METHOD FOR HEAT TREATING A NICKEL SUPERALLOY

摘要

A method for heat treating nickel superalloy forgings containing 11-13 wt % of Cr, 8-17 wt % of Co, 6-8 wt % of Mo, 4-5 wt % of Ti, 4-5 wt % of Al, no more than 0.5 wt % of Nb, and no more than 500 ppm of Hf, the balance to 100 wt % being Ni, is disclosed. According to the method, an intermediate heat treatment is carried out at a temperature between the gamma ' solvus minus 95 DEG C and the gamma ' solvus minus 30 DEG C, following hot forging at a temperature between the gamma ' solvus minus 95 DEG C and the gamma ' solvus minus 45 DEG C, with a strain rate of 5.10<-5>s<-1> to 2.10<-2>s<-1>, and a deformation ratio higher than 0.1, and prior to a supersolvus heat treatment at a temperature between the gamma ' solvus plus 5 DEG C and the gamma ' solvus plus 25 DEG C for 1 to 4 hours.