Effect of BainiticTreatment on Microstructure and Mechanical Properties of TRIP Cold-Rolled Steel Sheets

The effects of bainitic treatment on microstructure and mechanical properties of 0.10C-1.5Mn-1.5Al TRIP-aided cold-rolled steels have been investigated. The samples were heated by intercritical annealing at 820 degrees C for 2 min and quenched in banitic temperature with different hoding time for 5 to 300s, two salt bath were used for the heat treatment. Experimental results show that the yield strength and elongation increase with the increasing of bainitic holding time, while the tensile strength decrease. The volume fraction of retained austenite rise at the beginning of bainitic holding and then reduce, the carbon content of retained austenite increase during the bainitic holding. The tensile strengthen multiply elongation reaches the highest value at 120s. The mechanical stability of retained austenite fits well with strain hardening during deformation.