A billet is a cross sectional product, commercially produced. It is Produced through a manufacturing process of either directly using continuous casting or extrusion. The indirect method is also used to produced Billets. Indirect methods like hot rolling an ingot or bloom. This square or round cross section metal's final product are bar sticks and wire.
Sometimes centrifugal casting may be used to produce bullets. These bullets short circular tubes in shape. They are used as cylinder sleeves by grinding inner and outer diameters and machined to length. These bullets are not classified as semi finished products.