Effect of Mn content on mechanical properties of hot-rolled Ti-bearing low carbon high strength steels

摘要

The effect of Mn content on mechanical properties of hot-rolled Ti-bearing low carbon steels were investigated from the viewpoints of cementite dispersion, voids nucleation at cementite/ferrite interface and their coalescence process. The increase in tensile strength with increasing Mn content was attributed to the finer precipitation of TiC and the ferrite grain refinement in addition to solid solution hardening, but the excessive addition of Mn from 0.8mass% hardly affected ferrite grain refinement. The best balance of tensile strength and total elongation was obtained at Mn content of 0.8mass% because of the marked decrease in post-uniform elongation with higher Mn addition. The marked decrease in post-uniform elongation with addition of Mn above 0.8mass% is attributed to increased precipitation hardening by TiC which reduce deformability of ferrite grain and accelerate void coalescence.