Influence Of Heat Treatment On Microstructure And Property Of16Cr-3Mn High Chromium Cast Iron

High-chromium cast iron has excellent wear resistance. It has been widely used in metallurgy, electric power, building materials and other fields. For improving the mechanical performances of high-chromium cast iron, people have done a lot of research. In the expansion of its application, people have done a lot of work, and achieved good results. However, in practice, the wear resistance of homemade white cast iron which contained chromium still exist certain difference compared with some imported parts, and need further exploration and research. At present, the reports about using subcritical heat treatment to improve high-chromium cast iron arc few, and lack related research. For example, high-chromium cast iron hardened factors, alloying elements, sub-critical treatment parameters, and so on.In this paper, the16Cr-3Mn high-chromium white cast iron were used sub-critical heat treatment and unstable heat treatment. In order to find the optimum heat treatment process, researched in four aspects:sub-critical heat treatment process parameters on properties of high-chromium cast iron; The sub-critical heat treatment hardening behavior and mechanism on high-chromium cast iron; The unstable treatment parameters on the properties of high-chromium cast iron; And the tempering heat treatment parameters on the properties of high-chromium cast iron.Compared as-cast microstructure and sub-critical heat treatment microstructure of high-chromium cast iron, we know most of the retained austenite was transformed into martensite, but there is still a certain amount of residual austenite. Analysis of residual austenite content change, in subcritical treatment, the longer insulation the austenite less. And if the temperature and heat preservation time is appropriate, the content of residual austenite in the microstructure of alloy can be reduced to a very low level. In addition, the hardening behavior of high-chromium cast iron is influenced by multiple effect:strengthening and weakening. The best subcritical heat treatment temperature of high-chromium cast iron is about520℃.Analysis instability treatment and tempering heat treatment of high-chromium cast iron, we know after unstable treatment of high-chromium cast iron, the carbide are uniformly distributed in the matrix, and the particles are tiny, so it reinforced materials strength and toughness. However, the temperature of unstable treatment need to be controlled reasonably, so that the carbon and alloy element content of austenite are suitable. And through quenching heat treatment, austenite can be changed into martensite completely. So high-chromium cast iron have high hardness.