Welding Zone Gas and Sources
Gas welding, cutting and brazing operations involve the use of several different gas mixtures in the welding zone. The gases used depend on the types of processes being employed.
Oxygen is the most commonly used gas in the welding zone, and is typically used for welding, cutting and brazing processes. Oxygen is an odorless and colorless gas that is produced by the breakdown of water molecules. Oxygen is needed for the chemical processes used in many welding processes, as it helps to create the intense heat needed to achieve the desired result. It is a highly reactive gas and is usually supplied in pressurized cylinders.
Acetylene is a colorless and exceptionally flammable gas used in cutting and welding processes. Acetylene is manufactured by the reaction between calcium carbide and water, and is usually supplied in cylinders. The acetylene in the cylinders is dissolved in acetone, which acts as a stabilizer and allows the gas to be stored safely. Acetylene is an important gas in many welding processes, as it produces a flame of great intensity and is capable of burning at very high temperatures.
Argon is a colorless and odorless gas used in many welding processes, especially inert gas welding processes. Argon is a noble gas and is supplied in pressurized cylinders or flasks. It is an ideal welding gas because it does not react with other elements and does not react to form oxides at the extreme temperatures of welding. It is also used for shielding, as it prevents the oxidation and contamination of the weld pool.
Carbon dioxide is a colorless gas produced from the breakdown of carbonates. It is commonly used in MIG and TIG welding processes, as it is a good thermal conductor and provides a protective layer over the weld pool. Carbon dioxide also acts as a buffer and reduces the intensity of sparks emitted during welding, reducing the danger of spatter.
Helium is a colorless and odorless gas that is used mainly in gas welding and tungsten inert gas (TIG) welding processes. Helium is an inert gas and is supplied in high-pressure steel cylinders. Its low reactivity to other elements makes it ideal for welding, as it does not provide any additional chemical reaction or contaminate the weld pool. It is also a good thermal conductor, helping to increase the efficiency of the welding process.
In addition to the gases described above, inert shielding gases such as nitrogen, carbon monoxide and hydrogen may also be used in specific welding processes. These gases are typically used to help reduce the risk of contamination to the weld pool and to provide a protective layer to prevent oxidation during welding.
It is important to consider safety when using gas in the welding zone. Dangerous gases can cause serious injury or even death if not handled properly. All operators should be trained in the proper use of the equipment and be aware of the relevant regulations for working with hazardous materials. All cylinders of gas must be stored correctly and in accordance with manufacturers instructions.
