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Metal Fabrication

Plasma Arc Welding

Plasma arc welding (PAW) is an arc welding process similar to gas tungsten arc welding (GTAW) or TIG welding. The electric arc is formed between an electrode (which is usually but not always made of sintered tungsten) and the workpiece. The key difference from GTAW is that in PAW, by positioning the electrode within the body of the torch, the plasma arc can be separated from the shielding gas envelope. The plasma is then forced through a fine-bore copper nozzle which constricts the arc and the plasma exits the orifice at high velocities (approaching the speed of sound) and a temperature approaching 30,000°C. Plasma arc welding is an advancement over the TIG process.

Air Products' shielding gases are commonly used in several welding processes, mainly MIG/MAG and TIG welding. The shielding gases protect the weld area from atmospheric gases, such as Oxygen, Nitrogen, Carbon Dioxide and water vapour. Depending on the materials being welded, these atmospheric gases can reduce the quality of the weld or make the welding process more difficult to use.

Other Applications

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Product NameDescription/BenefitsDownloads
Gases

Shielding Gases
Argon

The primary function of the shielding gas in gas shielded arc welding has been to protect molten and heated metal from the damaging effects of the surrounding air and to provide suitable conditions for the arc. If air comes in contact with the molten or heated metal, the oxygen in the air will oxidise the metal, the nitrogen might cause porosity or brittleness in the weld metal, and moisture from the air might also cause porosity. Argon (Ar) is an inert gas. This means that it does not oxidise and that it has no effect on the chemical composition of the weld metal. Argon is the main component in most shielding gases for GMA, GTA and plasma welding.

The primary function of the shielding gas in gas shielded arc welding has been to protect molten and heated metal from the damaging effects of the surrounding air and to provide suitable conditions for the arc. If air comes in contact with the molten or heated metal, the oxygen in the air will oxidise the metal, the nitrogen might cause porosity or brittleness in the weld metal, and moisture from the air might also cause porosity. Argon (Ar) is an inert gas. This means that it does not oxidise and that it has no effect on the chemical composition of the weld metal. Argon is the main component in most shielding gases for GMA, GTA and plasma welding.

Helium

Helium (He) is, like argon, an inert gas. Helium is used together with argon and/or a few per cent of CO2 or O2 for GMA welding of stainless steel. In its pure state, or mixed with argon, it is used as a shielding gas for GTA and MIG welding. Compared with argon, helium provides better side wall penetration and higher welding speeds, by generating a more energy-rich arc. Helium has several unique characteristics that make it advantageous for welding applications. Its high ionisation potential, high thermal conductivity and inertness offer benefits—such as higher travel speeds and better quality welds—that can translate into greater productivity and reduced labour costs.

Helium (He) is, like argon, an inert gas. Helium is used together with argon and/or a few per cent of CO2 or O2 for GMA welding of stainless steel. In its pure state, or mixed with argon, it is used as a shielding gas for GTA and MIG welding. Compared with argon, helium provides better side wall penetration and higher welding speeds, by generating a more energy-rich arc. Helium has several unique characteristics that make it advantageous for welding applications. Its high ionisation potential, high thermal conductivity and inertness offer benefits—such as higher travel speeds and better quality welds—that can translate into greater productivity and reduced labour costs.

Shielding Mixtures

Air Products' shielding gases are commonly used in several welding processes, mainly MIG/MAG and TIG welding. The shielding gases protect the weld area from atmospheric gases, such as Oxygen, Nitrogen, Carbon Dioxide and water vapour. Depending on the materials being welded, these atmospheric gases can reduce the quality of the weld or make the welding process more difficult to use.

Air Products' shielding gases are commonly used in several welding processes, mainly MIG/MAG and TIG welding. The shielding gases protect the weld area from atmospheric gases, such as Oxygen, Nitrogen, Carbon Dioxide and water vapour. Depending on the materials being welded, these atmospheric gases can reduce the quality of the weld or make the welding process more difficult to use.

Audit Services/Leak Detection

Our applications engineers can work with your plant personnel to analyse and understand your entire process. Based on that analysis and your needs, they can recommend process improvement solutions that can help you enhance product quality and consistency, plus optimise gas use. Air Products' services include leak-checking, furnace profiling, analytical calibration, gas analysis process troubleshooting and overall process review.

Our applications engineers can work with your plant personnel to analyse and understand your entire process. Based on that analysis and your needs, they can recommend process improvement solutions that can help you enhance product quality and consistency, plus optimise gas use. Air Products' services include leak-checking, furnace profiling, analytical calibration, gas analysis process troubleshooting and overall process review.

Training

Training can include gas atmosphere safety, properties of gases, metal treating applications, NFPA 86, piping and flow control panel requirements and troubleshooting for atmosphere problems. This information can help keep your furnace operations safe and help prevent accidents.

Training can include gas atmosphere safety, properties of gases, metal treating applications, NFPA 86, piping and flow control panel requirements and troubleshooting for atmosphere problems. This information can help keep your furnace operations safe and help prevent accidents.

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