FBE Coated Pipe
What is FBE Coated Pipe?
Fusion Bonded Epoxy (FBE) coatings form a permanent protective barrier on metal surfaces through a unique molecular cross-linking mechanism. The coating system realizes charged adsorption of 5-10 μm powder by electrostatic spraying process, and forms a continuous film layer of 200-500 μm in the melting stage. Differential Scanning Calorimetry (DSC) analysis shows that the glass transition temperature (Tg) is up to 120°C, which ensures the dimensional stability under the working conditions from -30°C to 100°C.
Types of FBE Coated Pipes
There are two varieties of FBE coated pipe: one-layer coated pipe and dual-layer coated pipe.
FBE coated steel pipes are typically a single layer of coating applied to the steel pipe. The surface is rough and non-slip, which is ideal for a pipeline that will be covered with a concrete coating. This was accomplished through the use of a specific fusion bonded epoxy powder that was combined with solid epoxy resin and other adhesive materials to aid the pipe surface to adhere to the powder.
Dual-layer FBE coating is a pipe coating that consists of two layers of FBE. The first layer is applied to the pipe by electrostatic spraying, and the second layer is applied by roller coating. Dual-layer FBE coating provides excellent protection against corrosion and abrasion damage. It is often used on steel pipes that are buried or exposed to the elements. Dual-layer FBE coating is also used on Pipe fittings, valves, and flanges. It can be installed on new pipe or retrofitted on existing pipe. Dual-layer FBE coating is an effective way to protect your investment and extend the life of your pipeline.
Manufacturing Process of FBE EPOXY CoatING Pipe
FBE components are measured and pre-blended in high-speed mixers before being combined in the final formulation. After that, the mixture is delivered to a high-shear extruder. FBE extruders are equipped with a single or twin-screw system that rotates within a fixed clamshell barrel configuration. Within the extruder barrel, temperatures ranging from 50 degrees Celsius to 100 degrees Celsius are employed. This configuration compresses the FBE blend while simultaneously heating and melting it into a semi-liquid state.
It is during this procedure that the elements of the molten mixture are fully disseminated. Because of the rapid operation of the extruder and the relatively low temperature within the barrel, there will be no substantial chemical interaction between the epoxy and hardener components of the composite. It is then forced through cold-rollers, where it hardens and produces a solid, brittle sheet of plastic. It is then sent through a “Kibbler,” which slices it up into smaller chips for consumption. These chips are processed in high-speed grinders (classifiers) to a particle size of fewer than 150 micrometers, with a particle size of fewer than 150 micrometers (standard specifications require 100 percent pass-through in 250-micrometer sieves and a maximum of 3 percent retains in a 150-micrometer sieve).
The finished product is packaged in tightly sealed containers, with special attention paid to preventing moisture contamination. In air-conditioned warehouses, normal storage temperatures for FBE powder coatings are less than 25 degrees Celsius (77 degrees Fahrenheit).
The Process of FBE Coating Application
Regardless of the form and kind of steel surface to be coated, the application of FBE powder coating follows a three-step process:
- The pipe’s surface is cleaned and then subjected to high temperatures.
- Electrostatic application of epoxy powder to the surface of the pipe is performed.
- The FBE powder is melted into the pipe surface and dries fast, forming a regulated and consistent thickness.
The hardener and resin work together to form a bond or binder. The curing agent is responsible for forming the reaction, whereas the pigments, fillers, and extenders are responsible for imparting the required qualities. FBE dry powder normally has inactive hardener components and resin due to the way it is stored in a typical storage environment. Typical coating temperatures range from 180°C to 250°C, at which point the powder components melt and transform into a liquid condition. After flowing over the metallic surface, the liquid form of the FBE will quickly transition into its solid form as a result of element cross-linking, which is assisted by heat. “Fusion bonding” is the phrase used to describe the process involved in this. When it comes to chemistry, the cross-linking that happens cannot be reversed in this situation. Once the curing process is completed, the coating will not be able to be restored to its previous state. Due to the fact that subjecting the coating to additional heating will not cause the coating to melt, this form of coating is known as a thermoset type of coating.
Using pipe and rebar has the benefit of allowing continuous linear application over the outer surface as the pieces are transported via a conveyor through the powder application booth, allowing for high throughput.
Advantages of FBE Coated Pipe
- Long Term Corrosion Protection
- Pipelines running at moderate temperatures during the intended life of the pipeline are protected with FBE, which has good adhesion to steel and provides better long-term corrosion resistance and protection. Because of its excellent anticorrosive properties, its service life can be in excess of 100 years.
- Excellent cathodic disbondment resistance is provided by superior adhesion qualities, resulting in a reduction in the overall cost of cathodic protection during the pipeline’s operation.
- Special grades of FBE are available for use at higher working temperatures, for coating high-strength steels, and for a variety of other purposes.
- Good Mechanical and Chemical Resistance
- In addition, FBE may be used as a dual-layer product, which has robust physical features that help to limit damage during handling and transit as well as installation and operation.
- FBE has been engineered to provide excellent chemical resistance in a wide range of soil conditions.
- It is effective in preventing the growth of germs and the formation of mounds in the water. Have a great ability to prevent scale from forming. The potential of the pipe ends becoming blocked exists when the cement lining is employed, especially when the water capacity is low enough.
- It offers 15-20 percent greater water volume when compared to other types of coating pipes of the same diameter (cement Lining).
Performance of FBE Coated Pipe
| No. | Item | Performance Indicators |
|---|---|---|
| 1 | Adhesion, Classification | ≤2 |
| 2 | Cathode Racking (65℃，48h)/mm | Racking Distance ≤8 |
| 3 | Cathode Racking (65℃，30d)/mm | Racking Distance ≤15 |
| 4 | Anti-bending (-20℃，2.5°） | No Crack |
The Service Life of FBE Coated Pipe
As an important part of the infrastructure, the quality of pipeline protective coatings has a direct impact on operational safety. The latest assessment data on fusion bonded epoxy (FBE) coatings, validated over three decades of service, provides a valuable reference point for the industry. A recent integrity assessment of two FBE-coated pipelines laid in the 1990s showed that, after laboratory testing and site investigation, the original coatings still maintain excellent adhesion properties, and the synergistic effect of protection with the cathodic protection system is remarkable.
It is noteworthy that, despite several iterations of the FBE formulation (optimized for corrosion resistance and mechanical properties), the early engineering applications demonstrated exceptional durability. No significant signs of deterioration were detected during the evaluation, indicating that the protection system is capable of sustained service. This finding not only validates the reliability of the base formulation, but also provides historical data to support the development of new coatings.
In industry practice, integrity management focuses on modern coating technologies. However, the systematic testing of early engineering samples has special value: firstly, it can calibrate the existing technical standards by comparing the data over time; secondly, the study of degradation patterns of long-term service samples can help to improve the life prediction model; and thirdly, it can provide empirical references for the suitability of materials in different geological environments. It is recommended that the industry establish a database of historical engineering samples and incorporate this type of “time verification” into the technical specification updating system.
This time-validated study confirms that the scientifically designed protection system has cross-generational engineering applicability. For new projects, while adopting advanced technologies, historical engineering data should be systematically integrated to build a full-life-cycle protection model, thus realizing the organic unity of technology iteration and experience inheritance.
