Al、N含量对齿轮钢奥氏体晶粒度的影响  

Effect of Al and N contents on austenite grain size of gear steel

作　　者：郭涛 岁月 何肖飞[2] 薛彦均 黄峰[1] Guo Tao;Sui Yue;He Xiaofei;Xue Yanjun;Huang Feng(State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan Hubei 430081,China;Research Institute of Special Steel,Central Iron and Steel Research Institute Co.,Ltd.,Beijing 100081,China;Military Representative Office of the Army Garrison in Shiyan District,Shiyan Hubei 442000,China)

机构地区：[1]武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北武汉430081 [2]钢铁研究总院有限公司特殊钢研究院,北京100081 [3]陆装驻十堰地区军事代表室,湖北十堰442000

出　　处：《金属热处理》2024年第7期113-120,共8页Heat Treatment of Metals

基　　金：表面强化工艺技术项目(JTOM-22012)。

摘　　要：试验研究了两种Al、N含量的齿轮钢在980、1050和1100℃奥氏体化后的奥氏体晶粒长大行为,通过试验和模型计算,采用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)和碳膜复型等技术探究AlN析出相的平衡溶解规律及其对奥氏体晶粒度的影响。结果表明,随着Al、N含量的提高,齿轮钢中奥氏体晶粒异常长大的临界温度也随之升高,在Al含量0.038%、N含量0.019%下,试验钢奥氏体化温度可以提高到1050℃,且保温6 h后,奥氏体晶粒仍然细小均匀,晶粒度级别在7.5~8级;通过对AlN析出相的分析发现,随着奥氏体化温度的提高,AlN析出相由多边形和近球形向长棒状转变,且尺寸不断变大,AlN析出相等效半径大于30 nm以上时,将会导致AlN析出相无法钉扎奥氏体晶界,产生混晶;由于AlN析出相的粗化与回溶,使得奥氏体的极限晶粒尺寸增长速度越来越快,奥氏体晶粒异常长大的极限钉扎力在0.045~0.095 J/cm^(3)之间。Austenite grain growth behavior of two gear steels with different contents of Al and N austenitized at 980,1050 and 1100℃ was experimentally studied.Equilibrium dissolution of AlN precipitates and its effect on austenite grain size were studied by means of optical microscope(OM),scanning electron microscope(SEM),transmission electron microscope(TEM)and carbon film replicas.The results show that with the increase of Al and N content,the critical temperature for abnormal growth of austenite grains in the gear steel also increases.When Al content is 0.038% and N content is 0.019%,the austenitizing temperature of the tested steel can be increased to 1050℃,at which after holding for 6 h,the austenite grains are still small and uniform,with grain size levels ranging from 7.5 to 8.Through the analysis of AlN precipitates,it is found that with the increase of austenitizing temperature,the AlN precipitates transforms from polygonal and nearly spherical to elongated rod-shaped,and its size continuously increases.When its equivalent radius is greater than 30 nm,the AlN precipitates cannot pin the austenite grain boundaries,resulting in mixed grains.Due to the coarsening and dissolution of the AlN precipitates,the growth rate of the ultimate grain size of austenite becomes faster and faster,and the ultimate pinning force for abnormal growth of austenite grains is between 0.045 and 0.095 J/cm^(3).

关 键 词：齿轮钢 晶粒长大 混晶 AlN析出相 

分 类 号：TG142.1[一般工业技术—材料科学与工程]