含铌、钒、钛微合金钢连铸坯角部横裂纹研究现状

Research Present of Corner Transversal Crack on the Nb,V and Ti Micro-alloyed Steel Slab

在微合金钢连铸生产过程中,角部横裂纹一直未得到有效解决,裂纹的存在减少了铸坯热送量,严重影响生产顺行。综述了微合金连铸坯角部横裂纹的形成机理,重点分析了铌、钒、钛等微合金元素对角部横裂纹的影响,分析了防止横裂纹产生的措施,认为消除微合金钢连铸坯角部横裂纹的最有效方法是控制铸坯表层微观组织,使其具有较低的裂纹敏感性,克服连铸弯曲与矫直过程中产生的应力,而不产生裂纹。

Corner transversal cracks in the micro-alloyed steel slabs are not completely eliminated for the recent years, which seriously reduces the hot delivery of slabs and hinders process smooth operation. In the present study, the causes of corner transversal crack and the conventional measures to solve crack are summarized, and special emphases are placed on the effect of micro-alloyed elements such as Nb, Ti and V on corner transversal cracks during continuous casting operation. Controlling surface microstructure of slabs is considered to be the best measure to prevent corner transversal cracks. The type slabs with better surface microstructure have lower cracking susceptibility when suffered the stress during bending and straightening operations.