Epoxy Coal Tar Pitch Anti-Corrosive Steel Pipe

• ​Introduction

Epoxy coal tar pitch anti-corrosive steel pipe is a type of steel pipe that undergoes special anti-corrosion treatment. It is mainly prepared by coating the surface of the steel pipe with epoxy coal tar pitch paint and winding glass cloth after removing oil stains, rust and other substances. This kind of steel pipe has excellent anti-corrosion performance and can effectively resist the erosion of various corrosive media, thus extending the service life of the steel pipe. It is widely used in pipeline projects such as water supply, drainage, oil transportation and chemical industry.

• ​Main Functions

Anti-corrosion protection: It can isolate the steel pipe from the external corrosive environment, such as soil, water, chemicals, etc., preventing the steel pipe from rusting and being corroded, so as to ensure the normal operation of the pipeline.​

Extending service life: By reducing the corrosion damage of the steel pipe, the service life of the pipeline is greatly extended, reducing the frequency of pipeline replacement and maintenance, and saving costs.​

Ensuring pipeline safety: It can maintain the structural integrity of the steel pipe, avoid pipeline leakage caused by corrosion, and ensure the safe transportation of substances in the pipeline.​

Adapting to harsh environments: It has good resistance to acid, alkali, salt and other corrosive substances, and can be used in various harsh environmental conditions such as coastal areas, chemical industrial zones and saline-alkali lands.

• ​Tubing Standards

ASTM A53，ASTM A106，API 5L，AWWA C210-03； EN 10255，EN 10240，BS EN 10289，EN ISO 21809-2； GB/T 3091，GB/T 13793，GB/T 9711，GB/T 8163，SY/T 0447，GB/T 39636.

• ​Material & Performance

Base Material: ASTM A53: Grade A、B，ASTM A106: Grade A、B、C； EN 10255: S195T、S235JRH、S275JRH、S355JRH； GB/T 3091: Q215A/B、Q235A/B、Q355B, GB/T 8163：10#，20#，Q355，Q420， GB/T 13793: Q195、Q215A/B、Q235A/B、Q355B、Q390B；

Anti-corrosion Coating: 1.External Coating：Epoxy coal tar pitch paint (ECTP) and glass cloth. 2.Internal Coating：Fusion-Bonded Epoxy Powder (FBE).

Thickness: External Coating thickness: ≥1.0mm, Internal Coating thickness: ≥300μm.

Key Performance : The epoxy coal tar pitch paint has good adhesion, anti-corrosion and water resistance, and it can be brushed at room temperature, which makes the manufacturing conditions more convenient; the glass cloth plays a role in enhancing the strength and toughness of the anti-corrosive layer.The anti-corrosive layer has strong adhesion to the steel pipe surface, not easy to fall off. It has excellent anti-corrosion performance, can resist the erosion of various chemical media. At the same time, it has good water resistance and weather resistance, and can maintain stable performance in humid and changing climate environments. The service life of the anti-corrosive layer is long, which can effectively ensure the long-term use of the steel pipe.

• ​Manufacturing Process

Steel Pipe Base Material Pretreatment: Steel Pipe Inspection: Conduct dimension inspection (diameter, wall thickness), mechanical property testing (tensile, bending test) and non-destructive testing (ultrasonic testing, magnetic particle testing) on the incoming steel pipes, and reject unqualified base materials. Surface Derusting: Use shot blasting derusting process to completely remove the scale, rust and oil on the inner and outer walls of the steel pipe, so that the surface roughness reaches Ra 40-80μm ( Sa 2.5 standard) to enhance coating adhesion.

Internal Coating (FBE) Application:

Preheating: Heat the steel pipe to 230-250℃ (FBE powder curing temperature) through medium-frequency induction heating equipment to ensure that the powder can be cured quickly after coating. FBE Powder Coating: Use the “electrostatic spraying” process to uniformly spray FBE powder on the inner wall of the steel pipe. The powder melts and levels when heated to form a continuous and smooth coating. Curing & Cooling: The coated steel pipe enters a curing oven (maintain 230-250℃, curing time 10-15 minutes) to fully cure the FBE coating; then the temperature of the steel pipe is cooled to below 60℃ by water cooling or air cooling to avoid coating deformation.

External Coating (ECTP) Application:

Painting epoxy coal tar pitch paint: The epoxy coal tar pitch paint is evenly painted on the surface of the steel pipe. The number of coats can be determined according to the anti-corrosion requirements.​ Winding glass cloth: While the paint is still wet, the glass cloth is evenly wound on the surface of the painted steel pipe. The glass cloth should be tightly attached to the paint to form a composite anti-corrosive layer.​ Re-painting epoxy coal tar pitch paint: After winding the glass cloth, apply another layer of epoxy coal tar pitch paint on the surface of the glass cloth to ensure that the glass cloth is fully covered and integrated with the paint, further enhancing the anti-corrosion effect and the integrity of the coating. Curing: The steel pipe after painting and winding is placed in a suitable environment for curing, so that the paint can fully dry and cure, and form a firm anti-corrosive layer with the glass cloth.

Inspection: Conduct appearance inspection (no bubbles or scratches on the coating), thickness detection (coating thickness gauge), adhesion test, spark leak detection (detect coating pinholes) and impact resistance test on the finished steel pipes. Only qualified products can be put into storage.

Packaging: Use pipe end protection caps to protect the pipe orifices, wrap the outer wall of the steel pipe with waterproof film, and bundle it with steel strips for transportation and storage, preventing coating damage during transportation.

• Specifications