Production of Cold-Rolled Steel Sheet

The raw material for metal production is ordinary carbon, low-alloy, and high-alloy steel. The cost of rolled products largely depends on the chemical composition of the metal.

Cold-rolled steel sheet is produced from hot-rolled sheet that has been pre-treated by acid pickling and heated to a temperature of 180 °C by rolling the billet through mill rollers to give the product the required thickness. Cold-rolled sheet steel is more expensive to manufacture than hot-rolled sheet, but it becomes more ductile, smooth, and free of scale. To ensure the required mechanical properties, the cold-rolled sheet is either compressed or annealed in the cold state: this means additional costs and, accordingly, a higher price for the rolled metal products.

Production of Hot-Rolled Sheet Steel

As the name suggests, hot-rolled steel sheet is produced by passing billets (slabs) preheated to a temperature of 760 °C through the rollers of a rolling mill. After passing through a series of rollers, hot-rolled sheet with the specified geometric parameters is obtained at the output: length x width x thickness.

The range of hot-rolled steel sheet includes products of different thicknesses:

• thin sheet (metal thickness 0.4–3.9 mm);
• thick sheet (metal thickness 4.0–160 mm).

The maximum width of hot-rolled steel products can reach up to 3800 mm, and the length up to 12,000 mm.

Where Cold-Rolled Sheet Is Used

Cold-rolled steel sheet is widely used in everyday life and on construction sites when building metal structures (flooring, racks, fences, doors, gates, wickets). Sheet steel is also purchased by industrial enterprises for routine and major repairs of technological equipment. Cold-rolled steel sheet products are required by manufacturing companies as raw materials for the production of:

• automotive parts;
• tools and instruments;
• roofing materials;
• steel tanks;
• household goods;
• profiled sheet metal;
• welded pipes;
• cases and containers;
• ventilation pipes;
• furniture fittings, etc.;

Cold-rolled sheet is divided into general-purpose sheet, sheet for stamping, and sheet for coating applications (enameling, iron-zinc or zinc-aluminum coating).

To give the product resistance to oils and paint materials, sheet products are pre-treated with a solution of chromic and phosphoric acids.

If cold-rolled sheet products are planned to be used in conditions of high humidity and aggressive environments, it is better to choose galvanized sheet, which has excellent corrosion resistance.

Where Hot-Rolled Sheet Is Used

The range of applications for sheet steel is very wide:

1. Construction (bridge span elements, floor profiles, chimneys, and other building structures).
2. Manufacturing (boilers, road barriers, welded pipes).
3. Automotive industry (vehicle frames and bodies, clutch discs, wheel rims).
4. Machine building (housings and parts for metalworking and woodworking machines).
5. Railcar manufacturing (railway wagons, cladding of cargo tanks).
6. Agriculture (agricultural machinery and components: plows, harrows, seeders).
7. Household use (street fences, metal doors, cabinets, garage racks, and much more).

As a rule, hot-rolled sheet can be purchased as:

• a finished material for construction and repair (finishing, roofing, fencing, floors of workshops, warehouses, service stations, private garages, etc.);
• a raw material (blank) for manufacturing metal products (machine and mechanism parts, equipment, bent profile rolled metal, cold-rolled sheet, channel, angle, etc.).

Today, in construction, the more expensive cold-deformed sheet is often replaced with hot-rolled products (their price is significantly lower) in cases where strength and low cost are more important than aesthetics.

Advantages of Cold-Rolled Products

Unlike hot-rolled products, cold-rolled sheet blanks have more precise geometric dimensions and better physical and mechanical properties, with the possibility of producing items of minimal thickness.

In addition, cold-rolled metal sheet:

• is made from high-quality metal alloys;
• operates over a wide temperature range;
• can be coated with a layer of zinc for additional corrosion protection;
• is resistant to mechanical impacts (vibrations, deformations, loads);
• is easy to process (welding, cutting, drilling);
• is convenient to load and transport.

Advantages of Hot-Rolled Products

Compared to cold-rolled sheet, hot-rolled products have the following advantages:

1. Lower cost due to simpler manufacturing methods and, accordingly, lower production costs.
2. Availability of thin sheet steel up to 0.4 mm, used in the automotive industry.
3. Hot-rolled steel sheet has better corrosion resistance (to increase corrosion resistance, the steel sheet surface is coated with zinc, pickled, and lubricated).

Hot-rolled sheet is easy to process mechanically:

• cut;
• weld;
• turn;
• draw;
• roll;
• stamp.

Characteristics and Properties of Cold-Rolled Sheets

Cold-rolled sheet can be purchased with a wide range of technical parameters:

1. Geometric dimensions. Cold-rolled sheets are sold with widths from 500 mm, lengths from 2 meters, and thicknesses from 0.35 mm. The most popular sizes on the metal products market are: 1000*2000 mm; 1250*2500 mm; 1500*6000 mm.
2. Dimensional accuracy in thickness, length, and width (standard, improved, high). Purchasing high-precision sheets costs approximately 10–15% more.
3. Flatness – the quality of the sheet surface, determined by the presence or absence of irregularities and height differences. Sheets are classified as having standard, improved, or high flatness.
4. Edge type: trimmed or untrimmed sheet steel. The price of cold-rolled sheets with trimmed edges is higher.
5. Metal draw class (deep, complex, very complex).
6. Surface type: glossy, matte, rough surface.
7. Sheet weight – specified in GOST, DIN, EN (for example, 1 linear meter of sheet with a width of 1250 mm and a thickness of 0.5 mm weighs 4.91 kg). Wholesale steel prices are calculated per 1 ton of product.

Characteristics and Properties of Hot-Rolled Sheets

Any product range produced in Ukraine is regulated by the relevant documents, which specify characteristics, in particular:

1. Chemical composition of steel – hot-rolled sheets are made from ordinary or low-alloy steel (products made of low-alloy steel are more expensive).
2. Geometric dimensions – thickness, width, and length of the product. Hot-rolled sheets can be ordered in coils or standardized cut lengths.
3. Manufacturing accuracy: standard and improved accuracy.
4. Sheet flatness: standard, improved, high, and very high.
5. Edge type: trimmed or untrimmed.

How to Choose Correctly

Let's summarize the main criteria for selecting sheet products:

• Purpose (construction, stamping of parts, etc.).
• Surface type according to roughness size.
• Coating: uncoated sheet or galvanized.
• Geometric dimensions: thickness x width x length.
• Maximum allowable dimensional tolerances according to GOST.
• Flatness, edge type, metal draw class.
• Main physical and mechanical properties.

Example of Conditional Designation of Cold-Rolled and Hot-Rolled Products

Cold-rolled sheet 0.5x1000x2000 mm – a cold-rolled sheet with a thickness of 0.5 mm, width of 1 meter, and length of 2 meters, made from structural quality carbon steel. This product is mainly purchased by manufacturing enterprises for the production of gaskets, washers, pipes, and parts subjected to chemical and thermal strengthening (bushings, rods, eyes).

Buy Steel Sheet Wholesale at an Affordable Price at LEART

The international company LEART sells cold-rolled steel sheets and other rolled metal products at dealer prices.

Do you have any questions or want to buy metal products now? Call our manager or send a request by email.