Machine shops mainly concentrate on cutting the metal material to a desired shape and size by removing of material on machine tools. Cutting of parts of metal is also done. Fabrication comprises various specialties in metalwork like blacksmithing, weldments produced during welding, making of boilers and iron making by ironmakers.
Welding is the most common process during steel fabrication. The machined parts formed are checked for accuracy by tack welding and assembling them together. If multiple weldments are ordered, a fixture is used to locate parts of welding. Covering the weldment in sand during cooling, using a fixture that is stout, and using staggered fashion in welding and designing the weldment to use the least amount of weld are measures taken during welding to prevent warping due to heat. Oxy-acetylene torch is used to straighten the weldment. To relieve stresses on weldments, they are put in low temperatures. Bidding is done by the various fab shops based on drawings by engineers. When one gets the contract, making of stairs for buildings, hand railings, making structured frames for heavy equipment and buildings and loose parts is done. Contractors mainly employ shops venturing in fabrication. Other specialties done by the fab shops according to specification of the customer are forging, drawing, brazing, chipping, punching, spinning, powder coating, oven soldering, heat treatment and extrusion.
Highly specialized fabrication may include sub-contract manufacturing, hydraulic, technical drawing and electricals. Raw materials commonly used by metal fabrication and include fittings, metal plate, welding wire, metal that has been expanded and formed, hardware and castings. After cooling of the weldment is done, it is painted, primed and blasted using sand. Any additionals are done depending on specifications by the customer.