbide distributes on the matrix mainly composed martensite and austenite. The carbide consist Cr₇C₃,Mo₂C,VC, and the forming mechanism is discussed in the paper. The hardness of the carburization layers increase by 20 percent, up to HV_0.01912-HV_0.011025. At the same abrasion condition, the abrasion resistance increase by 90 percent. The mechanical properties of the machine part enhance a lot. And it is beneficial for the mechanical equipment to be miniature with higher capability. If the machine parts have the same size, through the super carburization process, the machine part would be used for a longer time.