Structural Steel Welding
If you require structural steel welding services for your home or business, you can’t afford to compromise on quality. Steel structures need to be fit for purpose, whether that’s supporting a domestic living room or a railway bridge; that means the welding work needs to be entrusted to an established, professional company with many years of experience of working with structural steel.
The Art and Science of Arc Welding
The idea of applying heat to melt metals and join them together may be easy to grasp but actually understanding and mastering the different arc welding techniques is another matter. While the basic principle, creating a high current, low voltage arc between an electrode and a base metal, is the same for every arc welding technique, there are important differences between them. The experienced welder will know which arc welding technique is most suitable for the project concerned and will be skilled in its execution.
Arc welding techniques can be broadly divided into those that use a shielding gas and those which rely on the burning of a flux to protect the welding environment from high-temperature oxidation and other types of contamination:
The most common arc welding method is shielded metal arc welding (SMAW), also known as ‘stick’ welding. This uses a consumable flux-coated electrode and coats the welded metal in solidified waste known as slag which must be brushed or scraped off afterwards.
Flux-cored arc welding (FCAW) differs from stick welding in that the flux is within the electrode. Some FCAW welding uses a gas shield whereas others don’t.
Gas metal arc welding (GMAW), often referred to as MIG (metal inert-gas) welding pipes non-reactive gases (e.g. argon or helium) through the welding torch. Adjusting the current, gas flow rate and type of gas, different welding effects can be produced.
Gas tungsten arc welding (GTAW) or tungsten inert-gas (TIG) welding makes use of a non-consumable tungsten electrode and a shielding gas.
Minimising Defects During Arc Welding
An important part of the welder’s role – particularly in structural steel welding – is to ensure that the final product is as free as possible from defects. Defects, such as weak spots and porosity, can lower strength and resistance to corrosion and an experienced welder will carefully control factors such as cooling rate and contamination to minimise defects.