Effect of intercritical annealing temperature and cooling rate on the microstructure and mechanical properties of low-carbon aluminum killed steel

In this study,the intercritical annealing process for a typical low-carbon aluminum killed steel is investigated.A cold-rolled sheet was annealed at intercritical temperatures ranging from 730 ℃ to 770 ℃ and then cooled in air or water.The annealed steel was then baked at 210 ℃,and its mechanical properties and microstructures were analyzed in detail.It is shown that after the air-cooling process,the strength of steel decreased and ductility increased with an increase in the annealing temperature.However,after water-cooling,the strength and ductility both increased with the increase of annealing temperature.These results are attributed to the propertyoptimization of the steel.