基于二次枝晶间距变化特征的连铸方坯<strong>CET</strong>位置判断新方法

doi:10.11900/0412.1961.2021.00170

金属学报

2022, Vol. 58

Issue (6): 827-836 DOI: 10.11900/0412.1961.2021.00170

研究论文

本期目录 | 过刊浏览

基于二次枝晶间距变化特征的连铸方坯CET位置判断新方法

郭东伟¹^,², 郭坤辉¹^,², 张福利¹^,², 张飞¹^,², 曹江海¹^,², 侯自兵¹^,²(

)

^1.重庆大学材料科学与工程学院重庆 400044
^2.重庆大学钒钛冶金及新材料重庆市重点实验室重庆 400044

A New Method for CET Position Determination of Continuous Casting Billet Based on the Variation Characteristics of Secondary Dendrite Arm Spacing

GUO Dongwei¹^,², GUO Kunhui¹^,², ZHANG Fuli¹^,², ZHANG Fei¹^,², CAO Jianghai¹^,², HOU Zibing¹^,²(

)

^1.College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China
^2.Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New Materials, Chongqing University, Chongqing 400044, China

引用本文:

郭东伟, 郭坤辉, 张福利, 张飞, 曹江海, 侯自兵. 基于二次枝晶间距变化特征的连铸方坯CET位置判断新方法[J]. 金属学报, 2022, 58(6): 827-836.
Dongwei GUO, Kunhui GUO, Fuli ZHANG, Fei ZHANG, Jianghai CAO, Zibing HOU. A New Method for CET Position Determination of Continuous Casting Billet Based on the Variation Characteristics of Secondary Dendrite Arm Spacing[J]. Acta Metall Sin, 2022, 58(6): 827-836.

全文: PDF(1994 KB) HTML

摘要:

从碳钢连铸坯实际凝固组织入手对典型枝晶二次枝晶间距(secondary dendrite arm spacing,SDAS)进行测量分析,并发现了铸坯表面向中心凝固过程中的SDAS突增现象。结合铸坯横断面二维温度场数值模型分析可知,柱状晶向等轴晶转变(columnar to equiaxed transition,CET)的过程会影响铸坯内部的传热过程,这种影响最终以典型枝晶SDAS突增的形式体现出来。基于典型枝晶SDAS突增现象,确立了铸坯内部CET定量判定的新方法,即将典型枝晶SDAS最大增加率的起始位置确定为铸坯内部CET起始位置。计算所得CET位置与铸坯内部温度梯度变化拐点的最大相对误差仅为8.3%,且与生长速率变化区间相对应,同时也与实际凝固组织形貌转变位置吻合,证明了该方法的有效性。

关键词 ：连铸坯, 凝固组织, 枝晶间距, 柱状晶向等轴晶转变, 偏析

Abstract：

High-end steel products play an essential role in economic development and infrastructure projects. Nowadays, continuous casting is an important production process of high-end steel products due to higher efficiency and lower energy consumption. However, the quality and properties of end products, such as steel billets, bloom, and bar, will be affected by internal segregation defects, which are closely related to solidification structure characteristics. In the research on the solidification structure characteristics of billets, the columnar to equiaxed transition (CET) determination is of great significance to determine equiaxed crystal zones and the quality control of continuous casting billets. In this work, the secondary dendrite arm spacing (SDAS) of typical dendrites was measured and analyzed using the actual solidification structure of continuous casting billets and the mutation of SDAS during the solidification process from the billet surface to the center was found. Combined with the two-dimensional temperature field numerical model of the billet cross section, it can be seen that the CET will affect the heat transfer process in the billet and this will be reflected as the mutation of SDAS in typical dendrites. This work proposed a new method for the quantitative determination of CET in the continuous casting billets based on this mutation, and the starting position of the maximum SDAS increase rate is determined as the starting position of the CET. The CET positions calculated using the new method correspond to changes in the thermal gradient and growth rate in the billet, and are consistent with the positions of the actual solidification structure morphology transformations, which prove the effectiveness of this method.

Key words： continuous casting billet solidification structure dendrite arm spacing columnar to equiaxed transition segregation

收稿日期: 2021-04-21

ZTFLH:

TF701.3

基金资助:国家自然科学基金委员会-中国宝武钢铁集团有限公司钢铁联合研究基金项目(U1860101)

作者简介: 郭东伟,男,1995年生,博士生

	服务

	把本文推荐给朋友
	加入引用管理器
	E-mail Alert
	RSS
	作者相关文章
	郭东伟
	郭坤辉
	张福利
	张飞
	曹江海
	侯自兵
44.8K

链接本文:

https://www.ams.org.cn/CN/10.11900/0412.1961.2021.00170 或 https://www.ams.org.cn/CN/Y2022/V58/I6/827

图1 连铸坯横断面取样方法示意图

表1 SCM440连铸方坯主要生产工艺参数

图2 连铸坯试样横断面二次枝晶间距(SDAS)测量位置

Section	Length	Water amount		Boundary condition	Computational formula
	m	m³·h^-1
		No.1	No.2
Mold	0.9	114	114	q_m	$q m = 2.68 - β t m × 103$
Foot roller section	0.5	4.16	5.19	q_f = h_f(T_b - T_f)	h_f = 153.6(w / 60)^0.351
First section of secondary cooling zone	2.7	6.69	8.24	q_k = h_k(T_b - T_w)	h_k = 160 + 8.35w^0.851
Second section of secondary cooling zone	2.9	2.08	2.48	q_k = h_k(T_b - T_w)	h_k = 200 + 10.44w^0.851
Third section of secondary cooling zone	3.5	1.63	2.04	q_k = h_k(T_b - T_w)	h_k = 200 + 10.44w^0.851
Air cooling zone	5.4	-	-	q_a = ɛσ(T_b⁴ - T_a⁴)	ε = 0.8

表2 温度场计算过程中各部分参数及计算公式[18~20]

表3 No.1铸坯右侧表面中心测温结果与温度场数值模拟结果对比

图3 No.1和No.2铸坯横断面左右侧各位置的SDAS变化

图4 No.1和No.2铸坯左侧中心线处的温度梯度变化

图5 No.1和No.2铸坯左侧中心线生长速率变化

图6 铸坯内部由表面至中心凝固组织典型形貌特征变化

图7 基于SDAS变化的铸坯CET判断过程示意图

表4 No.1和No.2铸坯横断面CET位置测量结果

图8 No.1和No.2铸坯CET计算位置

1	Lage M G, Da Costa e Silva A L V. Evaluating segregation in HSLA steels using computational thermodynamics [J]. J. Mater. Res. Technol., 2015, 4: 353 doi: 10.1016/j.jmrt.2015.06.002
2	Long M J, Chen D F. Study on mitigating center macro-segregation during steel continuous casting process [J]. Steel Res. Int., 2011, 82: 847 doi: 10.1002/srin.201100085
3	Ayata K, Mori T, Fujimoto T, et al. Improvement of macrosegregation in continuously cast bloom and billet by electromagnetic stirring [J]. Trans. Iron Steel Inst. Jpn., 1984, 24: 931 doi: 10.2355/isijinternational1966.24.931
4	Li P S, Lu J H, Qiu S T, et al. Control of equiaxed crystal ratio of high carbon steel billets by circular seam cooling nozzle [J]. J. Iron Steel Res. Int., 2011, 18: 24
5	Ludlow V, Normanton A, Anderson A, et al. Strategy to minimise central segregation in high carbon steel grades during billet casting [J]. Ironmak. Steelmak., 2005, 32: 68 doi: 10.1179/174328105X23978
6	Jiang D, Zhu M. Solidification structure and macrosegregation of billet continuous casting process with dual electromagnetic stirrings in mold and final stage of solidification: A numerical study [J]. Metall. Mater. Trans., 2016, 47B: 3446
7	Choudhary S K, Ganguly S. Morphology and segregation in continuously cast high carbon steel billets [J]. Trans. Iron Steel Inst. Jpn., 2007, 47: 1759
8	Hunt J D. Steady state columnar and equiaxed growth of dendrites and eutectic [J]. Mater. Sci. Eng., 1984, 65: 75
9	Shibata H, Itoyama S, Kishimoto Y, et al. Prediction of equiaxed crystal ratio in continuously cast steel slab by simplified columnar-to-equiaxed transition model [J]. ISIJ Int., 2006, 46: 921 doi: 10.2355/isijinternational.46.921
10	Niu L, Qiu S T, Zhao J X, et al. Processing parameter optimization for continuous casting of 38CrMoAl round bloom based on a prediction model of the equiaxed crystal ratio [J]. Ironmak. Steelmak., 2019, 46: 835 doi: 10.1080/03019233.2018.1518807
11	Luo S, Zhu M Y, Louhenkilpi S. Numerical simulation of solidification structure of high carbon steel in continuous casting using cellular automaton method [J]. ISIJ Int., 2012, 52: 823 doi: 10.2355/isijinternational.52.823
12	Hou Z B, Jiang F, Cheng G G. Solidification structure and compactness degree of central equiaxed grain zone in continuous casting billet using cellular automaton-finite element method [J]. ISIJ Int., 2012, 52: 1301 doi: 10.2355/isijinternational.52.1301
13	Biscuola V B, Martorano M A. Mechanical blocking mechanism for the columnar to equiaxed transition [J]. Metall. Mater. Trans., 2008, 39A: 2885
14	Zuo P F, Chen S Y, Wei M W, et al. Thermal behavior and grain evolution of 24CrNiMoY alloy steel prepared by pre-laid laser cladding technology [J]. Opt. Laser Technol., 2019, 119: 105613 doi: 10.1016/j.optlastec.2019.105613
15	Zhang K L, Li Y J, Yang Y S. Influence of the low voltage pulsed magnetic field on the columnar-to-equiaxed transition during directional solidification of superalloy K4169 [J]. J. Mater. Sci. Technol., 2020, 48: 9 doi: 10.1016/j.jmst.2020.02.009
16	Hou Z B, Guo Z A, Guo D W, et al. A new method for carbon content distribution based on grayscale image of casting blank macrostructure in carbon steel [J]. J. Iron Steel Res., 2019, 31: 620
16	侯自兵, 郭中傲, 郭东伟等. 利用碳钢铸坯组织灰度图获取C含量分布的方法 [J]. 钢铁研究学报, 2019, 31: 620
17	Cao J H, Hou Z B, Guo Z, et al. An application of fractal theory to complex macrostructure: quantitatively characterization of segregation morphology [J]. ISIJ Int., 2020, 60: 1188 doi: 10.2355/isijinternational.ISIJINT-2019-630
18	Wang W, Hou Z B, Chang Y, et al. Effect of superheat on quality of central equiaxed grain zone of continuously cast bearing steel billet based on two-dimensional segregation ratio [J]. J. Iron Steel Res. Int., 2018, 25: 9
19	Choudhary S K, Mazumdar D. Mathematical modelling of fluid flow, heat transfer and solidification phenomena in continuous casting of steel [J]. Steel Res. Int., 1995, 66: 199
20	Cai K K, Yang J C. Investigation of heat transfer in the spray cooling of continuous casting [J]. J. Univ. Sci. Technol. Beijing, 1989, 11: 509
21	Li B, Zhang Z H, Liu H S, et al. Characteristics and evolution of the spot segregations and banded defects in high strength corrosion resistant tube steel [J]. Acta Metall. Sin., 2019, 55: 762
21	李博, 张忠铧, 刘华松等. 高强耐蚀管钢点状偏析及带状缺陷的特征与演变 [J]. 金属学报, 2019, 55: 762
22	Ji Y, Tang H Y, Lan P, et al. Effect of dendritic morphology and central segregation of billet castings on the microstructure and mechanical property of hot‐rolled wire rods [J]. Steel Res. Int., 2017, 88: 1600426 doi: 10.1002/srin.201600426
23	Min Y, Liu C J, Wang D Y, et al. Prediction of equiaxed crystal ratio of continuous casting round billet of 37Mn5 steel [J]. J. Iron Steel Res., 2011, 23(10): 38
23	闵义, 刘承军, 王德永等. 37Mn5连铸圆坯中心等轴晶率预测 [J]. 钢铁研究学报, 2011, 23(10): 38
24	Esaka H, Wakabayashi T, Shinozuka K, et al. Origin of equiaxed grains and their motion in the liquid phase [J]. ISIJ Int., 2003, 43: 1415 doi: 10.2355/isijinternational.43.1415
25	Li J M, Jiang M F, Ning J X, et al. Effect of casting speed on dendrite arm spacing of Mn13 steel continuous casting slab [J]. J. Iron Steel Res. Int., 2020, 27: 665
26	Ziv I, Weinberg F. The columnar-to-equiaxed transition in Al 3 Pct Cu [J]. Metall. Trans., 1989, 20B: 731
27	Hu H Q. Metal Solidification Principle [M]. 2nd Ed., Beijing: Machine Industry Press, 2012: 84
27	胡汉起. 金属凝固原理 [M]. 第 2版, 北京: 机械工业出版社, 2012: 84

[1]	马德新, 赵运兴, 徐维台, 王富. 重力对高温合金定向凝固组织的影响[J]. 金属学报, 2023, 59(9): 1279-1290.
[2]	常松涛, 张芳, 沙玉辉, 左良. 偏析干预下体心立方金属再结晶织构竞争[J]. 金属学报, 2023, 59(8): 1065-1074.
[3]	刘继浩, 周健, 武会宾, 马党参, 徐辉霞, 马志俊. 喷射成形M3高速钢偏析成因及凝固机理[J]. 金属学报, 2023, 59(5): 599-610.
[4]	张利民, 李宁, 朱龙飞, 殷鹏飞, 王建元, 吴宏景. 交流电脉冲对过共晶Al-Si合金中初生Si相偏析的作用机制[J]. 金属学报, 2023, 59(12): 1624-1632.
[5]	陈学双, 黄兴民, 刘俊杰, 吕超, 张娟. 一种含富锰偏析带的热轧临界退火中锰钢的组织调控及强化机制[J]. 金属学报, 2023, 59(11): 1448-1456.
[6]	吴国华, 童鑫, 蒋锐, 丁文江. 铸造Mg-RE合金晶粒细化行为研究现状与展望[J]. 金属学报, 2022, 58(4): 385-399.
[7]	李亚敏, 张瑶瑶, 赵旺, 周生睿, 刘洪军. Cu对Inconel 718合金Nb偏析影响机理的第一性原理研究[J]. 金属学报, 2022, 58(2): 241-249.
[8]	冯苗苗, 张红伟, 邵景霞, 李铁, 雷洪, 王强. 耦合热力学相变路径预测Fe-C包晶合金宏观偏析[J]. 金属学报, 2021, 57(8): 1057-1072.
[9]	曹江海, 侯自兵, 郭中傲, 郭东伟, 唐萍. 过热度对轴承钢凝固组织整体形貌特征及渗透率的影响[J]. 金属学报, 2021, 57(5): 586-594.
[10]	郭中傲, 彭治强, 柳前, 侯自兵. 高碳钢连铸坯大区域C元素分布不均匀度[J]. 金属学报, 2021, 57(12): 1595-1606.
[11]	张壮, 李海洋, 周蕾, 刘华松, 唐海燕, 张家泉. 齿轮钢铸态点状偏析及其在热轧棒材中的演变[J]. 金属学报, 2021, 57(10): 1281-1290.
[12]	郑秋菊, 叶中飞, 江鸿翔, 卢明, 张丽丽, 赵九洲. 微合金化元素La对亚共晶Al-Si合金凝固组织与力学性能的影响[J]. 金属学报, 2021, 57(1): 103-110.
[13]	张勇, 李鑫旭, 韦康, 韦建环, 王涛, 贾崇林, 李钊, 马宗青. 三联熔炼GH4169合金大规格铸锭与棒材元素偏析行为[J]. 金属学报, 2020, 56(8): 1123-1132.
[14]	李师居, 李洋, 陈建强, 李中豪, 许光明, 李勇, 王昭东, 王国栋. 电磁振荡场作用下双辊铸轧制备2099Al-Li合金的偏析行为及组织性能[J]. 金属学报, 2020, 56(6): 831-839.
[15]	李根, 兰鹏, 张家泉. 基于Ce变质处理的TWIP钢凝固组织细化[J]. 金属学报, 2020, 56(5): 704-714.

Viewed

Full text

Abstract

Cited

Shared

Discussed