Fillet Weld Strength

The effective throat of an equal-leg fillet weld is 0.707 × leg size. The allowable load = throat × weld length × allowable shear stress. AWS D1.1 allows 0.30 × the electrode tensile strength (E70 = 482 MPa gives 145 MPa; E60 gives 124 MPa). This is a hand-calc estimate — structural welds need code design.