Question

A 3/16 inch thick plate is being welded to a 5/8 inch thick plate. What is the minimum size fillet weld that could be used?

Answer 1

The answer is simple .

Firstly convert the lengths from inches to mm

3/16 inch = 4.7625 mm

5/8 inch = 15.875 mm

Then we have to consider the thicker plate 15.875 mm, now according to the table below:

Thicker plate thickness	size of the weld in mm
0mm - 10 mm	3mm
10mm - 20mm	5mm
20mm - 32mm	6 mm
32mm and above	10mm

This table is according to the international standard code.

According to our given thickness.

T= 15.875mm

And the corresponding size of the fillet weld would be

​​​​​​5mm.

But here the thickness of the thinner plate is less than the size of the weld , in such case the size of the weld should be equal to the thickness of the 4.7625 mm.

EFFECTIVE THROAT THICKNESS = 0.7*SIZE OF THE WELD = 3.33375

SIZE OF THE K

The effective throat thickness= K * size of weld

So k = 0.7

So angle between fussion faces would be 60° - 90°

From below table

The size of the weld can also be calculated in the method of right hand rule and in tbis method also .