Effect of surface treatment on bonding strength of hot rolled steel aluminum clad plate

The surface of steel/aluminum clad plate was treated by 0. 3 mm steel wire brush and #180 sandpaper grinding before rolling, steel plate and aluminum plate adopt the same surface treatment. Then, it was rolled at 45% reduction rate and 450 °C rolling temperature. The rolled steel/aluminum clad plates were annealed at different times, and the steel/aluminum clad plates subjected to different surface treatments were compared for differences in bonding strength and microstructure after rolling and annealing. The surface treatment of steel wire brush formed a continuous hardened layer, and the hardened layer fragment into independent pieces during rolling. The exposed fresh steel matrix was combined with aluminum matrix to form high-strength metallurgical bonding. The surface polished with sandpaper had no obvious hardening layer, and the bonding strength after rolling was lower than that treated with wire brush. After annealing, the diffusion degree of elements at the bonding interface of clad plates subjected to different surface treatment methods increased significantly, and the bonding strength increased significantly. However, due to the oxygen concentration gradient between the steel surface hardening layer and the matrix, a new kind of iron oxide was formed between the hardening layer and the steel matrix during annealing, which connected the steel matrix and the independent hardening layer pieces, and the bonding strength increased rapidly. The research results can provide reference for the surface treatment of the hot-rolled steel/aluminum clad plate.