1994 Volume 80 Issue 12 Pages 938-943
The Effects of insoluble carbide on the microstructure and hardness of martensitic stainless steels were investigated in 12%Cr-(0.10.4%)C steels. In high carbon steels, carbide does not dissolve into austenite fully at a solution treatment temperature around 1300K and the insoluble carbide affects the mechanical properties of martensite at room temperature. By means of hardness testing in specimens solution-treated at different temperatures (T;K), the solubility of carbon in austenite ([C];mass%)was given by the equation ; log [C]=-6100/T +4.1. The relation between volume fraction of insoluble carbide (F;vol%) and carbon content of steels (C;mass%) was given by the equation ;F=20(C-[C]) by taking the densities of carbide and martensite into consideration. The contribution of insoluble carbide was added to the hardness of martensite matrix, so that the hardness of martensitic steels with insoluble carbide (Hv*) was represented by the equation ; Hv*=25+1250√[C]+500(C-[C])
