Method for gas metal arc welding (gmaw) of nitrided steel components using cored welding wire

Patent metadata

Field	Value
Publication number	US-2016101485-A1
Application number	US-201514961226-A
Country	US
Kind code	A1
Filing date	Dec 7, 2015
Priority date	Dec 17, 2010
Publication date	Apr 14, 2016
Grant date	—

Abstract

A method for gas metal arc welding a first component formed of nitrided steel to a second component with reduced porosity in the weld is provided. A welding wire including a core surrounded by a tube is used to weld the components. The material of the core is formed of mild steel including 0.7 to 3.0 wt. % aluminum and 0.7 to 1.5 wt. % titanium. The material of the tube is formed entirely of low carbon steel. During the weld process, the nitrogen from the nitrided steel combines with the aluminum and titanium of the welding wire to form aluminum nitride and titanium nitride, instead of nitrogen bubbles which lead to high porosity. The method can be used to weld components used in automotive applications, for example to weld a ring gear and can of a flexplate, but alternatively could be used for another automotive or non-automotive applications.

First claim

What is claimed is:

1 . A method for welding components, comprising the steps of:
disposing a first component formed of nitrided steel along a second component to present a joint therebetween; forming an electric arc between a welding wire and the joint; the step of forming the electric arc between the welding wire and the joint including transferring material of the welding wire to the joint and melting at least a portion of each component with the material of the welding wire to form a weld along the joint, wherein the material of the welding wire is iron-based and includes aluminum and/or titanium.

2 . The method of claim 1 , wherein at least a portion of the iron-based material of the welding wire includes 0.7 to 3.0 weight percent (wt. %) aluminum and 0.7 to 1.5 wt. % titanium, based on the total weight of the iron-based material.

3 . The method of claim 1 , wherein the welding wire includes a core surrounded by a tube, the material of the core includes the iron-based material having 0.7 to 3.0 wt. % aluminum and/or 0.7 to 1.5 wt. % titanium, and the material of the tube is formed of another iron-based material.

4 . The method of claim 3 , wherein the iron-based material of the core includes carbon in an amount of 0.1 to 0.3 wt. %, based on the total weight of iron-based material.

5 . The method of claim 3 , wherein the iron-based material of the tube includes carbon in an amount of 0.1 to 0.3 wt. %, based on the total weight of the iron-based material, and the iron-based material of the tube does not include titanium or aluminum.

6 . The method of claim 1 , wherein the weld formed along the joint includes aluminum nitride and/or titanium nitride.

7 . The method of claim 6 , wherein the weld formed along the joint includes the aluminum nitride in an amount of 0.3 to 2.9 wt. % and titanium nitride in an amount of 0.3 to 2.9 wt. %, based on the total weight of the material of the weld.

8 . The method of claim 1 , wherein the second component is formed of steel.

9 . The method of claim 1 including a gas metal arc welding process, which includes the steps of forming the electric arc and transferring material of the weld wire to the joint.

10 . The method of claim 9 further including the steps of:
disposing the components in an enclosed chamber before forming the electric arc;
disposing the welding wire in a welding gun;
pointing the welding gun toward the joint between the two components; and
applying a voltage and current to the welding wire to form the electric arc between the welding wire and the components while the components are located in the enclosed chamber and while feeding the welding wire through the welding gun.

11 . The method of claim 1 , wherein the step of transferring material of the welding wire to the joint includes at least one of transferring globules of the material of the welding wire, short-circuiting, spraying the material of the welding wire, and pulse spraying the material of the welding wire.

12 . The method of claim 1 , wherein the weld is free of pores having a porosity of 1.29 mm or greater.

13 . The method of claim 1 , wherein the first component forms a can of a flexplate, and the second component forms a ring gear of the flexplate.

14 . A welded structure, comprising:
a first component formed of nitrided steel; a second component welded to the first component, wherein the weld includes aluminum nitride and/or titanium nitride.

15 . The welded structure of claim 14 , wherein the weld includes aluminum nitride and titanium nitride.

16 . The welded structure of claim 15 , wherein the weld includes the aluminum nitride in an amount of 0.3 to 2.9 wt. % and the titanium nitride in an amount of 0.3 to 2.9 wt. %.

17 . The welded structure of claim 14 , wherein the second component is formed of steel.

18 . The welded structure of claim 14 , wherein the weld is free of pores having a porosity of 1.29 mm or greater.

19 . The welded structure of claim 14 , wherein the first component forms a can of a flexplate, and the second component forms a ring gear of the flexplate.

20 . The welded structure of claim 14 , wherein the weld is formed by gas metal arc welding.

Assignees

• Magna Powertrain Usa Inc

Inventors

• Yin Guobin
• Hogan Troy K

Classifications

• B23K2103/04

  Steel {or steel} alloys · CPC title

• B23K35/3053

  Fe as the principal constituent · CPC title

• B23K26/32

  taking account of the properties of the material involved · CPC title

• B23K26/28

  of curved planar seams · CPC title

• B23K35/0255

  for use in welding (B23K35/0205 takes precedence) · CPC title