40CrMnSiMoVA钢等温淬火复合组织与韧性

MIXED STRUCTURE AND ITS TOUGHNESS OF ISOTHERMALLY QUENCHED 40CrMnSiMoVA STEEL

1.引言 合理利用复合组织是实现超高强度钢强韧化的主要途径之一。文献[2]报道了复合组织的冲击韧性α_k随下贝氏体量的增多而升高,但其断裂韧性K_(IC)却比任何一种单一组织都低。超高强度钢的α_k值和K_(IC)值随下贝氏体量增多呈现不同变化的原因,尚未见报道。本文拟通过对40CrMnSiMoVA钢的等温淬火处理,来研究其复合组织与强韧性间的关系。

The study on the microstructure and mechanical properties of 40CrMnSi-MoVA steel isothermally quenched in the temperature region from 190℃ to 320℃ is dealt with.It is found from experiments that the impact-toughness an of this steel is increased monotonically with the increasing of isothermal temperatures, but the fracture toughness KIC is varied in a saddle-backed curve with the increasing of isothermal temperature.The explanation of the inconsistency between ak and KIC values has been put forward according to the microstructural characteristics of this steel isothermally quenched at different temperatures.