Billet
A billet is a semi-finished casting or wrought iron product of square or round cross-section used for subsequent rolling or drawing. It is a length of metal that has been formed by casting or hot rolling and is ready for further processing. Billets are typically smaller than blooms and slabs.
Manufacturing and Use:
Billets are created through various processes, including:
- Continuous Casting: Molten metal is poured into a continuous casting machine, solidified, and cut into billets.
- Rolling: Larger sections like blooms are hot rolled to reduce their size and form billets.
- Forging: In some cases, billets can be produced by forging.
The primary use of billets is as feedstock for further manufacturing processes, most commonly:
- Bar Rolling: Billets are rolled into various bar products, such as reinforcing bars (rebar), merchant bars, and specialty bars.
- Wire Rod Rolling: Billets are rolled into wire rod, which is then drawn into wire.
- Seamless Tube Manufacturing: Billets are used in the production of seamless tubes.
- Forging Stock: Smaller billets can be used as input stock for forging operations.
Distinction from Blooms and Slabs:
Billets are distinguished from blooms and slabs primarily by their cross-sectional dimensions. While there isn't a universally agreed-upon definition, the general consensus is:
- Bloom: A bloom has a square or rectangular cross-section with a cross-sectional area greater than that of a billet.
- Billet: A billet has a square or round cross-section, smaller than a bloom, and is typically used for rolling into bars and rods.
- Slab: A slab has a rectangular cross-section, significantly wider than it is thick, and is generally used for rolling into sheet, plate, and strip products.
Material:
Billets can be made from a variety of metals and alloys, including:
- Steel: Carbon steel, alloy steel, stainless steel
- Aluminum
- Copper
- Nickel Alloys
The specific material used for a billet depends on the desired properties of the final product.