Ni-based alloy member manufacturing method

Abstract

In an Ni-based alloy member manufacturing method, an Ni-based alloy casting material is casted, in which a γ′-phase in an amount of 50 vol. % or more can be deposited in a γ-phase in the aging step. The Ni-based alloy casting material obtained after the casting step is heated for 1 hour or longer in a first strain removing temperature range of Ts×0.90° C. to Ts° C., when Ts° C. represents the solid solution temperature of the ‘γ-phase. The Ni-based alloy casting material obtained after the first strain removing heat treatment step is heated from the first strain removing temperature range to a solutionizing temperature range of higher than Ts+t1° C. but not higher than Tm° C., when Tm° C. represents the melting point of the γ-phase and t1 represents a temperature 10° C. or lower, and the temperature is held in the solutionizing temperature range for 2 hours or longer.

1 . A Ni-based alloy member manufacturing method comprising:
 a casting step;   a first strain removal heat treatment step;   a solution heat treatment step; and   an aging heat treatment step,   wherein, in the casting step, a Ni-based alloy cast material having a chemical composition in which a γ′ phase is precipitable in an amount of 50 volume % or more in a γ phase in the aging heat treatment step is cast,   in the first strain removal heat treatment step, when a solid-solution temperature of the γ′ phase is denoted by Ts° C., the Ni-based alloy cast material after the casting step is heated in a first strain removal temperature range of Ts×0.90° C. or higher and Ts° C. or lower for one hour or longer,   in the solution heat treatment step, when a melting point of the γ phase is denoted by Tm° C., the Ni-based alloy cast material after the first strain removal heat treatment step is heated from the first strain removal temperature range to a solution heat treatment temperature range of higher than Ts+t1° C. and Tm° C. or lower, and a temperature is held for two hours or longer in the solution heat treatment temperature range, and the t1 is 10° C. or lower.   
     
     
         2 . The Ni-based alloy member manufacturing method according to  claim 1 , further comprising:
 a second strain removal heat treatment step between the first strain removal heat treatment step and the solution heat treatment step,   wherein, when a temperature range of higher than Ts° C. and Tm° C. or lower, and lower than the solution heat treatment temperature range by the t1° C. is set as a second strain removal temperature range, in the second strain removal heat treatment step, the Ni-based alloy cast material after the first strain removal heat treatment step is heated from the first strain removal temperature range to the second strain removal temperature range, and the temperature is held for one hour or longer in the second strain removal temperature range, and   in the solution heat treatment step, the Ni-based alloy cast material after the second strain removal heat treatment step is heated from the second strain removal temperature range to the solution heat treatment temperature range, and the temperature is held for two hours or longer in the solution heat treatment temperature range.   
     
     
         3 . The Ni-based alloy member manufacturing method according to  claim 1 ,
 wherein in the aging heat treatment step, the Ni-based alloy cast material after the solution heat treatment step is heated in an aging heat treatment temperature range of 850° C. or higher and 870° C. or lower for two hours to 20 hours.   
     
     
         4 . The Ni-based alloy member manufacturing method according to  claim 1 ,
 wherein in the first strain removal heat treatment step, a temperature rising rate from room temperature to the first strain removal temperature range is 50° C./min or slower.   
     
     
         5 . The Ni-based alloy member manufacturing method according to  claim 1 ,
 wherein in the solution heat treatment step, a temperature rising rate from the first strain removal temperature range to the solution heat treatment temperature range is 50° C./min or slower.   
     
     
         6 . The Ni-based alloy member manufacturing method according to  claim 1 ,
 wherein in the solution heat treatment step, after holding the temperature for two hours or longer, cooling from the solution heat treatment temperature range to room temperature is performed at a cooling rate of 10° C./min or faster.   
     
     
         7 . The Ni-based alloy member manufacturing method according to  claim 1 ,
 wherein a chemical composition of the Ni-based alloy cast material includes, by mass %,
 Cr: 5% to 15%, 
 W: 3% to 10%, 
 Al: 3.0% to 7.0%, 
 Ta: 3% to 15%, 
 Co: 0% to 15%, 
 Mo: 0% to 5%, 
 Ti: 0% to 5.0%, 
 C: 0% to 0.10%, 
 B: 0% to 0.05%, and 
 a remainder including Ni and impurities.