Weld Length Calculator
Calculate the minimum fillet weld length required to carry a given load based on weld size and allowable shear stress.
Minimum Weld Length
0.00 in
Minimum Weld Length vs Applied Load
Formule
## Fillet Weld Length **L = P / (t x Fv)** Where P is the applied load, t is the effective throat (0.707 x leg size for a 45-degree fillet), and Fv is the allowable shear stress on the weld metal. For E70 electrodes, Fv = 0.30 x 70,000 = 21,000 psi.
Exemple Résolu
10,000 lb load, 1/4-inch fillet weld, E70 electrode.
- 01Throat = 0.25 x 0.707 = 0.177 in
- 02Capacity = 0.177 x 21,000 = 3,713 lbs/in
- 03Min length = 10,000 / 3,713 = 2.69 in
- 04Use at least 3 inches of weld.
Questions Fréquentes
What does 0.707 represent?
For a 45-degree fillet weld, the shortest distance through the weld (the throat) is the leg size multiplied by sin(45) = 0.707. The throat is the weakest cross-section.
What is the minimum weld length?
The AISC requires minimum weld length of 4 times the weld size or 1.5 inches, whichever is greater. Very short welds may not develop full strength due to start/stop effects.
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