High-temperature strength analysis of welded joint of RAFs by small punch test

Type IV creep damage has recently been a worldwide issue for high Cr ferritic steels. The small punch (SP) creep test has been successfully applied to evaluate this damage of low alloy ferritic steel by the author’s group. However, the heat affected zone (HAZ) of fusion reactor material welded by electron-beam (EB) welding is so thin that it is not easy to evaluate its mechanical properties by the conventional SP test. In this study, the SP test using a further miniaturized specimen was applied to the EB welded joint of reduced activation ferritic steel (RAFs), for evaluating high-temperature tensile properties of the HAZs. As the result, the σy and σB of the tempered HAZ at 873 K were estimated to be as low as 275–300 MPa and 325–340 MPa, respectively.