How is Stainless Steel Produced In 10 Steps
Stainless steel is an extremely useful material. It is non-magnetic and corrosion resistant. The different alloys of stainless steel are used to easily integrate with application environments.
Pipes made of steel and other metals are not as durable and reliable as stainless steel. Stainless steel exhibits excellent corrosion and wear resistant properties.
Method of Production of Stainless Steel
When producing stainless steel, we need to pay attention to the raw materials used as well as the steps taken for production:
- Raw Materials Used
The raw materials are steel and chromium. For other alloys, carbon, nickel, manganese, nitrogen, and other elements can also be used.
- Steps of Production
Before the production process begins, decision regarding the constituents and their composition are made. This will depend on the application demands. The following are the steps of stainless steel production:
- Melting the Metal
Stainless steel bars, pipes, and tubes are manufactured inside a blast furnace. The raw materials are subjected to 8 to 12 hours of high temperatures in an electric furnace. The molten metal is poured in molds, and cast into various shapes. At this stage, the steel is present in semi-finished form.
- Forming the Metal
The semi-finished metal if needed will be put through some more forming processes. In this process, the tolerances of the metal are decided. The metal will then be hot rolled. This allows the manufacturers to produce the metal in various shapes like round, square, rectangular. The thickness and other specifications of the metal can be adjusted during this process.
- Heat Treating Process
After it is completely formed, the metal will be heat-treated. This process is known as annealing. This process helps soften the metal and reduce internal tension. The steel can also be treated for higher levels of strength, or fracture toughness.
- De-scaling the Metal
After annealing, the surface of the stainless steel develops some scales. Processes like pickling and electrocleaning are used to remove scales from the stainless steel. Pickling involves dipping the material in nitric-hydrofluoric acid. In the process of electrocleaning, a cathode and phosphoric acid is used to pass a current onto the surface of the stainless steel. Both the processes are effective in removing the scales or de-scaling the material. Depending on the final product, the steel might be subjected to hot and cold rolling as well.
- Further Processes (Repetition)
After the hot and cold rolling process is conducted, the annealing and descaling process will be repeated. On completion of the final descaling process, the product will be cold rolled. This is the final step in stainless steel fabrication. Cutting and cleaning steps will follow these fabrication processes.
- Cutting the Metal
The steel is then cut in the desired sizes. The product will be trimmed, sheared, and sawed. If shapes need to be punched out, then metal punches and dies will be used. Nibbling can also be used to fabricate irregular shapes. Apart from the traditional methods of cutting metal, flame cutting, plasma jet cutting and waterjet cutting can also be used. The employment of these processes depends on the properties of the metal, end use, finish required, and of course the budget.
- Metal Cleaning
Before polishing, the metal is thoroughly cleaned. This helps in creating a better surface for the polishing to take place.
- Polishing the Metal
Different grades of polishing are available in the market. The polishing grade of the stainless steel will vary according to the final use of the product. For example, for sanitary use, the polish is different. It is conducive to the applications in the food, medical, and other such industries. A variety of dull, polished, and mirror finishes are available. These finishes serve different advantages but on a general level, they help in better corrosion resistance. Some applications might require rough finishes as well. The type and grade of finish will be decided according to the application. Different grades of finishes are possible by using methods of annealing, cold rolling, hot rolling, wire brushing, pickling, etc. Reflective and mirror-like finishes are possible when the surface is polished with different grades of abrasives and buffed for a period of time.
- Welding the Metal
Depending on the need of the customer, the metal can be welded as well. Different types of welding processes will be employed according to the metal type.
- Shipping the Metal
Once all processes have been undertaken, the metal is ready to be shipped to the suppliers.
It is important to note that the manufacturing process will differ depending on the product being produced. The casting and forming methods are different for the type of alloy being used. Here, we will also take into consideration the shape of the final product.
Stainless steel bars and pipes are used in a variety of applications like automobiles, manufacturing equipment, building construction, pulp and paper manufacturing, shipbuilding, aircraft fabrication, and many more. Due to the useful properties of stainless steel, it is the preferred material used to manufacture various products.