Corrosion condition
1. The surface of stainless steel contains dust or alien metal particles containing other metal elements, in the humid air, the condensate between the attachment and stainless steel, the two are connected into a microbattery, causing an electrochemical reaction, the protective film is damaged, called electrochemical corrosion.
2. The surface of stainless steel adheres to organic juice (such as melons and vegetables, noodle soup, sputum, etc.), which constitutes organic acid in the case of water oxygen, and the organic acid corrods the metal surface for a long time.
3. Stainless steel surface adhesion containing acid, alkali, salt substances (such as alkaline water, lime water splash on the decoration wall), causing local corrosion.
4. In polluted air (such as the atmosphere containing a large number of sulfides, carbon oxide, nitrogen oxide), in the case of condensate, the formation of sulfuric acid, nitric acid, acetic acid liquid points, causing chemical corrosion can cause the damage of stainless steel surface protective film corrosion.
Corrosion resistance
The corrosion resistance of stainless steel plate mainly depends on its alloy composition (chromium, nickel, titanium, silicon, aluminum, manganese, etc.) and the internal organizational structure, which plays the main role of chromium. Chromium has high chemical stability, can form a passivation film on the surface of the steel, 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.
Identification method
Numbering and representation
① Use the international chemical element symbol and the national symbol to indicate the chemical composition, and use the Arabic alphabet to indicate the component content:
For example: China, Russia 12CrNi3A
② Use fixed digit numbers to represent steel series or numbers; Such as: the United States, Japan, 300, 400, 200.
③ Use the Latin alphabet and order to form the serial number, only to indicate the purpose.
International stainless steel labeling method
The American Iron and Steel Institute uses three digits to label various standard grades of malleable stainless steel. Among them:
① Austenitic stainless steel with 200 and 300 series of digital marks.
② Ferrite and martensitic stainless steel are represented by 400 series numbers. For example, some of the more common austenitic stainless steels are labeled 201, 304, 316, and 310.
③ Ferritic stainless steel is marked with 430 and 446, martensitic stainless steel is marked with 410, 420 and 440C, biphase (austenite-ferrite).
Stainless steel, precipitation-hardened stainless steel and high alloys with an iron content of less than 50% are usually named by patent names or trademarks.
Essentials of selection
The selection of stainless steel plates should consider the use of operating conditions, such as manual or automatic operation, the performance and type of hot press, and the quality requirements of the pressing material such as hardness, luster, etc. Also consider the economic accounting, each new polishing steel plate, the number of times that can produce a slow quality of decorative plate.
In addition, when selecting the most reasonable thickness of the steel plate, its use time, quality, stiffness should be considered, and the strength requirements of the plate under pressure should be considered; Heat conductivity; The distribution of pressure, the format specification of the pressure plate.
If the thickness of the steel plate is not enough, it is easy to bend, which will affect the production of decorative plates. If the thickness is too large and the steel plate is too heavy, it will not only increase the cost of the steel plate, but also bring unnecessary difficulties to the operation. At the same time, the margin should be considered when the stainless steel plate is processed or used. The thickness of the copper plate is not absolutely consistent, but strive to be as consistent as possible in the thickness of the same sheet of steel, generally medium size saw plate, thickness tolerance is 0.05 1 o.15 mm. If the requirements are too strict, the grinding cost will also increase. Generally, it is a steel plate with high tensile resistance and hardness, which has greater mechanical damage resistance and longer service durability, but the grinding and processing costs are also relatively high [1].
