Welding is a fabrication technique in which two or more materials are fused or joined together by the aid of pressure or heat. Sometimes both pressure and heat are used to fuse the materials that eventually join as the materials cool.
Generally, welding is done on thermoplastics and metals wherein high heat is used to melt the materials together and then let them cool down, causing fusion. Besides, you can also join both similar and dissimilar metals by the application of heat.
Table of Contents
Basic Welding Analogies
Let’s get a brief overview of Common Welding Terms:
- Parent Metal or Base Metal: It is the metal that is to be joined through welding, razing or braze welding.
- Filler Metal: This is the metal added during welding.
- Welding Torch: it is a device used for gas welding that controls the flow of gases to be used in welding.
- Cutting Torch: The equipment used in gas cutting which controls the gases. These gases are used for preheating and cutting metals.
- Brazing: It is a welding technique that uses a filler metal that liquifies above 800 F. this metal is distributed in the grooves or joints via capillary action.
- Flux: It is a cleaner that cleans metal to be welded. It releases the trapped gases in the metal, dissolves rust or corrosion and so on.
- Electrodes: these can be of different materials or metals which conduct the welding current between welding arc and electrode holder.
Types of Welding
Let’s quickly come to the different welding types which include arc, electron beam, laser, friction and resistance.
This is the most common type comprising conventional manual, semi-automatic and automatic techniques. All these processes utilize filler materials which are actually used for fusing or joining metals. The list of metal includes aluminum, nickel and copper alloys, stainless steel, titanium and cobalt.
The arc welding techniques are extensively used in various industries like automotive, oil and gas, aerospace, power, and other industries.
For a conclusive overview, I will list the most common arc welding types which I may cover in my upcoming blogs. These are basically the subtypes of arc welding.
1. Metal Inert Gas (MIG) Welding
MIG is also known as gas metal arc welding (GMAW). In this, the weldable surface is shielded with the help of inert gases like argon, helium, carbon-dioxide or their mixtures.This technique comprises a consumable electrode which is automatically fed through the nozzle into the welding arc.
MIG is suitable for welding both non-ferrous and ferrous metals. Also, this process is rapid, economical and works well to weld thin sheets. It is helpful for long welds without any interruption. Thus, it is mostly used in automobile industries.
2. Tungsten Inert Gas (TIG) Welding or Gas Tungsten Arc Welding (GTAW)
In GTAW, a non-consumable tungsten electrode is utilized to strike an arc with your weld workpiece. This electrode generates a stable arc at a constant current. The shielding is given by the gas such as Helium, Argon or their mixture.
It is suitable for welding aluminum, magnesium and so on. GTAW is able to produce autogenous welds. Not only this, it is capable of producing high quality welds with a decent surface finish.
3. Gas Welding
It is a process in which the metals are joined or fused by melting them with the aid of heating with a flame or arc produced by the reaction of fuel gas and oxygen. One of the famous methods is the Oxyacetylene welding in which high flame temperature is used.
Besides, the flux even helps in cleaning and oxidation of weld metal. This flux melts down, solidifies and then forms a slag on the weld metal. Further, oxyacetylene welding is applied with or without pressure and it can be used with or without using filler materials too.
The merits of gas welding are that it is portable, easy to use, low maintenance and inexpensive. Whereas the disadvantages are they have limited power density, low welding speed, severe distortion, and are not suitable for welding reactive metals like zirconium, titanium etc.
4. Flux Cored Arc Welding (FCAW)
FCAW is quite similar to GMAW. The exception is the electrode used in this process is tubular in shape and filled with flux (hence called flux cored). Such cored electrodes generate stable arcs, better weld contour and improved mechanical properties of the weld. Also, this technique doesn’t need external shielding
5. Plasma Arc Welding
This arc welding technique is very similar to GTAW. The key difference is that in plasma welding, the electrode is positioned inside the torch body so that the plasma arc is easily separated from the shielding gas envelope.
This process comprises two inert gases, one creates the arc plasma and the other one shields the arc plasma. It works well for materials such as aluminum, steel and so on.
6. Stick Welding or Shielded Metal Arc Welding (SMAW)
SMAW is one of the oldest and versatile techniques. It is used in 50% of the industrial welding processes. In this, by touching the tip of the coated electrode against your workpiece, an electric arc is produced and then withdrawn to balance the arc.
Some of its merits are that it is easily maintained, portable and best suited for thickness 3-19 mm. While its demerits include high labor cost, multiple passes are required for slag cleaning.
Electron Beam Welding (EBW)
In this technique, a beam of high-velocity electrons is used to fusion joining the materials. The strong kinetic energy of the electrons changes into heat energy on colliding with your workpieces. This impact melts the materials together.
To perform this technique, a vacuum chamber is used to avoid the beam from dissipation. Further, the electron beam welding is used in joining thick sections which makes it suitable for nuclear power, aerospace, rail and automotive industries.
The laser welding techniques are majorly used for joining thermoplastics (polymer plastics). In this process, a laser is used to generate a focussed heat for deep welds, barrow and high fusing rates.
Since this technique includes a high welding speed so it is ideally used in high volume applications mostly in automotive industries. Besides a laser, air can be used to join the materials.
As the name indicates, the fusing of material is done with the aid of mechanical friction. This technique can be easily performed on a variety of materials such as aluminum, steel and even wood.
The mechanical friction creates heat to soften the materials which further gets mixed to create a joint as they cool. Further, unlike arc welding, friction welding doesn’t utilize any filler metals, shielding gases or flux.
This process is broadly used in the aerospace industry and also in joining non-weldable lightweight aluminum alloys. The notable attribute is that this can be used for bonding wood without using any nail or adhesives.
The last type on my list is resistance welding which is a swift technique and largely used in automotive industries. It can further be categorized as:
1. Resistance Spot Welding
Spot type of resistance welding utilizes heat between the two electrodes. This heat is applied to the small areas since the materials are clamped together.
2. Resistance Seam Welding
In the seam welding, the electrodes are replaced with the rotating wheels. These wheels generate a continuous leak-free weld.
Summing it Up
This was brief and basic information about the welding types. Welding, fabrication and manufacturing have endless techniques and processes. As you dive in, you will get to explore new things every day.
I will try to bring such guides for you so that you can explore the welder within you. Keep reading and share your thoughts on this particular guide.