Why do we need to calculate Weld Deposition Rate?
The costs of any industrial process can be accurately estimated. A process such as welding will involve factors such as:
2. welding consumables
A cost analysis is needed prior to bidding on a contract involving welding, and it may be done at any time during the course of a project for verification of actual cost. The following methods may be used to determine the welding costs of any welding process, but only the most common processes are used as examples.
A most common question that is asked when fabricators are trying to determine costs associated with welding before they can quote to their customer is:
- How many Kilogram or pounds of wire can I deposit per hour? Or,
- how many pounds of wire can I deposit at a specific amperage or wire feed speed in the GMAW process?
- What will be the cost of welding wire for a project?
Deposition rate (DR) vs. melt off rate (MOR)
Before you use this calculation, it’s important to understand the difference between weld deposition rate and melt-off rate as both are different terms. Deposition rate (DR) in welding refers to the speed with which a welding filler metal is consumed and deposited to form a weld. The deposition rate is expressed in terms of lb/hr or kg/hr. Whereas, Melt off rate (MOR) is the weight or length of the electrode, wire, rod, or powder melted in a unit of time. Melt-off rate is also expressed in terms of lb/hr or kg/ hr.
Formula for Weld Deposition Rate Calculation
Deposition Rate = A (D²) (WFS)(EE)
D = electrode diameter
WFS = wire feed speed (in/min)
EE =Electrode Efficiency,
A =13.1 (Constant for Steel based on steel density. This constant is applicable for carbon steel and stainless steel welding filler wires. For Aluminum the value of A is 4.32).
Electrode Efficiency in Welding
Electrode efficiency is the Percentage of Melt off rate (MOR) contributing to Deposition efficiency. Electrode efficiencies for solid wires can basically depend on the mode of metal transfer. As each metal transfer mode has varied characteristics that define how molten metal is transferred to the weld pool & associated losses during transfer such as spatters or metal vaporization. Listed below the electrode deposit efficiencies for different metal transfer mode in GMAW:
- Short-circuit Transfer: 90-93%
- Surface Tension Transfer: 98% (STT is a trademark and of the Lincoln Electric Company)
- Globular Transfer: 88 – 90%
- Spray Transfer: 98%
- Pulsed Spray Transfer: 98% is typical, but can be lower depending on the parameters and power source.
General weld deposit rate in different welding processes
The below table gives indicative weld deposit rates for SMAW, GMAW, FCAW, and SAW. As we know, various factors (current, electrode diameters, single or double electrode, welding position, etc.) influence the weld deposit rates, values stated here are indicative purposes only.
Deposit rate in SMAW Process
E6010 x 3.2 mm @ 110 A … … … 1.27 kg/hr (2.8 lb/hr)
E6012 x 3.2 mm @ 110 A … … … 1.00 kg/hr (2.2 lb/hr)
E7014 x 4.0 mm @ 180 A … … … 1.82 kg/hr (4.0 lb/hr)
E7018 x 4.0 mm @ 180 A … … … 1.82 kg/hr (4.0 lb/hr)
E7024 x 3.2 mm @ 140 A … … … 1.41 kg/hr (3.1 lb/hr)
E7024 x 4.0 mm @ 210 A … … … 2.09 kg/hr (4.6 lb/hr)
Deposit rate in FCAW Process
E711T x 1.6 mm @ 275 A … … … 5.00 kg/hr (11 lb/hr)
E711T x 2.4 mm @ 400 A … … … 5.46 kg/hr (12 lb/hr)
Deposit rate in GMAW Process
ER70S-6 x 0.9 mm @ 175 A … … … 2.05 kg/hr (4.5 lb/hr)
ER70S-6 x 1.2 mm @ 175 A … … … 1.68 kg/hr (3.7 lb/hr)
ER70S-6 x 1.2 mm @ 225 A … … … 2.36 kg/hr (5.2 lb/hr)
ER70S-6 x 1.2 mm @ 270 A … … … 3.73 kg/hr (8.2 lb/hr)