Regular Article

TIG welding-brazing joints of aluminum-stainless steel with different thickness of base metals

¹ Department of Mechanical Engineering, Shandong Jiaotong University, Jinan 250023, PR China
² State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, PR China

^* e-mail: welderhehuan@yahoo.com

Received: 30 April 2018
Accepted: 17 October 2018

Abstract

The aluminum and stainless steel plates with different thickness (1.5, 3 and 4 mm) were joined by TIG welding-brazing process, respectively. The welding procedures, appearance, microstructures and mechanical behavior of the joints were investigated and analyzed. Results showed that reliable welding-brazing joints could be obtained with appropriate welding procedures. The thicker the base metal, the thicker the intermetallic compound (IMC) layer, and the lower the mechanical properties of the joints. There existed obvious microstructure and strength nonhomogeneity along the interface from the top to the bottom of the joint with 3 mm or thicker base metals. The fracture positions of the joints were different from each other. With 1.5 mm base metal, fracture occurred at the aluminum fusion side. While with 3 mm base material, fracture derived from the IMC layer at the root of the steel groove and subsequently occurred at the welded seam. Using 4 mm base metal, crack located mainly at the brazing interface. The differences of the mechanical behavior of the joints were mainly attributed to the change of IMC thickness.