As reported in the previous report, increasing velocity by high-speed impulsive energy could improve the formability of AZ31 magnesium alloy. The improvement of ductility of AZ31 magnesium alloys can be observed, which is difficult to observe in usual cold forging techniques. This paper (Part II) is a coutinuation of the reported work in the previous paper. The forming of the AZ31 casting magnesium alloy was done. The hardness distribution of the test specimen was investigated for each experiment, and the microstructures are analyzed. The microstructural results indicate that adiabatic shear bands are formed and the microstructure is changed by the formation of huge amount of fine grained recrystallized structure. Furthermore, solid state is retained in the materials as well as the surface.