Rapid determination of the S-N curve of Wire + Arc additively manufactured steel by infrared thermography

Wire + Arc Additive Manufacturing (WAAM) enables additive manufacturing of metals using electric arc welding. For widespread adoption, mechanical properties like fatigue performance must be characterised and benchmarked against conventionally manufactured materials. This research presents S-N curves from rotating bending fatigue tests on specimens produced from T50 6 1Ni M M21 1 H5 steel feedstock wire. No significant anisotropy was found between deposition and build directions, and fatigue performance exceeded reference curves from standards. Additionally, a rapid method for determining S-N curves using a specimen's surface temperature during stepped amplitude testing is proposed. While more data is needed for robust analysis, the mean S-N curves show good agreement with conventionally determined curves.