Gas shield arc welding method and method for manufacturing steel pipe

Patent metadata

Field	Value
Publication number	US-12544848-B2
Application number	US-202117759418-A
Country	US
Kind code	B2
Filing date	Mar 22, 2021
Priority date	Apr 10, 2020
Publication date	Feb 10, 2026
Grant date	Feb 10, 2026

Abstract

A gas shield arc welding method that reduces the number of joints, which are the sites where defects occur more readily, and that enables automatic welding with a welding robot. A gas shield arc welding method in which a steel pipe Wo is welded by multi-pass welding with a steel frame erection adjusting tool attached to an erection piece on the steel pipe Wo to immobilize an open end section of the steel pipe. An initial single or several layers are welded to the open end section, after welding, the steel frame erection adjusting tool is removed; and remaining layers are welded with a welding robot such that two bead joints are formed at no more than two sites.

First claim

The invention claimed is:

1 . A gas shield arc welding method for welding a steel pipe by multi-pass welding, comprising:
attaching a steel frame erection adjusting tool to an erection piece provided on the steel pipe, such that a groove of the steel pipe is fixed; welding up the groove, by semiautomatic welding or manual welding, to an initial single layer or several layers; removing the steel frame erection adjusting tool after the welding up of the groove is finished; welding remaining layers by a single piece of a welding robot such that bead joints are formed at two sites or less, wherein the welding the remaining layers includes, at the bead joints, in a first layer of the remaining layers, setting a weld start point to any position, setting a weld end point to a position exceeding the weld start point, and setting an overlapping portion of a weld bead from the weld start point to the weld end point to 10 to 20 mm; and welding next and subsequent layers, including setting a circle, the circle having a radius of 0 to 5 mm and a weld end point of a previous layer as a center of the circle, as a weld start point of a next layer, setting a weld end point to a position exceeding the weld start point, and setting an overlapping portion of a weld bead from the weld start point to the weld end point to 10 to 20 mm.

2 . A gas shield arc welding method for welding a steel pipe by multi-pass welding, comprising:
attaching a steel frame erection adjusting tool to an erection piece provided on the steel pipe, such that a groove of the steel pipe is fixed; welding up the groove, by semiautomatic welding or manual welding, to an initial single layer or several layers; removing the steel frame erection adjusting tool after the welding up of the groove is finished; and welding remaining layers by at least one welding robot such that bead joints are formed at two sites or less, wherein the at least one robot includes a plurality of welding robots, wherein the remaining layers are welded by the plurality of welding robots, wherein the welding the remaining layers includes, at the bead joints, in a first layer of the remaining layers, for each of the plurality of welding robots, setting a weld start point to any position, setting a weld end point of one of the plurality of welding robots to a position exceeding a weld start point of an adjacent another one of the plurality of welding robots, and setting an overlapping portion of a weld bead from the weld start point to the weld end point to 10 to 20 mm, and wherein the method further comprises welding next and subsequent layers, for each of the plurality of welding robots, including setting a circle, the circle having a radius of 0 to 5 mm and a weld end point of a previous layer as a center of the circle, as a weld start point of a next layer, setting a weld end point of one of the plurality of welding robots to a position exceeding a weld start point of an adjacent another one of the plurality of welding robots, and setting an overlapping portion of a weld bead from the weld start point to the weld end point to 10 to 20 mm.

3 . The method according to claim 1 ,
wherein in a weld start range of 10 to 30 mm from the weld start point, a welding condition for at least one of welding current, welding speed, and distance between chip and base material is changed, a start welding current in the weld start range is set to 50 to 90% of a welding current of a main welding, a start welding speed in the weld start range is set to 110 to 140% of a welding speed of the main welding, and a distance between chip and base material in the weld start range is set to 50 to 120% of a distance between chip and base material of the main welding.

4 . The method according to claim 1 ,
wherein in a welding of the overlapping portion, a welding condition for at least one of welding current, welding speed, arc voltage, and distance between chip and base material is changed, an end welding current in the overlapping portion is set to 50 to 90% of a welding current of a main welding, an end welding speed in the overlapping portion is set to 110 to 140% of a welding speed of the main welding, an end arc voltage in the overlapping portion is set to 50 to 90% of an arc voltage of the main welding, and an end distance between end chip and base material in the overlapping portion is set to 50 to 120% of a distance between chip and base material of the main welding.

5 . The method according to claim 1 ,
wherein welding the overlapping portion includes providing a period of 0.1 to 5 seconds for a crater filling process at an end of the welding.

6 . The method according to claim 5 , comprising:
setting a crater current, which is a welding current at a time of the crater filling process, to 50 to 90% of a welding current of a main welding, and providing a transition period of 0.1 to 1 second between the main welding and the crater filling process.

7 . The method according to claim 1 , wherein the radius of the circle is 0 mm such that the weld start point of the next layer is the weld end point of the previous layer.

8 . The method according to claim 2 , wherein the radius of the circle is 0 mm such that the weld start point of the next layer is the weld end point of the previous layer.

9 . The method according to claim 2 ,
wherein in a weld start range of 10 to 30 mm from the weld start point, a welding condition for at least one of welding current, welding speed, and distance between chip and base material is changed, a start welding current in the weld start range is set to 50 to 90% of a welding current of a main welding, a start welding speed in the weld start range is set to 110 to 140% of a welding speed of the main welding, and a distance between chip and base material in the weld start range is set to 50 to 120% of a distance between chip and base material of the main welding.

10 . The method according to claim 2 ,
wherein in a welding of the overlapping portion, a welding condition for at least one of welding current, welding speed, arc voltage, and distance between chip and base material is changed, an end welding current in the overlapping portion is set to 50 to 90% of a welding current of a main welding, an end welding speed in the overlapping portion is set to 110 to 140% of a welding speed of the main welding, an end arc voltage in the overlapping portion is set to 50 to 90% of an arc voltage of the main welding, and an end distance between end chip and base material in the overlapping portion is set to 50 to 120% of a distance between chip and base material of the main welding.

11 . The method according to claim 2 ,
wherein welding the overlapping portion includes providing a period of 0.1 to 5 seconds for a crater filling process at an end of the welding.

12 . The method according to claim 11 , comprising:
setting a crater current, which is a welding current at a time of the crater filling process, to 50 to 90% of a welding current of a main welding, and providing a transition period of 0.1 to 1 second between the main welding and the crater filling process.

Assignees

• Kobe Steel Ltd

Inventors

• Yashima Takashi

Classifications

• B23K37/0217

  the guide member being fixed to the workpiece · CPC title

• B23K2103/04

  Steel {or steel} alloys · CPC title

• B23K2101/04

  Tubular or hollow articles · CPC title

• E04G21/18

  Adjusting tools; Templates {(workshop marking tools B25H; for coverings or linings E04F21/18)} · CPC title

• B23K9/0282 Primary

  for welding tube sections · CPC title