PRODUCTION OF TWO-PHASE STAINLESS STEEL PRODUCT HAVING DIFFERENT DIAMETER PART

摘要

PURPOSE:To produce easily a two-phase stainless steel product having a different diameter part contg. a uniform amt. of ferrite by machining a casting which is formed by vertical centrifugal casting and has roughly an equal wall thickness thereby shaping out the product having a desired shape. CONSTITUTION:A vertical centrifugal casting mold 1 is placed on a rotary base 2 and is rotatively driven within a horizontal plane around the axial center. A molten metal is cast into such mold 1 and a cavity part V consisting of a parabolic surface (a) is formed in the central part of the molten metal by the balance between gravity and centrifugal force by which a casting 10 having roughly an equal wall thickness from the upper to lower part formed by the surface (a) and the inside wall (b) of the casting mold. The local fluctuation in the cooling rate of the casting 10 is mitigated and the two-phase structure contg. a uniform amt. of ferrite over the entire part of the casting 10 is formed in the solidifying stage thereof. The region 11 of the casting 10 is then shaped by machining to the two-phase stainless steel product having a different diameter part such as a flange or the like.