The fabrication process that joins materials (usually materials such as metals or thermoplastics) by using great degrees of heat to melt and fuse the parts together and allowing them to cool. Distinct from lower temperature metal-joining techniques like brazing and soldering, welding melts the base metal. Apart from melting the base metal, a filler material is generally added to the joint to form a pool of molten material known as the weld pool that cools to form a joint. It can be stronger, based on weld configuration (butt, fillet, full penetration, etc.) than the base parent metal. Pressure may also be used along with heat or by itself be used to weld. There are different types of welding used for different applications, few of which are given below.
One of the easiest types of welding for beginners, MIG welding is actually two different types of welding. The first one uses bare wire and the second one uses flux core. Bare wire welding is used to join thin pieces of metal together, while flux core MIG welding is used outdoors because it does not require a gas supply or flow meter. It is generally the welding of choice for hobby welders and DIY enthusiasts who don’t have the money to spend on costly equipment.
Also known as Arc welding, stick welding is the old fashioned style of welding. Stick welding is a bit more difficult to master than MIG welding, but with a little bit of practice at home, it can be mastered. Stick welding uses a stick electrode welding rod and requires little expenditure in terms of equipment.
An extremely versatile type of welding, TIG welding is one of the more difficult welding techniques to master. Unlike most other types of welding, two hands are needed for TIG welding. One hand holds a TIG torch while the other feeds the rod. The torch creates the heat and arc which are used to weld most commonly used metals, including steel, aluminum, nickel alloys, cobalt, copper alloys, and titanium.
Plasma Arc Welding
A precision technique in welding, plasma arc welding is most commonly used in aerospace applications where metal thickness can get as small as 0.015 of an inch. One such example would be welding on an air seal or an engine blade. The technique used in plasma arc welding is very similar to TIG welding, but the electrode is recessed, and it is the ionizing gases inside the arc that are used to create heat.
Electron Beam and Laser Welding
Electron beam welding and laser welding are extremely precise high-energy welding techniques.
Gas welding is hardly ever used anymore and has been largely replaced by TIG welding. The advantage of gas welding is that it only requires oxygen and acetylene canisters and hence makes it very portable.