Effect of boron element on microstructure and formability of interstitial free steel

The effects of boron element on the microstructure, texture and mechanical properties of IF steel were analyzed by using optical microscope, electron backscatter diffractometer and tensile testing machine. The effects of boron element on the formability of IF steel were analyzed by using online strain measurement system and forming testing machine. The results show that adding boron element to IF steel could significantly refine the grain size of IF steel structure, reduce the content of 111 texture components, increase the yield strength and tensile strength of IF steel, and reduce the plastic strain ratio. It was helpful for the two forming methods of IF steel plane strain and equal biaxial tensile strain, and improved the stamping qualification rate of IF steel in complex forming parts mainly based on stretch forming.