Method for manufacturing nickel-based alloy high-temperature component

Patent metadata

Field	Value
Publication number	US-11021780-B2
Application number	US-201616348774-A
Country	US
Kind code	B2
Filing date	Nov 16, 2016
Priority date	Nov 16, 2016
Publication date	Jun 1, 2021
Grant date	Jun 1, 2021

Abstract

This method for manufacturing a high-temperature component formed of a Ni-based alloy includes a step of subjecting a workpiece of the Ni-based alloy to hot die forging using predetermined dies to form a forge-molded article, the step including: a die/workpiece co-heating substep of heating the workpiece interposed between the dies to a forging temperature; and a hot forging substep of taking out the workpiece and the dies into a room temperature environment and immediately performing hot forging on the workpiece using a press machine. The predetermined dies are formed of another Ni-based superalloy comprising γ and γ′ phases, and have features in that: a solvus temperature of the γ′ phase is 1050-1250° C.; and the γ′ phase precipitates at least 10 vol. % at 1050° C. and has two kinds of forms of intra-grain γ′ phase precipitations within the γ phase grains and inter-grain γ′ phase precipitations between/among the γ phase grains.

First claim

The invention claimed is:

1. A method for manufacturing a high temperature component formed of a Ni-based alloy, the method comprising:
a melting/casting step of melting and casting a material of the Ni-based alloy to form a workpiece;
a hot die forging step of subjecting the workpiece to hot die forging using predetermined dies to form a forge-molded article, the predetermined dies being formed of a precipitation-strengthened Ni-based superalloy comprising a γ phase as a matrix and a γ′ phase; and
a solution/aging treatment step of subjecting the forge-molded article to solution treatment and aging treatment to form a precipitation-strengthened molded article,
wherein the hot die forging step comprises:
a die/workpiece co-heating sub step of heating the workpiece to a forging temperature together with the dies using a heater with the workpiece interposed between the dies; and
a hot forging substep of taking the workpiece and the dies heated to the forging temperature out of the heater into a room temperature environment and immediately performing hot forging on the workpiece using a press machine,
wherein in the predetermined dies of the precipitation-strengthened Ni-based superalloy, the γ′ phase is precipitated in an amount of equal to or more than 10 vol. % with respect to the γ phase at 1050° C.,
wherein a solvus temperature of the γ′ phase is higher than 1050° C. and lower than 1250° C., and
wherein the γ′ phase has two precipitation forms of intra-grain γ′ phase crystal particles that precipitate within crystal grains of the γ phase and inter-grain γ′ phase crystal particles that precipitate between or among crystal grains of the γ phase.

2. The method for manufacturing the component formed of the Ni-based alloy according to claim 1 ,
wherein the precipitation-strengthened Ni-based superalloy has a composition of: by mass,
10 to 25% of Cr;
more than 0% and equal to or less than 30% of Co;
1 to 6% of Al;
2.5 to 7% of Ti and 3 to 9% in total of Ti, Nb and Ta;
equal to or less than 4% of Mo;
equal to or less than 4% of W;
equal to or less than 0.08% of Zr;
equal to or less than 10% of Fe;
equal to or less than 0.03% of B;
equal to or less than 0.1% of C;
equal to or less than 2% of Hf;
equal to or less than 5% of Re; and
a balance of Ni with inevitable impurities.

3. The method for manufacturing the component formed of the Ni-based alloy according to claim 1 ,
wherein the forging temperature is equal to or higher than 900° C. and equal to or lower than a temperature lower than the solvus temperature of the γ′ phase in the precipitation-strengthened Ni-based superalloy by 20° C.

4. The method for manufacturing the component formed of the Ni-based alloy according to claim 1 ,
wherein the dies have a tensile strength of equal to or more than 450 MPa at 900° C.

5. The method for manufacturing the component formed of the Ni-based alloy according to claim 1 ,
wherein the method further comprises a softening step of preforming and softening the workpiece between the melting/casting step and the hot die forging step, the softening step comprising:
a preform forming substep of subjecting the workpiece to hot working at a temperature equal to or higher than 1000° C. and lower than a solvus temperature of a γ′ phase in the Ni-based alloy to form a preform in which crystal particles of the γ′ phase are precipitated between or among crystal grains of a γ phase as a matrix of the Ni-based alloy; and
a softened preform forming sub step of re-heating the preform to the temperature of the hot working to decrease γ′ phase crystal particles precipitated within the γ phase crystal grains and subsequently slowly cooling the heated preform at a cooling rate of equal to or less than 100° C./h to 500° C. to form a softened preform in which the inter-grain γ′ phase crystal particles have grown, and
wherein the hot die forging step is performed on the softened preform.

Assignees

• Mitsubishi Power Ltd

Inventors

• Ota Atsuo
• Imano Shinya

Classifications

• C22C19/055

  with the maximum Cr content being at least 20% but less than 30% · CPC title

• B21K3/04

  blades, e.g. for turbines; Upsetting of blade roots · CPC title

• B21J5/002

  Hybrid process, e.g. forging following casting · CPC title

• B21J1/06 Primary

  Heating or cooling methods or arrangements specially adapted for performing forging or pressing operations {(B21J5/063 takes precedence)} · CPC title

• C22F1/10 Primary

  of nickel or cobalt or alloys based thereon · CPC title