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利用Thermo-Calc软件对8Cr13Mo V马氏体不锈钢的凝固过程进行计算,利用光学显微镜、扫描电子显微镜和X射线衍射分析仪对铸态组织和碳化物形貌以及类型进行观察与分析,利用Gleeble热模拟试验机测定材料的静态连续冷却转变曲线.结果表明,8Cr13Mo V在平衡凝固条件下组织为铁素体和M23C6型碳化物,而在实际的凝固条件下,组织为铁素体、马氏体、残余奥氏体、M7C3型和M23C6型碳化物,由于偏析导致最终组织中碳化物以M7C3型为主,少量M23C6以薄片或树枝状分布在晶界上.由于较高的C和Cr含量,以0.1℃·s-1的冷却速率冷却时,奥氏体也会发生马氏体转变.
The solidification process of 8Cr13Mo-V martensitic stainless steel was calculated by Thermo-Calc software. The morphology and type of as-cast microstructure and carbide were observed and analyzed by optical microscope, scanning electron microscope and X-ray diffraction analyzer. The results show that the microstructure of 8Cr13Mo V is ferrite and M23C6 carbide under the condition of equilibrium solidification, while under the actual solidification conditions, the microstructure is ferrite and martensite , Retained austenite, M7C3 and M23C6 carbides, the carbides in the final structure are mainly M7C3 due to segregation, and a small amount of M23C6 is distributed on the grain boundaries in the form of flakes or dendrites.Because of the higher content of C and Cr, Austenite also undergoes martensitic transformation when cooled at a cooling rate of 0.1 ° C · s-1.