Continuous reducing and sizing process of hot rolled steel-copper clad tube

Steel-copper clad tubes with small diameters and super lengths are in widespread used as heat exchange elements because of good performances of corrosion resistance, thermal conductivity, and high strength. The key problems affecting clad tube quality are poor dimensional precision and low adhesion strength. In this paper, these problems were analytically solved by performing continuous reducing and sizing through Y-type rolling. The main procedure involved pretreatment, assembling, heating, continuous rolling, and heat treatment. The changes in diameter and wall thickness distributions of the external and internal tubes were predicted by executing a finite simulation for steel-copper clad rolling. Rolling trials were then conducted on the clad tube for the comparison of the simulation and real rolling results, both of which indicated the good compatibility between the shape and dimensions of the finished tube. Finally, the bonding surface was observed byVhx-2000 ultra-depth of field microscope. The adhesion strength of the steel-copper tube was checked on WDW-E100D electronic universal tensile machine. The result showed that the hot fusion has occurred on the surface of steel-copper, and the clad tube rolled from the Y-type mill was strong and the adhesion strength has far exceeded the requirement.