• Internal liquid epoxy coating and external 3PE coating steel pipe

Internal liquid epoxy coating and external 3PE coating steel pipes are more and more popular these years.It not only has the advantages of high strength, easy connection and water shock resistance of steel pipe, but also overcomes the disadvantages of easy corrosion, pollution and scaling of steel pipe in water, low strength of plastic pipe, poor fire-fighting performance and so on. The design life can reach 50 years.Please contact IMRI if you need coating design service for your steel pipes.

Specifications for 3PE coating:

Standard DIN30670
Processing ability OD:38mm-1620mm;WT:2mm-30mm
Length 6-14m
Packing PE/BE,Plastic cap,bundling
Technique External surface on Welded pipe or seamless pipe
Application Oil and Gas field,chemical engineering,energy engineering,water Transportation…
Service condition -40℃,+85℃;alkaline or sour;underground
Place of Origin China
MOQ 3 pices
Transportation 1.Sea port:Tianjin Xingang port,Qingdao port,Shanghai Luojing port
→America,Europe,Africa,Middle East,India, Pakistan,Japan,Korea,
Australia…(shipping)

2.Land port:Alataw pass port(Пограничный пункт “Алашанькоу”)
Khorgos port(Пограничный пункт “Хоргос”)→East Asia, Uzbekistan,Kazakhstan,Kyrgyzstan…(Train)
Erlianhot port→Mongolia(Train and Truck)
Manchuria port→Russia(Train and Truck)

Type of DIN30670 3LPE/3PE coating
Type N S
Design temperatures for
sintered polyethylene
coatings
from −20 °C up to +50 °C from −40 °C up to +70 °C
Design temperatures for
extruded polyethylene
coatings
from −20 °C up to +60 °C from −40 °C up to +80 °C
Coating thickness of 3LPE
Nominal size DN normal (n) increased (v)
DN≤  100 1,8 2,5
100< DN≤  250 2,0 2,7
250 < DN< 500 2,2 2,9
500 ≤ DN <800 2,5 3,2
DN ≥800 3,0 3,7
DIN30670 3LPE/3PE Coating Performance
Property Requirement Testing as in Notes
Degree of cure of epoxy resin ΔTg according to the manufacturer’s specification Annex B
Cathodic disbondment (CD test) 23 °C/28 d or 60 °C/2 d max. 7 mm Annex C Applies only to three  layer coatings
Peel strengthb Type N:
100 N/cm (23 °C)
20 N/cm (50 °C)
Type S:
150 N/cm (23 °C)
30 N/cm (70 °C)
Annex D For system testing single values shall be no more than 25 % lower than the required average value.
Continuity (holiday detection) No discharges Annex E 25 kV test
Elongation at break (23 °C ± 2 °C) min. 400 % Annex F
Impact resistance (23 °C ± 2 °C) Type N: ≥ 5 J/mm
Type S: ≥ 7 J/mm
Annex H 25 kV test No discharges
Low temperature impact resistance Type N:
≥ 5 J/mm (−20 °C ± 2 °C)
Type S:
≥ 7 J/mm (−40 °C ± 2 °C)
Annex H 25 kV test No discharges
Indentation resistance Type N:
max. 0,2 mm (23 °C)
max. 0,3 mm (50 °C)
Type S:
max. 0,2 mm (23 °C)
max. 0,4 mm (70 °C)
Annex I
Specific electrical coating resistance (23 °C ± 2 °C) ≥ 108Ωm² Annex J
UV resistance ΔMFR ± 35 % Annex K
Thermal ageing resistance ΔMFR ± 35 % Annex L
                                                                                                 3PE coating production process

3LPE/3PE/ three layer polyethylene coating for steel pipe line

Specifications for internal liquid epoxy coating:

Standard API RP-5L
Processing ability OD:38mm-1620mm;WT:2mm-30mm
Length 6-14m
Packing PE/BE,plastic cap,bundling
Technique Internal coating on welded pipe or seamless pipe
Application Oil and gas field,chemical engineering,energy engineering,water transportation…
Service condition salt,alkaline or sour;underground
Place of origin China
MOQ 3 pieces
Transportation 1.Sea port:Tianjin Xingang port,Qingdao port,Shanghai Luojing port
→America,Europe,Africa,Middle East,India, Pakistan,Japan,Korea,
Australia…(shipping)2.Land port:Alataw pass port(Пограничный пункт “Алашанькоу”)
Khorgos port(Пограничный пункт “Хоргос”)
→East Asia, Uzbekistan,Kazakhstan,Kyrgyzstan…(Train)
Erlianhot port→Mongolia(Train and Truck)
Manchuria port→Russia(Train and Truck)
Layer Type Dry film thickness(µm)
Type n (normal) ≥ 200
Type v (increasing) ≥ 250
Type s (special) ≥ 300
Note: The thickness of anti-corrosion layer at the welded places shall not be less than 80% of the specified thickness of the anti-corrosion layer of the pipe body.
The main performances of internal coating
Items Performance index Test method
Pinhole test Pinhole dispersion shall be held to a minimum API RP-5L
Dry film thickness 80μm
Cure test No softening, wrinking or blistering
Adhesion test No loss of adhesion
Bend test No loss of adhesion, spalling,crack
Soaking test No loss of adhesion,softening, wrinking or blistering
Stripping test Flake off,present powder particles when rolled

                                                                          Production process of liquid epoxy internal coating

API RP-5L liquid epoxy anti-corrosion coating for carbon steel tube

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