Abstract: The role of adiabatic shear bands within fragments of tubular steel ballistically loaded by explosive is investigated. The results show that adiabatic shear band is formed during dynamic expansion of tubalur steel. The steel cylinder fractures preferentially along the adiabatic shear bands. Using transmission electron microscope, fine microstructure of adiabatic shear band within the fragments has been observed. Within the adiabatic shear band, the microstructure was seen to be comparatively complex. In the center of the shear band, the equiaxial grain microstructure was formed, which could be attributed to dynamic recrystallization. The occurrence of dynamic recrystallization in adiabatic shear band showed that adiabatic temperature rise in the shear band was very high, whose softening effect gave rise to steel cylinder fracturing preferentially along the adiabatic shear bands.