Welding Rod Consumption: How Should It Be Calculated?

To calculate the consumption of welding rods, the most direct method used in operation is to calculate the weight of weld metal first, and then divide it by the utilization rate of welding materials.

It is necessary to calculate the utilization ratio of welding materials.

However, because the diameter of the welding rod and welding wire is different, the utilization rate will also be very different.

For industry, calculating the utilization rate of welding materials effectively can reduce unnecessary damage in welding.

The data shows that the utilization rate of welding wire is higher than that of welding rod according to the experience of welders.

Some industries will have a special recommended table for calculating the weight of welding materials.

This table is mostly divided according to the size of the groove, and the number of welding materials required per meter for the number of groove degrees (in this case, the utilization rate is generally included).

If you have such information, you can make a spreadsheet, make a formula, and then fill in the form every time.

During welding construction, it is very important to correctly estimate the demand for welding rods.

If too many values are calculated, the inventory will be overstocked;

If the estimate is too small, the project budget will be insufficient, and sometimes the normal progress of the project and the construction quality will be affected.

The consumption of welding rod is mainly determined by the joint type, groove type, weld length and other factors of the welding structure.

Here are some calculation formulas:

A) The calculation formula for electrode consumption is as follows:

m = A*L*ρ/1 – K_S

Where

• m — Consumption of welding rod (g);
• A — Cross-sectional area of weld (cm²); (Refer to Table 1)
• L — Weld length (cm);
• ρ — Density of deposited metal (g/cm³);
• K_s — electrode loss coefficient,

B) The other is the formula for calculating the consumption of non-ferrous powder electrode:

m = ALρ/Kn * (1+Kb)

Where,

• m — Consumption of welding rod (g);
• A — Cross-sectional area of weld (cm²); (Refer to Table 1)
• L — Weld length (cm);
• ρ — Density of deposited metal (g/cm³):
• Kb — Coating quality coefficient, see the table below:
• Kn — Transfer coefficient of metal from electrode to weld (including loss due to burning, splashing and electrode tip)

Eight common metal materials

1. The steel plate with a known thickness of 20mm is provided with a V-shaped groove, the weld length L is 3m, and the welding rod is 5015. How to calculate the consumption of welding rod?

(According to the table, the sectional area of deposited metal A=250mm², the density of steel ρ＝ 7.8g/cm³, conversion coefficient Kn=0.79, weight coefficient of electrode coating Kb=0.32.)

Solution: known sectional area of deposited metal A=250mm², steel density ρ＝ 7.8g/cm³, transfer coefficient Kn=0.79, Kb=0.32, L=3m.

From the formula:

m_rod = ALρ(1+Kb)/1000Kn = 250mm²×3m×7.8g/cm³(1+0.32)/(1000×0.79)=9.77kg

Answer: The consumption of welding rod is 9.77Kg.

2. Manual arc welding is used to weld a 10m carbon steel fillet weld. The electrode diameter is Φ4.0, and the fillet size is 10mm. How many electrodes are required? (Welding rod deposition rate is 55%)

Requirement of welding material W= D/η=1.2ALρ/η

A=10*10/2=50mm², L=10m, ρ=7.8*10³/kg/m³η=55%

Therefore, W=1.2*(50*10^-3)*10*7.8*10³/55%=8.509kg≈8.5kg

Answer: 8.5kg Φ4.0 welding rod is required for this weld.

Table 1 Sectional Area of Weld Deposited Metal

NO.	Weld name	Type and size of welded joint and groove/mm	Calculation formula
1	Single-side I-shaped weld
2	I-shaped weld
3	V-shaped weld (no back welding)
4	Single-side V-shaped weld (no back welding)
5	U-shaped weld (no back welding)
6	Back sealing weld without root overhang at the root of V-shaped and U-shaped weld
7	Root of V-shaped and U-shaped welds
8	Retain V of steel backing plate

Table 2 Weight coefficient Kb of electrode coating

Table 3 Transfer coefficient Kn of electrode