Gas Welding Defined and Explained

There are many welding processes used for melting and joining different metals and materials. The type of project being worked on and what kind of materials are being fused help determine which process should be used.

So, what is gas welding? Gas welding is one of the oldest forms of heat-based welding and is used in many industries. Gas welding joins metals by heating the materials to be joined so they can melt and fuse. There are several types of gas welding techniques, including oxy-acetylene welding and oxy-gasoline welding.

Gas welding equipment includes a welding torch, control valves for fuel and oxygen and cylinders for both gases. Gas welding differs from arc welding in terms of how heat is generated and the temperatures reached.

Having a knowledge and understanding of what gas welding is can benefit you if you’re trying to pursue a career in welding. Keep reading to find out more about how gas welding works and how it differs from the arc welding processes taught at Universal Technical Institute (UTI).¹

How Does Gas Welding Work?

Gas welding joins metals by using extreme heat. There are many gases that burn at extremely high temperatures, making this possible.

Base material is melted with a filler rod, using a flame from the combination of oxygen and fuel that goes through the welding torch. Fuel and oxygen are stored in pressurized steel cylinders, and gas flows through flexible hoses that the welder controls.

2 Types of Gas Welding

There are several gas welding techniques, but the most commonly used are oxy-acetylene welding and oxy-gasoline welding. Gas welding allows for the fusing of both nonferrous (not containing iron) and ferrous metals plus eliminates the need for electricity to get the welds going.

Oxy-acetylene welding uses a combination of oxygen and a fuel gas (typically acetylene) and is used primarily for welding thin metal sections.

Oxy-gasoline welding utilizes a combination of oxygen and gasoline. This method can be more effective than oxy-acetylene for torch-cutting steel plates.

Gas Welding Equipment

Gas welding is a lot like other welding processes regarding the type of equipment being used. A welding torch is used, which contains a mixture chamber that houses a combination of fuel and oxygen.

Control valves are present for each gas being used so the welder can control the amount being released from the cylinders. There are both fuel and oxygen cylinders.

GMAW and GTAW Welding

There are a few types of welding utilizing a shielding gas that are taught as a part of the Welding Technology program at UTI. Students are taught about the procedures and equipment used to perform these types of arc welds:

• Gas metal arc welding (GMAW): Also known as metal inert gas (MIG) welding, GMAW works when an electric arc is formed between the workpiece and the wire electrode. It utilizes constant-voltage equipment to create heat from a direct current electric arc. Current is carried from an electrode sent through the welding gun, accompanied by an inert shielding gas to prevent contamination.
• Gas tungsten arc welding (GTAW): Also known as tungsten inert gas (TIG) welding, GTAW uses constant-current equipment to generate heat. The GTAW process uses a tungsten electrode with a high melting point that delivers current to the welding arc, melting the metal in the process. It’s accompanied by an inert shielding gas that keeps it from getting polluted.

Arc Welding Shielding Gases

Shielding gases are important when performing GMAW and GTAW welds. The purpose of using a shielding gas in these types of welds is to help protect the weldment from oxidation and contamination.

The gases used in these processes are either inert or active. Inert gases are not chemically reactive and are suitable for all GTAW welds and nonferrous metals using the GMAW process. The most commonly used inert gases are argon and helium.

Active shielding gases are mixtures of carbon dioxide, argon and oxygen, which react to the weld puddle and melting wire. Developed primarily to weld carbon steels, these are not suitable gases for GTAW welds.

Argon is great for shielding welds that are in the flat position and have deep grooves, and it is often used on its own with aluminum and nonferrous metals or alloys. Pure argon is the most common shielding gas used for both GMAW and GTAW welds.

Helium is often used for mechanized applications but isn’t as effective with manual welds. It is considered a great gas for shielding welds with magnesium, copper and aluminum. It is typically only used on its own for more specialized GTAW applications.

Sometimes, a combination of both argon and helium is utilized in GMAW and GTAW welds.

Gas Welding vs. Arc Welding

There are several differences between gas welding and arc welding methods, even though the use of gas is present with the GMAW and GTAW methods discussed above.

The major difference between the two processes is how heat is generated. Arc welding uses electricity to generate heat for the melding of metals, but in gas welding, flammable gases are used. If there is no access to electricity, gas welding becomes the more viable option.

Also, arc welding generates higher temperatures than gas welding. Arc welding temperatures are typically around 6,500 degrees Fahrenheit, compared with around 5,600 degrees for gas welding.

Pursue a Career in Welding with an Education From UTI

If you’re interested in learning more about welding methods and want to pursue a career in the industry, the 36-week Welding Technology program at UTI can teach you the skills you need.

The UTI welding program covers both oxy-acetylene welding and arc welding methods, and students can graduate with the training needed to pursue an entry-level role as a welder.

Request more information to see how you can prepare for an in-demand career or call 1-800-834-7308.