热扩散对高碳线材碳偏析和网状渗碳体的影响
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摘要
改编了碳偏析指数随温度及时间的变化模型,研究了一种线材碳偏析指数在热扩散试验中的变化规律,通过试验验证了碳偏析模型的有效性,并根据模型公式预测了铸坯碳偏析指数需要的热扩散时间。试验结果表明:线材在1200℃经2 min和4 min热扩散后,其碳偏析可以降低至1. 10和1. 05以下,空冷组织网状渗碳体级别显著降低。线材热扩散试验数据与模拟数值趋势一致,存在着线材升温至稳定所需的约0. 5 min差值。经过数值模拟,铸坯经过1200℃-590 min热扩散后偏析指数可降低至要求范围,但在实际操作中需考虑铸坯在加热过程中的热扩散。
The variation of carbon segregation index with temperature and time was adapted in this paper,and the variation of carbon segregation index of wire rod in thermal diffusion test was obtained. The validity of the carbon segregation model was verified by experiments.The thermal diffusion time of carbon segregation index in the slab was predicted according to the model formula. The results show that the carbon segregation of high carbon steel wire can be reduced to less than 1. 10 and 1. 05 after 2 min and 4 min heat diffusion at 1200 ℃,the cementite net level of the air cooled microstructure is significantly reduced. The wire thermal diffusivity test data and numerical simulation trend are consistent. There is a 0. 5 min difference between wire rod heating and stability. The segregation index of the billet can be reduced to the required range after 590 min heat diffusion at 1200 ℃ through numerical simulation,but the heat diffusion of the billet during the heating process should be considered in the actual operation.
The variation of carbon segregation index with temperature and time was adapted in this paper,and the variation of carbon segregation index of wire rod in thermal diffusion test was obtained. The validity of the carbon segregation model was verified by experiments.The thermal diffusion time of carbon segregation index in the slab was predicted according to the model formula. The results show that the carbon segregation of high carbon steel wire can be reduced to less than 1. 10 and 1. 05 after 2 min and 4 min heat diffusion at 1200 ℃,the cementite net level of the air cooled microstructure is significantly reduced. The wire thermal diffusivity test data and numerical simulation trend are consistent. There is a 0. 5 min difference between wire rod heating and stability. The segregation index of the billet can be reduced to the required range after 590 min heat diffusion at 1200 ℃ through numerical simulation,but the heat diffusion of the billet during the heating process should be considered in the actual operation.
引文
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[11]孟宪成,刘宇,史秉华,等.帘线钢坯中心碳偏析的热扩散规律研究[J].金属热处理,2009,34(11):101-104.Meng Xiancheng,Liu Yu,Shi Binghua,et al.Study on the thermal diffusion law of carbon segregation in the center of cord billet[J].Heat Treatment of Metals,2009,34(11):101-104.
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[14]刘晓丽,高志平,张贺宗.硬线盘条组织中局部晶粒粗大原因分析[J].金属热处理,2005,30(11):85-87.Liu Xiaoli,Gao Zhiping,Zhang Hezong.Cause analysis of local grain coarsening in hard wire rod structure[J].Heat Treatment of Metals,2005,30(11):85-87.
[15]贾敏,刘靖,韩静涛.温度制度对帘线钢72A表面质量及微观组织的影响[J].材料热处理学报,2016,37(4):168-174.Jia Min,Liu Jing,Han Jingtao.Effect of temperature regime on surface quality and microstructure of 72A cord steel[J].Transactions of Materials and Heat Treatment,2016,37(4):168-174.
[2]Kyung Shik,Young Won Chang.Macrosegregation behavior in continuously cast high carbon steel blooms and billets at the final stage of solidification in combination stirring[J].ISIJ International,1995,35(7):866-875.
[3]李文竹,马惠霞,黄磊,等.高碳铬轴承钢网状组织遗传性及其危害[J].金属热处理,2012,37(8):36-38.Li Wenzhu,Ma Huixia,Huang Lei,et al.Network structure heredity and harm to high carbon and chromium bearing steel[J].Heat Treatment of Metals,2012,37(8):36-38.
[4]李俊杰,Godfrey Andrew,刘伟.奥氏体化与冷却速率对过共析钢组织的影响[J].金属学报,2013,49(5):583-592.Li Junjie,Godfrey Andrew,Liu Wei.Effect of austenitizing and cooling rate on microstructure of hypereutectoid steel[J].Acta Metallurgica Sinica,2013,49(5):583-592.
[5]王承宽.钢帘线钢的生产[J].钢铁技术,2003(6):38-41.Wang Chengkuan.Production of steel cord steel[J].Iron and Steel Technology,2003(6):38-41.
[6]施琦,章小峰,赵丹丹,等.加热工艺对SUP6弹簧钢连铸坯成分偏析影响的研究[J].热加工工艺,2017,46(9):101-103.Shi Qi,Zhang Xiaofeng,Zhao Dandan,et al.Study on the effect of heating process on composition segregation of SUP6 spring steel billet[J].Hot Working Technology,2017,46(9):101-103.
[7]佟倩,孙齐松,陈涛,等.ER50-6连铸小方坯枝晶偏析的热扩散动力学[J].连铸,2014(4):37-42.Tong Qian,Sun Qisong,Chen Tao,et al.Thermal diffusion kinetics of dendrite segregation in ER50-6 billet continuous casting[J].Continuous Casting,2014(4):37-42.
[8]沈世雕,黄福祥,陈书浩,等.堆垛缓冷对连铸坯中心偏析的影响[J].钢铁,2010,45(10):47-51.Shen Shidiao,Huang Fuxiang,Chen Shuhao,et al.Effect of stacking slow cooling on central segregation of continuous casting billet[J].Iron and Steel,2010,45(10):47-51.
[9]严春莲,鞠新华,其其格,等.高温加热制度对380CL连铸板坯枝晶偏析及轧材带状组织的影响[J].冶金分析,2016,36(9):1-8.Yan Chunlian,Ju Xinhua,Qi Qige,et al.Effect of high temperature heating system on dendrite segregation and strip structure of 380CLcontinuous casting slab[J].Metallurgical Analysis,2016,36(9):1-8.
[10]李平,王雷,周青峰.82B中心网状渗碳体产生原因及改善方法[J].钢铁研究学报,2014,26(9):33-36.Li Ping,Wang Lei,Zhou Qingfeng.82B center network cementite causes and improvement methods[J].Journal of Iron and Steel Research,2014,26(9):33-36.
[11]孟宪成,刘宇,史秉华,等.帘线钢坯中心碳偏析的热扩散规律研究[J].金属热处理,2009,34(11):101-104.Meng Xiancheng,Liu Yu,Shi Binghua,et al.Study on the thermal diffusion law of carbon segregation in the center of cord billet[J].Heat Treatment of Metals,2009,34(11):101-104.
[12]Porter D A,Easterling K E,Sherif M Y.Phase transformation in metals and alloys[M].Beijing:Higher Education Press,2011.
[13]Walton H W.Mathematical modeling of the carburizing process for microprocessor control[J].Heat Treatment of Metals,1983(1):23-26.
[14]刘晓丽,高志平,张贺宗.硬线盘条组织中局部晶粒粗大原因分析[J].金属热处理,2005,30(11):85-87.Liu Xiaoli,Gao Zhiping,Zhang Hezong.Cause analysis of local grain coarsening in hard wire rod structure[J].Heat Treatment of Metals,2005,30(11):85-87.
[15]贾敏,刘靖,韩静涛.温度制度对帘线钢72A表面质量及微观组织的影响[J].材料热处理学报,2016,37(4):168-174.Jia Min,Liu Jing,Han Jingtao.Effect of temperature regime on surface quality and microstructure of 72A cord steel[J].Transactions of Materials and Heat Treatment,2016,37(4):168-174.