The anti-corrosion properties
and capabilities—mostly resulting from the material characteristics and alloying elements of these
steels—are also influenced by the stages and processes of stainless steel sheet manufacturing.
Therefore, the method of production can directly impact the price, properties, features, applications,
and more. Below, we introduce the most important methods in the stainless steel sheet production
process.
What is Steel?
Stainless steel is an iron-based alloy that, in addition to a small amount of carbon, contains other
elements such as chromium, nickel, silicon, manganese, and nitrogen. The proportion of these
elements determines the final properties of the alloy. Chromium is of particular importance; without
it, stainless steel cannot exist. Chromium provides hardness and corrosion resistance—two vital
factors in stainless steels. The higher the chromium content, the greater the alloy’s resistance to
corrosion.
Chromium forms a thin passive layer of chromium oxide on the steel’s surface, which increases its
resistance to rust and corrosion. This high resistance is why stainless steel is also called
“corrosion-resistant steel.” However, it is important to note that the production process itself also
plays a significant role in defining the alloy’s properties.
Raw Materials Used in Stainless Steel Sheet Production
To produce stainless steel sheets, raw materials must first be prepared to obtain the desired alloy.
This alloy can be produced either by recycling or by combining iron with alloying elements. Raw
materials such as iron ore, nickel, chromium, molybdenum, silicon, carbon, and other elements are
melted and combined to create various stainless steel alloys.
The ratio of these raw materials and the refining process determine the alloy type. The intermediate
alloy is cast into ingots and then slabs (semi-finished flat products), which will be used to produce
sheets.
Stainless Steel Sheet Manufacturing Process
- Melting
Raw materials are placed in special furnaces and melted at extremely high temperatures. Today,
electric arc furnaces (EAF) are commonly used. This process typically lasts 8–12 hours until the
metal becomes molten. - Decarburization
Excess carbon is removed using argon-oxygen decarburization (AOD). For ultra-low-carbon
requirements, vacuum oxygen decarburization (VOD) is also employed. This step is critical for
determining tensile strength and hardness of the sheet. - Stirring
Stirring ensures proper chemical composition, uniform distribution of alloying elements, and
removal of unwanted components, ultimately resulting in a homogeneous sheet with consistent
properties. - Forming (Rolling)
The molten steel is cast into semi-finished products such as blooms, billets, and slabs. These are
then rolled into sheets or other forms using hot rolling or cold rolling:
- Hot Rolling: Performed above the recrystallization temperature, producing coils and plates with a
matte surface. - Cold Rolling: Conducted at room temperature, refining dimensions, improving surface quality, and
producing brighter finishes.
- Heat Treatment & Descaling
- Annealing: Relieves internal stresses, improves ductility, and enhances mechanical properties.
- Descaling: Removes oxide scales formed during hot rolling/annealing, typically through pickling or
electro-cleaning.
- Cutting & Finishing
Sheets are cut to required sizes and shapes using mechanical tools, plasma cutting, flame cutting,
or waterjet cutting. Surface finishes can range from matte to mirror polish, depending on the
intended application.
Hot Rolling vs. Cold Rolling Stainless Steel Sheets
- Hot Rolled Sheets:
- Larger sizes, matte finish.
- More affordable due to simpler equipment.
- Good flexibility, widely used in industries.
- Cold Rolled Sheets:
- Bright, smooth surface with tighter dimensional tolerances.
- Higher strength but less ductility.
- More expensive due to additional processing and equipment needs.
Conclusion
Stainless steel sheets are a popular material across industries due to their corrosion resistance.
They come in various grades and alloys, each suited for specific applications. Understanding the
technical specifications of stainless steel sheets is crucial for selecting the right product, ensuring
the best value and suitability for the intended use.
