Gases Used In Welding

Gases Used In Welding

Welding is the process of joining two pieces of materials such as thermoplastics or metal using high levels of heat. The melted parts are then left to cool in order to form a joint. Apart from electricity, there are gases which are often used in the welding process. Gases are often used with the aim of shielding the area which needs to be welded. This is due to the fact that there are some gases in the air which alter the way of the weld. The type of gas used will inevitably determine the welding process to be used. Some of the common gases used in welding are acetylene gas, argon, oxygen and even air among other types of common gases.

Argon Gas

Argon is a nonflammable, nontoxic inert gas; therefore it is known not to have any chemical reaction when it comes into contact with other materials and even metal. Argon is often used in the manufacture of steel, heat treatments and even manufacture of electronics. In other circumstances, argon is often blended with hydrogen, carbon dioxide or oxygen with the aim of enhancing the characteristic of the arc produced during the welding process. Since it provides a stable arc, this makes it an ideal shielding gas which can be used with different types of metals such as titanium.


Oxygen is one of the most popular gases known which makes combustion possible and also supports life. Oxygen is a colorless, tasteless and odorless gas. Oxygen often works with other types of gases that are necessary for the welding process. Therefore it is necessary to use oxygen when using high heat on metals. Oxygen is also known to promote arc stability and at the same time reduce the surface tension which may be exerted on the molten metal. This, in turn, increases the wetting of the metal. On the other hand, excessive application of the gas can lead to the brittleness of the area exposed to heat.

Acetylene Gas

Acetylene is a highly flammable, colorless gas and is also considered as the hottest of all types of hydrocarbon gases. This makes it the ideal gas for brazing, cutting and welding of steel alloys which are often considered to be less than 1inch thick. Acetylene is known to have a significant number of favorable characteristics such as the gas mixture often acquires a much higher temperature compared to other types of gases. It also has the ability to switch quickly into a cutting process and this is made possible by changing the welding tip to a cutting tip.

Carbon Dioxide

Carbon dioxide is also another popular reactive gas which is tasteless, nonflammable, odourless and colourless gas. It is also considered as the least expensive shielding gas. Although the gas is known to have drawbacks, it is also known to have a significant number of advantages. In cases where thick material needs welding, carbon dioxide is often preferred and this is due to the fact that it promotes a deeper penetration of the weld. In addition, carbon dioxide does not need an additional inert gas for it to be used.


Helium is also another common gas used in welding. Apart from the fact that helium gas is colorless, odorless and tasteless, it is also considered as one of the lightest gas elements aside from Hydrogen. Helium can also be added to carbon dioxide and argon in order to weld stainless steel. Helium is also known to have favorable properties such as producing a wide and deep penetration; therefore it is often used in welding thick pieces of metal. Helium ore often creates a gas shield which prevents oxidation of metals such as copper and stainless steel alloys during the welding process.


Hydrogen is considered as the lightest gas element. It is also a colorless, odorless and tasteless gas. The use of hydrogen in welding often increases the arc temperature and this, in turn, leads to better penetration during the welding process. Hydrogen often combines with argon and carbon dioxide with the aim of counteracting the oxidization effects which are often brought about by exposure to carbon dioxide. Although hydrogen has favourable properties, the application of the gas is often limited to a number of stainless steel types.


The above gases are the most common gas elements used in the welding process. Therefore in order for one to use a certain type of gas to weld, it is important to put some factors into consideration. Such factors include the type of metal being used and at the same time the degree of temperature which the gas can be able to produce in order for the welding process to become effective. Therefore it is paramount to consider the compatibility of the gases with the different types of metals.

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