CMT arc-assisted thermo-compensated resistance brazing welding immiscible pure copper to 304 stainless steel

Abstract

• The optimized Cu/steel interface was achieved by CMT pre-surfacing. • High-strength joints fractured in the Cu base metal were obtained. • The resistance brazing feature was manifested by molten amorphous alloy foil. The high-strength Cu alloy/stainless steel joints were obtained by a novelty hybrid welding technology (CMT arc-assisted thermo-compensated resistance brazing welding). Experimental results indicated that the traditional Cu/steel connection was converted into the Cu/Cu connection in the final welding process successfully utilizing the Cu insert layer by pre-surfacing. The maximum temperature of the welded joints in the whole process was less than the melting point of the base metal but greater than the melting point of the interlayer, achieving the brazing feature. Cu solid solutions (s.s), Fe 2 Si intermetallic compound (IMC), and a mechanical interlock were comprised at the interface, resulting in all the tensile-shear specimens fractured at the Cu base metal.