Pulsed-Electric-Current Bonding of Oxygen-Free Copper and Austenitic Stainless Steel

Abstract

Although pure copper has good electrical and thermal conductivity, it is often used in combination with other metals due to its poor strength. An inexpensive austenitic stainless steel that has excellent corrosion resistance is a good joining material for pure copper, and the joining of these dissimilar metals enables the fabrication of parts for a wide range of applications. However, it is difficult to weld pure copper and stainless steel due to the large differences between their thermal properties. Therefore, in this study, the pulsed-electric-current bonding was applied to achieve solid state bonding of oxygen-free copper (OFC) and SUS304 austenitic stainless steel, and the bonding characteristics were investigated. The results show that the joint tensile strength improves with the increase in the bonding temperature and the applied pressure, and the sample bonded at 973 K with an applied pressure of 20 MPa exhibited a high strength of greater than 200 MPa, which caused a fracture in the OFC base material.

Effect of Tool Geometry on the Microstructure of Friction Stir Welding of Copper and 316L Stainless Steel

“…Merging these properties in one single piece is particularly attractive in heat exchanger industry as well as in specific issues within the International Thermonuclear Fusion Experimental Reactor (ITER) project. [1,2] The joining of copper and stainless steel can be performed using various processes: electron beam welding, [3] explosion bonding, [4,5] spark plasma sintering, [6] hot isostatic pressing, [1,2,7] diffusion bonding, [8][9][10][11] or friction stir welding (FSW). [12][13][14][15][16][17] All these techniques, except for electron beam welding, belong to solid-state welding processes.…”

“…The joining of copper and stainless steel can be performed using various processes: electron beam welding, [ 3 ] explosion bonding, [ 4,5 ] spark plasma sintering, [ 6 ] hot isostatic pressing, [ 1,2,7 ] diffusion bonding, [ 8–11 ] or friction stir welding (FSW). [ 12–17 ] All these techniques, except for electron beam welding, belong to solid‐state welding processes.…”

Spark plasma welding joining of copper- AISI4140 steel: Microstructures and mechanical properties

“…However, in the research conducted by Oliveira et al [ 29 ], due to the precipitation of the alpha phase and the increase of strength in the fusion zone and HAZ, failure did not occur in these areas. Welding processes in the solid state can resolve the problems related to arc welding to some extent, providing the possibility of achieving a suitable joining strength [ 30 ]. Of course, there are limitations in carrying out the process and the dimensions and geometry of the parts.…”

“…By applying the pulsed DC current, plasma is formed at the interface of the contact areas of the pieces [ 33 ]. Thus, through the concurrent application of pressure and pulsed current, atomic diffusion occurs at the interface, leading to the possibility of joining different materials within a shorter time [ 30 ].…”

The Joining of Copper to Stainless Steel by Solid-State Welding Processes: A Review

“…Thus, bimetallic joints [ 12 , 13 , 14 , 15 , 16 , 17 ] are necessary, especially in a vacuum [ 18 , 19 , 20 , 21 , 22 , 23 ] and cryogenic systems [ 24 , 25 , 26 , 27 ]. Because of the unique combination of distinct properties, copper/stainless-steel bimetals are in great demand [ 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. Stainless steel (SS) combines high strength, low thermal diffusivity, reasonable ductility, and eliminates ductile-to-brittle transitional behaviour.…”