Stainless steel plates are classified into two main types based on their manufacturing method: hot-rolled and cold-rolled. They are further divided into five categories according to their microstructure: austenite, austenite-ferrite, ferrite, martensite, and precipitation hardening.
Manufacturing Methods
Hot-Rolled Stainless Steel Plates:
Produced by heating steel slabs above their recrystallization point and then rolling them into plates.
Suitable for applications requiring strength and toughness.
Cold-Rolled Stainless Steel Plates:
Produced at room temperature by rolling hot-rolled plates that have been pickled and annealed.
Known for their smooth surface finish and high dimensional accuracy.
Includes thin cold plates (0.02-4 mm thick) and medium to thick plates (4.5-100 mm thick).
Stainless Steel Plate Categories
Austenite:
Exhibits high ductility and corrosion resistance.
Austenite-Ferrite:
Combines the properties of austenite and ferrite, offering improved strength and resistance to stress corrosion cracking.
Ferrite:
Known for good formability and resistance to oxidation and stress corrosion.
Martensite:
Provides high strength and hardness, suitable for applications requiring wear resistance.
Precipitation Hardening:
Achieves high strength through heat treatment processes, ideal for aerospace and high-stress applications.
Applications
Stainless steel plates are essential in industries that require corrosion resistance against various acids, such as oxalic acid, sulfuric acid-ferrous sulfate, nitric acid, nitric acid-hydrofluoric acid, sulfuric acid-copper sulfate, phosphoric acid, formic acid, and acetic acid. Key industries and applications include:
Chemical Industry: Equipment and containers that handle corrosive chemicals.
Food Industry: Processing and handling equipment due to hygienic properties.
Medicine: Surgical instruments and medical devices.
Papermaking: Machinery exposed to harsh chemicals.
Petroleum: Pipelines and equipment for oil and gas extraction.
Atomic Energy: Components that require high resistance to corrosion.
Construction: Structural components and architectural elements.
Kitchen Utensils and Tableware: Due to their resistance to corrosion and ease of cleaning.
Vehicles: Parts exposed to varying environmental conditions.
Household Appliances: Durable and aesthetically pleasing finishes.
Properties
Surface Quality: Smooth with high plasticity, toughness, and mechanical strength.
Corrosion Resistance: Resilient against acids, alkaline gases, solutions, and other media. This property is primarily due to the presence of chromium, which forms a passivation film on the steel surface.
Heat Treatment: To meet specific mechanical property requirements (yield strength, tensile strength, elongation, and hardness), stainless steel plates undergo treatments like annealing, solution treatment, and aging before delivery.
Corrosion Resistance Mechanism
The corrosion resistance of stainless steel primarily depends on its alloy composition, including chromium, nickel, titanium, silicon, and aluminum, as well as its internal structure. Chromium is the key element that provides high chemical stability, forming a passivation film on the steel surface. This film protects the steel from oxidation and enhances its corrosion resistance. If the passivation film is damaged, the corrosion resistance of the steel plate diminishes.
