Mechanical properties of 9Cr–1W reduced activation ferritic martensitic steel weldment prepared by electron beam welding process

• Width of HAZ is smaller in the 9Cr–1W RAFM weldment prepared by EB process compared to that reported for TIG weldments in literature.
• Weld joint is stronger than that of the base metal.
• Toughness of weld metal prepared by EB welding process is comparable to that (in PWHT condition) prepared by TIG process.
• DBTT of as-welded 9Cr–1W RAFM weldment prepared by EB process is comparable to that reported for TIG weld metal in PWHT condition.

Microstructure and mechanical properties of the weldments prepared from 9Cr–1W reduced activation ferritic martensitic (RAFM) steel using electron beam welding (EBW) process were studied. Microstructure consists of tempered lath martensite where precipitates decorating the boundaries in post weld heat treated (PWHT) condition. Lath and precipitate sizes were found to be finer in the weld metal than in base metal. Accordingly, hardness of the weld metal was found to be higher than the base metal. Tensile strength of the cross weldment specimen was 684 MPa, which was comparable with the base metal tensile strength of 670 MPa. On the other hand, DBTT of 9Cr–1W weld metal in as-welded condition is similar to that reported for TIG weld metal in PWHT condition.