钼对高铬铸铁组织和热疲劳性能的影响  

Effect of Mo on Microstructure and Thermal Fatigue Properties of High Chromium Cast Iron

作　　者：王若宇 陈政 许婷 张海鸿 王永强 斯松华 WANG Ruoyu;CHEN Zheng;XU Ting;ZHANG Haihong;WANG Yongqiang;SI Songhua(School of Materials Science&Engineering,Anhui University of Technology,Maanshan 243032,China)

机构地区：[1]安徽工业大学材料科学与工程学院,安徽马鞍山243032

出　　处：《安徽工业大学学报（自然科学版）》2022年第2期140-144,152,共6页Journal of Anhui University of Technology（Natural Science）

基　　金：国家自然科学基金项目(51971003)。

摘　　要：以3种钼含量的铸态高铬铸铁为研究对象,对其进行冷热循环热疲劳试验,采用X射线衍射仪、光学显微镜、扫描电镜、透射电镜等研究钼含量对高铬铸铁组织结构及热疲劳性能的影响,探讨高铬铸铁的抗热疲劳机制。结果表明:铸态高铬铸铁主要由α-Fe,γ-Fe及(Cr,Fe)7C3相组成,随钼含量的增加组织中奥氏体相的含量增加;高铬铸铁以亚共晶方式结晶,显微组织主要由初生树枝晶固溶体(γ-Fe)及其间的共晶组织(α-Fe+(Cr,Fe)7C3)组成,添加Mo有助于细化枝晶组织,同时使杆状共晶碳化物发生细化与短化。在较高热疲劳试验温度下,高铬铸铁试样的主裂纹较长较粗,且有明显的二次裂纹,抗热疲劳性能较差;随添加Mo含量的增加,主裂纹变短、裂纹变细、二次裂纹减少;通过添加钼合金化,铸态高铬铸铁在900℃试验条件下的抗热疲劳性能可提高30%。Taking 3 kinds of as-cast high chromium cast iron with Mo content as the research object, the cold and hot cycle thermal fatigue test was carried out. The effects of Mo content on the microstructure and hermal fatigue properties of the high chromium cast iron were studied with X ray diffractometer, optical microscope, scanning electron microscope, transmission electron microscope, and the thermal fatigue resistance mechanism of high chromium cast iron was discussed. The results show that the as-cast high chromium cast iron is mainly composed of α-Fe, γ-Fe, and(Cr, Fe)7C3phases, with the increase of Mo content, the austenite content in the structure increases. The high chromium cast iron is crystallized in a hypoeutectic mode, and the microstructure is mainly composed of primary dendritic solid solutions(γ-Fe) and the eutectic structure(α-Fe+(Cr, Fe)7C3) between the dendritic solid solutions. The addition of Mo is helpful to refine the dendritic structure and refine shorten rod eutectic carbide. At a higher fatigue test emperature, the main crack length of the high chromium cast iron sample is longer and thicker, and there are obvious secondary cracks. With the increase of Mo content, the main crack becomes shorter, the crack becomes finer, and the secondary crack decreases. By adding Mo alloying, the thermal fatigue resistance of as-cast high chromium cast iron can be increased by 30% at 900 ℃.

关 键 词：高铬铸铁 显微组织 抗热疲劳性能 热疲劳机制 钼 

分 类 号：TG143.7[一般工业技术—材料科学与工程]