84 The process of casting was created in the Bronze Age (beginning 3,000 BC), when it was used to form most of the bronze pieces now found in museums. Define fine art in your own words. CASTING AND FORGING Hundreds of metalworking processes have been developed for specific applications and the method used depends on the metal involved and the part required. Common metal fabrication processes are forging and casting. Casting Metal casting is a process used in both manufacturing and fine art because it is an inexpensive way to create complex shapes and designs and to easily create multiples of the same object. During a metal casting process a metal is heated until it melts and is then poured into a mould to solidify into a specific shape. The metal and mould are cooled, and the metal object is removed and finished. Traditional metal casting techniques include: Lost-wax process: a molten metal is poured into a mould that has been created by means of a wax model. Once the mould is made, the wax model is melted and drained away; Molten metal Forging Forging is a manufacturing process involving the shaping of a metal through hammering, pressing, or rolling with a hammer or die. Forging is used to produce large quantities of identical parts, as in the manufacture of automobiles, and to improve the mechanical properties of the metal, as in aerospace parts or military equipment. It is more expensive for mass production than casting but produces much stronger parts. It is a process also used for plastic materials. Forging is often categorised according to the temperature at which it is performed: Polystyrene burns; gas escapes Cold forging is generally limited to relatively soft metals and improves material strength; Plaster casting: an inexpensive alternative which, however, can only be used with low melting point nonferrous materials, such as aluminium, copper, magnesium, and zinc; Die casting: molten metal is forced under high pressure into a mould cavity which is created using two hardened tool steel dies that have been machined into shape; Plaster Casting Process Support sand Polystyrene pattern Pattern Sand casting: sand is used to create a mould, and a liquid metal is poured into it. Sand casting is one of the most popular and simplest types of casting because sand insulates well, is relatively cheap, and can be formed into any number of shapes. Hot forging is for iron and its alloys and improves material ductility. die: stampo to drain away: defluire forging: fogliatura plaster: gesso 202 MECHANICS to pour: versare rolling: laminazione wax: cera