METHOD FOR HEAT TREATMENT OF STAINLESS MEMBER, AND METHOD FOR PRODUCING FORGED STAINLESS PRODUCT

摘要

A heating step, in which a stainless member is heated to a temperature within or above a heating phase-transformation temperature range (Ar) in which the stainless member is phase-transformed, is executed. A cooling step in which the stainless member heated in the heating step is cooled to a temperature below a cooling phase-transformation temperature range (Mr) in which the stainless member is phase-transformed, is executed. In the cooling step, cooling of the stainless member is suppressed in a control temperature range including the cooling phase-transformation temperature range (Mr).

主权项

1. A method for heat treatment of a stainless member,
a heating step, in which a stainless member is heated to a temperature within or above a heating phase-transformation temperature range in which the stainless member is phase-transformed when the stainless member is heated, is executed; and a cooling step, in which the stainless member heated in the heating step is cooled to a temperature below a cooling phase-transformation temperature range in which the stainless member is phase-transformed when the stainless member is cooled, is executed, wherein in the cooling step, a cooling medium is supplied to the stainless member, the flow rate of the cooling medium supplied to the stainless member per unit time is gradually increased from when the cooling step is started until when a predetermined length of time has elapsed, or from when the cooling step is started until when the temperature of the stainless member reaches a predetermined temperature, and the flow rate of the cooling medium in a control temperature range including the cooling phase-transformation temperature range is set to be smaller than those immediately before the temperature of the stainless member reaches the control temperature range and immediately after the temperature passes the control temperature range, wherein the predetermined length of time is shorter than a length of time from when the cooling step is started until when a temperature of the stainless member is a temperature within the heating phase-transformation temperature range, wherein the predetermined temperature is above the heating phase-transformation temperature range.