基于热辗扩工艺的低碳钢环坯晶粒长大规律  

Grain growth behavior of low carbon steel ring blanks in hot rolling process

作　　者：秦芳诚[1,2] 李永堂[1,2] 

机构地区：[1]太原科技大学材料科学与工程学院,山西太原030024 [2]金属材料成形理论与技术山西省重点实验室,山西太原030024

出　　处：《材料热处理学报》2015年第7期94-101,共8页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金重点(51135007);国家自然科学基金(51174140;51205270);高等学校博士点优先发展计划(20111415130001);山西省回国留学人员科研(2011-084)

摘　　要：低碳钢Q235是环件辗扩成形工艺的常用材料,辗扩前的加热规范对其辗扩过程及组织性能变化至关重要。利用箱式电阻炉在950-1200℃范围内,研究加热温度和保温时间对其加热过程中奥氏体晶粒长大规律的影响。借助于ZEISS显微镜观察分析其奥氏体晶粒长大组织,并采用截线法测定奥氏体晶粒平均直径。结果表明,随加热温度的升高和保温时间的延长,Q235钢奥氏体晶粒尺寸逐渐增大;且加热温度对奥氏体晶粒长大过程的影响要明显大于保温时间的影响,温度越高,晶粒生长指数越大;奥氏体晶粒的粗化温度为1100℃。在实验基础上,分别建立了Q235钢环坯在等温与非等温条件下晶粒长大动力学模型,并验证了等温长大模型预测结果与实验结果吻合良好。上述结果可为Q235环坯的辗扩成形提供准确的加热规范和奠定模型基础。Heating specification of Q235 steel ring blank before rolling is critical to its rolling process and microstructure evolution. The effects of heating temperature and holding time on austenite grain growth behavior of Q235 steel were studied in the temperature range of950-1200 ℃. The microstructure and mean austenite grain size of the steel were observed and measured by linear intercept method on a ZEISS metallographic microscope. The results show that austenite grain diameter of the Q235 steel ring blank increases with the increasing heating temperature and holding time. The signiticant effect of heating temperature on austenitic grain growth is observed compared with that of holding time. Coarsening temperature for the austenite grains is 1100 ℃. Based on the experimental data,a mathematical model of austenite grain growth for Q235 steel ring blank was proposed. A good agreement between the predicted and experimental results in isothermal condition is verified.

关 键 词：热辗扩 加热规范 晶粒长大 动力学模型 粗化温度 

分 类 号：TG142.3[一般工业技术—材料科学与工程]