Metal Welding

Depending On The Material And Production Specifications, Different Welding Methods Employed For Steel Fabrication.

1. Introduction

Welding is a metal fabrication process whereby two or more metal parts are fused together by means of heat forming a join as the parts cool. As there is no single welding process suited to all applications, different processes has different requirements and tools to operate.

The most common welding processes are MIG, FCAW, TIG and arc (Stick) welding. Each process comes with their pros and cons.

2. Welding Methods
  • MIG Welding

Figure 1 MIG Welding

MIG welding is one of the easier and most popular types of welding. It uses a shielding gas along the wire electrode which then heats the two metals to be joined. MIG Welding needs a constant voltage with direct-current power sources and is the most common industrial welding process used. CO2 is often used as a shielding gas for MIG Welding.

The major advantages of MIG Welding are;

  • Clean welds
  • Easy for learn
  • Continuous wire feed
  • Cost Effective

On the other hand, MIG welding can ideally be performed in workshops because wind might blow away the gas on site. Also the surface of the work pieces should be free from paint.

  • TIG Welding

Figure 2 TIG Welding

TIG Welding is an arc-welding process that uses a fixed consumable tungsten electrode to produce the weld. This process is much more time consuming and difficult than the other welding techniques. It is very common for welding non-ferrous metals and stainless steel.

TIG welding gives the operator greater control than other methods, resulting in strong, high-quality welds based on the talent and expertise of the welder. TIG Welding is also an indoor welding method. TIG Welding allows to weld very thin metals with high precision.

Apart from requiring very skilled welders, low speed, another pitfall of TIG Welding is their machines are very experience.

  • Stick Welding

Figure 3 Stick Welding

Stick welding, also known as Arc welding, is the most traditional method. It is a bit more difficult to master than MIG welding but much easier than TIG Welding. Stick welding uses a stick electrode welding rod. The stick uses an electric current to form an arc between the stick and the metals to be joined. With this particular type of welding, the welder follows a manual process of stick welding.This is often used in the construction project when welding needs to be carried on job site. Surface cleaning of the work pieces is not as important for stick welding as it is important in other welding techniques. It is one of the most cost effective welding method in terms of equipment and consumable cost.

Unlike MIG Welding, Stick Welding requires frequent rod changing and creates quite a lot of spatter. It also requires the cleaning of the weld.

  • Flux cored arc welding

Figure 4 Flux Core Welding

Flux cored arc welding is a semi-automatic arc welding process that is similar to metal active gas (MIG) welding. It uses a shielding gas similar to that used by MIG welding, but it can also be performed without a shielding gas. It is more productive than MAG welding. Like with MIG welding, flux cored welding is easy to learn and enables the formation of very clean welds on aluminium, mild and stainless steel.

It also requires less pre cleaning of metals than other techniques. The chances of porosity are also very low if FCAW is applied correctly. It is less prone to wind which makes it suitable for outdoor applications.

4. Conclusion

While there are a lot of welding techniques, the prevalent ones are listed above. Depending on several criteria such welding place, welding material, material type, budget, project requirements and operator experience, the ideal method should be determined in consultation with the project engineers.

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