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Effect of Slab Subsurface Microstructure Evolution on Transverse Cracking of Microalloyed Steel during Continuous Casting |
Yun-feng LI1,Guang-hua WEN1,Ping TANG1,Jian-quan LI2,Cheng-li XIANG2 |
1. College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China 2. Pangang Group Panzhihua Steel and Vanagium Co., Ltd., Panzhihua 617000, Sichuan, China |
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Abstract As to the continuous casting process of low carbon microalloyed steel, subsurface microstructure evolution plays an important role in the slab surface cracking. In order to study the effect of the slab subsurface microstructure evolution on the transverse cracking, three different secondary cooling patterns (i.e., mild cooling, strong cooling and controlled cooling) were performed in the corresponding slab curved continuous caster. Based on the metallographic results, three transformation regions were found to be formed with the evolution of microstructures at different depths in the slab subsurface. The three regions are strong cooling transformation (SCT) region, double phase transformation (DPT) region and mild cooling transformation (MCT) region, respectively. Meanwhile, it was also found that the crack index used for evaluating slab surface cracking susceptibility was decreased when the range of the DPT region was increased. This can be explained by the fact that the double phase transformation (austenite-ferrite-austenite) occurred resulting from thermal cycling in DPT region, which resulted in promoting the refinement of prior austenite grains and inhibiting the precipitation of film-like ferrite and chain-like precipitates. Under the controlled cooling pattern, the widely-distributed DPT region was formed in the range of 3.5-8.0 mm to the slab surface. And compared with other cooling patterns, the cracking susceptibility is lowest with a crack index of 0.4.
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Received: 14 June 2013
Published: 01 August 2014
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Fund:National Outstanding Youth Science Foundation of China |
Corresponding Authors:
Yun-Feng LI
E-mail: liyunfengcqu@163.com
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Li-jun Xu,Shu-lan Zhang,Chun-gen Qiu,Sheng-tao Qiu,Xing-zhong Zhang. Surface microstructure control of microalloyed steel during slab casting[J]. Chinese Journal of Iron and Steel, 2017, 24(8): 803-810. |
[2] |
Zhong Zheng,*,Jian-yu Long,Xiao-qiang Gao. Production scheduling problems of steelmaking-continuous casting process in dynamic production environment[J]. Chinese Journal of Iron and Steel, 2017, 24(6): 586-594. |
[3] |
Long Guo,Xing-zhong Zhang*,Chang-xi Feng. Continuous bending and straightening technology of Q345c slab based on high-temperature creep deformation[J]. Chinese Journal of Iron and Steel, 2017, 24(6): 595-600. |
[4] |
Bang-fu Huang,,*,Nai-yuan Tian,Zhe Shi,,Zhi-wei Ma,. Steel ladle exchange models during steelmaking and continuous casting process[J]. Chinese Journal of Iron and Steel, 2017, 24(6): 617-624. |
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