Static Softening Behavior of Low Carbon High Niobium X100 Pipeline Steel

The static softening behavior of low carbon high niobium X100 pipeline steel was studied by double pass hot compression test carried on thermal simulator. The static recrystallization kinetics model of the low carbon high niobium high strength pipeline steel was established. The results show that the static softening behavior of the tested steel was distinctly affected by deformation temperature and interval time. With the increase of deformation temperature and prolongation of the interval time, the static softening rate of the tested steel increased. When the deformation temperature was below 950℃, static recrystallization behavior did not occur.When the deformation temperature was higher than 1 000℃, the tested steel achieved complete static recrystallization. The activation energy of static recrystallization of the steel was 325 kJ·mol^-1 which calculated by the kinetics model. And the result was consistent with that calculated by the empirical formula based on the chemical composition.