Precipitation in low carbon steel microalloyed with Nb for automotive wheel

Carbonitride precipitation behavior of Nb microalloyed steel during holding at high temperature and low temperature was studied through thermal simulation.The results show that in high temperature region incubation period is necessary for strain induced NbC precipitation,and increasing the holding temperature leads to an increase of precipitation.Simple precipitation changes to complex precipitation when holding for 300 s at high temperature.Meanwhile,complex precipitation converges and grows,the amount of precipitation decreases and the shape of precipitation changes with the increasing of holding temperature.In low temperature region,the amount of precipitation goes higher appreciably with holding temperature and time.The size of precipitation increases little with increasing holding time.