(S297 )Strengthening of low carbon steel by nano-sized VC in ferrite and tempered martensite

摘要

Commercial ferritic steels are normally strengthened by precipitation of nano-sized alloy carbide due to its excellent contribution to strength-ductility balance. Generally, nano-sized alloy carbides in steels can be obtained by two different ways, i.e. by interphase precipitation during austenite/ferrite transformation or by tempering of martensite. Our previous study on a V-added low carbon steel revealed that with the same condition of isothermal treatment, the hardness of tempered martensite is higher than that of ferrite, although the dispersion of VC in ferrite formed by interphase precipitation is relatively finer [1]. In this study, tensile tests and microstructural analyses were performed on those isothermally transformed and tempered specimens, in order to compare their mechanical properties and to clarify the strength contributions by various factors.