TPEP Anti-Corrosion Steel Pipe

Product Introduction

TPEP Anti-Corrosion Steel Pipe: External 3PE anti-corrosion + internal fusion-bonded epoxy powder anti-corrosion, a double-layer anti-corrosion steel pipe on both the inner and outer surfaces. The outer wall adopts three-layer polyethylene (3PE) anti-corrosion, and the inner wall adopts fusion-bonded epoxy powder (FBE), abbreviated as TPEP, with the full name External Polyethylene and Internal Epoxy Powder Anti-Corrosion Steel Pipe.

Comparison: Plain 3PE only provides external wall anti-corrosion, with the inner wall left untreated; TPEP provides anti-corrosion on both the inner and outer surfaces, suitable for conveying water media, preventing internal corrosion and scaling.

• Structural Composition

1. Base steel pipe: Seamless steel pipe, longitudinally welded steel pipe, spiral steel pipe, materials Q235B, Q355B
2. Outer wall: 3PE three-layer anti-corrosion (epoxy powder primer layer + adhesive + polyethylene outer layer)
3. Inner wall: Fusion-bonded epoxy powder coating (FBE)

• Product Advantages: Smooth inner wall, low water flow resistance, not prone to scaling; dual anti-corrosion on both inner and outer surfaces, resistant to soil corrosion and media corrosion; service life of 30-50 years; strong adhesion, resistant to cathodic disbondment; hygienic for water conveyance, suitable for drinking water projects.
• Application Fields: Municipal water supply and drainage, tap water supply, reclaimed water reuse, sewage treatment, long-distance water conveyance projects, water conservancy diversion, mine slurry transportation.
• Executive Standards

1. Outer wall 3PE: GB/T 23257-2017
2. Inner wall epoxy powder: GB/T 23257-2017, CJ/T 120-2020 "Plastic-Coated Composite Steel Pipe for Water Supply"

Note: TPEP ≠ plastic-coated steel pipe; plastic coating means both inner and outer surfaces are polyethylene; TPEP has internal epoxy and external polyethylene.

Anti-Corrosion Coating Technical Parameters

Outer Wall (3PE Anti-Corrosion Coating, divided into Ordinary Grade / Reinforced Grade; Reinforced Grade is generally selected for water conveyance projects)

Table

Inner Wall - Fusion-Bonded Epoxy Powder FBE

Table

III. Applicable Conditions

1. Media: Tap water, reclaimed water, sewage, surface water; media temperature ≤60℃
2. Pressure: PN1.0MPa, PN1.6MPa, determined by the wall thickness of the base steel pipe
3. Diameter: DN50-DN1800; standard lengths 6m, 12m
4. Pipe end allowance: 100-150mm bare steel pipe reserved at both ends for field welding; weld joints externally repaired with 3PE heat-shrink sleeves; internal weld joints require internal repair coating

IV. Production Process

The inner and outer surfaces of the steel pipe are abrasive blast cleaned to Sa2.5 grade; the outer wall is induction heated and coated with 3PE by extrusion wrapping; the inner wall is sprayed with epoxy powder by high-temperature electrostatic spraying, then cured and cooled, with spark testing performed on each pipe on both the inner and outer surfaces.

V. Simple Comparison of Three Types of Pipes

1. 3PE Anti-Corrosion Steel Pipe: External anti-corrosion only, bare steel pipe on the inner wall; used for gas and oil & gas applications, not suitable for long-term water conveyance.
2. TPEP Anti-Corrosion Steel Pipe: External 3PE + internal epoxy powder; the preferred choice for water supply and conveyance.
3. Polyurethane Directly Buried Insulation Pipe: Polyurethane insulation + PE outer jacket, mainly used for heating and hot water, with insulation as the primary function.