There are many types of welding we use to join metals together, some modern and some ancient in their creation. From forge welding with hammers in the Middle Ages, to the discovery of carbon arc welding in the 1800s, up to today’s more contemporary types of welding, such as arc welding, resistance welding, solid state welding, and stud welding, there have been many advances in the field.
Types of Welding
Read on to find out more about the many types of welding and how they differ in functionality and applications in our introductory guide:
Arc welding is one of the most prominent types of welding. Arc processes involve using the concentrated heat of an electric arc to join metal materials together. These processes fall broadly into two categories: consumable electrode methods and non-consumable electrode methods. This distinction dictates whether the process involves the electrode melting and becoming part of the welded joint or not melting and only acting as an arc conductor.
Another arc welding variable is the use of current; some methods require a specific type of current, whereas others are more versatile. Furthermore, some arc welding processes require shielding gas, whereas others do not. Find out more about some of the most prominent arc types of welding:
Shielded Metal Arc Welding (Stick Welding)
Developed during the 1950s, Shielded Metal Arc Welding (informally known as Stick Welding) uses a flux-coated consumable electrode with an AC or DC power source to create an electric arc between the electrode and workpiece materials. The arc melts the workpiece and electrode into a molten pool that forms a joint when it cools. This type of welding is also referred to Flux Shielded Arc Welding due to the electrode’s flux coating disintegrating into a shielding gas during heating.
Gas Metal Arc Welding (MIG Welding)
Gas Metal Arc Welding also creates an electric arc but between a consumable wire electrode and the workpiece materials. A welding gun feeds through the electrode and a shielding gas to protect against contaminants. As a result, the workpiece melts and materials join. The subtypes of gas metal arc welding are MIG welding (metal inert gas) and MAG welding (metal active gas). The process was originally developed for non-ferrous metals, such as aluminium, but eventually became the most common process for a range of materials including steel.
Flux-cored Arc Welding is a similar process to MIG welding but tends to use a flux-filled hollow electrode wire instead of shielding gas.
Gas Tungsten Arc Welding (TIG Welding)
This welding process is commonly known as TIG welding (TIG standing for tungsten inert gas). Gas Tungsten Arc Welding requires a non-consumable tungsten electrode, a constant current power source, and an inert shielding gas to create a plasma arc (which consists of metal vapors and highly ionized gas). This process allows for more operator control than Stick or MIG welding, making it suited to welding thin sections of stainless steel and non-ferrous metals. As a downside, it is also a slower and more technically demanding procedure.
Plasma arc welding is a related type of welding, but in this case the plasma arc is separated from the shielding gas through placement within the welding torch body, exiting at a higher velocity via a copper nozzle.
Submerged Arc Welding
Submerged Arc Welding creates the electric arc beneath a bed of flux powder, which provides shielding gases and slag as well as alloying elements for the molten pool. The flux layer drastically reduces heat loss and works as an automated or semi-automated process. A hopper recycles the excess flux and slag layers are removed after welding.
In this process, a wire is fed into the welding area and flux is added to the electrical arc until the molten slag reaches the tip of the electrode and extinguishes the arc. Electroslag welding operators use a DC power source and tend to work with thick workpiece materials, such as low carbon steel plates and aluminium busbars. Electrogas welding is a similar process to electroslag welding, but the arc remains throughout the procedure.
Atomic Hydrogen Welding
Developed in 1926 by Irving Langmuir, atomic hydrogen welding (also known as arc-atom welding) creates an arc between two tungsten electrodes with hydrogen as a shielding gas. The resulting arc maintains itself independently from the workpiece. Though rarely used for most applications today, as MIG welding has become the preferred process, atomic hydrogen welding has proven invaluable for the welding of lifting chains.
Carbon Arc Welding
Arc types of welding began with the carbon arc welding process, which was patented in 1881. In this method, an electrical arc forms between a carbon electrode and the workpiece. Twin-carbon arc welding refers to creating an arc between two carbon electrodes. The process produces significant heat and a very bright light, whereas more modern techniques are much safer and more convenient for welders.
Resistance welding processes involve applying force upon and conducting a current through metal workpieces to heat up and melt them in areas predetermined by the electrodes and/or workpieces. Prominent resistance types of welding include:
Welders use spot welding for joining overlapping sheet metals in projects where strength and durability are not pressing concerns. Copper electrodes hold the workpieces together with force and an electrical current heats them to welding temperature. This process is more cost-effective than most arc welding methods. However, it has fewer applications and tends to harden and warp workpiece materials. We cover the differences between spot welding and stud welding in this guide.
As a modification of spot welding, projection welding involves locally heating and welding the raised sections (projections) on one or more the workpieces.
Butt welding joins together thick metal bars or plates by clamping electrodes to the workpieces and applying opposing forces. Heating occurs but often no melting, creating a solid-state weld.
This type of resistance welding joins sheet metals at seam joints by applying opposing forces with electrode wheels. The rotary wheels work to localise the current and heat generated.
In flash welding, the workpiece materials are placed at a predetermined distance from one another and current is applied, creating resistance in the gap between the materials and an arc for melting. Once the correct temperature is reached, the two pieces are pressed and forged together.
Also known as oxy-fuel welding, oxy welding, and gas welding in the United States. Oxyacetylene torch welding uses fuel gases and pure oxygen to increase flame temperature for the local melting of the workpiece. Engineers Edmond Fouché and Charles Picard developed the oxyacetylene welding method in 1903 and it has since become largely obsolete due to arc welding processes. However, this process is still popular for artwork applications and home use.
Solid State Welding
Solid state welding is characterised by the use of temperatures below the melting points of the base materials. Unlike resistance welding, it doesn’t always require pressure. Depending on the process used, solid state welding can take anything from milliseconds to hours. There are many types of solid state welding, including:
- Forge Welding: low carbon steel parts are heated and hammered together.
- Cold Welding: high pressure at room temperature coalesces very clean metals.
- Hot Pressure Welding: heat and pressure macro-deform the base material.
- Roll Welding: rolls induce heat and pressure deformation (instead of hammers).
- Friction Welding: a mechanical sliding motion rubs the materials together.
- Ultrasonic Welding: a transducer emits high-frequency vibrations to join materials together.
- Magnetic Pulse Welding: magnetic forces weld the workpieces together.
- Explosion Welding: a controlled detonation joins together rapidly moving parts.
- Diffusion Welding: joining refractory metals without affecting their metallurgical properties.
Electron Beam Welding
Electron beam welding uses a beam of high-velocity electrons in vacuum conditions to create powerful welds. The electrons transform from kinetic energy to heat when they hit the workpiece materials, melting them together.
Laser Beam Welding
The laser beam welding process uses a highly concentrated laser heat source for narrow and deep welds. Welders can use a continuous or pulsed laser beam, the former for deep welds and the latter for thin materials.
Stud welding is a specialised and highly effective method for joining studs and other fasteners to sheet metals. This type of welding avoids the pitfalls of many other stud joining processes, such as weakening the workpiece, studs working loose, cracking, and staining. Stud welding is rapid and creates strong welds without reverse marking or holes. Types of stud welding include:
Capacitors charge to a pre-set voltage depending on welding diameter. The stud makes contact with the sheet and then the capacitors trigger their energy to produce an arc and melt the pip. Return pressure forges the stud to the molten surface area of the sheet for a complete fusion. CD stud welding is very cost-effective and ideal for thin workpiece materials. However, the sheet surface needs to be clean and flat.
The Drawn Arc process involves triggering a pilot arc while the stud lifts to a pre-set height. The arc melts the weld end of the stud to create a molten pool. Return pressure forges the stud into the pool and the accompanying ferrule shapes the fillet. DA stud welding is the best process for attaching studs to thicker parent materials of 0.7mm and above, as it achieves strong welds. It is costlier than CD and requires ferrules but tolerates uneven surfaces and imperfections.
Short Cycle Stud Welding
The Short Cycle process has similarities to both CD and DA stud welding. Like CD stud welding, SC stud welding does not require ferrules and can use the same studs; like DA stud welding, the SC method is more tolerant of uneven and dirty surfaces. However, it achieves deeper welds than CD and costs less than DA.
Taylor Studwelding is a leading manufacturer and supplier of stud welding machines that are capable of the CD, DA, and SC types of welding processes. We have extensively tested all our equipment to ensure the strongest and most effective welds on a variety of metals. For more information browse our machines online or get in touch with us to find out what stud welding can do for you.