Billet (manufacturing)

Semi-finished casting products are intermediate castings produced in a foundry that need further processing before being a finished good. There are four types: ingots, blooms, billets, and slabs.

Ingots are large rough castings designed for storage and transportation. The shape usually resembles a rectangle or square with generous fillets. They are tapered, usually with the big-end-down.

In the era of commercial wrought iron, blooms were slag-riddled iron castings poured in a bloomery before being worked into wrought iron. In the era of commercial steel, blooms are intermediate-stage pieces of steel produced by a first pass of rolling (in a blooming mill) that works the ingots down to a smaller cross-sectional area, but still greater than 36 in² (230 cm²). Blooms are usually further processed via rotary piercing, structural shape rolling and profile rolling. Common final products include structural shapes, rails, rods, and seamless pipes.

A billet is a length of metal that has a round or square cross-section, with an area less than 36 in² (230 cm²). Billets are created directly via continuous casting or extrusion or indirectly via hot rolling an ingot or bloom. Billets are further processed via profile rolling and drawing. Final products include and wire.

...
Wikipedia