Method for manufacturing super-refractory nickel-based alloy and super-refractory nickel-based alloy

Abstract

A method for manufacturing a super-refractory nickel-based alloy with a constituent composition such that the gamma-prime average precipitation quantity at 700° C. is at least 35 mol % includes a preparation step in which a material with a crystal grain diameter of 200 μm or less is manufactured by hot extrusion and a processing step in which this material is subjected to cold plastic processing with a processing rate of at least 30%. The cold plastic processing can be performed a plurality of times with a cumulative processing rate of at least 30%, and heat treatment is not performed between instances of cold plastic processing. The super-refractory nickel-based alloy can have a linear organization of a gamma phase and a gamma-prime phase or can include a carbide aggregated in an isometric crystal organization that includes a gamma phase and a gamma-prime phase.

1 . A method of manufacturing a super heat resistant Ni-based alloy having a composition such that an amount of precipitated gamma prime phase in equilibrium at 700° C. is not less than 35 mol %, the method comprising:
 a preparation step of manufacturing a raw material through hot extrusion, the raw material having a grain size of not more than 200 μm; and 
 a working step of subjecting the raw material to cold plastic working at a working rate of not less than 30%. 
 
     
     
         2 . The method according to  claim 1 , wherein the cold plastic working includes multiple workings, a cumulative working rate of the multiple workings being not less than 30%, and no heat treatment is performed between the multiple workings. 
     
     
         3 . The method according to  claim 1 , wherein the Ni-based alloy has a composition such that an amount of precipitated gamma prime phase in equilibrium at 700° C. is not less than 40 mol %. 
     
     
         4 . The method according to  claim 1 , wherein the Ni-based alloy has a hardness of not less than 500 HV after the working step. 
     
     
         5 . The method according to  claim 1 , wherein the Ni-based alloy has a cross-sectional structure including not less than 5 grains per 1 μm 2  after the working step, the grains having a maximum grain diameter of not more than 75 nm. 
     
     
         6 . The method according to  claim 1 , further comprising a step of performing heat treatment after the working step. 
     
     
         7 . The method according to  claim 1 , wherein the Ni-based alloy has a composition including, by mass %, 0 to 0.25% of C, 8.0 to 25.0% of Cr, 0.5 to 8.0% of Al, 0.4 to 7.0% of Ti, 0 to 28.0% of Co, 0 to 8% of Mo, 0 to 15.0% of W, 0 to 4.0% of Nb, 0 to 5.0% of Ta, 0 to 10.0% of Fe, 0 to 1.2% of V, 0 to 3.0% of Hf, 0 to 0.300% of B, 0 to 0.300% of Zr, and the balance of Ni and impurities. 
     
     
         8 . The method according to  claim 7 , wherein the Ni-based alloy has a composition including, by mass %, 0 to 0.25% of C, 8.0 to 25.0% of Cr, 0.5 to 8.0% of Al, 0.4 to 7.0% of Ti, 0 to 28.0% of Co, 0 to 8% of Mo, 0 to 6.0% of W, 0 to 4.0% of Nb, 0 to 3.0% of Ta, 0 to 10.0% of Fe, 0 to 1.2% of V, 0 to 1.0% of Hf, 0 to 0.300% of B, 0 to 0.300% of Zr, and the balance of Ni and impurities. 
     
     
         9 . A super heat resistant Ni-based alloy having such a composition that an amount of precipitated gamma prime phase in equilibrium at 700° C. is not less than 35 mol %, and having a banded structure of gamma phase and gamma prime phase. 
     
     
         10 . The Ni-based alloy according to  claim 9 , wherein carbides are aggregated in a banded direction of the banded structure. 
     
     
         11 . The Ni-based alloy according to  claim 9 , having a hardness of not less than 500 HV. 
     
     
         12 . A super heat resistant Ni-based alloy having such a composition that an amount of precipitated gamma prime phase in equilibrium at 700° C. is not less than 35 mol %, and having an equiaxed structure including gamma phase and gamma prime phase, the structure including carbides aggregating in a banded form. 
     
     
         13 . The Ni-based alloy according to  claim 12 , having a hardness of less than 500 HV. 
     
     
         14 . The Ni-based alloy according to  claim 9 , wherein the Ni-based alloy has a composition such that an amount of precipitated gamma prime phase in equilibrium at 700° C. is not less than 40 mol %. 
     
     
         15 . The Ni-based alloy according to  claim 9 , having a composition including, by mass %, 0 to 0.25% of C, 8.0 to 25.0% of Cr, 0.5 to 8.0% of Al, 0.4 to 7.0% of Ti, 0 to 28.0% of Co, 0 to 8% of Mo, 0 to 15.0% of W, 0 to 4.0% of Nb, 0 to 5.0% of Ta, 0 to 10.0% of Fe, 0 to 1.2% of V, 0 to 3.0% of Hf, 0 to 0.300% of B, 0 to 0.300% of Zr, and the balance of Ni and impurities. 
     
     
         16 . The Ni-based alloy according to  claim 15 , having a composition including, by mass %, 0 to 0.25% of C, 8.0 to 25.0% of Cr, 0.5 to 8.0% of Al, 0.4 to 7.0% of Ti, 0 to 28.0% of Co, 0 to 8% of Mo, 0 to 6.0% of W, 0 to 4.0% of Nb, 0 to 3.0% of Ta, 0 to 10.0% of Fe, 0 to 1.2% of V, 0 to 1.0% of Hf, 0 to 0.300% of B, 0 to 0.300% of Zr, and the balance of Ni and impurities. 
     
     
         17 . The Ni-based alloy according to  claim 12 , wherein the Ni-based alloy has a composition such that an amount of precipitated gamma prime phase in equilibrium at 700° C. is not less than 40 mol %. 
     
     
         18 . The Ni-based alloy according to  claim 12 , having a composition including, by mass %, 0 to 0.25% of C, 8.0 to 25.0% of Cr, 0.5 to 8.0% of Al, 0.4 to 7.0% of Ti, 0 to 28.0% of Co, 0 to 8% of Mo, 0 to 15.0% of W, 0 to 4.0% of Nb, 0 to 5.0% of Ta, 0 to 10.0% of Fe, 0 to 1.2% of V, 0 to 3.0% of Hf, 0 to 0.300% of B, 0 to 0.300% of Zr, and the balance of Ni and impurities. 
     
     
         19 . The Ni-based alloy according to  claim 18 , having a composition including, by mass %, 0 to 0.25% of C, 8.0 to 25.0% of Cr, 0.5 to 8.0% of Al, 0.4 to 7.0% of Ti, 0 to 28.0% of Co, 0 to 8% of Mo, 0 to 6.0% of W, 0 to 4.0% of Nb, 0 to 3.0% of Ta, 0 to 10.0% of Fe, 0 to 1.2% of V, 0 to 1.0% of Hf, 0 to 0.300% of B, 0 to 0.300% of Zr, and the balance of Ni and impurities.