Stainless steel plates: core characteristics, classification and applications

Stainless steel is a type of alloy steel containing at least 10.5% chromium. Its dense chromium oxide passive film on its surface provides excellent corrosion resistance. Combined with its high strength, ease of processing, and attractive appearance, it has become an indispensable material in both industrial production and everyday life, found in everything from household kitchenware to large-scale industrial equipment.

I. Core Characteristics: Why is Stainless Steel So Widely Used?

Extreme Corrosion Resistance: This is stainless steel's most significant advantage. The passive film formed by chromium on the plate's surface prevents the ingress of corrosive media such as oxygen and moisture. Even if the surface is damaged, the passive film quickly self-repairs. For example, in humid kitchen environments, sinks made of 304 stainless steel remain resistant to rust despite prolonged contact with water and oil.

High Strength and Toughness: Stainless steel boasts a tensile strength of 500-1000 MPa, far exceeding that of ordinary steel. It also maintains excellent toughness even at low temperatures, resisting brittle cracking. Therefore, it is often used in applications requiring high load-bearing capacity and impact resistance, such as large steel structures (such as bridge supports) and chemical storage tanks. Easy to Clean and Hygienic: Its smooth surface resists stains and bacteria, allowing it to be cleaned with a simple wipe, meeting hygiene standards for the food and medical sectors. Conveyor belts in food processing plants and surgical instrument tables in hospitals are often made of stainless steel.
Aesthetic and Durable: Through various surface treatments, stainless steel can achieve a variety of finishes, including mirrored, brushed, and colored finishes. Combining decorative and durable qualities, it boasts a service life of decades and is widely used in architectural decoration (such as shopping mall curtain walls) and appliance housings (such as refrigerator doors).

II. Scientific Classification: Selecting the Right Sheet Based on Core Dimensions

(I) Classification by Chemical Composition: Determining Core Performance

Austenitic stainless steel sheet: Containing 18%-20% chromium and 8%-12% nickel, it is the most widely used type, accounting for over 45% of global stainless steel sheet production. Representative grades are 304 and 316, which offer excellent ductility, weldability, acid and alkali resistance, and are non-magnetic. 304 stainless steel: Offers high cost-effectiveness and is commonly used in food equipment (such as yogurt fermenters), household kitchenware (stainless steel pots), and decorative building materials (indoor columns).
316 stainless steel: 304 stainless steel with the addition of molybdenum offers enhanced seawater and corrosion resistance, making it suitable for coastal structures (such as dock guardrails) and medical equipment (surgical instruments).
Ferritic stainless steel: Contains chromium as the primary alloying element (12%-30%), with no nickel or a very low nickel content. Its cost is approximately 30% lower than austenitic stainless steel. A representative grade is 430, which offers good stress corrosion resistance but slightly lower plasticity.
Applications: Water heater linings (to prevent scale corrosion), automotive exhaust systems (high-temperature resistance), and affordable appliance panels (such as microwave oven housings).
Martensitic stainless steel: Contains a high carbon content (0.1%-1.0%) and can reach a hardness of HRC50 or above after heat treatment. It offers high strength but lower toughness. Representative grades are 410 and 420, and exhibit some magnetic properties. Applications: Knives (kitchen knives, scissors), valve cores (high-pressure pipes), bearings (mechanical transmission parts).
(II) Classification by Surface Condition: Adaptable to different appearance requirements
Cold-rolled stainless steel sheet: Through cold rolling, annealing, and polishing processes, the surface is smooth and flat with high precision (thickness tolerance ±0.02mm). Common surface grades are 2B (matte) and BA (mirror).
Applications: Home appliance housings (washing machine panels), decorative panels (indoor background walls), precision instrument housings.
Hot-rolled stainless steel sheet: Directly from the factory after hot rolling, it has a dark gray oxide scale and a high degree of roughness. The price is approximately 20% lower than cold-rolled sheet, and the thickness is generally over 3mm.
Applications: Chemical storage tanks (corrosion-resistant load-bearing), steel structure bases (building support), large machinery bases.
Colored stainless steel sheet: Through vacuum coating and chemical coloring processes, the cold-rolled sheet is coated with colors such as red, blue, gold, and black, combining decorative and corrosion resistance with a durable fade resistance. Applications: Hotel decoration (walls, elevator door panels), high-end furniture (tabletops), and shopping mall window decoration.

III. Diverse Applications: A "Universal Material" Penetrating Various Industries

(I) Industrial Sector

Chemical Industry: 316L stainless steel plate is used in reactors and pipelines, resisting corrosion from acidic and alkaline solutions.

New Energy Sector: Duplex stainless steel plate (2205 grade) is used in wind turbine tower flanges, withstanding strong wind loads and marine salt spray.

Automotive Industry: Ferritic stainless steel plate is used in automotive exhaust systems, offering high-temperature resistance and low cost, while austenitic stainless steel plate is used in battery trays for new energy vehicles, balancing corrosion resistance and lightweighting.

(II) Architecture and Decoration Sector

Architectural Structures: Hot-rolled stainless steel plate is used in the steel support structures of large venues (such as stadium roofs), and colored stainless steel plate is used in shopping mall curtain walls to enhance their aesthetics.

Residential Decoration: 304 cold-rolled stainless steel plate is used in interior screens and stair railings, while 430 stainless steel plate is used in balcony railings, achieving both practicality and aesthetics. (III) Daily Life

Kitchen Appliances: 304 stainless steel is used for sinks, woks, and rice cooker linings; it is safe, hygienic, and easy to clean.

Medical: 316L stainless steel is used for operating tables and medical device housings; it resists corrosion from disinfectants and prevents bacterial growth.

IV. Purchasing Tips: Avoid Mistakes and Choose the Right Plate

Select the model based on your needs: Choose 304/316 for kitchen and food-related applications, 430 for affordable decorative applications, and martensitic or duplex stainless steel for high-strength industrial applications.

Check the labeling to identify authenticity: Authentic products will have model numbers such as "304" or "SUS316" on the surface. Products without or with unclear labeling may be "stainless steel" (low in chromium and prone to rust).

Simple Test to Aid Identification: Using a magnet, 304/316 austenitic stainless steel plates will not attract magnets, while 430/410 ferritic and martensitic stainless steel plates will attract magnets (this is only a preliminary distinction and cannot be used to fully determine quality).