Acetylene (C2H2) is a colorless, highly flammable gas. Mostly used for oxy-fuel applications, acetylene has a high heat release in the primary flame and a low heat in the secondary flame. It has the hottest flame temperature of the commercially available fuel gases (6,300 °F/3, 480 °C) and is an excellent choice for welding, brazing and cutting of steel alloys less than 1 inch thickness.
Interesting Info: An Acetylene cylinder has a tank pressure of 250 psi at 70 Degrees F
Colorless, odorless, tasteless and non-toxic, argon (Ar) is a noble gas that comprises 0.93% of the earth's atmosphere. Argon can provide an inert and clean environment free from nitrogen and oxygen for annealing and rolling metals and alloys. In the casting industry, argon is used to flush porosity from molten metals to eliminate defects in castings. In the metal fabrication industry, argon is used to create an inert gas shield during welding. Argon is frequently blended with carbon dioxide (CO2), hydrogen (H2), helium (He) or oxygen (O2) to enhance the arc characteristics or facilitate metal transfer in Gas Metal Arc Welding (GMAW or MIG).
Because 100% argon can be used to TIG weld all metals and thicknesses you only need one type of gas in your shop to handle all of your welding projects. MIG welding aluminum is different than welding steel when it comes to shielding gas requirements. For aluminum, 100 percent argon is the gas of choice.
Carbon Dioxide (CO2) is a tasteless, colorless, odorless, nonflammable gas. It is commonly utilized with argon (Ar) as a shielding gas during welding or in some cases it is used in pure vapor state. This prevents atmospheric contamination of molten weld metal during gas shielded electric arc welding process.
Hydrogen (H2) is the lightest of all gases. Colorless, odorless, tasteless and nontoxic, hydrogen exists as a gas at atmospheric temperatures and pressures. In metal fabrication, hydrogen serves as a protective atmosphere in high-temperature operations such as stainless steel manufacturing; commonly mixed with argon for welding austenitic stainless. Hydrogen is used to enhance plasma welding and cutting operations.
Nitrogen (N2) is a diatomic gas which comprises 78% of the earth's atmosphere. Colorless, odorless, tasteless, and nontoxic, nitrogen exists as a nonflammable gas at atmospheric temperatures and pressures. Nitrogen is utilized as a purge gas with stainless steel tube welding. Nitrogen can enhance plasma cutting, food processing, heat-treating. Small additions to argon based shielding gases can be used for welding stainless steel by the Gas Metal Arc Welding (GMAW or MIG) process.
Oxygen (O2), which comprises 21% of the earth's atmosphere, supports life and makes combustion possible. Colorless, odorless and tasteless, oxygen is used to support oxyfuel cutting operations. Oxygen may be added in small quantities to shielding gases. Oxygen is also used as the plasma cutting gas (with Hafnium electrodes) on carbon steel.
Propane (C3H8) is a colorless, flammable, liquefied gas with a natural gas odor. The flame temperature of the oxy-propane flame is lower than acetylene and propylene. The primary flame releases low BTU when compared to propylene or acetylene, which increases preheat time. Propane is commonly used by scrap yards for cutting carbon steel, where the cut quality is not critical. Where cut quality is not a concern, propane may be a cost-effective fuel gas.
Interesting Info: A Propane cylinder has a tank pressure of only 110 psi at 70 Degrees F
Propylene (C3H6) is a colorless, flammable, liquified gas with a faintly sweet odor. It has high heat release in its primary and secondary flames. The heat release in the primary flame cone is similar to acetylene. The BTU capacity of the outer flame is superior to that of acetylene. Propylene combines the qualities of an acetylene flame with the secondary heating capacity of propane. The fuel gas burns hotter than propane; however, the cutting speed should be calculated on a case-by-case-basis before choosing this as the most economical choice as your fuel gas.
Interesting Info: A Propylene cylinder has a tank pressure of only 137 psi at 70 Degrees F