Welding is the process by which heat is applied to soften two or more materials such as metals and thermoplastics; and pressure is applied to join them together. Over the years, different types of welding process have been developed. Here are the various welding processes used today.
Arc welding is a process in which electric current is passed between an electrode and the item being welded in order to form the welding arc. The process brings about the melting of the materials being welded making it possible for them to join together when they cool down. The arc welding which was invented in 1802 is the most common type of welding process today owing to its affordability and the fact that it embraces other popular welding types such as stick, MIG and TIG welding processes.
Arc welding is of two types, namely, consumable and non-consumable arc welding.
Forms of consumable arc welding
Stick welding is a manual welding technique in which a consumable electrode coated in flux is utilized in laying the weld is today considered an outdated process. Though stick welding is highly affordable but it does not produce solid weld. The weld produced through stick welding is not only porous but susceptible to element of weather. These imperfections make a stick weld to be less durable.
MIG which is an acronym for metal inert gas is a type of welding process in which two metal materials are joined together by the use of a wire connected to an electric current. An inert gas is used to shield the wire through which the welding stick passes through. MIG welding is very easy to use and requires lower degree of precision from the operator. But weld resulting from MIG which is mainly utilized in automotive, plumbing, robotics, construction and maritime industry is porous and dross.
Flux-cored arc welding makes use of a special tubular wire filled with flux is utilized. Unlike MIG welding techniques, it is the type of filler that is used here which will determine whether the shielding gas will be used or not. Flux-cored arc welding abbreviated as FCAW is also easy to learn, versatile and affordable. But it does not produce a visually appealing weld like other types of welding techniques.
Submerged arc welding
Submerged arc welding normally shortened as SAW is a welding type done underneath a blanket of granular fusible flux comprising lime, calcium fluoride, silica, manganese oxide and other compounds. The flux is able to act as a channel through which electric current is passed between the electrode and the welding material. In this method, the welder is not exposed to UV and infrared radiation. It does not require much preparation. It is quick and does not give much emission and fumes.
Non-consumable arc welding
TIG is acronym for Tungsten Inert Gas provides pure and high quality weld using a non-consumable tungsten electrode and inert gas. In this type of arc welding, the welding arc for melting a metal wire is created by the passage of electric current via a tungen electrode.
Electroslag welding is a type of non-consumable arc welding utilized in joining large, thick and nonferrous materials which are normally vertically positioned. Here an electric arc struck by wire and flux are fed into the welding puddle until the slag gets to the electrode to end the arc. It is widely used in the maritime and aerospace industries but it requires high level of expertise.
Atomic Hydrogen Welding shortened as AHW is a type of welding in which two metal tungsten electrodes are placed in an atmosphere of hydrogen and this results in the breaking up and recombining of hydrogen molecules in an explosion of heat that can rise above 3000 degree Celcius in temperature.
Carbon Arc Welding (CAW) which is hardly utilized today is the first arc welding process to be invented. It uses non-consumable carbon electrode to heat metals up to 3000 degree Celsius in order to melt them.
Electrogas welding is non-consumable arc welding that resembles electroslag welding except that the arc is struck continuously and is never extinguished throughout the process. It is mainly utilized in the construction of storage tank and ships.
Gas welding is a type of welding technique that is also referred to as oxyfuel or oxyacetylene welding. In this welding process, the temperature of the flame of the welding torch is increased to up to 3500 degrees Celsius by combining fuel gases and pure oxygen.
Resistance welding is a welding technique in which force is applied to the adjacent surfaces before electric current is passed close and upon the surfaces to generate high heat. Resistance welding has different variations.
Energy Beam Welding (EBW) is done in a complete vacuum a beam of high-velocity electrons are fired at the welding materials.
Other types of arc welding are:
Gas tungsten arc welding
Shielded-metal arc welding
Solid-state welding does not make use of any filler material rather high temperatures that are below the melting point of the materials to be welded are used for the welding. Solid-state welding is available in a number of types which include ultrasonic welding, friction welding, cold welding, explosion welding, magnetic pulse welding, high frequency welding, diffusion bonding, exothermic welding, roll welding, induction welding and hot pressure welding.