The original color of stainless steel sculpture has been used for a long time, and sometimes brown spots appear on the surface. People may think that there is a problem with the stainless steel material. In fact, this is a misunderstanding of the lack of understanding of stainless steel. First of all, any stainless steel will rust under certain extreme conditions. Only the corrosion rate is different.
High-grade stainless steel has the ability to resist atmospheric oxidation - that is, rust resistance, but also has the ability to resist corrosion in the medium containing acid, alkali and salt - that is, corrosion resistance. However, its corrosion resistance varies with its chemical composition, state, service conditions and environmental media type. For example, 304 stainless steel plate has absolutely excellent corrosion resistance in dry and clean atmosphere, but when it is moved to the coastal area, it will rust quickly in the sea fog containing a lot of salt; 316 stainless steel performs well. Therefore, not any kind of stainless steel can resist corrosion and rust in any environment. Stainless steel sculptures in coastal cities are not recommended to be made of 304 stainless steel, let alone 201 stainless steel. High manganese stainless steel corrodes faster with high carbon and low nickel, especially iron plate, rust plate and galvanized plate.
Secondly, stainless steel has the ability to resist corrosion by forming a very thin, solid and fine stable chromium-rich oxide film (protective film) on its surface to prevent the continuous infiltration and oxidation of oxygen atoms. Once for some reason, the film is constantly damaged, oxygen atoms in the air or liquid will continue to penetrate or iron atoms in the metal will continue to separate, forming loose iron oxide, and the metal surface will also be constantly corroded. This kind of surface facial mask is damaged in many ways, and the common cases are as follows:
1. The original color of the stainless steel sculpture is that there are dust containing other metal elements or attachments of dissimilar metal particles on the surface. In the humid air, the condensate between the attachment and the stainless steel connects the two into a micro-battery, triggering an electrochemical reaction and damaging the protective film, which is called electrochemical corrosion.
2. Organic juices (such as bird droppings, sputum, etc.) adhered to the surface of the stainless steel sculpture form organic acids in the presence of water and oxygen, which will corrode the metal surface for a long time.
3. The surface of the stainless steel sculpture is adhered with acid, alkali and salt substances (such as alkaline water and lime water splashing), causing local corrosion.
4. In the polluted air (such as the atmosphere containing a large amount of sulfide, carbon oxide and nitrogen oxide), the condensate will form sulfuric acid, nitric acid, acetic acid liquid point, acid rain, etc., causing chemical corrosion.
The above conditions can cause damage to the protective film on the surface of stainless steel and cause corrosion. Therefore, in order to ensure that the metal surface is permanently bright and not rusted, it is suggested that the remote sculpture:
1. The surface of the stainless steel sculpture must be cleaned and scrubbed frequently to remove the attachments and remove the external factors that cause corrosion.
2. In coastal areas, stainless steel sculptures should be made of 316 or better stainless steel, which can resist seawater corrosion.
3. Select the stainless steel plates that meet the national standards and have stable chemical composition in the market, and purchase from the large iron and steel manufacturers with long-term cooperation.
4. Different types of stainless steel have different prices, toughness and ductility, The labor costs for sculpture forging and welding are also different (for example, large hollow stainless steel sculpture balls and double-sided arc forging sculptures must be made of 304 stainless steel, low nickel stainless steel plates are hard, brittle and hard to knock, easy to crack and not easy to form, if hyperboloid forging generally selects 1.5-2.5 thick stainless steel plates, and then it is difficult to forge manually, and 2.5-3.0 thick plate sculpture modeling is good at cost performance).
5. According to the installation environment, local needs and sculpting process requirements of sculpture, the sculpture cost needs to select different models and different thickness of stainless steel plates for detailed budget.
6. Although the price of aluminum plate sculpture is not high, its forging and welding are time-consuming and labor-intensive, so it is gradually eliminated by the sculpture industry. However, there are many signs and signs with plate anchors. Some plate sculptures, steel structure domes, and sculptures that reduce the dead weight of the structure can be made of aluminum plate.
7. High-strength cement sculpture, copper-plate sculpture, cast copper sculpture, rust-plate sculpture, iron-plate sculpture, weather-proof plate sculpture, GRC fiberglass sculpture Due to the particularity of the material and the needs of the sculpture, please refer to another article.
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