Stainless Steel Manufacturing Process
The manufacture of stainless steel involves a series of processes.
The first step is melting, in which the ingredients are melted together in an electric arc furnace. The second is the removal of excess carbon, which is done by treating the molten metal in an AOD (argon oxygen decarbonization) converter. The converter reduces carbon by injecting a mixture of oxygen and argon. At this stage, other alloying elements such as nickel and molybdenum can be added to the AOD converter. When a low carbon content is required, VOD (vacuum oxidation decarbonization) converters can be used.
Next comes the tuning and stirring. Most stainless steels have very strict quality requirements. The tuning process even allows for fine-tuning of the chemical composition. Adjustment is when the steel is stirred slowly to remove unwanted elements and improve consistency while keeping the desired composition within temperature limits.
The forming step is to cast molten steel into shape. These forms may be patterns (rectangles), billets (circles or squares), plates, rods, or tubes.
Hot rolling is then carried out, that is, hot rolling occurs at a temperature higher than the recrystallization temperature of the steel. The exact temperature depends on the grade of stainless steel required. Stainless steel plates are heated and passed through high rollers. Cloth and blank form rods and silk. Slabs form plates, strips, and plates. It can also be cold-rolled if necessary. Usually cold rolled stainless steel plates are used where very precise dimensions or attractive surface treatments are required.
After rolling, an annealing treatment will be carried out. Annealing is used to soften stainless steel, improve ductility and refine the grain structure of the process. It is also used to relieve the stress inside the metal caused by pre-processing. During annealing, steel is heated and cooled under controlled conditions.
Descaling is required after annealing because of the formation of a scale on the steel.
Then there is the cutting process, the stainless steel plate can now be cut to the desired size. Mechanical cutting is the most common method. Other methods include flame cutting, which uses flame-cutting torches powered by oxygen, propane, and iron powder, or uses ionized gas columns with arc-starting plasma jets to cut metal.
The last is finishing, because the surface finish is very important for stainless steel plate products, especially where appearance is important.