Production process of stainless steel
Stainless steel is widely used in many industries due to its corrosion resistance, strength and durability. Production of stainless steel can be quite complex and typically entails a variety of manufacturing processes. This article provides a brief overview of the production process of stainless steel.
The first step in the production of stainless steel is the melting of raw materials in electric furnaces. Typically, steel scrap, concentrated ore, and ferroalloys are used as the raw materials. Known as ‘charge materials’, the scrap and concentrated ore are melted by the electric arc furnaces and the ferroalloys are added for specific properties, to impart corrosion resistance.
The next phase in the production of stainless steel is the refining of the melts and casting of semi-finished items, such as blooms and billets. Depending on the requirements, the refining process can include de-sulphurization and de-phosphorization, as well as removal of other impurities from the melts. During the casting process, the molten steel is poured into the moulds and the semi finished items are then cut to standard shape and size.
The third step in the production of stainless steel is the rolling. In this phase, the billets are heated and then passed through a series of rolling processes, such as plate rolling, seamless tube rolling, or bar rolling. This is done in order to impart the desired shape and size to the finished product.
The fourth step in the production of stainless steel is heat treatment. During this process, the steel is heated in a furnace and then cooled rapidly, or cooling is done slowly in a furnace. Heat treatment is essential for certain inoculants and ferritic stainless steels.
The final stage in the production of stainless steel is surface treatment. Once the rolling and heat treatments are complete, the material may be subject to further surface treatments, such as pickling and passivation processes. This helps in creating a uniform and corrosion resistant surface. In addition, other treatments, such as electrolytic polishing, may also be applied to create a polished and aesthetically pleasing finish.
The production of stainless steel described above generally is used for wrought stainless steels, but stainless steel can also be produced by casting or number of other processes. Stainless steel can also be produced using powder metallurgy. In this technique, powdered metals are compressed and sintered to form a monolithic piece of stainless steel.
Overall, the production of stainless steel is a complex process which includes a variety of steps, treatments and processes. Each step plays an important role in ensuring the optimal performance of the stainless steel and maintaining its corrosion resistance, strength and durability.
