What is 3PE? 3PE Introduction
briefly
3PE is a form of external corrosion prevention of steel pipes, which implements the German standard DIN 30670-1991 "polyethylene plastic coating of steel pipes and pipe fittings" and SY/T 0413 "Technical standard for polyethylene anticorrosive coating of buried steel pipes"; According to SY/T 0413 "Buried steel pipe polyethylene anticorrosive layer technical standard", the external anticorrosive form has a two-layer structure or three-layer structure, the bottom layer of the two-layer structure is adhesive, the outer layer is polyethylene, referred to as 2PE, the bottom layer of the three-layer structure is epoxy powder, the middle layer is adhesive, the outer layer is polyethylene, referred to as 3PE. The thickness of the anti-corrosion layer is specified in Table 1:
Table 1 Two anti-corrosion coating process: 1. Before coating the anti-corrosion layer, remove the grease and dirt and other attachments on the surface of the steel pipe, and preheat the steel pipe for surface pretreatment, the preheat temperature of the steel pipe is 400C~600C. The surface pretreatment quality should meet the requirements of Sa21/2 class stipulated in "Rust grade and rust removal grade of steel surface before coating" G, and the anchor grain depth should reach 50µm~75µm. The welding slag burrs on the surface of the steel pipe should be cleaned.
2. After surface pretreatment, dust and abrasives attached to the surface of the steel pipe should be cleaned, and the surface of the steel pipe should be moistened, rusted or contaminated three times before coating. The steel pipe with pre-treated surface should be coated within 4h; When more than 4 hours or the surface rust of the steel pipe returns, the surface pretreatment should be re-performed.
3. After pretreatment, the steel pipe is heated to the appropriate coating temperature through the medium frequency induction heating circle, and the epoxy powder coating is evenly applied to the surface of the steel pipe.
4. Polyethylene and adhesives can be coated by longitudinal extrusion process or lateral winding process. For steel pipes with nominal diameter greater than 500 mm, lateral winding process should be adopted.
5. The longitudinal extrusion process is a heated steel pipe (2PE) or a heated steel pipe (3PE) that has been sprayed with powder coating through a die head of an adhesive extruder and a die head of a polyethylene extruder, thereby coating the outer surface of the steel pipe with a layer of molten adhesive and a layer of molten polyethylene. When the die head is close to the steel pipe by longitudinal extrusion process, the adhesive and polyethylene coated on the steel pipe have higher temperature, and the shrinkage is larger after cooling, so that the adhesive, polyethylene and the steel pipe are closely bonded together. When the longitudinal extrusion process is used, there should be no holes on both sides of the weld.
6. The lateral winding process is that the steel pipe rotates through the medium frequency induction heating ring, and two extruders constantly extrude the molten adhesive film tape and the molten polyethylene film tape, and the adhesive and polyethylene film tape are wrapped around the heated steel pipe (2PE) or the epoxy powder coating of the steel pipe (3PE) from the side. When the lateral winding process is used, it should be ensured that the polyethylene in the lap part and the polyethylene on both sides of the weld are completely roller compacted to prevent the surface of the polyethylene layer from being crushed. The wall thickness difference of the plastic layer using the lateral winding process is small.
Seven. After the polyethylene is coated, water cooling is applied to the steel pipe temperature not higher than 600C, and the adhesive, polyethylene and steel pipe are tightly bonded together as the polyethylene is cooled.
8. After coating the anti-corrosion layer, the polyethylene layer at the end of the tube should be removed. The reserved length of the pipe end is 100~150 mm, and the end face of the polyethylene layer should form a chamfer less than or equal to 30 degrees.
Three basic steel pipe: The base steel pipe is produced in accordance with GB/T9711-1997 "Technical Delivery Conditions for Oil and Gas Industry Transportation Steel Pipe" and API Spec 5L "Transportation pipe Specification". The steel pipe can be seamless steel pipe, straight seam submerged arc welded steel pipe, spiral seam submerged arc welded steel pipe, straight seam high-frequency welded steel pipe, and the weld heat treatment. Steel pipe diameter can be from DN 15-DN 1200, outer diameter from ¢21.3-¢1219, The wall thickness of the steel pipe is from 2.8-31.8mm, and the test pressure can be from 4.8MPa-20.7MPa. The steel pipe has undergone strict transverse tensile test, longitudinal tensile test, welded joint tensile test, welded joint ductility test, flattening test, bending test, fracture toughness test, metallographic plug test, hydrostatic test, and non-destructive test. Steel grades can be used B (i.e. L245), X42 (i.e. L290), X52 (i.e. L360), X60 (i.e. L415), X70 (i.e. L485). Steel grade L485 485 refers to the total elongation stress of 485 MPa.
Four interface welding: 1. The joint of the base pipe shall be welded, and the welding shall be carried out according to GB50236 "Construction and Acceptance Code for Field Equipment and Industrial Pipeline Welding Engineering". The pipes and fittings with the same wall thickness should be paired, and the inner wall should be flush, and the amount of the wrong side of the inner wall should not exceed 10% of the wall thickness of the pipe, and should not be greater than 1 mm.
2. When the pipe and pipe fittings are paired, the surface of the groove shall not have cracks, interlayers and other defects, and the paint, rust spots and burrs within 10 mm of the groove and its sides shall be cleaned up;
3. The process measures and welding materials for the point-solid welding of pipelines and pipe fittings should be consistent with those for formal welding. The spot welding length of the spot welding should be 10~15 mm, the height of 2~4 mm, and should not exceed 2/3 of the thickness of the pipe wall. If cracks and other defects are found in the welding flesh, they should be treated in time.
4. Weld surface quality should comply with GB50236 "Field equipment, industrial pipeline welding engineering construction and acceptance code"
Five. Weld protection 1. The outer coating of the welded joint of the pipe body can be made of hot condensation polyvinyl tape with glue. After baking by blowtorch, the hot condensation polyvinyl tape shrinks to form a polyethylene coating layer tightly covering the outer surface of the steel pipe. The surface of the heat shrinkable sleeve should be flat, no wrinkles, no bubbles, no charring and other phenomena; The circumference of the heat shrinkable sleeve should overflow the adhesive evenly. Each patch should be checked by an EDM leak detector. The leak detection voltage is 15kV. If there is a pinhole, the hole should be repaired again and checked until qualified. The peeling strength of the heat shrink sleeve at the patch should not be less than 50N/cm.
2. The external anti-corrosion coating can also be sprayed with polyurea on the outer surface of the weld. Polyurea is used in the market for floor and waterproof coating, we use polyurea for steel pipe lining and outer coating, steel and polyurea bond strength is very good, polyurea corrosion resistance is very good. Polyurea is a new type of anti-corrosion material and new coating technology with excellent performance, solvent-free, pollution-free and fast curing after materials and coating technology such as high-solid coatings (such as solvent-free epoxy), water-based coatings, light-curing coatings, powder coatings (such as PE powder) and three-layer structural coatings (such as 3PE, 3PP) in the past 10 years.
Polyurea is liquid at high temperature, divided into A component and R component, group A is divided into the end of the NCO group semi-prepolymer, R component is composed of the end of the amino polyether amine chain base and additives, in the A and R components by the two-component reaction jet molding special equipment sprayed to the room temperature steel pipe wall impact mixing, and chemical reaction, rapid glue into the coating. Because the sprayed steel pipe does not need heating, it can be constructed on the installation site, and can be sprayed on the inner wall of the pipe, the outer wall of the pipe and the weld part. Polyurea coating has high quality corrosion resistance, aging resistance, corrosion resistance and strong adhesion and mechanical strength, and its service life can reach more than 30 years.
Polyurea two-component, solid content 100%, no solvent, no pollution, the inner wall of the pipeline coated with polyurea coating, its curing of the carrier medium without any pollution, in line with health, safety, environmental protection requirements. Polyurea coating has excellent anti-invasion of atmospheric environmental factors and anti-ultraviolet radiation ability, which is suitable for outside the tube surface coating, the coating does not fade and does not fail. Polyurea can be prepared according to the requirements of different color coating, and long-term does not fade, can achieve good decorative effect.
6. Summary The 3PE coating process of steel pipe has been recognized by the majority of industry users for its practical, comprehensive and professional advantages. It has broad application prospects in the fields of petroleum, natural gas, chemical industry, electric power, HVAC and municipal engineering. Hebei Haochen Technology Co., Ltd. will be happy to provide you with quality services and products.
Hebei Haochen Environmental Protection Technology Co., LTD., to provide you with professional steel pipe 3PE coating process solutions!
Next for you to demonstrate the 3PE anti-corrosion steel pipe process flow chart
Small-caliber 3PE anti-corrosion steel pipe is under construction
3PE anti-corrosion steel pipe medium frequency technology
3PE anti-corrosion steel pipe production line large cyclone powder recovery system
3PE anticorrosive steel pipe production line spray water room
3PE anti-corrosion steel pipe production line spray room
Seamless steel pipe surface inner wall cleaning
Epoxy spraying effect in 3PE anti-corrosion steel pipe production line
3PE anti-corrosion steel pipe production line outside polyethylene spraying
3PE anticorrosive steel pipe production line supporting grinding machine
The above case is our 3PE anti-corrosion steel pipe production line spray finished products
Our quality you rest assured, if you have all the questions about anti-corrosion steel pipe production line, please contact Hebei Haochen Environmental Protection Technology Co., LTD., we will be the most professional attitude for you to answer.
FAQ:
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1. What do you do? Where is your company?
reply:
Our company is specialized in the production of pipeline anti-corrosion automatic spraying lines, including :3PE anti-corrosion steel pipe production line, large-caliber 12-meter coated plastic steel pipe automatic production line, six-meter small-caliber coated plastic steel pipe production line, automatic tube coating production line and so on. Our address is located in: Hebei Cangzhou City, Qingxian Wang town shop development zone
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We provide one-stop customized equipment installation services, our company's production of spraying equipment selection of domestic top technology, save time, save material, labor under the premise of greatly improve the production efficiency
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Our company is made in China online, is a high star reputation seller
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Because we are a new platform, in the early stage of promotion, we integrate resources to let customers recognize us, and in the later stage, we will adhere to our service standards as always, maintain a reasonable price, and bring our customers better all services on the automatic production line of coated steel pipes.
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We provide free design, free installation and other pre-sales services, we do not charge any fees before the final design plan is determined, and you are satisfied with the design plan before signing the contract.
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Because we are a new platform, as you can see, we are now doing a pre-launch promotion activity, our the same as our launch, we have a full range of after-sales support services
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reply: 10-15 business days after your equipment request
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reply: Our company in the domestic production of hundreds of spray lines, with customers reached a perfect cooperation, to ensure the normal production needs of customers, adhering to a customer, a lifetime friend, transaction is only the beginning, the concept of endless service for you to concentrate on service
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