METHOD OF CASTING INGOT FOR PRODUCTION OF FORGED-STEEL ROLL

摘要

PROBLEM TO BE SOLVED: To provide an ingot-making method of using a conventional ingot which suppress ghost segregation completely or at least contains ghost segregation closer to the center compared with the location where ghost segregation appears in a conventional ingot, in casting an ingot serving as a raw material for forged-steel rolls.SOLUTION: In casting an ingot for production of forged-steel rolls by an ingot-making method, Bi is added to molten steel to be used in casting in a concentration of Bi of 10-100 mass ppm in such a way that the condition Ra/Ra<1 is met from the surface to the central vicinity of an ingot, where Ra/Ra=(d/d); d is the dendrite primary arm spacing (μm) of an ingot containing Bi; and dis a dendrite primary arm spacing (μm) at the critical point of ghost segregation occurrence of the ingot containing no Bi.