Forging: is the process of shaping heated metal by the application of sudden blows (i.e., hammer forging) or steady pressure (i.e., press forging) and makes use of the characteristic of plasticity of the material. A metal such as steel can be shaped in a cold state but the application of heat lowers the yield point and makes permanent deformation easier. Forging may be done by hand or machine. Forging by machine involves the use of dies and is generally used in mass-production. Hand forging or Black-smithy is employed for small quantity production and for special work. It is essentially a manually controlled process even though some machinery such as power hammers are sometimes used. Black-smithy is, therefore, a process by which metal may be heated and shaped to its requirements by the use of blacksmithy tools either by hand or power hammer. In smithy small parts are shaped by heating them in an open fire or hearth. Shaping is done under hand control using hand tools. This work is done in a smithy shop. Forging refers to the production of medium size and heavy parts in large scale using closed heating furnaces and heavy hammers, forging presses and machine
- Although the metal piece has to be heated to the correct forging temperature before shaping, less metal will be used than if the shape were machined from a solid block of metal.
- It enhances the mechanical properties of metals and improves the grain flow which in turn increases the strength and toughness of the forged components.
To be a forgeable metal, it should possess the required ductility. Ductility refers to the capacity of a material to undergo deformation under tension without rupture. The selection of a forging material is made on the basis of certain desirable mechanical properties inherent in the composition and/or for those which can be developed by forging.such as strength, resistance to fatigue, shock or bending, good machining characteristics, durability etc.