Physical metallurgy and mechanical behaviour of FeCrWTaV low activation martensitic steels : Effects of chemical composition

Abstract This paper essentially deals with chemical composition effects on metallurgical and mechanical behaviour of Fe–7.5/11CrWVTa low activation martensitic steels. Materials investigated are experimental alloys as well as large-scale heats having different contents of Cr (7.5–11%), Ta (0–0.1%), W (0.8–3%) and interstitial elements, like carbon (0.09–0.17%) and nitrogen (0.004–0.045%). For this purpose, phase transformation during heating and cooling have been investigated in anisothermal and isothermal conditions to establish the corresponding Continuous Cooling Transformation (CCT) and Time–Temperature-Transformation (TTT) diagrams. Austenitisation (normalisation) and tempering treatments were performed in a wide range of temperatures. Tensile and impact properties as a function of composition and metallurgical conditions have been determined and compared to 9Cr–1Mo conventional martensitic steels.