Stainless steel is manufactured by mining chromite, converting the chromite to ferrochrome, melting the ferrochrome down with several other elements and putting the melted slabs through several temperature-regulation procedures. To be considered stainless steel, the final product must contain at least 11.5 percent chromium.
Initially, chromite is crushed and turned into chromite concentrate. The chromite concentrate is taken to a facility with a sintering plant and electric smelting furnaces. The concentrate is combined with other raw materials and converted into ferrochrome, which is a key component of all stainless steels. From there, the ferrochrome is taken to a steel melting shop and melted down with recycled steel, nickel and molybdenum oxide. The end product is a slab of stainless steel that must then undergo hot-rolling and cold-rolling processes.
The hot-rolling process turns the slabs of stainless steel into coiled bands. This is done by transporting the slabs to a furnace and heating them to a temperature of more than 1,000 degrees Celsius. The slabs are rolled backward and forward, eventually forming a band-like shape with reduced thickness. They are then coiled and can either be sold to a customer or undergo a cold-rolling process. During the cold-rolling process, the coiled bands are unrolled and undergo a chemical treatment that helps improve their finish.