SURFACE FLAW PREVENTIVE METHOD FOR HOT ROLLED STEEL MATERIAL AND COATING MATERIAL THEREFOR

摘要

PURPOSE:To enable utilization of an inferior scrap by providing a film having a specific thickness of a coating material consisting of a low-Ni-content low melting oxide on the surface of a high-temp. steel slab, contg. copper and tin at specific ratios and subjecting a slab to a hot rolling. CONSTITUTION:The film having 2 to 30mum thickness is provided by the coating material consisting of the Ni-containing low melting oxide on the surface of the high-temp. steel slab contg. >=0.3% copper and >=0.01% tin and the steel slab is hot rolled. The Ni-containing low melting oxide consisting of >=0.5 Na2/SiO2 and <=5.0% NiO is used for the coating material. The continuously cast slab 7 is coated uniformly and broadly with such Ni alloy powder 2 by a flame gun 5.