Mechanical properties of friction stir welded 11Cr-ferritic/martensitic steel.

Abstract: Friction stir welding was applied to the wrapper tube materials, 11Cr-ferritic/martensitic steel, designed for fast reactors and defect-free welds were successfully produced. The mechanical and microstructural properties of the friction stir welded steel were subsequently investigated. The hardness values of the stir zone were approximately 550Hv (5.4GPa) with minimal dependence on the rotational speed, even though they were much higher than those of the base material. However, tensile strengths and elongations of the stir zones were high at 298K, compared to those of the base material. The excellent tensile properties are attributable to the fine grain formation during friction stir welding. [Copyright &y& Elsevier]