Methods of forming superelastic seals

Patent metadata

Field	Value
Publication number	US-2017108123-A1
Application number	US-201615391031-A
Country	US
Kind code	A1
Filing date	Dec 27, 2016
Priority date	Oct 29, 2014
Publication date	Apr 20, 2017
Grant date	—

Abstract

A superelastic metal seal for use in a downhole tool, wherein the superelastic metal seal may be formed from a superelastic Ni—Ti alloy. The superelastic Ni—Ti alloy may be prestrained with a permanent strain. Superelasticity may be imparted to the superelastic Ni—Ti alloy through a thermal treatment process or through prestraining the superelastic Ni—Ti alloy. The superelastic Ni—Ti alloy may exhibit superelastic behavior. The superelastic Ni—Ti alloy may not exhibit shape memory behavior.

First claim

1 . A method of forming a superelastic metal seal, comprising:
forming an Ni—Ti alloy comprising from about 58 weight percent Ni to about 65 weight percent Ni and from about 35 weight percent Ti to about 42 weight percent Ti; and treating the Ni—Ti alloy to form a superelastic Ni—Ti alloy free of shape memory behavior.

2 . The method of claim 1 , wherein treating the Ni—Ti alloy comprises prestraining the Ni—Ti alloy with a strain of at least approximately 2%.

3 . The method of claim 1 , wherein treating the Ni—Ti alloy comprises hardening the Ni—Ti alloy by rapidly cooling the Ni—Ti alloy after hot working the Ni—Ti alloy.

4 . The method of claim 3 , further comprising forming the superelastic metal seal into an O-ring shape, a C-ring shape, a D-seal shape, a T-seal shape, a V-seal shape, a X-seal shape, a flat seal shape, a lip seal shape, a cup seal shape, a back-up ring shape, a bonded seal shape, and a packing element shape.

5 . The method of claim 1 , wherein forming an Ni—Ti alloy comprises forming an alloy comprising about 60 weight percent Ni and about 40 weight percent Ti.

6 . The method of claim 1 , wherein treating the Ni—Ti alloy to form a superelastic Ni—Ti alloy free of shape memory behavior comprises forming the superelastic Ni—Ti alloy to exhibit superelastic behavior at least up to a compressive strain of about 10%.

7 . The method of claim 1 , wherein treating the Ni—Ti alloy to form a superelastic Ni—Ti alloy free of shape memory behavior comprises forming the superelastic Ni—Ti alloy to exhibit a microcrystalline structure including a martensitic phase.

8 . The method of claim 1 , wherein treating the Ni—Ti alloy to form a superelastic Ni—Ti alloy free of shape memory behavior comprises forming the superelastic Ni—Ti alloy to exhibit a microcrystalline structure including an austenitic phase.

9 . The method of claim 1 , wherein treating the Ni—Ti alloy to form a superelastic Ni—Ti alloy free of shape memory behavior comprises forming the superelastic Ni—Ti alloy to exhibit a microcrystalline structure including a martensitic phase and an austenitic phase.

10 . The method of claim 1 , wherein treating the Ni—Ti alloy to form a superelastic Ni—Ti alloy free of shape memory behavior comprises forming the superelastic Ni—Ti alloy to have a Rockwell hardness of about HRC 35-40, about HRC 40-45, about HRC 45-56, about HRC 56-62, or greater than about HRC 62.

11 . The method of claim 1 , wherein treating the Ni—Ti alloy to form a superelastic Ni—Ti alloy free of shape memory behavior comprises forming the superelastic Ni—Ti alloy to substantially resist degradation in the presence of one or more of KCl, NaCl, CaCl 2 , CaBr 2 , and ZnBr 2 .

12 . A method of forming a superelastic metal seal, comprising:
forming an alloy comprising from about 58 weight percent Ni to about 65 weight percent Ni and from about 35 weight percent Ti to about 65 weight percent Ti; and subjecting the alloy to one or more of a thermal treatment process and a physical stress application process to form a superelastic alloy free of shape memory behavior.

13 . The method of claim 12 , wherein forming an alloy comprises forming the alloy through one or more of one or more of a powder sinter process, a powder metallurgy process, a vacuum melting process, an electron beam melting process, a vacuum arc melting process, a high frequency vacuum melting process, a vacuum induction melting process, and a plasma melting process.

14 . The method of claim 12 , wherein subjecting the alloy to one or more of a thermal treatment process and a physical stress application process comprises:
isostatically pressing and hot rolling the alloy to form a pressed, heated alloy; and quenching the pressed, heated alloy in oil or gas to form the superelastic alloy.

15 . The method of claim 12 , wherein subjecting the alloy to one or more of a thermal treatment process and a physical stress application process comprises:
isostatically pressing and hot rolling the alloy to form a pressed, heated alloy; and cooling the heated alloy to form a pressed, cooled alloy; and applying one or more of tensile stress and compressive stress to the pressed, cooled alloy to permanently strain the pressed, cooled alloy and form the superelastic alloy.

16 . The method of claim 12 , further comprising subjecting the superelastic alloy to one or more of a machining process, a grinding process, a cutting process, and a molding process to form a seal structure.

17 . A method of forming a superelastic metal seal, comprising:
forming an Ni—Ti alloy comprising from about 58 weight percent Ni to about 65 weight percent Ni and from about 35 weight percent Ti to about 65 weight percent Ti; forming a seal structure from the Ni—Ti alloy; and subjecting the seal structure to one or more of a thermal treatment process and a physical stress application process to convert the Ni—Ti alloy thereof into a superelastic Ni—Ti alloy free of shape memory behavior.

18 . The method of claim 17 , wherein forming a seal structure from the Ni—Ti alloy comprises processing the Ni—Ti alloy to form one or more of an O-ring, a C-ring, a D-seal, a T-seal, a V-seal, an X-seal, a flat seal, a lip seal, a cup seal, a back-up ring, a bonded seal, and a packing element.

19 . The method of claim 17 , wherein subjecting the seal structure to one or more of a thermal treatment process and a physical stress application process comprises subjecting the Ni—Ti alloy to a strain within a range of about 2% to about 15%.

20 . The method of claim 17 , wherein subjecting the seal structure to one or more of a thermal treatment process and a physical stress application process imparting the seal structure with a permanent strain of at least about 0.5%.

Assignees

• Baker Hughes Inc

Inventors

• Roy Sayantan
• Sadana Anil K

Classifications

• F16J15/3284

  characterised by their structure; Selection of materials · CPC title

• F16J15/328

  Manufacturing methods specially adapted for elastic sealings (moulding B29C) · CPC title

• F16J15/0806 Primary

  characterised by material or surface treatment · CPC title

• C22F1/10

  of nickel or cobalt or alloys based thereon · CPC title

• C22C19/007

  with a light metal (alkali metal Li, Na, K, Rb, Cs; earth alkali metal Be, Mg, Ca, Sr, Ba, Al Ga, Ge, Ti) or B, Si, Zr, Hf, Sc, Y, lanthanides, actinides, as the next major constituent · CPC title