65Mn矩形坯单点矫直的凝固行为研究及工艺优化
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摘要
以国内某厂65Mn矩形坯为研究对象,建立了矩形坯的传热和热弹塑性模型,模拟矩形坯凝固过程的温度场,以及在进行单点矫直时矫直点处的应力场分布情况;分析温度场及热应力的分布对铸坯质量的影响,为优化连铸工艺提高矩形坯的质量提供了理论依据。模拟结果表明:采用普碳钢工艺浇铸65Mn钢时,在矫直点还存在大量液芯,高拉速下铸坯处于带液芯矫直,较全凝固矫直而言,其应力云图出现了不规则分布,且应力梯度增大,大大增加了内裂的产生几率。通过对工艺优化前后的铸坯低倍进行对比分析发现,本研究所提出优化工艺方向合理,铸坯质量大幅提高,取得较好的实践效果。
The heat transfer and thermal plastic models had been established based on industrial 65 Mn rectangular billet,and been used to simulate solidification temperature field and stress field in straightening point,in order to determine the effect of the distribution of temperature field and thermal stress filed on casting slab quality. The simulation results indicate that when plain carbon steel casting process is used to cast 65 Mn steel,there is a large number of liquid core retained in the straightening point,high speed casting causes a irregular distribution of stress nephogram and the stress gradient increases,this will greatly increase the internal crack occurrence; Macro observation on billet indicates that the proposed process optimization can greatly improve the quality of casting billet.
The heat transfer and thermal plastic models had been established based on industrial 65 Mn rectangular billet,and been used to simulate solidification temperature field and stress field in straightening point,in order to determine the effect of the distribution of temperature field and thermal stress filed on casting slab quality. The simulation results indicate that when plain carbon steel casting process is used to cast 65 Mn steel,there is a large number of liquid core retained in the straightening point,high speed casting causes a irregular distribution of stress nephogram and the stress gradient increases,this will greatly increase the internal crack occurrence; Macro observation on billet indicates that the proposed process optimization can greatly improve the quality of casting billet.
引文
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[11]Sun Ligen.Research on model for breakout diagnosis and prediction in continuous casting mold[D].Beijing:University of Science and Technology Beijing,2010.(孙立根.连铸结晶器漏钢行为及其预报模型研究[D].北京:北京科技大学,2010.)
[12]Angela Jablonka,Klause Harste,Klause Schwerdtfeger.Thermomechanical properties of iron and iron-carbon alloys:Density and thermal contraction[J].Steel Research,1991,62(1):24-33.
[13]Uehara M,Samarasekera I V,Brimacombe J K.Mathematical modeling of unbending of continuously cast steel slabs[J].Ironmaking and Steelmaking,1986,13:138-153.
[14]Cai Kaike,Dang Zijiu.The high temperature mechanical properties of cast steel[J].Journal of University of Science and Technology Beijing,1993,15(2):39-46.(蔡开科,党紫九.连铸钢高温力学性能[J].北京科技大学学报,1993,15(2):39-46.
[2]Wang Yan,Ye Liang,Sun Xiaohua.2D and 3D numerical simulation of temperature field and stress field of electro-spark overlaying welding[J].Welding,2007,36(7):78-81.(王燕,叶良,孙小华.电火花堆焊温度场、应力场的二维和三维数值模拟[J].热加工工艺,2007,36(7):78-81.)
[3]Li Donghui,Wang Fang.On-line control method to secondary cooling zone in billet continuous caster[J].Special Casting and Nonferrous Metallurgy,2009,29(10):934-937.(李东辉,王芳.方坯连铸二冷水量在线控制方法的研究[J].特种铸造及有色冶金,2009,29(10):934-937.)
[4]Luo Zhencai.Steelmaking machinery[M].Beijing:Metallurgical Industry Press,1989.(罗振才.炼钢机械[M].北京:冶金工业出版社,1989.)
[5]Grill A,Brimacombc J K.Ironmaking&steel-making[M].London:Mancy Publishing,2004.
[6]Jing Dejun.Numerical simulation on thermo-mechanical behavior of strands in continuous casting mold[D].Beijing:University of Science and Technology Beijing,2001.(荆德君,连铸结晶器内钢水凝固过程热和应力状态数值模拟研究[D].北京:北京科技大学,2001.)
[7]Rosen,Zhu Miaoyong,Ji Cheng,et al.Solute microsegregation model for continuous casting process of steel[J].Iron and Steel,2010,45(6):78-81.(罗森,朱苗勇,祭程,等.钢连铸过程的溶质微观偏析模型[J].钢铁,2010,45(6):78-81.
[8]Yoshiyuki Ueshima,Shozo Mizoguchi,Tooru Matsumiya,et al.Analysis of solute distribution in dendrites of carbon steel withδ/γtransformation during solidification[J].Metallurgical Transactions B,1986,17(11):845-859.
[9]Voller V R,Swaminathan C R,Thomas B G.Fixed grid techniques for phase change problems:A review[J].International Journal for Numerical Methods in Engineering,1990,30:875-898.
[10]Gan Yong.Modern continuous casting practical handbook[M].Beijing:Metallurgical Industry Press,2010.(干勇.现代连续铸钢实用手册[M].北京:冶金工业出版社,2010.)
[11]Sun Ligen.Research on model for breakout diagnosis and prediction in continuous casting mold[D].Beijing:University of Science and Technology Beijing,2010.(孙立根.连铸结晶器漏钢行为及其预报模型研究[D].北京:北京科技大学,2010.)
[12]Angela Jablonka,Klause Harste,Klause Schwerdtfeger.Thermomechanical properties of iron and iron-carbon alloys:Density and thermal contraction[J].Steel Research,1991,62(1):24-33.
[13]Uehara M,Samarasekera I V,Brimacombe J K.Mathematical modeling of unbending of continuously cast steel slabs[J].Ironmaking and Steelmaking,1986,13:138-153.
[14]Cai Kaike,Dang Zijiu.The high temperature mechanical properties of cast steel[J].Journal of University of Science and Technology Beijing,1993,15(2):39-46.(蔡开科,党紫九.连铸钢高温力学性能[J].北京科技大学学报,1993,15(2):39-46.