连铸中低碳钢小方坯内部裂纹影响因素分析

Analysis on Influential Factors for Internal Crack of Medium and Low Carbon Billet

对天津钢铁集团有限公司生产的连铸中低碳钢小方坯内部裂纹影响因素进行分析,结果表明按工艺要求的上限控制碳含量以避开包晶反应区,有利于减少铸坯内部裂纹的发生;降低钢水硫含量或提高锰硫比,增强了钢的临界应变值,减少了铸坯内部裂纹的发生;低过热度、高拉速及降低二冷强度,使柱状晶的发展受到抑制,有利于扩大等轴晶的形成,从而降低铸坯内部裂纹发生的几率。

The paper analyzes the factors influencing the internal crack of medium and low carbon billet produced by Tianjin Iron and Steel Group Company Limited. Results show that the possibility of billet internal crack formation can be lowered by controlling carbon content according to the upper limit of process requirement to avoid peritectic reaction zone, reducing sulfur content or increasing manganese-sulfur ratio in liquid steel and enhancing steel critical strain value, and curbing the development of columnar grain and enlarging equiaxed grain by low superheat, high casting speed and reduced secondary strength.