Effect of melting and casting parameters on the hot ductility behavior of Nb-bearing beams, billets and slabs

The production of defect free continuously cast microalloy Nb-bearing steel slabs, blooms and billets have increased in importance for both the producer and the end user. The minimization of surface and internal defects has a substantial impact on steel producing operating costs, internal and external cost of quality and delivery performance. A keen and thorough understanding of the hot ductility behavior of various steel grades is essential to successfully melt and cast high quality microalloy steels. This paper describes current steelmaking and casting considerations and recommendations to successfully cast high quality niobium-bearing slabs, billets and blooms. This study also integrates the process metallurgy and the physical metallurgy to better understand the hot ductility mechanisms and process metallurgy control practices in use today for the high quality production of Nb-bearing steels.