3PE anti-corrosion steel pipe base materials include seamless steel pipes, spiral steel pipes, and straight seam steel pipes. The three-layer polyethylene (3PE) anti-corrosion coating has been widely used in the water supply, natural gas, and petroleum pipeline industries due to its excellent corrosion resistance, water vapor permeability, and mechanical properties.

Description:
3PE anti-corrosion coating production line means the steel pipe is protected by three layer to prolong the life of use from 5-10years to 50-100years.
First layer is Fusion bonded epoxy layer (FBE> 100µm), the second layer of adhesive (AD) 170 ~ 250µm, the third layer of polyethylene (PE) 2.5 ~ 3.7mm. Present we can made the machinery for diameter range Φ159 ~ Φ1220.
3PE steel pipe outer coating has a high mechanical strength, excellent electrical insulation performance. The merits include high degree of mechanization, process parameters stable, not pollute the environment, etc. In recent years, the intensive of the pipeline corrosion engineering has been widely used.

Specific process description:
1.The bare pipe to be produced is lifted by a crane to the bare pipe entry platform, and the surface is cleaned of sediment and dirt, and the welds are inspected for defects. After passing the preliminary inspection, the bare pipe to be shot blasted and derusted is transported to the central axis of the spiral conveyor roller by a hydraulic transverse pipe transport truck, and the steel pipe is dropped onto the conveyor roller. Under the drive of the power wheel of the transmission roller, the steel pipe rotates and moves forward in a straight direction with its head and tail connected.

2.Under the conveying of the rust removal conveyor, the steel pipe enters the cleaning room of the outer wall shot blasting rust removal machine after intermediate frequency preheating. When the impeller of the shot blasting machine rotates at high speed, the abrasive (steel shot+multi edge sand mixture) is ejected onto the outer surface of the steel pipe under the action of large centrifugal force. The oxide scale and rust layer on the outer surface of the steel pipe are cleaned under the impact of abrasive jet, achieving the surface cleanliness specified by the coating standard. Simultaneously obtaining a certain depth of anchor pattern to enhance the adhesion of the coating.

3.After completing the outer wall shot blasting and rust removal, the steel pipe is transported to the lower pipe station. The hydraulic transverse pipe transport vehicle lifts the steel pipe off the conveyor roller and transfers it to the inner rust removal station to blow away the residual dirt inside the pipe. Start the internal blower and use high-pressure airflow to blow away residual sand and dirt inside the steel pipe, followed by rust removal quality inspection.

4. After the rust removal quality inspection of the steel pipe is qualified, the rotating roller is started to drive the steel pipe to rotate. According to the production plan and construction specifications, the pipe end is pasted with masking paper.

5. After the pipe end avoidance treatment is completed, the steel pipe is transferred through the pipe transport vehicle, straight conveyor roller, and platform. Then, the steel pipe is transported to the central axis of the coating spiral conveyor roller by the pipe transport vehicle and dropped onto the conveyor roller. Under the drive of the power wheel of the transmission roller, the steel pipe rotates on one side and moves straight forward on the other side. After cleaning the fine dust on the outer wall, the steel pipe enters the coating heating medium frequency induction heating coil and is heated to 200-220 ℃ (determined according to the requirements of the material supplier). Turn on the epoxy powder electrostatic spraying equipment, evenly coat the surface of the electric steel pipe with epoxy powder, and pay attention to the melted and gelatinized state of the powder. When the steel pipe with good powder gelatinization enters the winding area, two single screw extruders are turned on separately for AD winding and PE winding. The pneumatic silicone bonding roller is operated to roll the winding coating, and the pressure of the roller is controlled to avoid the coating thickness at the weld seam not being less than 70%. At the same time, observe the overlap of each material strip, measure the coating thickness of the trial production pipe, adjust the extruder parameters at any time until the operation is stable, and complete the continuous coating of the 3PE coating.

6. After completing the coating of the steel pipe, it immediately enters the coating water cooling area. At this time, pay attention to the surface morphology of the PE layer, adjust the cooling water flow rate, flow velocity, and water pressure to avoid water induced spots on the coating surface. Under the action of cooling water, the surface of the anti-corrosion coating rapidly cools to below 60 ℃ to a cured state, preventing damage to the coating in subsequent processes and facilitating subsequent construction.

7. After the coating cooling of the steel pipe is completed and it exits the cooling water shower room, the front pipe accelerates and separates from the rear pipe in the separation area. Use a transverse pipe transport truck to lift the steel pipe off the conveyor roller, pass through the transfer of the pipe transport truck, straight conveyor roller, and platform, and then be transported to the pipe end coating groove polishing station of the finished product outlet platform by the pipe transport truck.

No.	Name	Set
A. Derusting Equipment
1	Pipe-converying Equipment	1
2	Shot Blast Cleaning Machine	1
3	Cyclone Dust Collector	1
4	Pulse dust collector	1
5	Centrifugal exhaust fan	1
6	Rust removal equipment PLC	1
B. Coating equipment
1	Coating transfer equipment	1
2	IF heating device	1
3	Powder spraying device	1
4	Automatic loading dryer	2
5	SJ-65/30 Extruder	1
6	SJ-180/30 Extruder	1
7	Hot melt adhesive extruder die	1
8	PE sheet extruder head mold	1
9	Hot melt adhesive/PE sheet coating device	1
10	Environmental Protection Ventilation equipment	1
11	Cooling Spray equipment	1
C.Platform Equipment
1	Steel pipe platform	1
2	Post-rust removal transition platform	1
3	Product tube storage platform	1
4	Hydraulic Equipment	3
D.Groove Equipment
1	PE Beveling Machine	2
2	Hydraulic Lifting and Turning Machinery	1
3	Hydraulic Equipment	1
4	PLC	1
E.Compressed air Equipment
1	Screw Air Compressor	1
2	Cold dry machine	1
3	Precision filters	3
4	Gas tanks	1

The technological processes employed by Huashida Machinery for the 3LPE coating of steel pipes involve a series of meticulous steps designed to ensure the highest level of quality and durability. Here's a detailed overview of the process:

Upload Pipes:
- The process begins with the loading of the steel pipes onto the production line. This step ensures that the pipes are positioned correctly and ready for processing.
Pipes Screw Conveyor:
- Once loaded, the pipes are transported through the production line using a screw conveyor. This efficient system gently moves the pipes forward, allowing for continuous and uninterrupted processing.
Rust Removal via Intermediate Frequency Heating:
- To ensure a smooth and even coating, it's crucial to remove any rust or impurities from the pipe surface. This is achieved through intermediate frequency heating, which raises the temperature of the pipe surface to effectively burn off rust and contaminants.
Epoxy Powder Coating:
- Following rust removal, the pipes are coated with an epoxy powder primer. This layer acts as a corrosion-resistant barrier, providing a strong foundation for the subsequent coatings.
Outer Layer Solidification & Polyethylene Coating:
- Next, the pipes undergo the application of the outer layer, which consists of a solidified coating and a polyethylene layer. The solidification process ensures that the coating adheres firmly to the pipe surface, while the polyethylene layer provides additional protection against corrosion and wear.