PREVENTIVE METHOD FOR HOT CRACKING OF STEEL INGOT

摘要

PURPOSE:To obtain a steel ingot having no hot cracking by subjecting a low alloy steel of which the carbon equiv. value calculated by the prescribed equation is within a specific range to in-mold electromagnetic stirring thereby adjusting the carbon equiv. value in the part of the ingot where the surface layer is formed to a specific value or below. CONSTITUTION:The low alloy steel of which the value of CP calculated by the equation CP=C-Mn/33+Ni/25+Cu/44+N/1.7 (respectively in weight %) is in a 0.13-0.23 range is continuously cast. The part near the meniscus 2 in the mold 4 is slowly cooled by a heating means 8 and the molten steel 1 in the mold 4 is stirred by an electromagnetic stirrer 6 to adjust the CP value in the part of the ingot where the surface layer is formed to <0.13. The surface flawing by the hot cracking of the steel ingot is thus prevented.