First results on the characterisation of the reduced-activation-ferritic-martensitic steel EUROFER

Reduced activation ferritic/martensitic (RAFM) steels are being considered for structural application in potential fusion energy systems. Based on the substantial experience with RAFM developmental steels of OPTIFER type, an industrial 3.5 tons batch of a 9CrWVTa-RAFM steel, called EUROFER 97 had been specified and ordered. A characterisation programme has now been launched to determine the relevant mechanical and physical-metallurgical properties in order to qualify it for fusion application. The hardening, tempering and transformation behaviour of EUROFER is in good agreement with that of other RAFM-steels like OPTIFER and the Japanese industrial scale heat F82H mod. Tensile tests, performed between RT and 750 °C, show comparable strength and ductility values that are not strongly affected by ageing at 580 and 600 °C up to 3300 h. Impact bending tests indicate a superior ductile to brittle transition temperature (DBTT) of EUROFER in the as-received condition compared to that of F82H mod. First results of creep tests between 450 and 650 °C up to test times of 4000 h reveal a creep strength similar to OPTIFER and F82H mod. The first results of the investigations show that it is possible to transfer the good mechanical and structural properties of precursor laboratory melts to an industrial scale melt.