Method for starting a submerged arc welding process and welding apparatus

Patent metadata

Field	Value
Publication number	US-11701731-B2
Application number	US-202117142609-A
Country	US
Kind code	B2
Filing date	Jan 6, 2021
Priority date	Nov 2, 2012
Publication date	Jul 18, 2023
Grant date	Jul 18, 2023

Abstract

A method comprising an arc ignition phase (IP), an arc-stabilizing phase (AP) and a stable arc phase (SP). The arc stabilizing phase comprises an initial sub-phase (IS) comprising the step of feeding at least one hot wire (4, 12) at constant feed speed and a main sub-phase (MS) comprising the steps of feeding said hot wire at constant feed speed and feeding at least one cold wire (22) at constant feed speed. The stable arc phase comprises the steps of continuously adjusting the feed speed of the hot wire and continuously adjusting the feed speed of the cold wire. The invention also relates to a welding apparatus (1) for carrying out the method. The welding apparatus comprises a hot wire feeding means (150), a contact means (2), a cold wire feeding means (35) and a control unit (31). The control unit is adapted to control said hot wire feeding means to feed the hot wire at a constant feed speed during the initial sub-phase, feed the hot wire at a constant feed speed during the main sub-phase and to continuously during the stable arc phase adjust the feed speed of the hot wire. The control unit is adapted to control said cold wire feeding means to feed the cold wire at a constant feed speed during the main sub-phase and continuously during the stable arc phase adjust the cold wire feed speed.

First claim

The invention claimed is:

1. A method for starting a submerged arc welding process comprising:
initiating, via a control unit, an arc ignition phase (IP) of a starting process comprising igniting an arc;
subsequent to the arc ignition phase (IP), executing, via the control unit, an arc-stabilizing phase (AP) of the starting process comprising at least an initial sub-phase (IS) and a main sub-phase (MS) that is subsequent to the initial sub-phase (IS), wherein:
said initial sub-phase (IS) comprises feeding at least one hot wire towards a work piece at a first constant feed speed, and
said main sub-phase (MS) comprises feeding said at least one hot wire towards the work piece at a second constant feed speed and feeding at least one cold wire towards the work piece at a third constant feed speed; and

subsequent to the arc-stabilizing phase (AP), executing, via the control unit, a stable arc phase (SP) of the starting process comprising continuously adjusting a fourth feed speed of the at least one hot wire in dependence on at least a welding current transferred through said at least one hot wire and continuously adjusting a fifth feed speed of the at least one cold wire in dependence on the first constant feed speed, the second constant feed speed, or the fourth feed speed of the at least one hot wire.

2. The method according to claim 1 , wherein a sixth feed speed of the at least one cold wire in a direction towards said work piece during the initial sub-phase (IS) remains equal to or lower than 9 cm/min.

3. The method according to claim 1 , wherein the at least one cold wire remains stationary during the initial sub-phase (IS).

4. The method according to claim 1 , wherein the first constant feed speed of the at least one hot wire is equal to the second constant feed speed of the at least one hot wire so that the at least one hot wire is fed at a constant speed throughout the arc-stabilizing phase (AP).

5. The method according to claim 1 , wherein the first constant feed speed of the at least one hot wire varies from the second constant feed speed.

6. The method according to claim 1 , wherein:
at least one of the first constant feed speed of said at least one hot wire and the second constant feed speed of the at least one hot wire is in a range of 0-200% of an expected speed of the fourth feed speed of said at least one hot wire during the stable arc phase (SP) based on a welding current during the stable arc phase (SP); and
the third constant feed speed of the at least one cold wire during at least one of the initial sub-phase (IS) and the main sub-phase (MS) is in a range of 0-100% of said at least one of the first constant feed speed of said at least one hot wire and the second constant feed speed of the at least one hot wire.

7. The method according to claim 6 , wherein at least one of the first constant feed speed of said at least one hot wire and the second constant feed speed of the at least one hot wire is in a range 0-100% of the expected speed of the fourth feed speed of said at least one hot wire during the stable arc phase (SP).

8. The method according to claim 7 , wherein at least one of the first constant feed speed of said at least one hot wire and the second constant feed speed of the at least one hot wire is in a range 80-95% of the expected speed of the fourth feed speed of said at least one hot wire during the stable arc phase (SP).

9. The method according to claim 6 , wherein the third constant feed speed of the at least one cold wire is in a range of 70-90% of the second constant feed speed of the at least one hot wire during the main sub-phase (MS).

10. The method according to claim 1 , wherein said arc-stabilizing phase (AP) has a predetermined length in a range of 1-6 seconds.

11. The method according to claim 10 , wherein the predetermined length in a range of 1-3 seconds.

12. The method according to claim 1 , wherein the initial sub-phase (IS) has a predetermined length in a range of 0.5-5 seconds.

13. The method according to claim 1 , comprising feeding more than one hot wire towards the work piece.

Assignees

• Esab Ab

Inventors

• Raudsepp Hannes
• Andersson Martin
• Johansson Tomas
• Ljungkvist Rikard

Classifications

• B23K9/188 Primary

  making use of several electrodes · CPC title

• B23K9/067 Primary

  Starting the arc · CPC title

• B23K9/073

  Stabilising the arc · CPC title

• B23K9/0732

  Stabilising of the arc current · CPC title

• B23K9/186

  making use of a consumable electrodes · CPC title