连铸板坯角部纵裂原因分析及控制措施

针对双流板坯连铸机提拉速至1.4~1.5 m/min后,铸坯角部裂纹发生率升高的问题,通过对纵裂试样进行化学成分分析,对纵裂处进行金相显微镜组织观察、扫描电镜及能谱分析,同时结合水模拟试验对角部裂纹的形成机理进行研究。结果表明,裂纹两侧有大量氧化圆点,纵裂在结晶器内产生;通过对结晶器冷却水水量进行优化、控制合理的结晶器倒锥度及结晶器通钢量等措施,减少了连铸坯角部纵裂现象的发生。

Research and control of longitudinal corner cracks in continuous casting slab

Aiming at the problem that the incidence of cracks at the corners of the cast slab increases after the double-strand slab caster is raised to 1.4-1.5 m/min, through chemical composition analysis of the longitudinal crack specimen and metallographic microscopic observation, scanning electron microscopy of the longitudinal crack and energy spectrum analysis, water simulation experiment to study the formation mechanism of corner cracks. The results show that there are a large number of oxidation dots on both sides of the crack, and the longitudinal crack occurs in the mold. By optimizing the amount of cooling water in the mold, controlling the reasonable inverted taper of the mold and the amount of steel through the mold, the occurrence of longitudinal cracks at the corners of the continuous casting slab is reduced.