METHOD OF HEAT TREATMENT OF HEAT-RESISTANT ALLOY FOR EXCELLENT RESISTANCE TO INTERGRANULAR CRACK AND HEAT-RESISTANT ALLOY THE SAME

摘要

The present invention relates to a heat treatment method of a heat resistant alloy having excellent intergranular cracking resistance and an alloy thereof. The heat treatment method after a heat resistant alloy is manufactured and processed comprising: a step of solution heat treating for a predetermined time at 1260-1280°C; a step of slowly cooling at a cooling rate of 5-10°C/min at 800-950°C to immediately perform an aging treatment after the solution treatment; a step of age treating since maintaining a predetermined time at 800-950°C after the slow cooling step; and a step of air cooling after the aging treatment. According to the present invention, a shape of a grain boundary of the heat resistant alloy is formed as a serration, and a shape of the grain boundary is changed into a serration shape while maintaining the basic characteristics of a nickel group heat resistant alloy. Therefore, the present invention has the effects of inducing precipitation of a stable carbide whose surface energy is low, and improves a binding force of a grain boundary and a matrix; thereby improving resistance with respect to intergranular crack damage such as creep, fatigue, oxidation, corrosion, or the like at very high temperature of 900°C or more.