Nb微合金化对齿轮钢高温渗碳奥氏体晶粒度的影响  

Influence of Nb microalloying on grain size of austenite in high-temperature carburized gear steel

作　　者：刘华松[1] 董延楠 郑宏光 兰鹏[1] 柳向椿 张家泉[1] LIU Huasong;DONG Yannan;ZHENG Hongguang;LAN Peng;LIU Xiangchun;ZHANG Jiaquan(School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China;Central Research Institute of Baoshan Iron and Steel Co.,Ltd.,Shanghai 201900,China)

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083 [2]宝武钢铁股份有限公司中央研究院,上海201900

出　　处：《钢铁研究学报》2021年第8期828-838,共11页Journal of Iron and Steel Research

基　　金：中央高校基本科研业务费资助项目(FRF-TP-19-017A3);国家自然科学基金资助项目(U1860111)。

摘　　要：通过Nb微合金化提高渗碳温度是当前发展高端齿轮钢的重要思路。以20Cr钢为基准成分,通过实验室熔炼、锻造以及977~1 134℃范围内高温伪渗碳实验,研究了0.02%、0.04%、0.06%、0.08%等不同Nb质量分数下渗碳后的奥氏体晶粒结构。在此基础上,依据热力学计算及析出颗粒熟化模型,对AlN、Nb(C,N)颗粒的钉扎强度进行估算并与晶粒尺寸建立联系,得到了适用于含Al、Nb齿轮钢的奥氏体晶粒度控制预测模型。最后,依据此模型分析了Nb含量对20Cr钢渗碳温度的影响,并基于高温渗碳目标提出了Nb微合金化的成分建议。It is an important approach to develop the high-quality gear steels through Nb microalloying to increase the carburizing temperature. Based on 20 Cr steel, the influence of Nb addition of 0.02%, 0.04%, 0.06% and 0.08% on the prior austenite grain after carburizing was investigated with laboratory smelting, forging and high temperature pseudo-carburizing experiments in the range of 977—1 134 ℃. On this basis, according to the thermodynamic calculation and the kinetic modeling for precipitation particle ripening, the pinning strength of AlN and Nb(C,N) particles was estimated and used for establishing the relationship with the austenite grain size. Then, the predictive model for Al-and Nb-containing gear steels to control the austenite grain size was obtained. Finally, the influence of Nb content on the carburizing temperature of 20 Cr steel was analyzed based on the predictive model, and the composition suggestion for Nb microalloying was proposed for the target of high-temperature carburizing process.

关 键 词：齿轮钢 高温渗碳 NB微合金化 Zener钉扎 异常晶粒长大 

分 类 号：TG161[金属学及工艺—热处理]