New weld toe magnification factors for semi‐elliptical cracks in plate‐to‐plate butt‐welded joints

British Standard 7910:2013 includes a single set of equations for estimating the weld toe magnification factor ( M k ) of different types of welded joints with a semi‐elliptical surface crack. In this study, extensive finite element analyses are performed to determine the M k of plate‐to‐plate butt‐welded joints subjected to axial and bending loading. The M k values at the crack deepest points and the crack ends are determined. It is found that the M k results of butt welds are different with those of single T‐butt joints with percentage difference in values being as high as 63.8% and 97.4% for axial and bending loading cases, respectively. Percentage differences of 60.4% and 358.2% for axial and bending loading cases are observed between butt welds and X‐joints. New M k equations for butt welds are proposed using multiple regression analyses.