Metal Fabrication is one of the traditional ways of creating heavy equipment and today many welding companies are providing a modern touch to this technique. Metal fabrication may be described as a value addition process that entails the construction of machines and structures from various raw materials.
There can be no doubt that metal fabrication welding imparts strength and stability for a working equipment or device. Metal Fabrication and welding for heavy industrial devices lends itself to different work patterns and outputs.
Fabrication is rather a wide term to denote building metal structures through the three different steps -cutting, bending, and assembling. The cutting part of fabrication is done by sawing/shearing/chiseling (either manual or powered); cutting is done via CNC cutters using laser, torch, or water jet). The bending is by means of hammering (manual or powered) or press brakes. The assembling is achieved mostly by welding – if not, through adhesives, riveting, threaded fasteners etc.
Structural steel and sheet metal are the standard materials for fabrication – not to speak of the welding wire, flux, and fasteners that will join the cut pieces. There are fabrication shops that undertake these jobs. The products produced by welders, which are often referred to as weldments are classic examples of fabrication. The field of welding continues to evolve with significant advancements in technology. There are highly skilled infrastructure fabrication welding operators who are adepts in basic welding and fabrication methods, blueprint reading etc.
Several welding processes are used in metal fabrication. The two most common welding processes we know for fabricating metals are TIG (Tungsten Inert Gas) welding and MIG (Metal Inert Gas) welding. The other name for TIG is GTAW (Gas Tungsten Arc Welding) and MIG also is oftentimes referred to as GMAW (Gas Metal Arc Welding).
The third is Arc Welding that is a type of welding that uses a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. You can use either direct (DC) or alternating (AC) current and consumable or non-consumable electrodes.
The term ‘Metal’ in Gas Metal Arc Welding denotes the wire that is used to create the arc. It is shielded by inert gas and the feeding wire also acts as the filler rod. MIG is a semi-automatic welding process and it is quite straightforward. Versatility is the key advantage of MIG welding process. It is capable of joining several types of metals and it can be performed in different positions.
TIG welding starts with a tungsten electrode shielded by inert gas and filler rod is fed into the weld puddle separately. The gas shielding that is needed to protect the molten metal from contamination and amperage is supplied during the TIG welding operation. TIG welding, though slower than MIG process, produces a more precise weld and can be used at lower amperages for thinner metal and even exotic metals.
Even though TIG is a well known welding process, it has some limitations. It requires greater welder dexterity, it yields lower deposition rates and it is costlier for welding thick metal sections.
Article Source: http://EzineArticles.com/6984155