IMPROVEMENT OF INTERNAL QUALITY IN CONTI NUOUSLY CAST SLAB

摘要

PURPOSE: To promote equi-axed crystals in a carbon steel cast slab and to drastically improve the internal quality in the cast slab, such as center segregation, center porosity. ;CONSTITUTION: At the time of producing the carbon steel cast slab having 0.40-0.50% carbon content by a continuous casting method, Be, Mo, Nb, Ti and Zr in the molten steel is contained so as to satisfy (1) inequality and (2) equation and cast and further, the molten steel in a strand is electromagnetic- stirred. R≥0.01(%)...(1). Wherein, R=1.30×Be+0.03×Mo+0.06×Nb+0.15×Ti+0.1× Zr...(2). In the (2) equation, Be, Mo, Nb, Ti and Zr: each content (wt%) of berylium, molybdenum, niobium, titanium and zirconium in the molten steel in a tundish. In this way i.e., by promoting the equi-axed crystals in the carbon steel cast slab having 0.40-0.50% carbon, the internal quality in the cast slab, such as center segregation, center porosity, is drastically improved, and in this result, the development of defect caused by the segregation at the time of cold-working is restrained. By avoiding the low temp. casting, the nozzle clogging and the deterioration of inclusion quality can be prevented.;COPYRIGHT: (C)1993,JPO&Japio