Weld Metal and Consumable Calculator

How is weld consumable quantity calculated?

The calculation has three steps. First find the cross section of the weld. Then multiply by the weld length for volume and by density for weld metal weight. Finally divide by the deposition efficiency, because not all of the purchased electrode or wire ends up in the joint.

Weld cross section

An equal leg fillet weld has a right triangle section. With throat thickness a, A = a². With leg length z, A = z² / 2. The two are related by z = a × √2.

In a V groove butt weld the section is the rectangle formed by the root gap plus the triangles formed by the bevels: A = g × t + (t − c)² × tan(α / 2), where t is plate thickness, g the root gap, c the root face and α the included groove angle.

Deposition efficiency

With covered electrodes the coating turns to slag, the stub is discarded and some metal is lost as spatter, so only about 60 percent of the electrode weight reaches the joint. Solid wire loses very little. These figures are approximate and vary with current, position and electrode type.

Example

A fillet weld with 6 mm legs has a theoretical section of 6² / 2 = 18 mm², or 19.8 mm² with a 10 percent allowance. A length of 100 metres needs 1980 cm³, which is 15.5 kg of weld metal. With covered electrodes at 60 percent efficiency that takes about 25.9 kg of electrodes.

Limits

The result is a quantity estimate. Deviations in joint preparation, tack welds and repairs increase consumption. U, double V and K preparations are not included in this tool.