Copper Clad Steel Strips Produced by a Modified Twin-Roll Casting Process

Abstract

Twin-roll strip casting of steel provides a resource and energy efficient way to produce thin hot strips directly from the liquid phase. Clad metals offer less costly alternatives to monolithic alloys for a wide range of applications, but their various production routes are extensive, expensive, or slow. In order to exploit the strengths of twin-roll strip casting to provide a possibly more cost and energy efficient production route for clad thin strips, research into the expansion of twin-roll strip casting process is conducted. The aim of the current research is the combination of steel with copper. For this purpose, a prefabricated cladding strip of commercially pure copper is inserted into the twin-roll strip casting process. Bonding between the copper strip and the cast steel strip (DC01) is realized by exploiting the process heat. The bonding zone of the clad strip is subsequently analyzed under the optical microscope and in the electron micro probe analyzer. The imagery shows an irregular bonding interface with straight and locally altered regions alternating. These irregularities can be classified into four groups based on their morphology and suspected forming mechanism. Bond strength and formability of the clad strips is qualitatively examined in rolling and bending tests. Rolling was possible without delamination and a total height reduction of approx. 40% while defect-free bending of 2 mm and 3 mm thick specimens was possible up to a bending angle of 90° for a bending radius of 5 mm.