FBE Coated Pipe
What is FBE Coated Pipe?
An epoxy powder coating, also known as Fusion Bonded Epoxy (FBE) coating, is widely used to give protection to pipelines, steel pipes, and a wide range of other piping connections. By their very nature, FBE coatings are thermoset polymers.
Fusion bonded epoxy coatings are categorized as protective coatings using the terminology used in the coatings industry. Its term was obtained from the application methods used and the cross-linking of resin used, which distinguishes it from traditional painting.
The following are the most critical components of the powder coating:
- Curing agent or hardener
- Resin
- Extenders and fillers
- Color pigments
Table of Contents
Types of FBE Coated Pipes
There are two varieties of FBE coated steel 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 Coated 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
Pipelines are a vital part of our infrastructure, and it is essential that they are well-protected in order to prevent damage and leaks. One type of coating that is used on pipelines is fusion bonded epoxy (FBE). Recently, two segments of pipeline that were coated with FBE more than 30 years ago underwent exploratory inspection as part of the risk assessment process. The data derived from laboratory tests and field inspections indicated that the coating was properly applied and is still in good condition. This is positive news, as it shows that FBE can provide long-term protection for pipeline segments. The inspection also provided additional validation of the ability of the FBE coating to work in unity with cathodic protection to provide superior pipeline protection. This information is valuable not only for pipeline operators but also for those involved in specifying pipeline coatings for new construction projects.
The pipeline industry has long relied on FBE coatings to protect their pipelines from corrosion and degradation. Although the FBE manufacturer has revised their coating formulation several times in order to improve corrosion protection and mechanical properties, the older generation of FBE-coated pipe installed more than 30 years ago is still performing well. There are no indications of significant coating degradation and it appears that there are many years of remaining life on the FBE system. This is a testament to the durability and effectiveness of FBE coatings, and pipeline operators can continue to rely on this tried-and-true coating technology for many years to come.
Although pipeline integrity management programs typically focus on more recent coatings, excavations and inspections can provide valuable insights into the long-term performance of early generation FBE coatings. These evaluations can help to validate the current formulations and give a greater degree of confidence in their efficacy. Many changes and developments have taken place in FBE coating technology since the 1970s, so these older coatings can provide valuable data points. In addition, coated pipe that has been in service for many years can be inspected for any signs of degradation. Overall, these excavations and inspections can yield valuable information about the long-term performance of early generation FBE coatings.
