Question

The effective length of filet weld should not be less than:
1. Two times weld size
2. Six times weld size
3. Weld size
4. Four times weld size

Answer 1

Correct Answer - Option 4 : Four times weld size

Concepts:

A minimum effective length of weld is four times the size of weld.

When placing a fillet weld, though the welder tries to build up the weld to its full dimension from the beginning, there is always a slight tapering off where the weld starts and where it ends. The width of this tapering is called end returns and is equal to two times the size of weld on either side of welding. This tapered portion of weld is not able resist or carry any load hence cannot be the part of weld length. Therefore, the length of weld which is actually effective to resist loads, called effective length, is taken as overall length of weld minus two times the size of weld in case fillet weld as per IS 800:2007 codal provisions.

Note:

1. The effective length of weld is taken equal to overall length of weld minus twice the size of weld.  This is done to avoid stress concentration at ends.
2. To avoid stress concentration at edges of plate, the length of longitudinal (side) fillet weld shall not be less than the width of plate.
3. The perpendicular distance between longitudinal fillet welds is limited to 16 times the thickness of the thinner plate jointed.
4. In case of Groove weld in butt joints, the effective length is taken as the length of continues full size weld, but in no case, it should not be less than the four times the size of weld.