Arc welding

Patent metadata

Field	Value
Publication number	US-11213918-B2
Application number	US-201816768623-A
Country	US
Kind code	B2
Filing date	Nov 26, 2018
Priority date	Nov 30, 2017
Publication date	Jan 4, 2022
Grant date	Jan 4, 2022

Abstract

A weld is formed in a workpiece such as a pipeline by first activating a melting device, such as a laser, to form a molten weld pool in the workpiece and then activating a welding device, such as a GMAW torch, to initiate a weld in the weld pool. The weld therefore incorporates the weld pool homogeneously. Relative movement between the activated welding device and the workpiece continues and completes the weld while the melting device remains deactivated.

First claim

The invention claimed is:

1. A method of welding a workpiece comprises:
activating a melting device;
forming a molten weld pool in the workpiece using the activated melting device;
activating a welding device to initiate a weld in the weld pool;
deactivating the melting device;
effecting relative movement between the activated welding device and the workpiece to continue the initiated weld while the melting device is deactivated; and
protecting the deactivated melting device from radiated heat emitted by the activated welding device by moving a barrier into a blocking position between the deactivated melting device and the activated welding device;
wherein the welding device and the melting device are in fixed relation during said relative movement between the activated welding device and the workpiece.

2. The method of claim 1 , comprising completing the initiated weld while the melting device is deactivated throughout.

3. The method of claim 1 , comprising moving the barrier into the blocking position in response to deactivation of the melting device.

4. The method of claim 1 , wherein the welding device and the melting device are both supported by a welding bug or robot that is moved relative to the workpiece.

5. The method of claim 1 , comprising:
directing a flow of shielding gas at the workpiece;
defining a shielding atmosphere by the flow of the shielding gas; and
activating the melting device to form the weld pool in the shielding atmosphere.

6. The method of claim 5 , wherein the weld is initiated and continued in the shielding atmosphere.

7. The method of claim 5 , wherein the shielding gas flows from the welding device and the weld pool is formed in the shielding atmosphere, defined by the flow of shielding gas from the welding device.

8. The method of claim 5 , wherein the shielding gas flows from the melting device and the weld pool is formed in the shielding atmosphere, defined by the flow of shielding gas from the melting device.

9. The method of claim 5 , comprising maintaining the composition of the shielding atmosphere between forming the weld pool and initiating and continuing the weld, such that the composition of the shielding atmosphere is substantially the same when forming the weld pool as when initiating and continuing the weld.

10. The method of claim 5 , comprising changing the composition of the shielding atmosphere between forming the weld pool and initiating and continuing the weld, such that the composition of the shielding atmosphere is substantially different when forming the weld pool than when initiating and continuing the weld.

11. The method of claim 1 , comprising:
monitoring characteristics of the weld pool; and wherein
activating the welding device occurs in response to the monitored characteristics of the weld pool.

12. The method of claim 1 , comprising applying welding heat from the welding device to the workpiece before deactivating the melting device.

13. The method of claim 12 , comprising:
determining activation of the welding device; and
deactivating the melting device in response to activation of the welding device.

14. The method of claim 1 , comprising:
directing melting heat along a first axis from the melting device to the workpiece; and
directing welding heat along a second axis from the welding device to the workpiece; wherein the first and second axes converge and intersect the weld pool.

15. The method of claim 1 , wherein the welding device is, individually, capable of making an effective weld in the workpiece.

16. The method of claim 1 , wherein the melting device is, individually, incapable of making an effective weld in the workpiece.

17. The method of claim 1 , wherein the welding device comprises a GMAW torch that forms the weld by a shielded arc.

18. The method of claim 1 , wherein the melting device comprises a laser or a plasma torch.

19. The method of claim 1 , wherein the melting device comprises a tungsten electrode that forms the weld pool by an arc.

20. The method of claim 19 , wherein the tungsten electrode is retracted upon deactivation of the melting device.

21. A welding apparatus comprises:
a melting device for forming a weld pool at a weld initiation point;
a welding device for forming a weld to be initiated at the weld pool;
a controller that is programmed to deactivate the melting device and to activate the welding device to complete the weld with the melting device remaining deactivated; and
a barrier that is movable, on deactivation of the melting device, into a blocking position between the deactivated melting device and the activated welding device;
wherein the welding device and the melting device are mounted together on a common supporting structure for movement relative to a workpiece.

22. The apparatus of claim 21 , wherein:
the melting device is arranged to direct melting heat to a workpiece along a first axis; and
the welding device is arranged to direct welding heat to the workpiece along a second axis that converges with the first axis.

23. The apparatus of claim 22 , wherein the welding device is arranged to direct a flow of shielding gas toward the workpiece to intersect the first axis.

24. The apparatus of claim 21 , wherein the controller is responsive to a weld pool sensor to activate the welding device in response to monitored characteristics of the weld pool.

25. The apparatus of claim 21 , wherein the controller is responsive to an activation sensor to deactivate the melting device in response to activation of the welding device.

26. The apparatus of claim 21 , wherein the welding device and the melting device share a common power supply.

27. The apparatus of claim 21 , wherein the welding device comprises a GMAW torch.

28. The apparatus of claim 21 , wherein the melting device comprises a laser or a plasma torch.

29. The apparatus of claim 21 , wherein the melting device comprises a tungsten electrode.

30. The apparatus of claim 29 , wherein the tungsten electrode is retractable upon deactivation of the melting device.

31. The method of claim 6 , wherein the melting device is deactivated after the welding device is activated.

32. The method of claim 16 , wherein the monitored characteristics of the weld pool comprise the temperature and/or homogeneity thereof.

Assignees

• Acergy France SAS

Inventors

• Atin Kouassi Gnamien Cesar-Auguste

Classifications

• B23K2101/10

  Pipe-lines · CPC title

• B23K9/067

  Starting the arc · CPC title

• B23K9/0956

  using sensing means, e.g. optical · CPC title

• B23K9/235 Primary

  Preliminary treatment · CPC title

• B23K26/354

  by melting · CPC title