Argon
Argon is a chemical element with the symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in the Earth’s atmosphere at 0.93%
Argon is the most common shielding gas, widely used as the base for the more specialized gas mixes. Argon is used when welding to displace oxygen around the weld to prevent it from oxidizing.
Chemical Formula: Ar
Molecular Composition: Argon is a noble gas and exists as a single atom (monatomic) in its gaseous form, unlike diatomic gases like nitrogen or oxygen.
Appearance: Argon is colorless, odorless, and tasteless, similar to other noble gases.
State at Room Temperature: Argon is a gas at room temperature and pressure, but it can be liquefied at very low temperatures.
Density: Argon gas is denser than air, with a molecular weight of about 39.948 grams per mole.
Boiling and Melting Points: The boiling point of argon is -185.8°C (-302.4°F), and its melting point is -189.3°C (-308.7°F).
Argon Mixed Gases
Argon-Oxygen Mixtures: Argon can be mixed with oxygen for use in specific welding applications. The addition of oxygen increases the heat of the weld and enhances the arc stability. It can also help increase the penetration depth of the weld, especially on thinner materials.
Argon stainless - 2% oxygen in Argon
Argon-Co2 Mixtures: One of the most common argon mixes is with carbon dioxide (CO₂), particularly in MIG welding. Higher CO₂ percentages result in greater penetration and can help produce stronger welds. The higher the CO₂ content, the more spatter is produced during welding, which can affect the quality of the weld and necessitate additional clean-up.
Argon Heavy 75/25 - 25% Co2 in Argon
Argon-Oxygen-Co2 Mixtures: This combination is often used in MIG welding, especially for carbon steel and low-alloy steel. The addition of CO₂ provides deeper penetration into the base metal, especially when working with thicker materials. Adding oxygen to the mix can enhance the arc stability and increase the penetration while reducing the need for high amperages.
Argon 5/2 - 2% oxygen, 5% Co2 in Argon
Argon 16/3 - 3% oxygen, 16% Co2 in Argon
Argon Applications:
Metal Inert Gas (MIG) and Tungsten Inert Gas (TIG) welding
Inert atmospheres
Filler gas in incandescent and neon lamps
Plasma cutting
Gas chromatography
Spectometry
