Hot roll bonding of Al–Pb-bearing alloy strips and steel sheets using an aluminized interlayer

This article describes a study of the application of a hot roll bonding technique to Al–Pb-bearing alloy strips and steel sheets using an aluminized interlayer. It was found that the overall bond between these two metals resulted from two different types of bonds: a “block” bond, linking the Al–Pb alloy strips and aluminum topcoat layer to the Fe–Al intermetallic compound, and a “blank” bond, linking the Al–Pb alloy strips and aluminum topcoat layer to the bare steel surface in the area where the block has separated from the steel substrate. The study investigated the effects of dipping time on the thickness of the intermetallic layers and of the area fraction of blank bond on the bond strength. The overall bond strength depends mainly on the strength and the area fraction of the blank bond. A linear relationship exists between the overall bond strength and the area fraction of blank bond. The bond strength of the blank bond is four times greater than that of the block bond. The area fraction of the blank bond increases with increasing intermetallic thickness up to a thickness of 73 μm, but thereafter decreases due to the rotation of the intermetallic blocks.