Welding is a metal fabrication process that is used to connect two pieces of metal into a monolithic structure. The joint location is heated to melting with a torch or an electrical arc, and the gap is filled in with additional metal material in the form of a welding rod or wire. Welded connections, when created properly, can be as strong as or stronger than the base material.
Types of Welding
The primary types of welding include:
- Gas Welding – This process uses a gas torch to locally heat and melt the base metal. The most common gas combination used for welding is a mixture of oxygen and acetylene. Gas welding is commonly used for welding pipes. Because the temperature of the torch flame can be varied, gas welding equipment can also be used for brazing, cutting, and heating metal for bending.
- Arc Welding – Arc welding employs an electric current to locally melt the base metal. There are several types of arc welding, with each type being appropriate for different metals, equipment, and conditions.
- Spot Welding – Spot welding is used to join thin sheets of metal using an electric current to create a weld at a single location. Spot welding is especially applicable to robotic processes, and robots perform hundreds of spot welds in automobile assemblies.
Other welding processes, such as beam welding, are more recent innovations and only currently used in specific applications.
Welding Applications
Welding is used in nearly every industry, from transportation to electronic equipment. Given the right equipment, welding can be performed underwater or in the vacuum of space. Welding is generally performed on steel parts, but can also be used to join aluminum parts, although some aluminum alloys are easier to weld than others.
Welding Safety
Welding invariable involves high temperatures, electrical currents, or both, and extreme care has to be taken by welders to protect themselves. Some safety equipment includes:
- Welding Masks – Welding masks include shields that cover the head and neck, and include darkened glass to protect the eyes from the intense light of the welding spark. Welding masks are generally hinged, so that the welder can easily lift the mask to look at his work without removing the mask completely.
- Gloves – Gloves protect the welder’s hands from sparks thrown off by the welder and burns from the heated metal.
- Aprons and Coveralls – Welders often wear leather aprons or other covering garments to protect themselves and their clothes from burns.
In addition to personal safety equipment, welders often operate behind tinted shields to prevent passersby from seeing the welding spark directly.
The welding process results in a permanent, strong bond between two metal parts that will not shift or creep over time.
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