To put it simply, gas welding is the process of joining metals using the heat transmitted from the flames. The process involves heating the juncture of two metals to a certain point so that they will melt and fuse.
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Even though it carries a relatively simple definition, the process of gas welding has many specifics. In this article, we will take an in-depth look into gas welding, its applications, advantages, and methodology.
Metals can be joined in many different ways. Gas welding is one of the most important ones because of its scope of application. Gas welding is one of the oldest forms of heat-based welding and remains the go-to option for many industries.
The reason why this welding technique has a great fanfare is because of its ease of use and low-cost nature. Carrying out a welding process with gas welding is relatively easy and does not necessarily require expert welders.
When a fuel such as Acetylene is used, the flame can reach up to temperatures of 3100°C. This temperature is lower than what we get from an arc welding machine, but the advantages such as cost savings in the form of simple equipment and labor make gas welding the best choice for repair and construction work.
As we discussed earlier in the article, gas welding is all about heating the ends of the materials to a point that they melt and fuse. To achieve this feat, the welder must have a piece of equipment that can create high-temperature flames.
Gas welding ticks this box using the combination of oxygen and highly flammable gas. Most commonly, oxygen is mixed with gases like acetylene, hydrogen, gasoline, propylene, butane, and others.
Each fuel has its characteristics that show upon combustion. Some fuel gases may burn at very high temperatures while others may not reach the same temperatures. Choosing one for gas welding depends on the type of project, cost, and flame control.
The most commonly used gas welding fuel gases are acetylene and gasoline. They are so popular in fact, many replace the term gas welding with either Oxy-Acetylene Welding or Oxy-Gasoline welding based on the fuel that they use.
Once the flame is put on the joint, it starts to gradually heat the metal. The high temperatures will cause the metal to melt and a weld pool to form. The filler material can be added per discretion at this point.
The outer zones of the flame protect the weld pool from the atmosphere. Completion of weld requires the welder to slowly remove the flame from the joint, giving it time to harden without oxidation.
Gas welding requires a system where two gases, oxygen, and fuel gas, can be safely mixed and burnt together. It also requires a mechanism for the welder to control the flames.
To satisfy all these conditions, gas welding equipment consists of:
A fuel cylinder: The fuel cylinder holds the fuel required for the combustion. The cylinder is sealed and is made from heavy-gauge steel to prevent the compressed fuel from weakening the cylinder.
An oxygen cylinder: The oxygen cylinder holds the compressed oxygen required for the weld. Both the oxygen and fuel cylinders are made to withstand the pressure from the respective gases.
Control valves: Both gases have their separate control valves. A control valve is used to control the amount of gas being released from the cylinder. Control valves are also crucial for controlling the fuel to oxygen ratio.
Mixer chamber: It is a housing in which the fuel and the oxygen mix. The control valves are used to regulate the flow of gases from the cylinder to the mixer chamber.
Welding torch: A welding torch contains the mixer chamber and the control values. At the other end of the torch is a nozzle where the fuel-oxygen mixture is burnt together.
Certain key features of gas welding make it so popular in the field. We will discuss some of them here.
Weld ferrous and non-ferrous metals: One of the great strengths of gas welding is that it can weld non-ferrous and ferrous metals together.
No requirement for electricity: When we compare gas welding to the other popular weld methods like arc welding, gas welding does not require any electricity to operate. Hence, you can use gas welding in places that do not have access to electricity.
Cheap Equipment costs: The initial capital for gas welding is very low as it doesn’t require specialized machinery.
Doesn’t require specialized labor: Gas welding doesn’t require highly specialized labor. This makes it easier to find gas welders, as well as keeps the labor charge low.
Portable equipment: The whole setup for Gas Welding is easily portable.
Disadvantages of gas welding
The popular term “no one-size-fits-all” is true for gas welding too. These are some of the disadvantages of using gas welding. These include:
- Not suitable for thick sections
- Cannot be used for high strength steel
- The slow rate of heating
- Cannot reach the temperatures of arc welding
- Doesn’t have a dedicated flux shielding system
Gas welding is used in a variety of industries. Here is a list of some of the most common applications of gas welding.
Repair works: One of the most common applications of gas welding is for repair works.
Fabrication of sheet metal: Thin to medium sheet metals are easily weld using gas welding.
Aircraft industry: Oxy-Acetylene welding is used in joining various aircraft parts.
Automotive industry: Used to weld parts of the frame and the chassis.
Joining High carbon Steel: Gas welding is very effective in melting high carbon steel.
Gas welding is one of the many weld methods that we use today. The low cost and the easy availability of labor make gas welding one among the most popular weld methods that we use today.
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Quite often, novice welders build their foundation in gas welding and then move forward to more advanced forms of welding. If you are looking to establish a career in welding, gas welding is an ideal technique to start.