INGOT MAKING METHOD OF HIGH-CHROMIUM STEEL CONTAINING NITROGEN

摘要

PURPOSE:To prevent segregation of a giant carbide near the central hole of a steel ingot by melting a high-chromium steel contg. >=1 kinds of Nb and Ta and adding a reference value of N to the molten steel subjected to a vacuum degassing treatment then maintaining a nitrogen atmosphere in a casting mold, pouring the molten metal into the mold and casting the ingot. CONSTITUTION:A high-chromium steel contg. >=1 kinds of Nb and Ta is melted and a prescribed reference value of N is added to the molten steel subjected to a vacuum degassing treatment. A nitrogen atmosphere is then maintained in the mold and a molten steel is poured into the mold to cast an ingot. The ratio (H/D) between the height (H) and diameter (D) in the mold space is made 0.5-1. The chromium equiv. expressed by the equation for the high-chromium steel contg. N is made 5-7.