What is weld deposition rate?

Deposition rate is the weight of weld metal deposited into the joint per hour, in lbs/hr. It equals wire feed speed times wire weight factor times deposition efficiency, with a x60 to reach per-hour. In the example, 350 IPM of 0.045 in ER70S-6 at 0.000631 lbs/in and 0.88 efficiency gives 11.7 lbs/hr net, the figure used for filler cost and arc time estimates.

How do I calculate deposition rate from wire feed speed?

Multiply wire feed speed (IPM) by the wire weight factor (lbs/in) by 60 to get lbs/hr gross, then multiply by deposition efficiency. For 350 IPM, 0.000631 lbs/in: 350 x 0.000631 x 60 = 13.25 lbs/hr gross. At 0.88 efficiency, 13.25 x 0.88 = 11.7 lbs/hr net. The wire weight factor comes from the manufacturer for that diameter and alloy.

What is a good deposition rate for MIG welding?

Single solid-wire MIG typically deposits 6 to 12 lbs/hr, so the example 11.7 lbs/hr sits at the high end. Metal-cored wire pushes 12 to 18 lbs/hr, and tandem or twin-wire setups reach 20 to 30 lbs/hr. SMAW is far lower at 2 to 5 lbs/hr. Higher is not always better; match rate to joint thickness and heat input limits.

Why is my actual filler consumption higher than calculated?

You probably used too high a deposition efficiency. Solid MIG wire runs 0.92 to 0.96, but flux-core drops to 0.75 to 0.85 and SMAW to 0.55 to 0.70 because of slag and stub loss. If you assumed 1.0 for flux-core, your wire purchases will exceed net deposited weight by 15 to 25 percent. Also check for excess spatter from a hot, unstable arc.

How do I find the wire weight factor for a given diameter?

Use the manufacturer datasheet or compute it: cross-sectional area (pi/4 x diameter squared) times steel density of about 0.283 lbs/in cubed. For 0.045 in wire, area is 0.00159 in squared, giving roughly 0.00045 lbs/in for pure steel; catalog values like 0.000631 lbs/in for ER70S-6 account for real density and tolerance. Always match the factor to both diameter and alloy.

What is the difference between deposition rate and melt-off rate?

Melt-off (burn-off) rate is how fast the wire is consumed at the arc; deposition rate is how much of that metal ends up in the weld. The gap is deposition efficiency. At 350 IPM the wire burns off 13.25 lbs/hr, but only 11.7 lbs/hr deposits at 0.88 efficiency. The lost 1.55 lbs/hr leaves as spatter, slag, and fume.

Engineering and Process

Weld Deposition Rate Formula

Weld deposition rate is the weight of weld metal deposited per hour. Use it when estimating filler metal consumption, comparing wire processes, or calculating arc time for a given weld weight.

Formula

Deposition Rate = Wire Feed Speed x Wire Weight Factor x Deposition Efficiency

Variables

Wire Feed Speed: Wire or electrode feed rate in inches per minute
Wire Weight Factor: Weight of wire per inch of length in lbs/in (from wire manufacturer data for the diameter and alloy)
Deposition Efficiency: Fraction of wire deposited into the weld vs. lost to spatter, slag, and smoke (0 to 1)

Understanding the Weld Deposition Rate Formula

Deposition rate is the weight of weld metal actually laid into the joint per hour, and it is the number that drives filler consumption and arc time. It is not the same as burn-off rate, because spatter, slag, and smoke carry away part of the wire. In the example, 350 IPM of 0.045 in ER70S-6 gross at 13.25 lbs/hr becomes 11.7 lbs/hr net after applying the 0.88 deposition efficiency.

Get wire feed speed from the machine readout or by measuring wire fed over a timed interval. Pull the wire weight factor from the manufacturer datasheet for that exact diameter and alloy; 0.045 in ER70S-6 is about 0.000631 lbs/in. The x60 converts inches per minute to per hour. Deposition efficiency comes from the process: MIG solid wire runs 0.92 to 0.96, flux-core 0.75 to 0.85, SMAW 0.55 to 0.70. Skipping it inflates your numbers.

Use net deposition rate to size jobs and compare processes. Divide total weld metal weight by the rate to get arc-on hours, then divide by operator factor to get real clock time. A single-wire MIG cell at 11.7 lbs/hr is solid; if you need more, raise wire feed speed or move to metal-cored or tandem setups reaching 15 to 25 lbs/hr. Low actual output usually points to low duty cycle, not the deposition rate itself.

Worked Example

Wire feed speed is 350 IPM. Wire weight factor for 0.045-in ER70S-6 is 0.000631 lbs/in. Deposition efficiency is 0.88.

Gross rate = 350 x 0.000631 x 60 = 13.25 lbs/hr
Effective deposition rate = 13.25 x 0.88 = 11.7 lbs/hr

Result: 11.7 lbs/hr net deposition rate

Common Mistake

Using 100% deposition efficiency. MIG solid wire typically runs 92-96%, but flux-core wire runs 75-85% and SMAW runs 55-70% due to slag and stub losses. Using 100% will overstate how much weld metal is actually deposited and understate filler consumption.

Frequently Asked Questions

What is weld deposition rate?: Deposition rate is the weight of weld metal deposited into the joint per hour, in lbs/hr. It equals wire feed speed times wire weight factor times deposition efficiency, with a x60 to reach per-hour. In the example, 350 IPM of 0.045 in ER70S-6 at 0.000631 lbs/in and 0.88 efficiency gives 11.7 lbs/hr net, the figure used for filler cost and arc time estimates.
How do I calculate deposition rate from wire feed speed?: Multiply wire feed speed (IPM) by the wire weight factor (lbs/in) by 60 to get lbs/hr gross, then multiply by deposition efficiency. For 350 IPM, 0.000631 lbs/in: 350 x 0.000631 x 60 = 13.25 lbs/hr gross. At 0.88 efficiency, 13.25 x 0.88 = 11.7 lbs/hr net. The wire weight factor comes from the manufacturer for that diameter and alloy.
What is a good deposition rate for MIG welding?: Single solid-wire MIG typically deposits 6 to 12 lbs/hr, so the example 11.7 lbs/hr sits at the high end. Metal-cored wire pushes 12 to 18 lbs/hr, and tandem or twin-wire setups reach 20 to 30 lbs/hr. SMAW is far lower at 2 to 5 lbs/hr. Higher is not always better; match rate to joint thickness and heat input limits.
Why is my actual filler consumption higher than calculated?: You probably used too high a deposition efficiency. Solid MIG wire runs 0.92 to 0.96, but flux-core drops to 0.75 to 0.85 and SMAW to 0.55 to 0.70 because of slag and stub loss. If you assumed 1.0 for flux-core, your wire purchases will exceed net deposited weight by 15 to 25 percent. Also check for excess spatter from a hot, unstable arc.
How do I find the wire weight factor for a given diameter?: Use the manufacturer datasheet or compute it: cross-sectional area (pi/4 x diameter squared) times steel density of about 0.283 lbs/in cubed. For 0.045 in wire, area is 0.00159 in squared, giving roughly 0.00045 lbs/in for pure steel; catalog values like 0.000631 lbs/in for ER70S-6 account for real density and tolerance. Always match the factor to both diameter and alloy.
What is the difference between deposition rate and melt-off rate?: Melt-off (burn-off) rate is how fast the wire is consumed at the arc; deposition rate is how much of that metal ends up in the weld. The gap is deposition efficiency. At 350 IPM the wire burns off 13.25 lbs/hr, but only 11.7 lbs/hr deposits at 0.88 efficiency. The lost 1.55 lbs/hr leaves as spatter, slag, and fume.