System And Method For Heat Treating A Tubular

• US 20140263284A1
• Filed: 03/15/2013
• Published: 09/18/2014
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: National Oilwell Varco LP (NOV, Inc.)
• Original Assignee: National Oilwell Varco LP (NOV, Inc.)
• Inventors: Wyble, Kevin Joseph, Hannahs, Daniel Lyle, Stevenson, Daryl, Cunningham, Shawn Lee
• Granted Patent: US 10,034,330 B2
• Time in Patent Office: Days
• US Class Current: 219/602
• CPC Class Codes: H05B 6/06 Control, e.g. of temperature, of power
• CPC Class Codes: H05B 6/101 for local heating of metal pieces
• CPC Class Codes: H05B 6/38 specially adapted for fitting into hollow spaces of workpieces

Abstract

A system and method for heat treating a tubular. In one embodiment, a system for heat treating a tubular includes a first coil and a second coil. The first coil is configured to circumferentially surround the tubular and induce, from without the tubular, current flow in a cylindrical portion of the tubular adjacent the first coil. The second coil is configured to be inserted into a bore of the tubular and induce, from within the tubular, in conjunction with the first coil, current flow in the cylindrical portion of the tubular.

Claims

1. A system for heat treating a tubular, comprising:

a first coil configured to circumferentially surround the tubular and induce, from without the tubular, current flow in a cylindrical portion of the tubular adjacent the first coil;

a second coil configured to be inserted into a bore of the tubular and induce, from within the tubular, in conjunction with the first coil, current flow in the cylindrical portion of the tubular.

2. The system of claim 1, further comprising one or more controllers that controls current flow to the first coil and the second coil for inducing current flow in the tubular, the one or more controllers configured to:

provide alternating current to the first coil at a first frequency; and

provide alternating current to the second coil at a second frequency;

wherein the first frequency is different from the second frequency.

3. The system of claim 2, wherein the second frequency is higher than the first frequency.

4. The system of claim 2, wherein the first frequency is approximately 180 hertz.

5. The system of claim 2, wherein the second frequency is in a range of approximately 3 kilohertz to approximately 10 kilohertz.

6. The system of claim 2, wherein the one or more controllers are configured to provide at least approximately 150 kilowatts of power to the first coil.

7. The system of claim 2, wherein the one or more controllers are configured to provide at least approximately 125 kilowatts of power to the second coil.

8. The system of claim 2, further comprising a pyrometer coupled to the one or more controllers and configured to measure temperature of the tubular;

wherein the one or more controllers are configured to determine a level of current to provide to at least one of the first coil and the second coil based on temperature measurement values received from the pyrometer.

9. The system of claim 2, wherein the one or more controllers are configured to:

store for each of a plurality of different tubulars;

a heat treatment temperature value, and

a heat treatment time; and

cause the first and second coils to heat treat each of the different tubulars in accordance with the temperature and treatment time values stored for the tubular.

10. A method for heat treating a tubular, comprising:

positioning a first coil to encircle a portion of a tubular to be heat treated;

positioning a second coil within a bore of the tubular at a location of the portion of the tubular to be heat treated; and

heat treating the portion of the tubular by inducing current flow about an exterior cylindrical wall and an interior cylindrical wall of the portion of the tubular via the first coil and the second coil.

11. The method of claim 10, further comprising:

providing alternating current to the first coil at a first frequency; and

providing alternating current to the second coil at a second frequency;

wherein the first frequency is different from the second frequency.

12. The method of claim 10, further comprising providing alternating current to the second coil at a frequency that is higher than the frequency at which current is provided to the first coil.

13. The method of claim 10, further comprising:

providing alternating current to the first coil at a frequency of approximately 180 hertz; and

providing alternating current to the second coil at a frequency in a range of approximately 3 kilohertz to approximately 10 kilohertz.

14. The method of claim 10, further comprising:

providing at least approximately 150 kilowatts of power to the first coil; and

providing at least approximately 125 kilowatts of power to the second coil.

15. The method of claim 10, further comprising:

measuring temperature of the tubular during the heating treating; and

determining a level of current to provide to at least one of the first coil and the second coil based on the measured temperature;

providing the determined level of current to the at least one of the first coil and the second coil.

16. The method of claim 10, wherein the heat treating comprising:

increasing the temperature of the portion of the tubular to at least a predetermined temperature value associated with the tubular; and

maintaining the predetermined temperature value for a predetermined time period associated with the tubular.

17. Inductive heat treatment apparatus, comprising:

an exterior induction coil configured to surround an outside diameter of a tubular;

an interior induction coil configured to occupy a bore of the tubular; and

one or more controllers coupled to the exterior induction coil and the interior induction coil; and

configured to simultaneously energize the exterior induction coil and the interior induction coil to concurrently heat treat a selected cylindrical portion of the tubular from exterior and interior of the tubular.

18. The apparatus of claim 17, wherein the one or more controllers are configured to provide alternating current to energize the exterior induction coil and the interior induction coil;

wherein the frequency of the alternating current provided to the exterior induction coil has a frequency that is lower than the frequency of alternating current provided to energize the interior induction coil.

19. The apparatus of claim 17, wherein the one or more controllers are configured to:

provide alternating current to the exterior induction coil at a frequency of approximately 180 hertz; and

provide alternating current to the interior induction coil at a frequency in a range of approximately 3 kilohertz to approximately 10 kilohertz.

20. The apparatus of claim 17, wherein the one or more controllers are configured to:

provide at least approximately 150 kilowatts of power to the exterior induction coil; and

provide at least approximately 125 kilowatts of power to the interior induction coil.

21. The apparatus of claim 17, further comprising a pyrometer coupled to the one or more controllers and configured to measure temperature of the tubular during heat treatment;

wherein the one or more controllers is configured to provide alternating current to at least one of the exterior induction coil and the interior induction coil based on temperature measurement values received from the pyrometer.

22. The apparatus of claim 17, wherein the one or more controllers is configured to:

store for each of a plurality of different tubulars;

a heat treatment temperature value, and

a heat treatment time; and

cause the interior induction coil and the exterior induction coil to heat treat each of the different tubulars in accordance with the values stored for the tubular.

23. The apparatus of claim 17, wherein the one or more controllers are configured to produce a heat affected zone having a parabolic outline that faces away from a weld line in a heat treated wall of the tubular.