Quantification of bake hardening effect in DP600 and TRIP700 steels

• Effect of bake hardening was quantified on DP600 and TRIP700 steels.
• Effect of prestrain, BH holding time and temperature is studied on the mechanical properties.
• Amount of retained austenite in TRIP700 was described as a function of BH time.

Recently developed advanced high-strength steels with multiphase microstructures show interesting bake-hardening (BH) properties. This research work aims to quantify the effect of BH on dual-phase (DP) and transformation induced plasticity (TRIP) steel. Different pre-strains from 0% to 10% with a subsequent BH annealing cycle with temperatures of 60–220 °C for varying BH holding times from 1 to 10,000 min were applied for both materials. Mechanical properties such as yield and tensile strengths, elongation and BH values in dependency of the BH parameters have been determined and related to specific microstructural features in order to characterize the age and strain hardening behavior.