Twin-roll strip casting of AZ61 magnesium alloy and improvement of formability by structure-control rolling

Continuous strip casting and direct rolling method are receiving attention as the integrated producing process to obtain wrought magnesium alloys. In this research, AZ61 strip was cast from molten metal by twin-roll strip caster and rolled by “Structure-Control rolling process”. The effects of casting conditions and rolling parameters on surface aspects and microstructure of the rolled sheet were investigated. The results obtained were as follows: (1) By casting 1.5 mm strip, a better surface and finer microstructure were obtained compared to 3 mm strip. (2) By using structure-control rolling with R.T. pass, a microstructure of mean grain size of 5 μm was obtained. (3) By lowering the starting rolling temperature, mean grain size and duplex grain size degree decreased and hardness increased. In addition, the deformation resistance decreased and the fracture strain increased.