Method and fixture for counteracting tensile stress

Patent metadata

Field	Value
Publication number	US-2018282829-A1
Application number	US-201715475661-A
Country	US
Kind code	A1
Filing date	Mar 31, 2017
Priority date	Mar 31, 2017
Publication date	Oct 4, 2018
Grant date	—

Abstract

A method for counteracting tensile stress in an article is disclosed, including heating the article and applying compressive stress to the article along a compressive stress vector, the compressive stress vector including a compressive stress vector component opposite in direction to a tensile stress vector of a thermally-induced tensile stress of the article. The compressive stress is applied by thermally-induced autogenous pressure by a fixture contacting the article. A fixture for counteracting tensile stress is disclosed, including a first compression member and a second compression member, and a position lock connecting the first compression member to the second compression member and reversibly fixing the first compression member relative to the second compression member. The first compression member and the second compression member include compressive surfaces having mating conformations for surfaces of an article. The position lock includes a material composition.

First claim

What is claimed is:

1 . A method for counteracting tensile stress in an article, comprising:
heating the article; and applying compressive stress to the article along a compressive stress vector, the compressive stress vector including a compressive stress vector component opposite in direction to a tensile stress vector of a thermally-induced tensile stress of the article, wherein the compressive stress is applied by thermally-induced autogenous pressure applied by a fixture contacting the article.

2 . The method of claim 1 , further including:
contacting a first compression member having a first compressive surface including a first mating conformation in contact with a first surface of the article; contacting a second compression member having a second compressive surface including a second mating conformation in contact with a second surface of the article; and reversibly locking a first position lock connecting the first compression member to the second compression member, fixing the first compression member relative to the second compression member, the first position lock including a first material composition.

3 . The method of clam 2 , wherein the first material composition includes a first phase transformation from body-centered cubic to face-centered cubic, and the first material composition undergoes the first phase transformation during the heating, the first phase transformation contracting the first position lock and applying the compressive stress to the article.

4 . The method of claim 3 , wherein the thermally-induced tensile stress is generated by a feature including a thermally-induced decrease in ductility over a ductility dip range, and the first phase transformation occurs within the ductility dip range.

5 . The method of claim 4 , wherein the ductility dip range is between about 1,200° F. to about 1,700° F.

6 . The method of claim 2 , wherein the first material composition includes a lower thermal expansion coefficient than the article, and expands less than the article during the heating, applying the compressive stress to the article.

7 . The method of claim 2 , wherein:
the first position lock includes:
a bolt, the first compression member and the second compression member being disposed on the bolt;
a first nut; and
a second nut, the first compression member being disposed between the first nut and the second compression member along the bolt, and the second compression member being disposed between the second nut and the first compression member along the bolt; and
reversibly locking the first position lock includes tightening the first nut against the first compression member and the second nut against the second compression member.

8 . The method of claim 1 , wherein the article includes an article alloy selected from the group consisting of superalloys, nickel-based superalloys, cobalt-based superalloys, iron-based superalloys, non-weldable alloys, hard-to-weld alloys, refractory alloys, austenitic stainless steel, copper alloys, titanium alloys, GTD 111, GTD 262, GTD 444, INCONEL 100, INCONEL 738, INCONEL 939, MAR-M-247, MGA 2400, Rene 108, and combinations thereof.

9 . The method of claim 1 , wherein heating the article includes at least one of a heat treatment, a pre-weld heat treatment, a weld heat treatment, an aging heat treatment, a solutioning heat treatment, a stress reduction heat treatment, a tempering heat treatment, and annealing heat treatment, a post-weld heat treatment, a brazing thermal cycle and a coating process.

10 . A fixture for counteracting tensile stress, comprising:
a first compression member having a first compressive surface; a second compression member having a second compressive surface; and a first position lock, the first position lock connecting the first compression member to the second compression member and reversibly fixing the first compression member relative to the second compression member, the first position lock including a first material composition, wherein the first compressive surface includes a first mating conformation for a first surface of an article and the second compressive surface includes a second mating conformation for a second surface of the article, the first surface of the article being distal to the second surface of the article across a first portion of the article, the first compressive surface and the second compressive surface being oriented relative to one another to apply compressive stress to the article by thermally-induced autogenous pressure.

11 . The fixture of clam 10 , wherein the first material composition includes a first phase transformation from body-centered cubic to face-centered cubic.

12 . The fixture of claim 11 , wherein the first phase transformation occurs between about 1,200° F. to about 1,700° F.

13 . The fixture of claim 10 , wherein the first material composition includes a lower thermal expansion coefficient than the article.

14 . The fixture of claim 10 , wherein the first portion includes a feature, the feature including a thermally-induced tensile stress.

15 . The fixture of claim 10 , wherein the first position lock includes:
a bolt, the first compression member and the second compression member being disposed on the bolt; a first nut; and a second nut, wherein the first compression member is disposed between the first nut and the second compression member along the bolt, and the second compression member is disposed between the second nut and the first compression member along the bolt.

16 . The fixture of claim 10 , wherein the article is a turbine component.

17 . The fixture of claim 10 , wherein the first material composition is selected from the group consisting of martensitic stainless steel, 410SS, 416SS, 431SS, carbon steel, 1018 steel, 4340 steel, precipitated stainless steel, 17PH SS, CMC, supermartensitic stainless steel, super 13 chrome, X80, zirconium, and combinations thereof

18 . The fixture of claim 10 , further including:
a third compression member having a third compressive surface; a fourth compression member having a fourth compressive surface; and a second position lock, the second position lock connecting the third compression member to the fourth compression member and reversibly fixing the third compression member relative to the fourth compression member, the second position lock including a second material composition.

19 . The fixture of claim 18 , wherein the third compressive surface includes a third mating conformation for a third surface of the article and the fourth compressive surface includes a fourth mating conformation for a fourth surface of the article, the third surface of the article being distal to the fourth surface of the article across a second portion of the article.

20 . The fixture of claim 18 , wherein the third compressive surface is disposed on a first rear surface of the first compression member and the fourth compressive surface is disposed on a second rear surface of the second compression member.

Assignees

• Gen Electric

Inventors

• Cui Yan
• Kottilingam Srikanth Chandrudu
• Tollison Brian Lee
• Henderson Brian Leslie
• Eminoglu Cem Murat

Classifications

• C22F1/08

  of copper or alloys based thereon · CPC title

• C22F1/183

  of titanium or alloys based thereon · CPC title

• C22F1/10

  of nickel or cobalt or alloys based thereon · CPC title

• C21D1/30 Primary

  Stress-relieving · CPC title

• F05D2230/40

  Heat treatment · CPC title