Microstructure and mechanical properties of induction rolling welded joint for A283GRC steel and 5052 aluminum alloy

In order to realize the welding of Fe/Al composite structure of automobile body, an induction rolling welding (IRW) was proposed. In this method, the eddy current and rolling force were generated by an induction heater and a rolling device respectively, which were applied on the steel surface together. The Fe/Al welded joint under the combined action of eddy current heat and rolling force can be formed. The input power, feed velocity and rolling force were considered in this process. The results showed that IRW can realize the welding of A283GRC steel and 5052 aluminum alloy successfully. A continuous, uniform macroscopic morphology of welded joint and an optimal shear strength with 75 MPa can be obtained with the power 35 kW, the feed velocity 1 mm/s, and the rolling force 800 N. The intermetallic compound (IMC) in the welded joint consists of a lingulate Fe2Al5 towards the steel matrix and a saw-tooth FeAl3 towards the aluminum alloy matrix. The Fe2Al5 phase has the smallest Gibbs free energy and is the first to be generated at the interface. The weld joint width and IMC thickness in the IRW process increase with increasing power and decreasing feed velocity due to a larger heat input and longer heating time while increases with increasing rolling force due to a higher heat conducting efficiency. The shear strength can be increased significantly with increasing rolling force, due to a more contact area on the interface and a finer grain near the interface, which can prevent cracking effectively.