Weld Size & Weld Groups

Equal-leg fillet: effective throat a = 0.707·leg; direct shear τ = P/(a·L). Units: leg and length in mm, load in N → stress in MPa.

This sizes a weld against an allowable stress you supply. For the rest of a weldment: code capacity and minimum sizes in Fillet Weld Capacity, heat input, carbon equivalent and preheat, weld metal and consumables, and weld fatigue.

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Eccentric weld group (weld as a line)

The weld is treated as a line, so A_w and J_u are per unit throat and the patterns are Shigley’s Table 9–1. Direct and torsional shear combine vectorially at the critical point. On an L or a channel the centroid is not the middle of the bounding box, and the eccentricity below is measured from that centroid — the figure shows both.