Effect of superheat on carbon segregation in continuous casting billet of cord steel
HU Zhi-yong1, CHEN Xin-hua1, TANG Ping2, HOU Zi-bing2
(1. Nanjing Iron and Steel Group Co., Ltd., Nanjing 210044, Jiangsu China 2. College of Materials Science and Engineering, Chongqing University Chongqing 400044, China
Abstract:The influence of different superheat on the transverse and vertical carbon segregation of cord steel continuous casting billet was studied by means of drilling cutting composition analysis and solidification microstructure analysis for the quality fluctuation in cord steel production. The results show that the center carbon segregation degree of the higher degree of superheat (34 ℃) is lower than the lower superheat (29 ℃), and the carbon element content fluctuation of center line position smaller than the lower superheat. The V-shaped segregation zone is the direct cause of longitudinal fluctuation of the carbon segregation index. It also shows that there are some limitations in revealing the segregation situation of the billet only by cross section. The lower the superheat degree, the higher the equiaxed ratio is, but at the same time due to the greater amount of solute liquid phase can be draw to the center of the vicinity, the central location of the degree of segregation and the degree of volatility may be greater. Therefore, the use of higher superheat in our plant, the carbon distribution of cord steel billet is more uniform, more stable quality.