工程科学学报，第37卷，第11期：1434-1441,2015年11月 Chinese Journal of Engineering,Vol.37,No.11:1434-1441,November 2015 D0l:10.13374/j.issn2095-9389.2015.11.007:http://journals..ustb.edu.cn 表面温度波动对微合金钢连铸板坯热塑性的影响 杜辰伟2)区，文进》，李阳，兰鹏2》，刘春秀12》，张晓峰12)，张家泉2》 1)北京科技大学钢铁治金新技术国家重点实验室，北京1000832)北京科技大学治金与生态工程学院，北京100083 3)中信戴卡股份有限公司，秦皇岛0660114)武汉科技大学钢铁治金及资源利用省部共建教育部重点实验室，武汉430081 ☒通信作者，E-mail:dudegh@163.com 摘要由于铸坯表面与二冷辊列夹持辊发生的间断式接触传热，其表面温度存在一定程度的上下波动.基于J55微合金 钢，考虑温度波动的影响，研究了钢在不同热状态下的热塑性.结果表明，高于850℃时温度波动制度下测得的断面收缩率低 于常规恒温制度下的测量值，而等于或低于850℃时情况相反.分析了两种不同温度制度下测试结果的差异，认为对于微合 金钢，存在着略高于所测钢种A,温度的某一分界温度，高于该温度时恒温制度下测得的塑性值相比波动制度下塑性值偏 高，而低于该温度时则偏低.这一认识有助于更加合理地制定实际连铸过程的矫直温度 关键词连铸：微合金钢：温度波动：热塑性 分类号TF777.1 Influence of surface temperature fluctuations on the hot ductility of microalloyed steel slabs during continuous casting DU Chen-wei,WEN Jin,LI Yang,LAN Peng,LIU Chun-xiu),ZHANG Xiao-feng),ZHANG Jia-quan' 1)State Key Laboratory of Advanced Metallurgy,University of Science and Technology Beijing,Beijing 100083,China 2)School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China 3)CITIC Dicastal Co.,Ltd.,Qinhuangdao 066011,China 4)Key Laboratory for Ferrous Metallurgy and Resources Utilization of the Ministry of Education,Wuhan University of Science and Technology,Wuhan, 430081 China Corresponding author,E-mail:dudegh@163.com ABSTRACT Temperature fluctuations exist on the slab surface due to unstable heat flux during repeated contact and departure between the hot slab surface and the relatively cold supporting rollers in the secondary cooling zone.Considering thermal oscillations, hot ductility test under different thermal conditions was carried out on J55 microalloyed steel.The results show that at a temperature higher than 850 C,the hot ductility under the oscillating condition is lower than that under the isothermal condition,but it is on the contrary when the temperature equals or falls below 850C.By analyzing results from experiment and from literature comprehensively, for the microalloyed steel,it is inferred that there exists a critical temperature a bit higher than the Ae,temperature.Above this critical temperature the hot ductility under the isothermal condition is higher than that measured by the more accurate oscillating way,while below it the result is opposite.This conclusion is meaningful to determine the straightening temperature for microalloyed steel produc- tion during continuous casting. KEY WORDS continuous casting:microalloyed steel:temperature fluctuations:hot ductility 连铸钢坯在第三脆性区的热塑性是影响其表面质 量的重要因素.较低热塑性易使铸坯在弯曲与矫直阶 收稿日期：2014-06-28 基金项目：钢铁治金新技术国家重点实验室资助项目(41603013)工程科学学报，第 37 卷，第 11 期: 1434--1441，2015 年 11 月 Chinese Journal of Engineering，Vol． 37，No． 11: 1434--1441，November 2015 DOI: 10． 13374 /j． issn2095--9389． 2015． 11． 007; http: / /journals． ustb． edu． cn 表面温度波动对微合金钢连铸板坯热塑性的影响 杜辰伟1，2) ，文 进3) ，李 阳4) ，兰 鹏1，2) ，刘春秀1，2) ，张晓峰1，2) ，张家泉1，2) 1) 北京科技大学钢铁冶金新技术国家重点实验室，北京 100083 2) 北京科技大学冶金与生态工程学院，北京 100083 3) 中信戴卡股份有限公司，秦皇岛 066011 4) 武汉科技大学钢铁冶金及资源利用省部共建教育部重点实验室，武汉 430081  通信作者，E-mail: dudegh@ 163． com 摘 要 由于铸坯表面与二冷辊列夹持辊发生的间断式接触传热，其表面温度存在一定程度的上下波动． 基于 J55 微合金 钢，考虑温度波动的影响，研究了钢在不同热状态下的热塑性． 结果表明，高于 850 ℃时温度波动制度下测得的断面收缩率低 于常规恒温制度下的测量值，而等于或低于 850 ℃时情况相反． 分析了两种不同温度制度下测试结果的差异，认为对于微合 金钢，存在着略高于所测钢种 Ae3温度的某一分界温度，高于该温度时恒温制度下测得的塑性值相比波动制度下塑性值偏 高，而低于该温度时则偏低． 这一认识有助于更加合理地制定实际连铸过程的矫直温度． 关键词 连铸; 微合金钢; 温度波动; 热塑性 分类号 TF777. 1 Influence of surface temperature fluctuations on the hot ductility of microalloyed steel slabs during continuous casting DU Chen-wei1，2)  ，WEN Jin3) ，LI Yang4) ，LAN Peng1，2) ，LIU Chun-xiu1，2) ，ZHANG Xiao-feng1，2) ，ZHANG Jia-quan1，2) 1) State Key Laboratory of Advanced Metallurgy，University of Science and Technology Beijing，Beijing 100083，China 2) School of Metallurgical and Ecological Engineering，University of Science and Technology Beijing，Beijing 100083，China 3) CITIC Dicastal Co． ，Ltd． ，Qinhuangdao 066011，China 4) Key Laboratory for Ferrous Metallurgy and Ｒesources Utilization of the Ministry of Education，Wuhan University of Science and Technology，Wuhan， 430081 China  Corresponding author，E-mail: dudegh@ 163． com ABSTＲACT Temperature fluctuations exist on the slab surface due to unstable heat flux during repeated contact and departure between the hot slab surface and the relatively cold supporting rollers in the secondary cooling zone． Considering thermal oscillations， hot ductility test under different thermal conditions was carried out on J55 microalloyed steel． The results show that at a temperature higher than 850 ℃，the hot ductility under the oscillating condition is lower than that under the isothermal condition，but it is on the contrary when the temperature equals or falls below 850 ℃ ． By analyzing results from experiment and from literature comprehensively， for the microalloyed steel，it is inferred that there exists a critical temperature a bit higher than the Ae3 temperature． Above this critical temperature the hot ductility under the isothermal condition is higher than that measured by the more accurate oscillating way，while below it the result is opposite． This conclusion is meaningful to determine the straightening temperature for microalloyed steel produc￾tion during continuous casting． KEY WOＲDS continuous casting; microalloyed steel; temperature fluctuations; hot ductility 收稿日期: 2014--06--28 基金项目: 钢铁冶金新技术国家重点实验室资助项目( 41603013) 连铸钢坯在第三脆性区的热塑性是影响其表面质 量的重要因素． 较低热塑性易使铸坯在弯曲与矫直阶