Stainless steel plate is generally a general term for stainless steel plate and acid-resistant steel plate. Coming out at the beginning of this century, the development of stainless steel plates laid an important material and technological foundation for the development of modern industry and technological progress. There are many kinds of stainless steel plates and steel plates with different properties. It has gradually formed several major categories in the development process. According to the organization structure, it can be divided into four categories: austenitic stainless steel plate, martensitic stainless steel plate (including precipitation hardened stainless steel plate), ferritic stainless steel plate, and austenitic plus ferritic duplex stainless steel plate. The main chemical composition or some characteristic elements in the steel plate are classified into chromium stainless steel plate, chromium nickel stainless steel plate, chromium nickel molybdenum stainless steel plate and low carbon stainless steel plate, high molybdenum stainless steel plate, high purity stainless steel plate and so on. According to the performance characteristics and use of the steel plate, it is divided into nitric acid resistant stainless steel plate, sulfuric acid resistant stainless steel plate, pitting corrosion resistant stainless steel plate, stress corrosion resistant stainless steel plate, high-strength stainless steel plate, etc. According to the functional characteristics of the steel plate, it is divided into low temperature stainless steel plate, non-magnetic stainless steel plate, free-cutting stainless steel plate, superplastic stainless steel plate and so on. The commonly used classification method is based on the structural characteristics of the steel plate and the chemical composition of the steel plate, as well as the combination of the two. Generally divided into martensitic stainless steel plate, ferritic stainless steel plate, austenitic stainless steel plate, duplex stainless steel plate and precipitation hardening stainless steel plate, etc. or divided into two categories: chromium stainless steel plate and nickel stainless steel plate. It has a wide range of uses. Typical uses: heat exchangers for pulp and papermaking equipment, machinery and equipment, dyeing equipment, film washing equipment, pipelines, exterior materials for buildings in coastal areas, etc.
The stainless steel plate has a smooth surface, high plasticity, toughness and mechanical strength, and is resistant to corrosion by acids, alkaline gases, solutions and other media. It is an alloy steel that is not easy to rust, but it is not absolutely rust-free.
The stainless steel plate has the ability to withstand general corrosion similar to the unstable nickel-chromium alloy 304. Long-term heating in the temperature range of chromium carbide may affect alloys 321 and 347 in harsh corrosive media. Mainly used in high temperature applications. High temperature applications require materials to have strong sensitization resistance to prevent intergranular corrosion at lower temperatures.
High temperature oxidation resistance
Stainless steel plates have high temperature oxidation resistance, but the oxidation rate will be affected by inherent factors such as exposure environment and product form.
1. The surface of stainless steel has accumulated dust containing other metal elements or attachments of foreign metal particles. In humid air, the condensation between the attachments and stainless steel connects the two to form a micro battery, which initiates an electrochemical reaction. , The protective film is damaged, which is called electrochemical corrosion.
2. The surface of stainless steel adheres to organic juices (such as melon, vegetable, noodle soup, sputum, etc.), which form organic acid in the presence of water and oxygen, and the organic acid will corrode the metal surface for a long time.
3. The surface of stainless steel adheres to acid, alkali, and salt substances (such as alkali water and lime water splashing on the decoration wall), causing local corrosion.
4. In polluted air (such as the atmosphere containing a large amount of sulfide, carbon oxide, and nitrogen oxide), contact with condensed water will form sulfuric acid, nitric acid, and acetic acid liquid spots, causing chemical corrosion. The above conditions can cause damage to the protective film on the surface of stainless steel. Damage causes rust.
The corrosion resistance of stainless steel plate mainly depends on its alloy composition (chromium, nickel, titanium, silicon, aluminum, manganese, etc.) and internal structure, and the main role is chromium. Chromium has high chemical stability and can form a passivation film on the surface of the steel to isolate the metal from the outside world, protect the steel plate from oxidation, and increase the corrosion resistance of the steel plate. After the passivation film is destroyed, the corrosion resistance decreases.
Divided by purpose
Organized by steel type
(1) Austenite type (2) Austenite-ferrite type (3) Ferrite type (4) Martensite type