Process, Properties and Main Grades of Hot Rolled Stainless Steel Plates

1. Core Production Process

Heating: Slabs are heated to 1150–1250°C and kept warm for 2 to 4 hours for uniform temperature. Specifically, austenitic grades like 304 and 316 are heated to 1200–1250°C, while ferritic grade 430 is heated to 1150–1200°C.

Rough Rolling: Scale is removed by high-pressure water before rough rolling to form intermediate thickness and control plate shape initially.

Finish Rolling: Continuous rolling via multiple stands is adopted. The finishing temperature is strictly controlled at 800–900°C to guarantee accurate thickness, mechanical properties and dimensional tolerance.

Cooling & Pickling: Austenitic steel adopts laminar cooling and ferritic steel uses air cooling. Pickling is conducted to remove oxide scale, forming the standard No.1 industrial matte surface.

Finishing: Procedures including straightening, shearing, flaw detection and marking are carried out before finished products are put into storage.

2. Key Properties & Specifications

Thickness: 3.0–60 mm, extra-thick plates up to 200 mm; Common width: 1500/1800/2000 mm; Standard length: 6000 mm.

Typical Mechanical Properties (304): Yield strength ≥205 MPa, Tensile strength ≥520 MPa, Elongation ≥40%.

Surface Feature: No.1 hot rolled finish with silver-grey matte appearance, suitable for industrial processing and welding.

Executive Standards: GB/T 4237 (China), ASTM A240 (USA), EN 10088 (EU), JIS G4305 (Japan).

3. Main Grades & Characteristics

304 (18-8): The most widely used austenitic stainless steel. It boasts outstanding corrosion resistance, good weldability and formability, applied for chemical tanks, food processing equipment and building structures.

316L (Low Carbon): Contains molybdenum, delivering superior resistance to acid, alkali and seawater. Ideal for marine engineering, chemical pipelines and medical devices.

201 (Nickel-saving Grade): Low nickel and high manganese composition with competitive cost and high strength, mainly used for decoration, municipal facilities and general structural parts.

430 (Ferritic Grade): Nickel-free material with good thermal conductivity and oxidation resistance, widely used for kitchen utensils, home appliances and automotive exhaust systems.

321/347 (Stabilized Grades): Added with titanium or niobium to resist intergranular corrosion, applicable to high-temperature welding components such as boilers and heat exchangers.

4. Hot Rolled vs Cold Rolled Stainless Steel Plates

Processing Temperature: Hot rolling above recrystallization temperature; Cold rolling at room temperature.

Thickness: Hot rolled: 3–200 mm; Cold rolled: 0.3–3 mm.

Surface: Hot rolled: No.1 matte surface; Cold rolled: 2B/BA bright finish.

Performance: Hot rolled plates have low internal stress and easy machinability; Cold rolled products feature high precision and premium surface quality.

Cost & Application: Hot rolled type is more cost-effective for bulk structural components; Cold rolled type fits precision and decorative applications.