How To Calculate Welding Leg Length. Fig1 illustrates how simple this calculation is for an equal leg length fillet weld. TW of the theoretical throat design throat thickness and effective weld length as shown in Fig.
When using this formula do not forget that welders seldom deposit precisely the size of weld called up on the drawing or in the welding procedure and that there may be some excess weld. Length of weld required 30 in. Fillet weld sizes are measured by the length of the legs of the largest right triangle that may be inscribed within the fillet weld.
Z a X 1414.
Leg length s of the weld can be calculated from the following equation. Z a x sqrt 2 2. Failing this as a rule-of-thumb at least two passes should be deposited with a minimum leg length of 6mm 14in considering that the first run is likely to be defective. See BS EN ISO 25532019 for further information on symbolic representation of fillet welds.