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4 Different Types of Mig Welding Gas

Different Types of Mig Welding Gas: How to Choose the Best

The weld site is equipped with a wire electrode supplied from a spool, and a gas nozzle discharges a stream of gas into the weld site. Different types of Mig welding gas are available, each with its own advantages.

Selecting the right gas is crucial for optimal performance and avoiding contamination, ensuring reliable and strong results. Welding processes involving the use of environmental gases, such as oxygen and nitrogen, can lead to strong results due to their effective control.

MIG welding utilises four common shielding gases: argon, helium, carbon dioxide, and oxygen. Argon, a combination of 75-95% Argon and 5-25% CO2, is ideal for weld quality, attractiveness, and minimising post-weld cleaning.

It offers arc stability, puddle control, and less spatter, allowing for a spray transfer approach. It creates a thinner penetration profile and is suitable for butt and fillet welds. Oxygen, used in ratios of nine percent or less, enhances penetration, arc stability, and fluidity in mild carbon, low alloy, and stainless steel.

However, it is not recommended for aluminium, magnesium, copper, or other unusual metals as it oxidises the weld metal. Helium, similar to pure argon, is used with stainless steel and non-ferrous metals due to its wide, deep penetration profile. However, it costs more and requires a greater flow rate.

Carbon dioxide, a semi-inert gas, is commonly used in MIG welding for its cost-effectiveness and ability to fuse deeply into metals. It is particularly useful for handling ferrous metals like mild steel.

A tri-mix of CO2, argon, and helium, or 72/25 Argon/CO2, is more common for conventional MIG welding applications. Hydrogen, often combined with argon, serves as a protective gas in high-temperature environments, such as stainless steel.

Nitrogen is used to remove contaminants during welding stainless steel tubes and can also be used as a shield gas for stainless steel when added to argon. Propane is used in scrap yards to cut carbon steel when quality is not crucial.

MIG welding involves the use of two primary gases: pure argon and a mixture of argon and carbon dioxide. The most popular Ar/CO2 mixture is 75/25, which is used for mild steel or stainless steel, while pure argon is best for aluminium. This combination produces an excellent arc characteristic and a fully penetrative weld with minimal spatter.

There are several midweld shielding gases for different types of metals, such as 75% argon and 25% carbon dioxide for mild steel, C100 for silicon bronze, and helium trimix shielding gas for stainless steel.

For stainless steel, a combination of 98% argon and 2% CO2 is an excellent choice, but too much CO2 can result in porosity or other weld defects. A flexible solution is a blend of CO2 and argon gas, which is less expensive than a helium gas combination and still has an excellent bead profile with excellent wetting properties.

For aluminium, 100% argon is the most frequently used gas for MIG welding aluminium due to its low ionisation value and its ability to enter spray transfer or pulsed spray transfer modes. It is also useful for TIG welding aluminium, as it covers both methods.

However, most do-it-yourselfers don’t find these gases viable due to the high cost of helium. Additionally, as aluminium is susceptible to contamination, it is important to avoid using a gas containing CO2, as this may cause carbon to enter the weld.

FAQs

What type of gas is best for MIG welding?

MIG welding utilizes pure argon and an argon/carbon dioxide mix, with a 75/25 ratio being the most common, with 75% argon and 25% CO2 being the primary gases used.

What is 90/10 welding gas used for?

10% CO2, 90% Argon (C10)

Argon shielding gas is a crucial component in spray transfer, providing a shielding effect and reducing the energy required for pulsed spray transfer, making it an ideal choice for shielding applications.

What are the three most common MIG welding gases used in our shop?

The optimum gases for Mig welding include air, argon, and helium. Air is the most common and cheapest option, while argon offers advantages over air but is more expensive. Welders must choose the right gas for their specific needs.

What is 90 gas used for?

Gasoline, found in octane, has been tested for its compatibility with engines but has not been thoroughly tested for cars and trucks due to potential damage caused by other gasoline blends.

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