The choice of CO ₂ pressure reducer for welding (more accurately referred to as CO ₂ arc+CO ₂ pressure reducer) is very important, as it directly affects the stability of gas output and welding quality. The following are the key points for selection, you can refer to this process to choose:
1、 Firstly, confirm the core requirements: gas type and interface thread
This is the most basic and important point, choosing the wrong one can lead to leakage or equipment damage.
Gas type: Either “CO ₂” or “Argon+CO ₂” dual-purpose pressure reducer must be selected.
Why? Pure CO ₂ is liquid under high pressure, and when it flows out, it absorbs heat and vaporizes, causing ordinary pressure reducers to freeze and block. Specialized CO ₂ pressure reducers have special heating or anti icing structures (such as high flow channels).
Suggestion: If you may use Ar+CO ₂ mixture now or in the future, choose the “dual-purpose argon/carbon dioxide pressure reducer” directly for stronger versatility. This type of pressure regulator is usually labeled as “Ar/CO ₂”.
Inlet thread (Gauge interface): must match the thread of the CO ₂ cylinder valve.
The most common CO ₂ steel cylinder interface in China is G5/8 “(an imperial thread).
How to confirm? Please inform the seller directly when purchasing that it is for “CO ₂ welding steel cylinders”, or check the interface specifications of your existing pressure regulator. Thread mismatch is absolutely impossible to install.
2、 Secondly, pay attention to key performance parameters
1) Flow range: Choose according to your welding current
Low pressure gauge (output pressure/flow rate): When welding, our main focus is on gas flow rate, measured in liters per minute (L/min).
Selection: Ensure that the flow meter range of the pressure reducer meets your needs. For example, the flow rate for MIG/MAG welding is usually between 15-25 L/min. Choose a pressure regulator with a maximum flow rate slightly higher than your usual flow rate (such as 0-30 L/min).
Input pressure (range of high pressure gauge):
2) High pressure gauge (cylinder pressure): displays the pressure of the gas inside the cylinder (or the inventory of liquid CO ₂). When the CO ₂ steel cylinder is full, the pressure is about 5-7 MPa (50-70 kg).
Selection: Ensure that the maximum range of the high-pressure gauge can cover this range (usually 0-25 or 0-40 MPa), which is basically the standard configuration.
3) Output pressure stability:
This is the core function of a pressure reducer. A good pressure reducer should be able to provide stable output pressure without significant fluctuations as the pressure inside the bottle decreases. This is usually related to the quality of the internal diaphragm and spring.
2、 Secondly, pay attention to key performance parameters
1) Flow range: Choose according to your welding current
Low pressure gauge (output pressure/flow rate): When welding, our main focus is on gas flow rate, measured in liters per minute (L/min).
Selection: Ensure that the flow meter range of the pressure reducer meets your needs. For example, the flow rate for MIG/MAG welding is usually between 15-25 L/min. Choose a pressure regulator with a maximum flow rate slightly higher than your usual flow rate (such as 0-30 L/min).
Input pressure (range of high pressure gauge):
2) High pressure gauge (cylinder pressure): displays the pressure of the gas inside the cylinder (or the inventory of liquid CO ₂). When the CO ₂ steel cylinder is full, the pressure is about 5-7 MPa (50-70 kg).
Selection: Ensure that the maximum range of the high-pressure gauge can cover this range (usually 0-25 or 0-40 MPa), which is basically the standard configuration.
3) Output pressure stability:
This is the core function of a pressure reducer. A good pressure reducer should be able to provide stable output pressure without significant fluctuations as the pressure inside the bottle decreases. This is usually related to the quality of the internal diaphragm and spring.
3、 Consider additional features and materials
1) Heating function (important!):
Problem: During high current and long-term continuous welding, the gas consumption is high, and the heat absorption of CO ₂ gasification can cause the pressure regulator to freeze, resulting in unstable or interrupted airflow.
Solution: Choose a pressure reducer with an electric heater. It is powered by a 220V power supply to prevent icing and ensure long-term welding stability. For professional or high-intensity assignments, it is strongly recommended to use models with heating function.
2) Material and Durability:
Case: Materials that are shock resistant and impact resistant are preferred.
Internal pressure gauge: Made of anti-corrosion material to prevent corrosion by wet CO ₂ gas (containing a small amount of moisture).
Overall workmanship: Solid touch, smooth knob adjustment, no burrs.
3) Functional design:
Equipped with a flow meter: necessary for precise adjustment of the protective gas flow rate.
Two stage pressure regulation: Some high-end models have two-stage voltage regulation, which provides more stable output.
Safety valve: essential to prevent excessive output pressure
In summary, for most welding scenarios, choosing a pressure reducer with a correct interface (G5/8 “), flow meter, and Ar/CO ₂ dual-use is the foundation. If you frequently weld for long periods of time with high current, it is necessary to invest in a model with heating function.
We hope this detailed guide from DERKIA can help you make the right choice!