Manufacturing copper-stainless steel composite tube by pressure bonding

Abstract

Pressure bonding technique was applied for joining stainless steel and copper tubes radially. During processing, stainless steel outer tube was held in the die, copper inner tube was inserted inside the stainless steel tube and connected to a gas pressure system at one end; other end was sealed and closed. Gas pressure was applied through the inner tube, and the total assembly was heated in the muffle furnace. Due to temperature and pressure, copper tube expanded radially and joined with stainless steel tube. To avoid oxidation, the entire work was carried out in nitrogen atmosphere. At 900°C temperature and 30MPa pressure, copper to stainless steel joint was achieved with maximum strength. Joint strength, microstructure, hardness and elemental analysis were carried out after bonding and the results were discussed in detail.