A unified model for isothermal and non-isothermal phase transformation in hot stamping of 22MnB5 steel

The hot stamping of tailored properties is widely established in the automotive industry. However, unlike conventional press hardening, this technique designed to generate varying mechanical by controlling cooling rate locally. Current material models cannot accurately represent locally very different thermomechanical paths. This research aims address problem developing a new phase transformation model capable handling complicated thermal histories and effects deformation. A ’unified JMAK‘ proposed capture various thermal-mechanical loading conditions. These conditions include deformation effect paths where isothermal range from 450° 725°C non-isothermal 5° 40°C/s. Furthermore, for extension linear non-linear paths, correction factors transformations are introduced into model. Finally, model's performance compared well-known models, such as JMAK K-V (Kirkaldy Venugopalan), comparing results obtained dilatometer tests scaled-down b-pillar experiment. comparison classified 3 cases, isothermal, continuous (b-pillar). Case 1 shows that provide low accuracy, while yields an error below 2 %. For 2, non-iso agreeable with experiment, maximum 15 case study mean absolute errors hardness predictions 33.06 HV (mean relative 9 %), 43.92 (13 67.70 (20 %) unified JMAK, model, respectively.