The right Gas Pressure for MIG welding is very important to prevent weld porosity, decreased weld strength & reduce wastage of welding gas to help cost saving.
what is Gas Pressure for MIG Welding and how does it affect MIG welding?
The pressure of the gas affects the MIG welding process in a few ways. For one, if the pressure is too low, then the shielding gas will not be able to do its job properly.
This can cause the weld to be less protected from contaminants, results: Welding Porosity. A low gas flow rate aids the formation of the oxides and cause the welding to be rejected.
Additionally, if the gas pressure is too high, it may not form proper shielding blanket and create turbulence. A high gas pressure can also brittle weld metals that are prone to air-hardening.
What is the best Gas flow rate for MIG Welding?
MIG welding, or Metal Inert Gas welding, is a popular type of welding that uses an electric arc to weld metals.
The welder controls the welding amperage, voltage and the rate of gas flow in MIG welding. The right gas flow rate is essential for a successful MIG weld.
The gas flow rate should be set at 20 to 30 cubic feet per hour (cfh) for most of metals. This will provide enough shielding gas to protect the weld from contamination.
Too much gas can cause the weld to be cool fast, while too little gas can allow contaminants to enter the weld. The best way to determine the correct gas flow rate is to experiment with different settings until you find the one that works best for your project.
What should be the minimum Gas flow rate in MIG Welding?
Generally, for most welding applications, a minimum gas flow rate of 15-20 cubic feet per hour (cfh) is sufficient.
If you are welding thick material or using a large wire diameter with a big nozzle, you may need to increase the gas flow rate to 20-30 cfh or higher.
Minimum & Maximum Gas Pressure for MIG Welding for different metals
The optimum gas flow rate for MIG welding differs depending on the type of metal being welded.
Related reading: Shielding gases of TIG MIG and FCAW welding of stainless-steel, duplex steel
Below tables provides a general recommended minimum and maximum range for Gas Flow rate in MIG Welding.
| Welding Gas | Mild Steel/ Carbon Steel | Stainless Steel | Aluminum |
|---|---|---|---|
| Pure CO2/ Argon, 75-25 Welding gas | 15- 30 CFH | 18- 30 CFH | N.A. |
| Tri-mix gas (Ar+He+O) | N.A. | 25- 35 CFH | N.A. |
| Pure Argon | N.A. | 25- 35 CFH | 25- 35 CFH |
| Argon+Helium Mix | N.A. | N.A. | 30- 50 CFH |
What is the difference between a Pressure Gauge & Flow meter in MIG Welding?
There are two types of devices that control & measure the pressure of a gas in MIG Welding:
- Pressure gauge and
- Flow meter.
A pressure gauge measures the force exerted by the gas in the line, while a flow meter measures the rate of flow of the gas.
Pressure gauges does not control the gas flow rate but instead they supply welding gas at a given pressure and not at given flow rate. Flow meters are the right device to measure the gas flow rate.
Some factors to consider when choosing between a pressure gauge and a flow meter include accuracy, cost, installation, and maintenance.
