Known for its excellent corrosion resistance, stainless steel is one of the most common and widely-used metals in the modern world. It has used in everything from heavy industry and architecture to automobile manufacturing, surgery, and even dentistry.
At Wasatch Steel, our steel services include numerous stainless steel options. A big part of the rise in stainless steel’s popularity has to do with changing manufacturing processes since the 1960s – let’s look at how stainless steel is made today.
Raw Materials and Chromium
Stainless steel is an iron alloy, but one that also contains added elements. These might include chromium, nickel, silicon, manganese, nitrogen or carbon. The various amounts of these elements will determine some of the final properties of the alloy.
Chromium is of particular importance here – there can be no stainless steel without it, in fact. Chromium provides hardness and corrosion resistance, two vital factors for stainless steel. The higher the chromium content, the more corrosion resistance is present in the material.
Steps to the Process
Here are the basic steps to the stainless steel manufacturing process:
- Melting: Raw materials are melted together in a furnace. This takes between eight and 12 hours until the metal turns to molten.
- Removing carbon: From here, excess carbon is removed by processing the molten metal in an Argon-Oxygen Decarburization converter. This reduces carbon and allows for alloying elements like nickel or molybdenum to be added. If a very low carbon content is needed, a Vacuum Oxygen Decarburization converter.
- Tuning: This allows for fine adjustments to chemical composition – the steel is stirred to remove unwanted elements and help with consistency.
- Forming: From here, the molten steel is cast into forms. These come in blooms, billets, slabs, rods or tubes.
- Hot rolling: While the steel is still at a temperature above its recrystallization threshold, hot rolling occurs. The steel is passed through high rolls – blooms and billets are formed into bar and wire, while slabs are formed into plate, strip and sheet.
- Cold rolling: This is a process using supporting roles to improve surface finishes when precise dimensions are needed.
- Annealing: The process used to soften the metal, improve ductility and refine grain structure. It also relieves internal stresses caused by processing.
- Descaling: Annealing may cause scales to form on the steel, but these can be removed using pickling or electrocleaning, two descaling methods.
- Cutting: Stainless steel can now be cut into various sizes, using mechanical cutting, flame cutting, or plasma gas cutting.
- Finishing: Finally, the surface finish will be applied if appearance is important at all. There are a few finishing options available here.
For more on the process of manufacturing stainless steel, or to learn about any of our steel services, speak to the pros at Wasatch Steel today.