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How to deal with the corrosion protection of steel structure economically?
The application of spraying fire prevention and corrosion protection technology for steel structures plays an extremely important role in the safety performance and durability of steel structures. As far as the fire prevention technology of steel structure is concerned, fire retardant paint or fire retardant board is generally used for early protection. Fire retardant coatings are divided into three types: ultra-thin, expansive and thick. Roll coating, brush coating or spray coating with an ultra-thin fireproof coating thickness of only 2.6 mm; Intumescent fire retardant coating, the maximum thickness can reach 7mm, and it is constructed by spraying method; When there is no decoration requirement, a non-expansive thick inorganic fire retardant coating containing no mineral fiber can be used, with a maximum thickness of 50mm, which can be daubed or sprayed. When some beams and columns need to be wrapped, they can also be wrapped with fireproof boards to achieve the purpose of protection. All kinds of fire retardant coatings and materials used must be tested by the testing organization designated by the fire department, and must be sprayed or brushed as required during construction to strictly meet the thickness requirements of fire retardant coatings for steel structure design. The anticorrosion of steel structure depends on the use requirements of steel structure. Generally, conventional antirust paint can be used. When the environmental conditions are harsh, anticorrosive coatings with excellent performance, such as zinc-rich coatings or weather-resistant steel, must be used. (2) According to the building fire protection requirements of the components and the appearance of the structure, select the appropriate fire retardant coating according to the technical indicators, and the ultra-thin fire retardant coating with a thickness of 0.6mm-2.6mm has a fire resistance limit of 0.5-2.5 hours; 3.0mm-7 thick intumescent fire retardant coating. Omm and fire resistance limit of 0.5 to 2.5 hours; Thick inorganic fire retardant coating with a thickness of 8. Omm-5O。 The fire resistance limit of Omm is 0.5h to 3.0h..3) Scope of application Fire-retardant coatings or fire-retardant boards are widely used for the protection of various steel structures. Ultra-thin fire retardant coatings are used in various public buildings with high appearance requirements. Expansive fire retardant coatings are often used in various long-span structures, while a large number of high-rise steel structures are often protected by thick fire retardant coatings. Anti-corrosion coating of steel structure should be a scientific and systematic steel structure project, and reasonable anti-corrosion coating design of steel structure is the basis of creating high-quality anti-corrosion engineering. Scientific and reasonable painting scheme can greatly improve the quality of anti-corrosion painting of steel structure, prolong the anti-corrosion life and maintenance interval, and reduce the anti-corrosion cost. The following factors should be considered in the scientific and reasonable design of anti-corrosion coating for steel structure: requirements of anti-corrosion coating: including anti-corrosion years, decoration requirements, light and color preservation requirements, and easy maintenance.

Anti-corrosion environment: what kind of corrosion environment the steel structure is in, including general atmospheric environment, industrial atmospheric corrosion environment, chemical atmospheric corrosion environment, marine atmospheric corrosion environment, tropical or cold areas, indoor or outdoor, with or without liquid or other gaseous media (except atmosphere) corrosion, etc.

Painting environmental conditions: painting site conditions (temperature and humidity, indoor or outdoor, whether painting is carried out in a special painting room) and so on.

A New Anticorrosion Technology for Steel Structure —— Thermal Spraying Metal Step Coating

With the implementation of the West-to-East Gas Transmission Project and the South-to-North Water Transfer Project, the use of hydraulic steel structures has increased rapidly. Developing new anti-corrosion technology for hydraulic steel structures is of great significance for reducing project cost and prolonging project life. Therefore, metal thermal spraying metal step coating with complementary advantages of various metal coatings is gradually applied to hydraulic steel structures and becomes a new metal anticorrosion technology. Metal thermal spraying is superimposed spraying on the same workpiece substrate. Firstly, zinc coating is used as the bottom layer, then stainless steel coating is used as the top layer, and finally a stepped coating is formed, which is applied to hydraulic steel structures. After a lot of research and experiments, both economic and satisfactory anti-corrosion effect of steel structure has been achieved. Its principle is to use some form of heat source to heat the metal spraying material to form molten particles, which will impact and sink on the surface of the substrate at a certain speed under the action of power to form a metal coating with certain characteristics. Thermal spraying technology is used to treat the surface of hydraulic steel structure and other matrix materials to obtain a corrosion-resistant and wear-resistant metal protective coating, thus enhancing the corrosion-resistant and wear-resistant performance of hydraulic steel structure. Metal thermal spraying is to use some form of heat source to heat metal spraying materials to form molten particles. Under the action of power, these particles impact and sink to the surface of the substrate at a certain speed, forming a metal coating with certain characteristics. The corrosion-resistant and wear-resistant metal protective coating is obtained on the surface of matrix materials such as hydraulic steel structure by thermal spraying technology, so as to enhance the corrosion-resistant and wear-resistant performance of hydraulic steel structure. Many materials can be used for metal spraying, such as zinc and stainless steel. Among them, stainless steel coating has the characteristics of wear resistance and long protection period. Galvanized coating not only has coverage and corrosion resistance, but also has cathodic protection function (galvanic cell principle). They are important materials for anticorrosion spraying of hydraulic steel structures, so they are widely used. With the implementation of the South-to-North Water Transfer Project in China, the use of hydraulic steel structures will increase rapidly. It is of great significance to research and develop new anti-corrosion technology of hydraulic steel structure for reducing project cost and prolonging project life. Therefore, the advantages of the above two metal coatings are complementary, and they are sprayed on the same workpiece substrate. Firstly, zinc coating is used as the bottom layer, then stainless steel coating is used as the top layer, and finally a stepped coating is formed, which is applied to hydraulic steel structures. After a lot of research and experiments, both economic and satisfactory anti-corrosion effect of steel structure has been achieved. More contents about steel structure anticorrosion are: China Engineering Construction Network and China Steel Structure Network. Structural characteristics of steel bridge and the necessity of adopting heavy anti-corrosion technology

At present, there are many structural forms of steel structure bridges in China, including large steel box girder structure, steel truss structure, steel tube arch or steel box arch structure, and various steel composite beam structures. Compared with ordinary concrete bridges, steel bridges have the advantages of large span capacity, high strength and short construction period. Since the completion of Wuhan Yangtze River Bridge, the first steel truss bridge across the Yangtze River in 1955, large-scale steel bridges have emerged continuously. The steel consumption of such bridges is generally above 1 10,000 t or even 65,438+1100,000 t. Surface corrosion, stress corrosion and corrosion fatigue are one of the important reasons for the appearance defects, reduced service life and even loss of working ability of this super-large steel bridge. So far, the corrosion problem of steel structure is bringing huge losses to the national economy of all countries in the world. At present, the annual economic losses caused by steel structure corrosion in the world have reached hundreds of billions of dollars. Moreover, accidents caused by corrosion of steel structures endanger the safe operation of structures, and catastrophic accidents caused by corrosion are common, especially for welded steel structures and steel structures with large stress, because corrosion will be greatly accelerated under the action of stress. Anti-corrosion of bridge steel structure has become a topic of increasing concern. Only when the steel structure is designed and built, according to its own structural characteristics and environmental conditions, the corresponding anti-corrosion technology of heavy steel structure is adopted, and the later coating maintenance is reasonably considered, so as to ensure the normal use of steel bridges. Reference: 99 Steel Network Papers /show.php? id=4522