Method for stack-welding dissimilar metal members

• US 11,413,706 B2
• Filed: 10/07/2019
• Issued: 08/16/2022
• Est. Priority Date: 10/26/2018
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kobayashi, Hiroomi, Shibata, Yoshinori, Nakayama, Hiroyuki
• Primary Examiner(s): Kosanovic, Helena
• Assistant Examiner(s): Samuels, Lawrence H
• Application Number:
  US16/594,442
• Publication Number:
  US 20200130100A1
• Time in Patent Office: 1,044 Days
• Field of Search: 219118
• CPC Class Codes: B23K 2103/10 Aluminium or alloys thereof
• CPC Class Codes: B23K 2103/12 Copper or alloys thereof
• CPC Class Codes: B23K 2103/18 Dissimilar materials
• CPC Class Codes: B23K 26/21 by welding
• CPC Class Codes: B23K 26/244 Overlap seam welding
• CPC Class Codes: B23K 26/323 involving parts made of dissimilar metallic material

Abstract

A method for stack-welding dissimilar metal members by placing a first metal member and a second metal member having a melting point higher than that of the first metal member on top of one another and performing laser welding is provided. The second metal member is placed on the first metal member, and a molten pool in which only the second metal member is melted is formed by applying a laser beam for thermal-conduction welding from above the second metal member. After the molten pool comes into contact with the first metal member and hence the first metal member melts in the molten pool, the molten pool solidifies, so that the first and second metal members and are welded together.

Claims

1. A method for stack-welding dissimilar metal members by placing a first metal plate and a second metal plate having a melting point higher than that of the first metal plate on top of one another and performing laser welding, the method comprising:

placing the second metal plate having the higher melting point on the first metal plate, such that when the second metal plate is placed on the first metal plate prior to the irradiation with the laser beam, a gap is formed directly below an angled portion of the second member, between the first and second metal plates in a place where the laser beam is applied above it, and forming a molten pool in which only the second metal plate is melted, including the angled portion of the second metal plate, by applying a laser beam for thermal-conduction welding from above the second metal plate to the second metal plate only,

wherein after the molten pool comes into contact with the first metal plate and the first metal plate melts in the molten pool only via heat conduction from the molten pool without the laser beam being further applied, and creating a combined molten pool, the combined molten pool solidifies, so that the first and second metal plates are welded together.

2. The method for stack-welding dissimilar metal members according to claim 1, wherein

the first metal plate is made of a metallic material containing aluminum as a main component, and

the second metal plate is made of a metallic material containing copper as a main component.

3. The method for stack-welding dissimilar metal members according to claim 2, wherein the laser beam is applied under a condition in which for irradiation energy [J] of the laser beam, a time [ms] from the end of the irradiation with the laser beam to the completion of the solidification of the molten pool is 0.2 [ms/J] or shorter.