What is it?
Welding is used to join materials and welding gases are used during cutting and welding processes by using shielding gases or gases from the extraction of ultraviolet rays or produced by the decomposition of fluxes.
- Gases used in cutting and welding processes include carbon dioxide, helium, argon (shielding gas), propane, butane (fuel gas), and oxygen.
- Gases produced during cutting and welding processes include carbon dioxide (decomposition of fluxes), carbon monoxide ( breakdown of carbon dioxide during arc welding), nitrogen oxides ( heating of atmospheric nitrogen and oxygen), etc.
- Gases are even produced from the thermal breakdown of coatings like vinyl paints producing hydrogen chloride, epoxy coatings, carbon monoxide and dioxide.
What is the use of gas in welding?
Welding gases are used in various ways. Some of which include shielding the arc from impurities like dust, air, and other gases. It is also used for keeping welds clean on the underside and also for heating metals.
Different categories of gases in welding:
Shielding gas: A weak and ugly weld is created when air enters the arc, causing air bubbles within the molten metal. One cannot weld without shielding gas or filler material called flux-cored. This flux-core keeps away the impurities but in a different way. They are usually inert, which means they are stable even in extreme conditions.
Heating gas: Certain welding requires the heating of metals for achieving proper welding. In this case, the arc is not required. This gas is a fuel with air or oxygen lit by a flame to warm the metal.
Inert and Reactive gases: Inert gases are stable gases that do not react when in contact with any temperature or substance. Reactive gas is the reverse; it reacts according to the conditions it is exposed to. Inert gases are more useful when it comes to welding purposes.
Purging gas: It is a natural process of welding that helps cover the bottom of the material when welding.
Blanketing gas: It is used to fill confined spaces with gases to prevent any damage or reactions with other gases.
Different gases in welding shops:
- Argon: This gas is used as a shielding gas to prevent air from entering the welding arc. It is used in both the primary and welding stages and to purge the back of the joint. Sometimes, it is also used in MIG welding operations.
- Carbon dioxide: It is also used as a shielding gas, although it is less expensive. Though it is less expensive, the quality is low, and there is a risk of spatter during welding processes. This is why this gas is more commonly used in mixtures rather than in its pure form.
- Oxygen: Oxygen is mixed in small amounts in the shielding gas to add fluidity and speed to the welding process. It creates the hot flame necessary for welding.
- Nitrogen: It is used as a shielding gas for plasma cutting and laser welding. It also increases the alloy’s mechanical properties, stabilising the arc. It is also popularly used as a blanketing gas.
One might be confused to find a reliable place to buy these welding gases. Buying good quality and suitable gases is crucial, as the wrong one can lead to an explosion or unfortunate incident. Well, one must not worry because there are many professional manufacturers available out there. The professionals of the team manufacture the best gases.