Method For Laser Welding End Faces

Patent metadata

Field	Value
Publication number	US-2019375047-A1
Application number	US-201816487383-A
Country	US
Kind code	A1
Filing date	Mar 19, 2018
Priority date	Mar 20, 2017
Publication date	Dec 12, 2019
Grant date	—

Abstract

The invention relates to a method for laser welding the end faces of joints (2, 2.1) of two connecting flanges, which are held against each other, of two connecting partners (1, 1.1) made from a steel material, of which at least one is provided with a metallic coating with an evaporation temperature that is below the melting temperature of the steel material. The method is carried out such that, for the process of laser welding, the connecting flanges (1, 1.1) of the two connecting partners (1, 1.1) are held against each other enclosing an angle that opens pointing in a direction from the joint side on which the laser is applied, as a result of which a degassing gap (5), which increases in the direction of heat introduction, is provided between the connecting flanges (3, 3.1), through which degassing gap evaporation products of the coating material (8, 8.1) resulting from the introduction of heat are carried off.

First claim

1 . A method for laser welding the end faces of joints ( 2 , 2 . 1 ) of two connecting flanges, which are held against each other, of two connecting partners ( 1 , 1 . 1 , 1 . 2 , 1 . 3 ) made from a steel material, of which at least one is provided with a metallic coating with an evaporation temperature that is below the melting temperature of the steel material, characterized in that, for the process of laser welding, the connecting flanges ( 1 , 1 . 1 , 1 . 2 , 1 . 3 ) of the two connecting partners ( 1 , 1 . 1 , 1 . 2 , 1 . 3 ) are held against each other enclosing an angle that opens pointing in a direction from the joint side on which the laser is applied, as a result of which a degassing gap ( 5 ), which increases in the direction of heat introduction, is provided between the connecting flanges ( 3 , 3 . 1 , 3 . 2 ), through which degassing gap evaporation products of the coating material ( 8 , 8 . 1 ) resulting from the introduction of heat are carried off.

2 . The method according to claim 1 , characterized in that the connecting flanges ( 3 , 3 . 1 , 3 . 2 ) are held in a linear contact against each other in the region of their mutually facing joint edges ( 2 . 2 , 2 . 3 ) for performing the laser welding.

3 . The method according to claim 1 or 2 , characterized in that the connecting flanges ( 3 , 3 . 1 , 3 . 2 ) are held at an angle between 1° and 20° inclined to each other.

4 . The method according to any one of claims 1 to 3 , characterized in that the laser spot incident on the joints ( 2 , 2 . 1 ) is set with a diameter which is greater than the maximum gap width between the connecting flanges ( 3 , 3 . 1 , 3 . 2 ) in the region of the joints ( 2 , 2 . 1 ), which are held against each other, wherein the width of the degassing gap ( 5 ) increases starting from the maximum gap width.

5 . The method according to any one of claims 1 to 4 , characterized in that the laser beam ( 6 . 1 ) is directed onto the connecting zone of the joints ( 2 , 2 . 1 ) transversely to the feed direction, while being inclined with an inclination angle which is not greater than 25 degrees.

6 . The method according to any one of claims 1 to 5 , characterized in that an air flow flowing transversely with respect to the direction of the laser beam and guided by the laser beam is provided on that side of the joint, on which the laser beam is applied.

7 . The method according to any one of claims 1 to 6 , characterized in that the laser beam is oscillated back and forth transversely to the feed direction following the longitudinal extension of the joints.

8 . The method according to claim 7 , characterized in that the oscillation frequency of the laser beam does not exceed 1000 Hz.

9 . The method according to claim 7 or 8 , characterized in that the path amplitude of the oscillation movement of the laser beam does not exceed two thirds of the joint surface width formed by the joints, which are held against each other.

10 . The method according to any one of claims 1 to 9 , characterized in that the connecting zone of the joints ( 2 , 2 . 1 ) intended for melting is gradually preheated in the feed direction before melting.

11 . The method according to claim 10 , characterized in that the laser beam is directed with a leading orientation onto the connecting zone at an angle between 5° and 45° with respect to the perpendicular.

12 . The method according to any one of claims 1 to 11 , characterized in that the metallic coating of the at least one connecting partner is a zinc coating ( 8 , 8 . 1 ).

13 . The method according to any one of claims 1 to 12 , characterized in that the width of the connecting zone to be melted is smaller than the width of the joint surface formed by the joints ( 2 , 2 . 1 ) held against each other, and that the laser beam ( 6 , 6 . 1 ) is guided in such a way that, at both joints ( 2 , 2 . 1 ), an outer edge region for forming a respective weld pool support is not melted.

Assignees

• Kirchhoff Automotive D Gmbh

Inventors

• Stuhrmann Jan
• Dahmen Christian

Classifications

• B23K2103/04

  Steel {or steel} alloys · CPC title

• B23K26/322 Primary

  involving coated metal parts (using absorbing layers on the workpiece B23K26/18) · CPC title

• B23K2101/34

  Coated articles {; Surface treated articles} · CPC title

• B23K26/16 Primary

  Removal of by-products, e.g. particles or vapours produced during treatment of a workpiece (by a fluid stream B23K26/142) · CPC title

• B23K26/26

  of rectilinear seams · CPC title