What is welding?

Welding is the process of joining two materials such as aluminium, steel, plastic, brass, stainless steel, or polymer and fusing them together. Different welders use different kinds of energy sources such as gas, laser, flame, electric arc, friction, electron beam, or ultrasound. When joining two pieces of metal together through heat, the weld is stronger than the metal you're using, and you need to ensure you're using the correct metal for the type of weld you're going to use. Welding increases the rigidity and toughness of the metal.

Types of metal

Iron conducts electricity well and is very malleable but is rarely recycled. When it is recycled, it’s melted down and sent for re-refining.

Steel is generally stronger than iron. However, it's more challenging to work with since steel is much denser than iron, making it more difficult to bend. There are two primary choices for this alloy:

Tensile steel has varying levels of stiffness and toughness, is strong, and can be controlled through heat application.

Alloy steel has low levels of thermal expansion with a low modulus, meaning it’s more likely to bend.

How do you know which type of welding to use?

Welders do not only use different energy sources but also different processes of welding, like shield metal arc welding (SMAW), metal inert gas (MIG) welding or tungsten inert gas (TIG) welding.

Stick welding is also known as shield metal arc welding (SMAW) and is slightly harder to learn than MIG welding and uses a stick electrode welding rod. However, you can buy stick welding equipment for very little. SMAW is used for welding cast iron, steel, and stainless steel.

A MIG welding machine is used to join aluminium with other non-ferrous metals and join many types of alloys and metals. MIG welding uses a wire that is coated with a shielding gas that helps to keep the weld clean.

MIG welding is one of the easier types of welding. Bare wire MIG welding is used to join thin pieces of metal together. Flux core MIG welding is used outdoors and doesn’t require a flow meter or gas supply. MIG welding is preferred by DIY enthusiasts and hobby welders who don’t have money to spend on expensive equipment.

The TIG welding machine is used for reactive metals like magnesium and aluminium, which are joined together with this process. TIG welding uses a non-consumable tungsten electrode to create and burn the weld.

TIG welding is extremely versatile but is one of the more difficult welding techniques to learn. Two hands are needed for TIG welding. One hand feeds the rod while the other holds a TIG torch that creates the heat and arc used to weld metals such as aluminium, steel, nickel alloys, copper alloys, cobalt, and titanium.

Plasma arc welding is a precision technique commonly used in aerospace applications where metal is as thin as 0.38 mm. Plasma arc welding is a similar technique to TIG welding, except the electrode, is recessed and the ionising gas inside the arc creates heat.

Alternatives to welding

Occasionally, the application of heat may lead to crack formation, brittle phases, and alignment and fit problems. In these situations, special procedures are necessary. Among alternatives that can be considered, brazing and soldering require less heat and may provide acceptable properties to the joint.

Brazing and soldering are similar processes where materials are joined with the use of filler metal. The filler metal is distributed to flow between closely fitted surfaces to form a joint. For brazing, the filler metal needs to have a liquidus above 450°C, and for soldering, it needs to have a liquidus below 450°C.

What skills do you need to be a welder?

Welding is a trade skill that requires both education and training. You can get a qualification from a technical college or through an apprenticeship. Despite automation in various industries, there is a shortage of skilled welders.

Contact Tru-Butt for details

For all your welding needs, including welding machine repairs, welding transformer repairs or manufacturing, welding and gas cutting consumables, and welding safety equipment, contact Tru-Butt today for more information.