Melt-bonded Epoxy Powder Coated Steel PipeConstruction employs automated production lines to replace manual labor, suitable for the anti-corrosion treatment of pipelines in construction projects with larger diameters and longer distances. This article will discuss the concept and advantages.
Double-layer熔结环氧粉末coatingtechnologyconcept
Melted Epoxy Powder钢管 typically comes in two types: single-layer and double-layer. Addressing the issues of weaker mechanical impact resistance and poor waterproofing in the single-layer melted epoxy powder coated钢管, an American corrosion prevention company has researched a multitude of coating materials, structures, and construction techniques. They have proposed a technical approach for modified epoxy powder materials, establishing a double-layer melted epoxy powder corrosion prevention system. This system employs standard single-layer melted epoxy powder as the base coating and modified melted epoxy powder as the outer protective layer. This significantly improves the mechanical properties of the coating, greatly enhancing its high-temperature resistance to permeation, high-temperature performance, and impact resistance. Additionally, it retains the compatibility of the single-layer melted epoxy powder coating with cathodic protection, preventing the occurrence of cathodic protection shielding. The overall coating thickness of the double-layer melted epoxy powder corrosion prevention system ranges from 525 to 1000 um, with a service temperature up to 115°C, making it suitable for corrosion prevention requirements on various pipe diameters, elbows, non-standard parts, and flanges.
The double-layer fused epoxy powder coated steel pipe system employs a coating process and standard fused epoxy powder spray technology that are essentially the same, with only variations in the arrangement of the powder spray chamber and spray gun, without the need for additional complex equipment. The arrangement of the powder spray guns includes both dual powder spray chambers and an integrated powder spray chamber, both of which are used for the coating of the double-layer fused epoxy powder corrosion protection system. Laboratory testing and field application trials have proven that the double-layer fused epoxy powder corrosion protection system for long-distance pipelines offers superior comprehensive performance compared to single-layer epoxy powder coatings, with high cost-performance. Moreover, it boasts a longer effective service life, lower maintenance costs, and various types of corrosion protection layers. It can be selectively tailored to different needs and is suitable for various pipeline construction projects, especially those requiring construction across or in mountainous areas. It can resist the corrosion of strongly corrosive soils, has a wide temperature and applicable pipe diameter range, and is adaptable to various non-standard components. During on-site construction, there are well-established techniques for jointing and repairing, making quality control easier. It exhibits excellent scratch resistance and impact resistance that is even comparable to three-layer PE corrosion protection structures. The system has strong adhesion properties and good water permeability resistance, and has been widely used in long-distance pipeline projects.
Section 2: Advantages of Double-Layer Sintered Epoxy Powder Coated Steel Pipe
High degree of automation in production process
During production, a one-time coating process is employed, ensuring that each powder particle of the epoxy powder coating can melt and bond together, allowing all components to blend uniformly. This guarantees a continuous and stable uniformity of the coating during the application process and after the coating film forms. Moreover, the painting process does not produce any kind of waste pollution.
2. Excellent bonding performance with steel
During construction, fused epoxy powder coating can melt and bond with the surface, fully melting and flowing to uniformly cover the steel pipe's surface without any gaps, achieving complete adhesion. Typically, the shear bonding strength of anti-corrosion coatings is below 10MPa, while the shear bonding strength of epoxy powder can reach over 80MPa. Moreover, a chemical reaction occurs during the bonding process, mainly due to the curing and cross-linking of the epoxy powder resin upon heating, forming a continuous thermosetting polymer. This results in a chemical bond with the steel pipe surface.
3. Excellent resistance to cathodic spalling
As a key indicator for determining the compatibility of anticorrosive coatings with cathodic protection, cathodic spalling is generally measured by applying cathodic protection current, and then evaluating the area (measured by radius) of the coating that can be removed after a period of time. The spalling radius of other coatings is usually greater than 10mm, while that of epoxy powder coatings is less than 8mm. Due to its thermosetting cross-linked molecular structure characteristics and the certain degree of chemical bond formation with steel pipes, the fused epoxy anticorrosive coating exhibits excellent performance as an anticorrosive coating system.
4. High impact resistance
Epoxy powder coatings are relatively hard, capable of forming a strong bond with metallic materials, and exhibit impact resistance up to 10J, which is generally unattainable by most coatings. This allows for the fusion bonded epoxy corrosion-resistant coating to meet the mechanical performance requirements of steel pipes under various working environmental conditions, including during storage, transportation, and pipeline laying, for compression, impact, friction, and bending.
5. Good temperature resistance properties
Epoxy powder coating is one of the most heat-resistant types of anticorrosive coatings currently in use, with an operational temperature range of up to 40-110°C. Moreover, the patching methods included in the fusion epoxy anticorrosive coating technology are simple, feasible, and boast excellent performance, as well as being compatible with the anticorrosive treatment of the pipe body.
6. Excellent environmental resistance
The fused epoxy anti-corrosion coating can meet the requirements of resistance to corrosion, aging, physical stress, biological erosion, and penetration by plant roots in various underground, overhead, and underwater environments during pipeline operation.
