FBE Coated Carbon Steel Pipe

Common FAQs about Carbon Steel Pipes with Molten Polyethylene Coating on the Inner Wall

Q1. Question: What chemical media can the inner wall coating of the pipe withstand?

Answer:
The molten polyethylene coating on the inner wall is resistant to most alkalis, acids, salts, and organic solvents, but its resistance to strong oxidizers (such as concentrated nitric acid and chlorine) is limited.

Solution:
Before purchasing, confirm the concentration, temperature, and pressure of the transported medium, refer to the chemical corrosion resistance table provided by the supplier, and conduct small-scale pipeline corrosion resistance tests if necessary.
For special media, consider increasing the inner lining thickness or using a double-layer composite coating to improve corrosion resistance.

Q2. Question: Will high-temperature chemical media transportation in pipelines affect the PE coating?

Answer:
The temperature resistance of polyethylene coatings is generally -20℃ to 80℃. Prolonged exposure to high temperatures (>80℃) will reduce coating adhesion and corrosion resistance.
Solution:
Under high-temperature conditions, high-temperature resistant PE or FBE+PE composite coatings can be used, or high-temperature resistant epoxy or PTFE lined pipes can be selected.
When purchasing, the medium temperature should be clearly defined to ensure the coating grade is suitable for long-term use.

Q3. Question: How should the inner wall coating thickness be selected to guarantee service life?

Answer:
The inner wall coating thickness directly affects corrosion resistance and service life. Generally, it is 0.5–1.0 mm; a thicker thickness can be appropriately applied in the chemical industry.
Solution:
Select an appropriate thickness based on the corrosiveness of the medium, pipe diameter, and operating pressure, and request the supplier to provide a coating thickness test report.
Special protective sleeves or thicker coatings can be used at edges or bends to avoid localized corrosion.

Q4. Question: What should I do if the inner coating of a pipe is damaged after welding?

Answer:
The heat during welding can damage the coating, creating a potential corrosion hazard.

Solution:
After welding, use a special repair sleeve to treat the weld joint.
Ensure the repair thickness is consistent with the original coating and perform adhesion and corrosion resistance tests.
For highly corrosive media, local cathodic protection can be added to the weld joint.

Q5. Question: How to solve the problem of scaling or blockage on the inner wall of chemical pipelines?

Answer:
Although the inner coating is smooth and has a low coefficient of friction, scaling or blockage can still occur when transporting suspended particles or high-salt liquids.

Solution:
Select PE-coated pipes with high smoothness and uniform coating.
Perform regular online cleaning or flushing, using chemical cleaning agents if necessary.
Select a pipe diameter slightly larger than the flow design requirements to reduce the risk of deposition.

Q6. Question: How to ensure reliable quality of the inner wall coating during procurement?

Answer:

Substandard inner wall coating quality can lead to accelerated corrosion or leaks.

Solution:

Require suppliers to provide test reports on coating thickness, adhesion, corrosion resistance, and temperature resistance.

Select manufacturers with mature FBE/PE coating technology and international certification (ISO 21809-1).

For critical pipe sections, third-party testing or sampling re-inspection can be conducted to ensure long-term reliable pipeline operation.