hot rolling stand after withdrawal to take advantage of the metal's hot condition to pre-shape the final strand. Finally, the strand is cut into predetermined lengths by mechanical shears or by travelling oxyacetylene torches, is marked for identification, and is taken either to a stockpile or to the next forming process. In many cases the strand may continue through additional rollers and other mechanisms which may flatten, roll or extrude the metal into its final shape. Developments since the mid 1980s reduced the thicknesses that can be cast, initially to transfer bars of ~50mm thickness, also called thin slabs, and then more recently down to thin strip castings of 2mm thickness. Casting machines for aluminium and copper Aluminium and copper can be cast horizontally and can be more easily cast into near net shape, especially strip, due to their lower melting temperatures. Range of continuously cast sections Casting machines are designated to be billet, bloom, slab or strip casters. Slab casters tend to cast sections that are much wider than thick: Conventional slabs lie in the range 100–1600 mm wide by 180–250 mm thick and up to 12 m long with conventional casting speeds of up to 1.4 m/minute; however slab widths and casting speeds are currently increasing. Wider slabs are available up to 3250×150 mm Thick slabs are available up to 2200×450 mm at a specific steel facility, generically ranging typically from 200mm to 300mm Thin slabs (low-carbon steel): 1680×50 mm at a specific facility, generically ranging from 40mm to 110mm thick depending on an individual machine's design Conventional bloom casters cast sections above 200×200 mm. The bloom length can vary from 4 to 10 m Billet casters cast smaller section sizes, such as below 200 mm square, with lengths up to 12 m long. Cast speeds can reach up to 4 m/minute. Rounds: either 500 mm or 140 mm in diameter Conventional beam blanks: look similar to I-beams in cross-section; 1048×450 mm or 438×381 mm overall Near net shape beam blanks: 850×250 mm overall Strip: 2–5 mm thick by 760–1330 mm wide Startup and control of the process Starting a continuous casting machine involves placing a dummy bar (essentially a curved metal beam) up through the spray chamber to close off the base of the mould. Metal is poured into the mould and withdrawn with the dummy bar once it solidifies. It is extremely important that the metal