Introduction to the double-layer epoxy coating (double-layer FBE) for pipelines
Thread Content
Double-layer epoxy combines the corrosion resistance of single-layer FBE with the mechanical damage resistance of the plastic outer layer of FBE, offering advantages such as strong adhesion, high operating temperatures, resistance to soil stress, impact resistance, and good resistance to cathodic disbonding. Double-layer FBE is formed by applying two epoxy powders with different properties in a single spraying process to create the coating layer. The underlying epoxy anti-corrosion layer is the same as that in single-layer FBE, serving to provide corrosion protection, while the outer layer of FBE is a plasticized epoxy powder layer designed primarily to resist mechanical damage. The thickness of the two layers is generally 525–1,000 mm; it can be used for pipes of various diameters, as well as to meet the anti-corrosion requirements of joints, elbows, and other custom-shaped components. Different types of double-layer FBE structures can be selected according to various application environments and requirements. Its impact resistance and cathodic protection current density are comparable to those of three-layer PE; it is the only anti-corrosion system that can be used in cathodic protection systems without any shielding, while also possessing failure safety, which makes it even more superior. The price of double-layer FBE varies depending on its structure and thickness, but it is generally cheaper than triple-layer PE; its cost continues to decrease as manufacturing technologies advance.
The anti-corrosion coating for double-layer epoxy (double-layer FBE) pipes is a dual-layer structure formed by applying two types of epoxy powders in one application: 1. The bottom layer of epoxy: similar to that in single-layer FBE, it primarily serves to provide corrosion protection. 2. Outer epoxy: A plasticizing epoxy powder to improve resistance to mechanical damage. This structure combines the excellent adhesion strength, high-temperature tolerance, and resistance to cathodic delamination of single-layer FBE, along with the good impact resistance and wear resistance of the epoxy coating on the surface, resulting in superior overall performance. The total thickness of double-layer FBE is usually between 525 and 1000 microns; it is suitable for pipes of various diameters and is widely used for corrosion protection in special areas such as joints, elbows, and custom-shaped pipe fittings. In terms of performance, the double-layer FBE offers impact resistance and compatibility with cathodic protection currents comparable to those of triple-layer PE; however, it does not cause shielding effects, making it safer and more reliable. At the same time, its mature technology and low cost result in significant economic advantages, which is why it is widely used in the field of pipeline anti-corrosion. .