Have you ever wondered what Types of Gas Welding Are Commonly Used?
“Gas welding” is a term you will hear if you spend much time around machine shops. It can mean different welding processes, depending on what kind of shop you are working in. The different welding processes use different tools and techniques and are useful for different kinds of projects.
What are the different types of gas welding used for? Understanding the basics of gas welding will help you figure out which process is best for your project. There are two different kinds of gas used in welding: shielding gasses, and fuel gasses.
Let’s start by looking at shielding gasses.
The extreme heat of welding enables chemical reactions to work much faster than they normally would. Oxygen and water vapor in the air can combine with your fresh, hot weld bead to cause rust and corrosion. This corrosion weakens the weld and makes your product less valuable.
To protect the weld from corrosion, welders use shielding gasses. The gas is blown through the electrode handpiece onto the hot weld bead, protecting the weld from corrosion for the crucial few seconds when it’s hottest. Shielding gasses have different characteristics. The best gas to use depends on what metal you are welding, what process you are using, and what the needs of your project are.
Some common shielding gasses include:
- Carbon Dioxide, or CO2. This is the least expensive shielding gas available. CO2 works best on carbon steels
- Argon is more expensive than CO2 but works on a broader range of materials. It is also blended with other gasses to improve performance and save money. Argon is used for stainless steel, aluminum, and other non-ferrous metals.
- Helium is a costly gas but gives the best heating and weld penetration. Helium is most often used for welding aluminum, copper, and other metals that disperse heat quickly.
- Oxygen is sometimes added to weld gas mixes to improve the working characteristics of the weld pool. However, it’s only used at very low rates because oxygen is corrosive to metal, especially when it’s hot from welding.
- Blends of gas are used in some circumstances to make welding easier, help the weld penetrate more deeply, or let you weld faster.
It’s best to plan your project in advance before you choose a shielding gas. The welding process, type of metal, and even the thickness of the metal you are welding will impact the type of gas to use. Check the project specs or the manual for your welder for recommendations on which gas will give you the best results.
MIG stands for “metal inert gas” welding. This welding process is formally known as “gas metal arc welding,” or GMAW. This kind of welding uses a wire that serves as both the electrode to create an arc and a rod to provide filler material. MIG welders consist of the following components:
- An electrode power source that produces power to create the arc for welding
- Wire spool and feeder holds a large quantity of the electrode/welding wire and a power feeder that pushes out the wire at the right rate
- A gas source that holds the shielding gas for welding
- Welding torch that feeds out the wire and pushes shielding gas over the weld. The welding torch is the piece you hold in your hand to perform the work.
MIG welding uses a variety of different shield gasses, depending on the materials being welded and the type of filler used. CO2 and blends of CO2 are the most common MIG welding gasses.
The torch is wired to both the gas source and the wire feeder. Pulling the trigger on the torch cracks an arc, starts gas flow, and makes the wire feeder push more wire out. This system is simple to use and an easy way to get good looking welds.
MIG is a popular process for beginning welders because it’s easy to learn and produces attractive results. You don’t have to worry about trying to crack an arc with a rod or getting filler placement just right as with TIG. You just pull the trigger, build a puddle, and start welding.
Tungsten inert gas, or TIG, welding is another welding process that uses gas. It is formally known as “gas tungsten arc welding,” or GTAW for short. This welding process uses an electrode made of tungsten and a separate filler rod.
Tungsten has an incredibly high melting point, so the heat of the arc isn’t enough to melt it. Instead, the electrode is used to heat the metal along the joint while you dab the filler rod into the joint to make a weld pool. TIG welding is known for making a very attractive bead (assuming you know what you are doing). It is often used for furniture and other decorative purposes.
The extreme heat of the TIG arc leads to corrosion problems if the metal is not shielded, so this process always requires the use of shielding gas. Argon is the gas most often used for TIG welding. For welding aluminum, copper, or very thick pieces of steel, helium may be used. Helium transfers heat to the metal more effectively than argon; it is an excellent choice for metals that conduct lots of heat.
The drawback of using helium is the cost. Helium/argon blends are also common in TIG welding. These blends have better heat transfer than argon, but at a more affordable price than pure helium. Many gas companies offer a range of helium/argon blends that help you balance weld bead penetration and cost.
Standard TIG welding setups include a welder, gas supply, a torch with a hand or foot control, and filler rods. Starting the arc with the controller starts the gas flow over the arc. Once the arc is working, you can start dabbing the filler rod over the joint to make a bead.
TIG is popular with advanced welders and people who want to show off their skills. It isn’t easy to get a perfect weld bead with TIG that has what welders call the “stack of dimes” look. However, once you are confident in your skills and have mastered this technique, it’s possible to fabricate lovely projects using a TIG welder.
Oxy-fuel welding is the original form of gas welding, but it is not as common today as it once was.
Unlike the processes that use gas to shield a weld bead made by an electric arc, oxy-fuel welding uses oxygen and a fuel source to heat the pieces to be welded. The heat causes the pieces to melt and fuse into each other. This may be done with or without a filler rod.
In addition to oxygen, a fuel source is needed. Acetylene is the most common, although other gasses like propane or butane can be used. The gas and fuel setup is the same for oxy-acetylene welding as for cutting, but a different torch is used.
The most significant advantage that oxy-acetylene welding has over MIG or TIG welding is that it doesn’t need electricity. This is handy for farmers, off-roaders, and other people who may need to perform welds in places where power isn’t available. The disadvantage is cost – it’s much cheaper to produce welding heat with electricity than by burning oxygen and acetylene.
You won’t get the prettiest welds with an oxy-acetylene setup, but it’s great when you crack the frame on your 4×4 while off-roading or crack a piece on your harvester in the field.
Even if you can’t bring the machine to the shop, oxy-acetylene welders let you bring the shop to the machine and get running again.
Here, you can find an article from our website about the different types of gas welding flames and their applications.
Gas is used in welding to protect the fresh, hot weld bead from corrosion. Different gasses are used to create heat and weld without electricity.
Whether you are looking for an easy welding method, one that can produce a lovely bead, or one that works without power, there is a gas welding method that is right for you.