Stainless steel is made from iron ore, silicon, chromium, carbon, nickel, manganese and nitrogen. The manufacturing of stainless steel comprises a series of processes. The raw materials are first melted in an elec
tric furnace. They are subjected to at least 12 hours of intense heat. Thereafter the mixture is cast into either blooms, slabs or billets, before taking on a semi-solid form. This initial form of steel is then processed via 'forming' operations that include hot-rolling into bars, wires, sheets and slabs. From here, the steel is subjected to annealing. This is a heat treatment in which the metal is first heated and then cooled under extreme, controlled conditions. The metal is thus treated for internal stresses and is duly softened and strengthened. This segment of processing stainless steel is also referred to as 'age hardening'. It requires careful monitoring of temperature and heating and cooling times. The aging temperature seriously affects metal properties; while lower temperatures generate high strength and low fracture toughness, higher temperatures result in a lower strength, but tougher material. The heat treatment involved in the manufacture of stainless steel depends on the type and grade of steel being produced. Annealing or the heat treatment leads to the development of a scale. The scale can be removed via several processes such as:Pickling or the use of nitric-hydrofluoric acid bath. Electro-cleaning or the application of an electric current, using phosphoric acid and a cathode. De-scaling of the material is introduced into the manufacturing process at different times, depending on the type of steel being produced.
tric furnace. They are subjected to at least 12 hours of intense heat. Thereafter the mixture is cast into either blooms, slabs or billets, before taking on a semi-solid form. This initial form of steel is then processed via 'forming' operations that include hot-rolling into bars, wires, sheets and slabs. From here, the steel is subjected to annealing. This is a heat treatment in which the metal is first heated and then cooled under extreme, controlled conditions. The metal is thus treated for internal stresses and is duly softened and strengthened. This segment of processing stainless steel is also referred to as 'age hardening'. It requires careful monitoring of temperature and heating and cooling times. The aging temperature seriously affects metal properties; while lower temperatures generate high strength and low fracture toughness, higher temperatures result in a lower strength, but tougher material. The heat treatment involved in the manufacture of stainless steel depends on the type and grade of steel being produced. Annealing or the heat treatment leads to the development of a scale. The scale can be removed via several processes such as:Pickling or the use of nitric-hydrofluoric acid bath. Electro-cleaning or the application of an electric current, using phosphoric acid and a cathode. De-scaling of the material is introduced into the manufacturing process at different times, depending on the type of steel being produced.For further details visit at : www.buzzle.com/articles/process-to-make-stainless-steel.html
