Effect of microstructure on void nucleation and coalescence during forming of three different HSLA steel sheets under different stress conditions

The microstructure of any metal influences the void formation statistically. The geometrical nature and the distribution of the second phase particles viz. carbides, sulphides, etc. and inhomogeneities present in the microstructure play a vital role in determining mode of void formation during fracture. The analysis of microstructure and its impact on void nucleation, their growth, and coalescence during the fracture of three different HSLA steel sheets of different thicknesses is presented in this work. The analysis shows that the criterion of void nucleation and coalescence depends on geometrical shape factor or aspect ratio (L/W) of both ferrite grains and second phase particles.