【摘要】 利用正交试验研究了碳含量、铬含量、淬火温度和回火温度四因素对高铬铸铁综合力学性能的影响,优化了主要合金成分及热处理工艺参数。采用光学显微镜(OM)、X射线衍射仪(XRD)、扫描电镜(SEM)、能谱分析仪(EDS)表征了热处理前后试验高铬铸铁微观组织与成分,并测试了其力学性能。结果表明:铸态高铬铸铁以奥氏体相为主,淬火+回火后基体主要以马氏体为主,马氏体中析出细小的二次碳化物颗粒,导致高铬铸铁的硬度升高,冲击韧度略有降低。试验高铬铸铁力学性能较优工艺为:C=2.7%,Cr=18%;淬火温度为960℃,保温1h后空冷;回火温度为280℃,保温1h后空冷。该优化条件下铸态高铬铸铁硬度为60.3HRC,冲击韧度为8.0J/cm~2,热处理后高铬铸铁的硬度为61.2HRC,冲击韧度为7.8J/cm~2。更多还原

【Abstract】 The effect of the four factors on the mechanical properties of the high chromium cast iron has been investigated by orthogonal test system,these four factors include carbon and chromium contents,the quenching temperature and tempering temperature,respectively.The main alloy composition and heat treatment process parameters are optimized.The microstructure of the test high chromium cast iron before and after heat treatment are characterized by OM,XRD,SEM and EDS,and the mechanical properties are tested.The results show that the main phase is composed of austenite in the ascast high chromium cast iron,however,the main phase is composed of the martensite after quenching and tempering.The small secondary carbide particles are precipitated in the martensite,which lead to the hardness increased and the impact toughness decreased of the high chromium cast iron.An optimum process for the mechanical properties of high chromium cast iron is as follows:the content of carbon is 2.7%,and the content of chromium is 18%,and the quenching temperature is 960℃,holding1 hour then air cooling,and the tempering temperature is 280℃,holding 1hour then air cooling.Under the optimization the condition,the hardness of the as-cast high chromium cast iron is 60.3HRC,impact toughness is 8.0J/cm~2,after heat treatment the hardness of high chromium cast iron is 61.2HRC,impact toughness is 7.8J/cm~2.更多还原