Why do seamless steel pipes need anti-corrosion?
Jul. 14, 2025
Why do seamless steel pipes need anti-corrosion?
Why do seamless steel pipes need anti-corrosion?
Why do steel pipes need to be anti-corrosion? As the name suggests, steel pipe anti-corrosion is to prevent steel pipes from corroding and reducing their service life. In PE anti-corrosion steel pipe processing and transportation of oil, water, natural gas and other pipeline projects, steel pipes are used as economic transmission materials. However, the material and chemical elements of some steel pipes determine that they do not have long-term corrosion resistance, thus greatly shortening the service life. , whether it is buried underground or elevated, we will face this problem. So, how to solve this problem? Later, people invented a method of coating the outer or inner walls of steel pipes to effectively control and prevent steel pipe corrosion.
This article will introduce to you which coating should be used for anti-corrosion of different steel pipes. At present, the main anti-corrosion coatings for steel pipes include:
1.Grease paint
Oil paint is a paint that uses dry oil as the main film-forming material. It is characterized by easy production, good brushability, good wettability, low price, and flexible paint film; however, the paint film dries slowly, is soft, has poor mechanical properties, has poor acid and alkali resistance, poor water resistance, and poor resistance to organic solvents. Dry oil is usually combined with anti-rust pigments to form anti-rust paint, which is used in atmospheric environments and has low corrosion resistance.
2.National paint
National lacquer, also known as raw lacquer and lacquer, is unique to China. Raw lacquer is a milky white viscous liquid produced by cutting the bark of the lacquer tree and filtering it to remove impurities. After raw lacquer is applied to the surface of an object, the color quickly changes from white to red, and from red to purple. If it takes a long time, it can turn into a hard and bright black paint film. Urushiol is the main component of raw lacquer, with a content of 30-70% (the higher the urushiol content, the better the quality of the raw lacquer). National paint has strong adhesion, tough paint film, good gloss, soil corrosion resistance, water resistance and oil resistance. The disadvantage is that it is toxic and can easily cause skin allergies. In addition, it is not resistant to strong oxidants and has poor alkali resistance.
3.Phenolic resin coating
It mainly includes alcohol-soluble phenolic resin, modified phenolic resin, pure phenolic resin, etc. Alcohol-soluble phenolic resin coating has good corrosion resistance, but its disadvantages are inconvenient construction, poor flexibility, and weak adhesion, so its application is limited to a certain extent. Phenolic resin needs to be modified during use. For example, rosin-modified phenolic resin and tung oil are refined, various pigments are added, and various magnetic coatings can be made after grinding. The paint film is tough and cheap, and is widely used in painting furniture, doors and windows. Pure phenolic resin coating has strong adhesion, water resistance, moisture resistance, heat resistance, corrosion resistance and good weather resistance.
4.Epoxy resin coating
Epoxy coatings have good adhesion to metal, concrete, wood, glass and other materials, good alkali resistance, and good insulation properties. The disadvantage is poor aging resistance. Epoxy anticorrosive coatings usually consist of epoxy resin and curing agent. The nature of the curing agent also affects the performance of the paint film. Epoxy resin coating is a one-component coating system that uses epoxy resin as a film-forming material. Epoxy resin consists of epoxy resin and vegetable oil fatty acid esters. Compared with general epoxy coatings, this coating has the advantages of low cost and poor alkali resistance. Commonly used in various metal primers in chemical plants and anti-corrosion coatings for outdoor equipment.
5.Polyurethane coating
Polyurethane resins used in anti-corrosion coatings usually contain two components: isocyanate-NCO and hydroxyl groups. Polyurethane (polyurethane) is a two-component product that is mixed and reacted to cure during use.
Polyurethane coatings have the characteristics of good physical and mechanical properties, hard, flexible, bright, full paint film, wear resistance, strong adhesion, corrosion resistance, resistance to oil, acid, chemicals, industrial waste gas, etc. The alkali resistance is slightly lower than that of epoxy coating; the aging resistance is better than that of epoxy coating, and it is often used as topcoat or primer; polyurethane resin can be mixed with various resins, and the formula can be widely adjusted to meet various usage requirements; It can be cured at room temperature or heated, and can also be cured at low temperatures (0°C); polyisocyanate components have poor storage stability and must be isolated from moisture to avoid freezing. Polyurethane coatings are expensive and have a long service life.
6.Long fiber wound fiberglass reinforced epoxy lining
A unique embedded lining process is used to form corrosion-resistant material in the steel pipe. This corrosion-resistant material can isolate oilfield corrosive liquids and gases from steel pipes, providing an internal anti-corrosion lining system for oilfield steel pipes and pipelines. Damaged downhole production tubing or subsea flow lines can be very costly to replace. It can provide good corrosion resistance protection in very harsh environments, which is unmatched by other products.
7.Polyethylene, polypropylene resin coating
Polyethylene resin anticorrosive coating is a film-forming coating made of monomer resin. Polyethylene coatings have been widely produced and used.
Polyethylene pipes have strong anti-corrosion and sealing properties, high mechanical strength, strong waterproofing, stable quality, convenient construction, good applicability, and do not pollute the environment. PE has low water absorption (less than 0.01%), high epoxy strength, low water absorption of PE, good hot melt adhesive softness, and high anti-corrosion reliability. The disadvantage is that the cost is higher than other repair materials. The raw materials of this coating are rich in sources and have been widely used in corrosion.
8.Furan resin coating
Furan resin coatings are resistant to various non-oxidizing inorganic acids, electrolyte solutions, and various organic solvents. They also have outstanding alkali resistance, but their oxidation resistance is not good. Furan resin series anti-corrosion coatings include furfuryl alcohol coatings, furfural acetone formaldehyde coatings and modified furan resin coatings.
9.Rubber coating
Rubber anti-corrosion coating is made from chemically treated or mechanically processed natural rubber or synthetic rubber, with solvents, fillers, pigments, catalysts, etc. added.
10.Asphalt coating
Asphalt is one of the important anti-corrosion coatings. In particular, coal tar pitch is the best. Coal tar pitch coating is inexpensive and has the advantages of water resistance. After being immersed in water for ten years, its water absorption rate is only 0.1% - 0.2%; it is resistant to erosion by some chemical media; it still has good wettability to the steel surface that has not been completely rusted; its solid content is high, and thick films can be obtained ; Low price. Its disadvantage is that it is crispy in winter and soft in summer. After exposure, some components volatilize and escape, causing the paint film to crack. These shortcomings can be improved by adding some other resins. For example, adding chlorinated rubber can improve the dryness of asphalt coatings and improve the shortcomings of being brittle in winter and soft in summer; epoxy asphalt coatings made of epoxy resin have the advantages of asphalt coatings and epoxy coatings, and have achieved very satisfactory results in anti-corrosion Effect. Asphalt coatings have been used in container bottoms, ship bottoms, dock gates, cofferdams, etc., and have good anti-corrosion effects.
11.Heavy anti-corrosion coating
Why do steel pipes need to be anti-corrosion? As the name suggests, steel pipe anti-corrosion is to prevent steel pipes from corroding and reducing their service life. In PE anti-corrosion steel pipe processing and transportation of oil, water, natural gas and other pipeline projects, steel pipes are used as economic transmission materials. However, the material and chemical elements of some steel pipes determine that they do not have long-term corrosion resistance, thus greatly shortening the service life. , whether it is buried underground or elevated, we will face this problem. So, how to solve this problem? Later, people invented a method of coating the outer or inner walls of steel pipes to effectively control and prevent steel pipe corrosion.
This article will introduce to you which coating should be used for anti-corrosion of different steel pipes. At present, the main anti-corrosion coatings for steel pipes include:
1.Grease paint
Oil paint is a paint that uses dry oil as the main film-forming material. It is characterized by easy production, good brushability, good wettability, low price, and flexible paint film; however, the paint film dries slowly, is soft, has poor mechanical properties, has poor acid and alkali resistance, poor water resistance, and poor resistance to organic solvents. Dry oil is usually combined with anti-rust pigments to form anti-rust paint, which is used in atmospheric environments and has low corrosion resistance.
2.National paint
National lacquer, also known as raw lacquer and lacquer, is unique to China. Raw lacquer is a milky white viscous liquid produced by cutting the bark of the lacquer tree and filtering it to remove impurities. After raw lacquer is applied to the surface of an object, the color quickly changes from white to red, and from red to purple. If it takes a long time, it can turn into a hard and bright black paint film. Urushiol is the main component of raw lacquer, with a content of 30-70% (the higher the urushiol content, the better the quality of the raw lacquer). National paint has strong adhesion, tough paint film, good gloss, soil corrosion resistance, water resistance and oil resistance. The disadvantage is that it is toxic and can easily cause skin allergies. In addition, it is not resistant to strong oxidants and has poor alkali resistance.
3.Phenolic resin coating
It mainly includes alcohol-soluble phenolic resin, modified phenolic resin, pure phenolic resin, etc. Alcohol-soluble phenolic resin coating has good corrosion resistance, but its disadvantages are inconvenient construction, poor flexibility, and weak adhesion, so its application is limited to a certain extent. Phenolic resin needs to be modified during use. For example, rosin-modified phenolic resin and tung oil are refined, various pigments are added, and various magnetic coatings can be made after grinding. The paint film is tough and cheap, and is widely used in painting furniture, doors and windows. Pure phenolic resin coating has strong adhesion, water resistance, moisture resistance, heat resistance, corrosion resistance and good weather resistance.
4.Epoxy resin coating
Epoxy coatings have good adhesion to metal, concrete, wood, glass and other materials, good alkali resistance, and good insulation properties. The disadvantage is poor aging resistance. Epoxy anticorrosive coatings usually consist of epoxy resin and curing agent. The nature of the curing agent also affects the performance of the paint film. Epoxy resin coating is a one-component coating system that uses epoxy resin as a film-forming material. Epoxy resin consists of epoxy resin and vegetable oil fatty acid esters. Compared with general epoxy coatings, this coating has the advantages of low cost and poor alkali resistance. Commonly used in various metal primers in chemical plants and anti-corrosion coatings for outdoor equipment.
5.Polyurethane coating
Polyurethane resins used in anti-corrosion coatings usually contain two components: isocyanate-NCO and hydroxyl groups. Polyurethane (polyurethane) is a two-component product that is mixed and reacted to cure during use.
Polyurethane coatings have the characteristics of good physical and mechanical properties, hard, flexible, bright, full paint film, wear resistance, strong adhesion, corrosion resistance, resistance to oil, acid, chemicals, industrial waste gas, etc. The alkali resistance is slightly lower than that of epoxy coating; the aging resistance is better than that of epoxy coating, and it is often used as topcoat or primer; polyurethane resin can be mixed with various resins, and the formula can be widely adjusted to meet various usage requirements; It can be cured at room temperature or heated, and can also be cured at low temperatures (0°C); polyisocyanate components have poor storage stability and must be isolated from moisture to avoid freezing. Polyurethane coatings are expensive and have a long service life.
6.Long fiber wound fiberglass reinforced epoxy lining
A unique embedded lining process is used to form corrosion-resistant material in the steel pipe. This corrosion-resistant material can isolate oilfield corrosive liquids and gases from steel pipes, providing an internal anti-corrosion lining system for oilfield steel pipes and pipelines. Damaged downhole production tubing or subsea flow lines can be very costly to replace. It can provide good corrosion resistance protection in very harsh environments, which is unmatched by other products.
7.Polyethylene, polypropylene resin coating
Polyethylene resin anticorrosive coating is a film-forming coating made of monomer resin. Polyethylene coatings have been widely produced and used.
Polyethylene pipes have strong anti-corrosion and sealing properties, high mechanical strength, strong waterproofing, stable quality, convenient construction, good applicability, and do not pollute the environment. PE has low water absorption (less than 0.01%), high epoxy strength, low water absorption of PE, good hot melt adhesive softness, and high anti-corrosion reliability. The disadvantage is that the cost is higher than other repair materials. The raw materials of this coating are rich in sources and have been widely used in corrosion.
8.Furan resin coating
Furan resin coatings are resistant to various non-oxidizing inorganic acids, electrolyte solutions, and various organic solvents. They also have outstanding alkali resistance, but their oxidation resistance is not good. Furan resin series anti-corrosion coatings include furfuryl alcohol coatings, furfural acetone formaldehyde coatings and modified furan resin coatings.
9.Rubber coating
Rubber anti-corrosion coating is made from chemically treated or mechanically processed natural rubber or synthetic rubber, with solvents, fillers, pigments, catalysts, etc. added.
10.Asphalt coating
Asphalt is one of the important anti-corrosion coatings. In particular, coal tar pitch is the best. Coal tar pitch coating is inexpensive and has the advantages of water resistance. After being immersed in water for ten years, its water absorption rate is only 0.1% - 0.2%; it is resistant to erosion by some chemical media; it still has good wettability to the steel surface that has not been completely rusted; its solid content is high, and thick films can be obtained ; Low price. Its disadvantage is that it is crispy in winter and soft in summer. After exposure, some components volatilize and escape, causing the paint film to crack. These shortcomings can be improved by adding some other resins. For example, adding chlorinated rubber can improve the dryness of asphalt coatings and improve the shortcomings of being brittle in winter and soft in summer; epoxy asphalt coatings made of epoxy resin have the advantages of asphalt coatings and epoxy coatings, and have achieved very satisfactory results in anti-corrosion Effect. Asphalt coatings have been used in container bottoms, ship bottoms, dock gates, cofferdams, etc., and have good anti-corrosion effects.
11.Heavy anti-corrosion coating
Heavy-duty anti-corrosion coatings are compared to ordinary anti-corrosion coatings. It refers to an anti-corrosion coating whose anti-corrosion effect is several times higher than that of ordinary corrosive coatings under severe corrosive conditions. It is characterized by excellent resistance to corrosive media, outstanding durability, and a service life of more than several years. Mainly used in marine structures and chemical equipment, storage tanks and pipelines.
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Exploring the secrets of anti-corrosion steel-plastic pipes
In today's industrial and civil fields, the quality and performance of pipeline systems as the "arteries" for the transportation of various fluids are crucial. Anti-corrosion steel-plastic pipes are gradually emerging with their unique advantages and becoming the preferred material for many engineering projects.
1. Structural analysis: a perfect combination of rigidity and flexibility
The structure of anti-corrosion steel-plastic pipes is like a symphony of exquisite material fusion. Its core is usually a thermoplastic plastic with excellent toughness, and common ones are polyethylene (PE) and polypropylene (PP). These plastics are naturally corrosion-resistant with their excellent chemical stability. They can effectively resist the erosion of corrosive media such as acids, alkalis, and salts, and build a safety line for the fluid inside the pipeline.
Super strong anti-corrosion: In chemical industrial parks, various highly corrosive chemical raw materials need to be transported frequently. Traditional metal pipes are often corroded and perforated in a short time, causing material leakage, safety accidents and environmental pollution. The anti-corrosion steel-plastic pipe, with its plastic lining, can withstand the erosion of strong acid and strong alkali solutions for a long time, making the fluid transportation in the chemical production process safe and worry-free, greatly extending the service life of the pipe and reducing the high cost of frequent pipe replacement.
Good hydraulic properties: For urban water supply systems, the hydraulic performance of the pipe is directly related to the residents' water experience. The inner wall of the anti-corrosion steel-plastic pipe is smooth and has low roughness. Compared with traditional cast iron pipes and cement pipes, the water flow resistance is significantly reduced. This means that under the same water supply pressure, more water can be transported, effectively improving water supply efficiency, reducing pump station energy consumption, and reducing the probability of water hammer phenomenon, ensuring the stability of water supply.
Adapt to complex environment: In the desalination project in coastal areas, the pipeline has to face the high salt corrosion of seawater and withstand the humidity and impact brought by sea breeze and waves. The double protection structure of the anti-corrosion steel-plastic pipe makes it easy to handle. The outer steel structure resists external forces, and the inner plastic layer blocks salt penetration, which provides reliable guarantee for the transportation of fresh water after desalination and the introduction of seawater in the pretreatment stage, helping to solve the problem of fresh water shortage in coastal cities.
3. Convenient installation: time-saving and labor-saving construction advantages
The advantages of anti-corrosion steel-plastic pipes are not only reflected in performance, but also in the installation process. Due to its relatively light weight, compared with the heavy traditional steel pipes, the labor intensity of workers in the handling and hoisting links is greatly reduced, and the construction risk is reduced. Moreover, it can adopt a variety of connection methods, such as hot melt connection, electric fusion connection, flange connection, etc., to meet the needs of different scenarios. Hot melt connection is easy to operate. By heating the pipe and pipe fittings to integrate them, the interface is firm and the sealing performance is good, which reduces the risk of leakage. It can quickly and efficiently complete the pipeline laying task, saving valuable construction time for the project.
4. Environmental protection and sustainability: in line with the development trend of the times
With the increase of global environmental awareness, the sustainability of materials has become increasingly critical. In the production process, the energy consumption of anti-corrosion steel-plastic pipes is relatively low compared with some high-energy consumption and high-pollution traditional pipeline manufacturing processes. At the same time, its long life reduces the waste generated by frequent replacement of pipes, reducing resource consumption and environmental burden. Moreover, when some waste anti-corrosion steel-plastic pipes are recycled, they are easy to classify, recycle and reuse because the inner and outer layer materials are relatively simple, contributing to the development of the circular economy.
With its excellent comprehensive performance, anti-corrosion steel-plastic pipes are gradually penetrating various fields, from the harsh industrial environment to the daily water supply of civilians, escorting the infrastructure construction and fluid transportation of modern society, and becoming a rising star in the field of pipeline materials.
1. Structural analysis: a perfect combination of rigidity and flexibility
The structure of anti-corrosion steel-plastic pipes is like a symphony of exquisite material fusion. Its core is usually a thermoplastic plastic with excellent toughness, and common ones are polyethylene (PE) and polypropylene (PP). These plastics are naturally corrosion-resistant with their excellent chemical stability. They can effectively resist the erosion of corrosive media such as acids, alkalis, and salts, and build a safety line for the fluid inside the pipeline.
The outer layer is a strong and rigid galvanized steel pipe or seamless steel pipe, which is like a steel guard, giving the pipeline strong mechanical strength. Whether it is buried deep underground to bear the heavy pressure of the soil, or laid overhead to withstand the stress impact caused by wind, sun, and temperature changes, it can firmly stick to its post to ensure the integrity of the pipeline system. The inner and outer layers are closely connected through a special bonding process, working together to achieve the unity of rigid support and flexible protection.
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2. Excellent performance: a capable person in multiple fieldsSuper strong anti-corrosion: In chemical industrial parks, various highly corrosive chemical raw materials need to be transported frequently. Traditional metal pipes are often corroded and perforated in a short time, causing material leakage, safety accidents and environmental pollution. The anti-corrosion steel-plastic pipe, with its plastic lining, can withstand the erosion of strong acid and strong alkali solutions for a long time, making the fluid transportation in the chemical production process safe and worry-free, greatly extending the service life of the pipe and reducing the high cost of frequent pipe replacement.
Good hydraulic properties: For urban water supply systems, the hydraulic performance of the pipe is directly related to the residents' water experience. The inner wall of the anti-corrosion steel-plastic pipe is smooth and has low roughness. Compared with traditional cast iron pipes and cement pipes, the water flow resistance is significantly reduced. This means that under the same water supply pressure, more water can be transported, effectively improving water supply efficiency, reducing pump station energy consumption, and reducing the probability of water hammer phenomenon, ensuring the stability of water supply.
Adapt to complex environment: In the desalination project in coastal areas, the pipeline has to face the high salt corrosion of seawater and withstand the humidity and impact brought by sea breeze and waves. The double protection structure of the anti-corrosion steel-plastic pipe makes it easy to handle. The outer steel structure resists external forces, and the inner plastic layer blocks salt penetration, which provides reliable guarantee for the transportation of fresh water after desalination and the introduction of seawater in the pretreatment stage, helping to solve the problem of fresh water shortage in coastal cities.
3. Convenient installation: time-saving and labor-saving construction advantages
The advantages of anti-corrosion steel-plastic pipes are not only reflected in performance, but also in the installation process. Due to its relatively light weight, compared with the heavy traditional steel pipes, the labor intensity of workers in the handling and hoisting links is greatly reduced, and the construction risk is reduced. Moreover, it can adopt a variety of connection methods, such as hot melt connection, electric fusion connection, flange connection, etc., to meet the needs of different scenarios. Hot melt connection is easy to operate. By heating the pipe and pipe fittings to integrate them, the interface is firm and the sealing performance is good, which reduces the risk of leakage. It can quickly and efficiently complete the pipeline laying task, saving valuable construction time for the project.
4. Environmental protection and sustainability: in line with the development trend of the times
With the increase of global environmental awareness, the sustainability of materials has become increasingly critical. In the production process, the energy consumption of anti-corrosion steel-plastic pipes is relatively low compared with some high-energy consumption and high-pollution traditional pipeline manufacturing processes. At the same time, its long life reduces the waste generated by frequent replacement of pipes, reducing resource consumption and environmental burden. Moreover, when some waste anti-corrosion steel-plastic pipes are recycled, they are easy to classify, recycle and reuse because the inner and outer layer materials are relatively simple, contributing to the development of the circular economy.
With its excellent comprehensive performance, anti-corrosion steel-plastic pipes are gradually penetrating various fields, from the harsh industrial environment to the daily water supply of civilians, escorting the infrastructure construction and fluid transportation of modern society, and becoming a rising star in the field of pipeline materials.