What Is a Billet?
Billets are a type of raw material used in metalworking.
Billets are generally cylindrical or rectangular, have a fixed length, and are mainly manufactured from metallic materials such as steel or aluminum. They are transformed into products of various shapes and sizes through casting and forging processes and are processed into bar, plate, or pipe materials.
Billets are usually mass-produced using equipment such as molten steel furnaces and continuous casting machines. Proper quality control is important because material uniformity, strength, and workability affect the quality of billets.
Uses of Billets
Billets are processed in a variety of ways, including extrusion, forging, cutting, welding, and cold forging.
- Extrusion
Construction materials, automotive parts, railroad parts, electric power equipment, etc. - Forging
Drill bits, milling blades, hammers, etc. - Cutting
Gears, bearings, pistons, valves, bolts, etc. - Welding
Manufacturing of structures, ships, bridges, pipes, tanks, plants, etc. - Cold Forging
Hammerheads, automobile crankshafts, valves, etc.
Properties of Billets
1. Strength
Billets are usually manufactured from high-strength metal materials. Therefore, they are resistant to physical loads and stresses and are not easily deformed or destroyed.
2. Durability
Billets have excellent durability and have the advantage that their performance is not easily degraded by repeated loading or prolonged use. The durability of billets is a factor in the crystalline structure and uniformity of the material.
Strength and durability are critical to the continued stable functioning of a product or structure. For example, parts and structures made from billets play an important role in the construction and automotive industries.
These products and structures must withstand external loads and environmental conditions and provide safe and reliable performance over the long term.
3. Uniformity
Billets are machined to a consistent shape during the manufacturing process, and their internal crystalline structure is uniformly aligned to ensure consistent material properties and performance. Uniformity is important for product quality control and reliability.
For example, in parts and structures made from billets, uniform material structure increases the dimensional accuracy of the product. Material uniformity also reduces variations in product strength and hardness, resulting in consistent quality.
4. Processability
Billets have uniform dimensions and crystalline structure, making them suitable for shape change, machining, drilling, and cutting. For example, they can be machined to the required shape and dimensions using a CNC machine or CNC lathe.
Having a certain shape and dimensions, it is relatively easy to control dimensional accuracy during processing. This ensures consistency and accuracy of product dimensions.
5. Heat Treatability
The heat treatability of billets allows the following processing
Adjustment of Strength
Heat treatment can change the crystal arrangement and grain size, increasing or decreasing the strength of the material.
Hardness Control
By controlling the appropriate temperature and cooling rate, the surface and internal hardness of billets can be altered.
Improvement of Durability
Heat treatment can improve material durability and creep performance by changing the crystal arrangement and grain growth.
Stress Relief
Billets can be relieved of internal stress by heat treatment. In particular, when billets accumulate stress during processing and cooling, heat treatment can release the stress and improve the stability of the material.
Types of Billets
There are many different types of billets. The following are some of them
1. Steel Billets
Steel billets are alloys consisting primarily of iron and carbon and are used as raw materials for steel products. Steel billets are melted at high temperatures and used for casting and manufacturing steel products. They are usually square or rectangular and are heated before being used in processing steps such as forging and rolling.
2. Aluminum Billets
Aluminum billets are materials consisting of pure aluminum or aluminum alloys. Aluminum is lightweight, corrosion-resistant, and a good conductor of heat and electricity. Aluminum billets are used in processing methods such as rolling and extrusion and are useful in a wide range of industries including automotive parts, aircraft parts, and construction materials.
3. Copper Billets
Copper billets are made of pure copper or copper alloys, which conduct heat and electricity well and are corrosion-resistant. Copper billets are used in the production of wires, tubes, and fabricated parts, and are formed by forging, rolling, extruding, and casting.
4. Magnesium Billets
Magnesium billets are made of a lightweight, high-strength magnesium alloy. Magnesium billets are used in processing methods such as extrusion and forging and are useful in the manufacture of engine parts, frames, wheels, etc.
5. Zinc Billets
Zinc billets are materials consisting of pure zinc and are used as raw material for galvanizing and zinc alloys. Zinc is widely used to protect iron and steel from corrosion and is a material used in the manufacture of building materials, automotive parts, electronics, etc.
Zinc billets are easily melted, and after melting, they are processed into the desired shape through casting or extrusion processes. In galvanizing, zinc billets are used as raw material for electrolytic plating to form a uniform zinc coating on metal surfaces.
Billets typically have a cylindrical or rectangular shape, but not all billets are necessarily the same. Depending on the material and industry, there may be additional specific types of billets, and they may have different names.
Other Information on Billets
How Steel Billets are Produced
1. Raw Material Preparation
Iron ore or scrap is fed into a molten steel furnace and melted to produce liquid steel called molten steel.
2. Casting
Molten steel is taken out of the furnace and poured into molds. The mold is shaped like a billet, and the molten steel cools and solidifies to form a billet. In casting, the quality and crystal structure of billets can be adjusted by vibrating the molds and cooling them with cooling water.
3. Scouring
To improve the quality of steel billets, scouring is sometimes performed. In scouring, impurities and unwanted gases in the steel are removed, for example, by desulfurization or deoxidization to improve the purity and composition of the steel.
4. Cooling
After casting, the billets are cooled. Cooling methods include natural cooling and water cooling. By selecting the appropriate cooling method, the crystal structure and physical properties of the billets can be adjusted.
5. Inspection and Finishing
The produced steel billets are inspected. The dimensions, appearance, and microstructure of the billets are checked to determine if they meet quality standards. Final finishing operations are carried out, and the surfaces are pickled if necessary.