Threaded Connection for Pipe and Method for Producing Threaded Connection for Pipe

• US 20190331262A1
• Filed: 06/08/2017
• Published: 10/31/2019
• Est. Priority Date: 06/30/2016
• Status: Abandoned Application

• Current Assignee: Nippon Steel Corporation
• Original Assignee: Nippon Steel & Sumitomo Metal Corporation (Nippon Steel Corporation), Vallourec Oil And Gas France
• Inventors: GOTO, Kunio
• Application Number:
  US16/310,644
• Publication Number:
  US 20190331262A1
• Time in Patent Office: Days
• CPC Class Codes: C22C 19/03 based on nickel
• CPC Class Codes: C25D 3/565 containing more than 50% by weight of zinc
• CPC Class Codes: C25D 3/58 containing more than 50% by weight of copper
• CPC Class Codes: C25D 5/12 at least one layer being of nickel or chromium
• CPC Class Codes: C25D 5/36 of iron or steel
• CPC Class Codes: C25D 7/003 Threaded pieces, e.g. bolts or nuts
• CPC Class Codes: F16L 15/00 Screw-threaded joints hose connections with parts screwed directly on or into the hose F16L33/24; joining pipes to wall F16L41/00; Forms of screw-threads for such joints
• CPC Class Codes: F16L 15/006 with straight threads
• CPC Class Codes: F16L 15/04 with additional sealings
• CPC Class Codes: F16L 15/08 with supplementary elements F16L15/04, F16L41/00 and F16L43/02 take precedence

Abstract

There is provided a threaded connection for pipe the tightening torque of which is easy to adjust. A threaded connection for pipe according to the present embodiment includes a pin and a box. The pin and the box have contact surfaces that include a thread part, a metal seal part, and a shoulder part, respectively. The threaded connection for pipe includes a Zn—Ni alloy plating layer on the contact surface of one of the pin and the box, and includes a Cu—Sn—Zn alloy plating layer on the contact surface of the other one. The threaded connection for pipe further includes a lubricating coating in a liquid state or a semisolid state on at least one of the Zn—Ni alloy plating layer and the Cu—Sn—Zn alloy plating layer.

Claims

1. A threaded connection for pipe comprising:

a pin and a box each of which has a contact surface including a thread part, a metal seal part, and a shoulder part;

a Zn—

Ni alloy plating layer on the contact surface of one of the pin and the box, the Zn—

Ni alloy plating layer being made of a Zn—

Ni alloy;

a Cu—

Sn—

Zn alloy plating layer on the contact surface of another of the pin and the box, the Cu—

Sn—

Zn alloy plating layer being made of a Cu—

Sn—

Zn alloy; and

a lubricating coating on at least one of the Zn—

Ni alloy plating layer and the Cu—

Sn—

Zn alloy plating layer, the lubricating coating being in a liquid state or a semisolid state.

2. The threaded connection for pipe according to claim 1, wherein

the Zn—

Ni alloy plating layer has a thickness of 1 to 20 μ

m, the Cu—

Sn—

Zn alloy plating layer has a thickness of 1 to 20 μ

m, and the lubricating coating has a thickness of 30 to 300 μ

m.

3. The threaded connection for pipe according to claim 1, wherein

the Zn—

Ni alloy consists of 85 to 91 mass % of Zn and 9 to 15 mass % of Ni, with the balance being impurities.

4. The threaded connection for pipe according to claim 1, wherein

the Cu—

Sn—

Zn alloy consists of 40 to 70 mass % of Cu, 20 to 50 mass % of Sn and 2 to 20 mass % of Zn, with the balance being impurities.

5. A method for producing a threaded connection for pipe comprising a pin and a box each of which has a contact surface including a thread part, a metal seal part, and a shoulder part, the method comprising:

a step of forming a Zn—

Ni alloy plating layer on the contact surface of one of the pin and the box, the Zn—

Ni alloy plating layer being made of a Zn—

Ni alloy;

a step of forming a Cu—

Sn—

Zn alloy plating layer on the contact surface of another of the pin and the box, the Cu—

Sn—

Zn alloy plating layer being made of a Cu—

Sn—

Zn alloy; and

a step of forming a lubricating coating on at least one of the Zn—

Ni alloy plating layer and the Cu—

Sn—

Zn alloy plating layer, the lubricating coating being in a liquid state or a semisolid state.

6. The threaded connection for pipe according to claim 2, wherein

the Zn—

Ni alloy consists of 85 to 91 mass % of Zn and 9 to 15 mass % of Ni, with the balance being impurities.

7. The threaded connection for pipe according to claim 2, wherein

the Cu—

Sn—

Zn alloy consists of 40 to 70 mass % of Cu, 20 to 50 mass % of Sn and 2 to 20 mass % of Zn, with the balance being impurities.

8. The threaded connection for pipe according to claim 3, wherein

the Cu—

Sn—

Zn alloy consists of 40 to 70 mass % of Cu, 20 to 50 mass % of Sn and 2 to 20 mass % of Zn, with the balance being impurities.

9. The threaded connection for pipe according to claim 6, wherein

the Cu—

Sn—

Zn alloy consists of 40 to 70 mass % of Cu, 20 to 50 mass % of Sn and 2 to 20 mass % of Zn, with the balance being impurities.