低碳Si-Mn钢的直接淬火-动态配分(DQ&P)工艺  

Direct quenching and dynamic partitioning processes of low carbon Si-Mn steel

作　　者：李晓磊 李云杰[1] 康健[1] 袁国[1] 王国栋[1] 

机构地区：[1]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110819 [2]首钢迁安钢铁有限责任公司,河北迁安064404

出　　处：《金属热处理》2017年第12期95-100,共6页Heat Treatment of Metals

基　　金：国家自然科学基金(51504063);中央高校基本业务费(N160706001)

摘　　要：以含碳量为0.078%的Si-Mn钢为研究对象,采用直接淬火-动态配分(DQ&P)工艺,研究了不同淬火温度对显微组织和宏观硬度的影响。结果表明,经DQ&P工艺处理后的低碳钢,组织以铁素体、马氏体/贝氏体为主,残留奥氏体的含量在4.3%~7.2%之间,当淬火温度为320℃时,达到最大值7.2%。通过透射电镜观察发现,残留奥氏体主要以块状的形式分布于铁素体/马氏体和铁素体/贝氏体的界面,少量尺寸较小的残留奥氏体以薄膜状的形态分布于马氏体/贝氏体板条间。不同淬火温度下,硬度值在253~264 HV10之间,随淬火温度变化幅度较小,并且在240℃和320℃时达到最大值264 HV10。该研究表明,采用轧制变形和元素配分的方式能极大限度地稳定残留奥氏体,使得含碳量为0.078%的低碳钢能获得高达7.2%的残留奥氏体,为合金元素减量化的Q&P钢生产提供了新方法。Effect of quenching temperature on microstructural evolution and hardness was studied for low carbon Si-Mn steel （0. 078% C） treated by direct quenching and dynamic partitioning processes. The results show that the microstrncture in Q＆P steels mainly consists of ferrite, martensite/bainite and 4.3% N 7.2% retained austenite. When the quenching temperature is 320 ℃, the retained austenite reaches the highest level of 7.2%. The TEM observation results show that the blocky retained austenite is located at interfaces of ferrite/martensite and ferrite/bainite and that with small size is more likely to be film which is located between martensite or bainite laths. In addition, the hardness is not sensitive to quenching temperature, and is between 253 HV10 and 264 HV10. When the quenching temperature is 240℃ and 320 ℃, the maximum hardness is 264 HV10. The study indicates that the combination of rolling deformation and elements partitioning can retain austenite effectively, which obtains 7.2% retained austenite and provides a new approach to produce low alloy Q＆P steels.

关 键 词：低碳钢 直接淬火-动态配分 淬火温度 残留奥氏体 宏观硬度 

分 类 号：TG142.1[一般工业技术—材料科学与工程]