Fillet weld sizes are measured by **the length of the legs of the largest right triangle that may be inscribed within the fillet weld cross section**.

What is the maximum size of the fillet weld?

- The maximum size of fillet weld will be=
**0.7 x T**, where T is the base metal thickness. In case of dissimilar thickness, we should consider the thinner base metal thickness. Fillet welds joints are most commonly used in fabrication and structures. A fillet weld joint can be loaded in any direction in shear, compression, or tension loading.

One of the quickest and easiest ways to check fillet weld leg length and fillet weld throat dimension against weld specifications is with a **Fillet Weld Gauge**. These gauges come in a variety of sets with sizes ranging from 1/8 of an inch to 3 inch in both inch and metric sizes.

Contents

- 1 How is weld length measured?
- 2 What is the minimum size of a fillet weld?
- 3 What is the maximum size of fillet weld?
- 4 What is the weakest plane in fillet weld?
- 5 How much weight can a 1/4 fillet weld hold?
- 6 What is the main reason for the minimum fillet weld sizes?
- 7 How minimum & maximum size of fillet weld is determined?
- 8 What is a fillet weld symbol?
- 9 What is size of fillet weld?
- 10 How thick should a fillet weld be?
- 11 What is the maximum size of fillet weld made with a single pass?

## How is weld length measured?

The leg size is the length of the legs of an imaginary triangle that can be inscribed within the actual weld as shown with feature L1 and L2 in the image below for both a convex and concave fillet weld. In the case of the convex fillet weld shown on the left, the measured leg (L) is equivalent to the size (S).

## What is the minimum size of a fillet weld?

Explanation: The minimum size of fillet weld should not be less than 3mm and not more than thickness of thinner part joined.

## What is the maximum size of fillet weld?

The maximum size of fillet weld is obtained by subtracting 1.5mm from the thickness of the thinner member to be jointed. When welds are applied to round toe of steel sections, the maximum size of the weld should not be more than 1/3 of the thickness of the section at toe.

## What is the weakest plane in fillet weld?

For a given amount of weld material, the fillet weld is not as strong as due to the heavy concentration of the stress. ∴ For fillet weld, the weakest plane is along the throat section.

## How much weight can a 1/4 fillet weld hold?

Because we are using an ER70S-6 wire, is equal to 70,000 psi. Now we have all the values except for the one we are solving for, F. We rearrange the formula to solve for F. So our 20-inch long, double-sided, ¼” fillet welds have a load carrying capacity able to withstand a tensile force of almost half a million pounds.

## What is the main reason for the minimum fillet weld sizes?

Remember, we are concerned about heat input, not the final size of the weld. The premise behind this is that the required minimum weld size will provide a sufficiently high heat input into the plate to provide the desired slow rate of cooling.

## How minimum & maximum size of fillet weld is determined?

The size of a fillet weld should be calculated by the designer of the welded structure, based on the nature and magnitude of applied loads, on the material and on the design basis.

## What is a fillet weld symbol?

The fillet weld symbol is a right triangle placed on the reference line with the perpendicular leg always on the left. The dimension specifying the leg size of a fillet weld is placed to the left of the fillet weld symbol, and on the same side of the reference line.

## What is size of fillet weld?

Fillet welds may have a size associated with them. This size is called out on the left side of the symbol before the vertical side. The size is indicating the leg length of the weld. If a single size is called out this is specifying that weld should have equal leg sizes.

## How thick should a fillet weld be?

A basic understanding of related terminology is assumed. To develop the full strength of a plate using fillet welds, it is necessary that the leg size of the fillet be 3/4 of the plate thickness. A fillet weld with this leg size will out-pull its plate under any magnitude and direction of loading.

## What is the maximum size of fillet weld made with a single pass?

For GMAW and FCAW, the largest single pass fillet weld in the horizontal position, for prequalified WPSs, is one size larger — 3/8”. All of the above has lead to the general rule-of-thumb that 5/16” is a reasonable maximum weld size for single pass welds, made in the horizontal position.