Investigation of hot rolled galvanised steel without acid pickling

Abstract

Hot rolled galvanised steel via hydrogen reduction in oxidation scale, instead of acid pickling, has been studied. X-ray diffraction and SEM results show that scale reduction could be almost completed at 900°C for 4 min in a mixing atmosphere of 50%H₂–50%N₂. The reduction kinetics was estimated by measuring scale thickness, indicating that the scale reduction process might be a diffusion controlled reaction. Bending tests demonstrate that hot rolled galvanised steel at 600°C exhibits superior coating adherence compared to conventional coating.