Eiffel Trading 101: Steel Pipe Coating
Epoxy, 3LPE, 3LPP, or CTE coating? Whether you’re considering using steel pipe for pile driving/foundation work, to create water/oil and gas pipelines, or for another reason entirely, the type of coating on your steel pipe can make or break your project.
A damaged pipe can be an engineer’s worst nightmare. Buried steel pipes are susceptible to corrosion that can cause service interruptions, or worse, explosions. Whether you choose seamless or welded steel pipe, it’s important to ensure the coating and pipe itself are right for your type of project. In this post we’ll cover the most common types of steel pipe coatings and their best uses.
Epoxy Coating
Epoxy coatings consist of epoxy resins, hardeners, pigments, flow control additives, and stabilizers. The stabilizers help to ease the application process and provide performance enhancement.
Fusion-Bonded Epoxy
Fusion-bonded epoxy (FBE) is a one-part coating, applied in powder form and bonded to the exterior of a pipe through heat curing and chemical cross-linking. Once the coating cools, it hardens and becomes very resistant to chemical reactions. This type of coating can be single or double layered. A major benefit of FBE coating is that it solidifies as a uniform layer on the surface of the pipe. The bonding stays hardened despite exposure to further heat.
Internal FBE coating can be applied to protect the steel pipe from corrosion and some mechanical impacts. It also provides resistance to cathodic disbondment (loss of adhesion) in oil and gas pipelines where solid particles travel at high speeds, creating a risk for internal damage to the steel pipe.
FBC coating a popular choice for piping connections and pipeline construction. It can be applied either at the pipe mill or in the field. External FBE coating is extremely effective as a coating for providing solvent, electrical, water, and cathodic disbondment resistance.
Coal Tar Epoxy
Coal tar epoxy (CTE) coating is a type of liquid epoxy. In this type of coating, some of the mineral fillers are replaced with a semi-liquid-state coal tar pitch. As with FBE, CTE is hardened through heat-fueled reaction of resin and hardener. CTE coating takes significantly longer to cure than FBE coating. CTE coatings can be either mill-applied or field-applied.
This type of CTE coating should not be used in situations where solvent and impact resistance are of high importance, but has is excellent for resisting water penetration, electrical impact, and cathodic disbondment. However, it’s a popular choice for underground pipeline systems, as it is well-suited to resist natural conditions like soil contamination, extreme temperatures, and moisture.
3LPE & 3LPP Coating
Three-layer polyethylene/propylene (3LPE/3LPP) steel pipe coatings are a type of hybrid coating consisting of a high-performance FBE base layer, a copolymer adhesive later, and a third, outer layer of side-extruded medium-density polyethylene (MDPE) or high-density polyethylene (HDPE). These outer layers help protect the steel pipe from elements which can lead to external corrosion, but are also helpful in protecting the pipe during transportation and installation. 3LPE and 3LPE coatings can only be applied at a steel pipe mill.
3LPE has some of the strongest resistance properties, protecting against electrical currents, water, solvent, and impact penetration, abrasions, and cathodic disbondment. 3LPP has a higher threshold for impact and abrasion resistance but is also suitable for protecting against electrical currents, water and solvent penetrations, and cathodic disbondment.
CTE Coating
Coal tar enamel (CTE) coating – not to be confused with coal tar epoxy – is what’s referred to as a thermoplastic polymeric coating, meaning the plastic polymer is heated to be applied, then solidifies once cooled. CTE coating can be applied in the mill or on the field. It is one of the oldest methods for steel pipe coating, and is also one of the least expensive types of steel pipe coating and easily repaired in the field.
This type of coating consists of four parts: primer, coal tar enamel, a glass fiber inner-wrap, and a glass fiber outer-wrap. Enamel and wrap grades are selected based on the pipe’s intended application. It is primarily used today under concrete weight-coated pipe as corrosion protection.
Applying Coatings
In all of the above cases, steel pipe must be prepped for the coating application process. The preparation process ensures that the surface of the pipe is clean and free of rust, debris, or mill scale. The method of steel pipe preparation will vary by coating type and manufacturer, but may include using solvents or hand/power tools.
Always check with your state DOT to see if any specific type of coating is required in your area.
Buy and Sell Used and Surplus Steel Pipe with Eiffel Trading
Our online marketplace currently has a host of used and surplus steel pipe for sale ranging from under 10 inches to 100-plus inches for sale. Looking for other steel materials? Check out our selections of wide flange beams, H-pile, and steel plates.
All of our listings are constantly being updated, but if you don’t see what you’re looking for, create a wanted listing for free.
Ready to sell your used heavy equipment or construction material? List your products today for free on Eiffel Trading’s online marketplace.
If you have any questions or would like additional information, please call us at 1-800-541-7998 or email sales@eiffeltrading.com.