How is Stainless Steel Made?
1. Melting and Casting
The raw materials are melted together in a furnace, which usually requires about 8-10 hours of intense heat. When the steel is liquidised, it's cast into semi-finished forms such as blooms, billets and slabs, rods and tube rounds.
2. Forming
The steel is heated and passed through huge rolls. Blooms and billets are formed into bar and wire ,and slabs are formed into plate, strip and sheet which are all available in different sizes.
3. Heat Treatment
After the stainless steel is formed, it needs to be annealed. Annealing is a process where the metal is heated and cooled to relieve internal stressors and soften the metal. The process is delicate as the steel is sensitive to different cooling rates and temperatures.
For example, a rapid cooling process can increase the strength of steel without affecting toughness. Different types of steel receive different treatments.
4. Descaling
Annealing causes a scale or build-up on the steel, which can be removed with several processes. Pickling uses a nitric-hydrofluoric acid bath to clean the steel. Electrocleaning applies an electric current to the surface of the steel using a cathode and phosphorous acid. The descaling process will depend on the type of steel.
5. Cutting
Cutting is usually required to get the desired shape or size before the steel is finished. Mechanical cutting is done with a variety of methods, such as straight shearing with guillotine knives, circular shearing with circular knives, sawing using high-speed blades, blanking and nibbling. Stainless steel can also be cut using flame cutting and plasma jet cutting.
6. Finishing
Surface finish is important in steel manufacturing, especially if the material is going to be customer-facing. In addition, steel is also easier to clean with a surface finish. There are several different types of finish, which include a dull finish, a bright finish, a reflective finish, and a mirror finish.
Once the steel has been through this process, it's ready to be sold.
What is Stainless Steel Used For?
Stainless steel is part of everyday life. Whether it's the knife and fork you use or the oil you put in your car, steel has probably had a direct or indirect impact on what you do.
Most industries use steel in some form, but some industries have a more active interest in the product, such as manufacturers that need parts for machinery or production.
Automotive industry – catalytic converters, exhaust systems, and structural purposes. Steel helps to reduce long-term maintenance costs, lifetime value and environmental impact.
Construction industry – facades, cladding and roofing. Stainless steel is known for its anti-vandalism properties and is popular for public equipment like ticket machines.
Mining & materials – stainless steel has played a part in many large-scale projects, with improved tools and better facilities for workers to live in.
Railway industry – stainless steel is corrosion-resistant and offers excellent mechanical properties, which is ideal for the railway industry. Austenitic stainless steel has been used for carriages, and ferritic stainless steel is used for freight wagons.
Oil and gas industries – stainless tanks, pipes, pumps and valves. The oil and gas industry relies on steel due to its corrosion-resistant properties.
