In the process of oil and gas transmission pipeline anticorrosion construction, straight seam steel pipe surface treatment is one of the key factors determine the service life of the pipeline corrosion, it is a solid combination of anti-corrosion layer and straight seam steel pipe can be provided. Research study of the specialized institutions, the life of the coating depends on the quality of coating types, coating and construction environment factors, such as straight seam steel pipe surface treatment effects on coating life accounted for about 50%, therefore, should be in strict accordance with the specification on the coating on the surface of straight seam steel pipe requirements, continuously improve the straight seam steel pipe surface treatment.
Straight seam steel pipe in addition to embroider method:
1.the spray derusting
Spray derusting is driven by high-power motor jet high-speed rotating blade, steel shot, steel grit, wire section, minerals and other abrasive in motor power under the action of centrifugal force of the straight seam steel pipe surface spray processing, not only can thoroughly remove oxide, rust and dirt, and straight seam steel pipe under the action of abrasive violent impact and friction, also can achieve the required uniform roughness.
2.cleaning
Using solvent, emulsion steel surface cleaning, to remove oil, grease, dirt, lubricants, and similar organic matter, but it cannot remove rust, scale, such as welding flux on the surface of the steel, so only as auxiliary means in the anti government job.
3.tools, cleaning
Main USES steel wire brush tool for steel surfaces such as grinding, can remove loose scale, rust, slag, etc. Hand tools can achieve derusting Sa2 level, power tool cleaning can reach grade Sa3, if solid iron oxide adhered on the surface of the steel, tool cleaning effect is not ideal, anchor pattern depth of anticorrosion construction requirements.
4.pickling
Commonly used chemical and electrolytic pickling process, two methods do use only pipeline anticorrosion chemical pickling, can remove scale, rust, old coating, sometimes can be used as sandblasting derusting after reprocessing. Chemical cleaning while can make the surface reaches a certain cleanness and roughness, but the anchor lines shallow, and easy to damage to the surrounding environment.
Anti-corrosion steel pipe is the three process of electrochemical degradation in buried pipeline, pipe anti-corrosion measures also from curbing a process into the hand, and if you give the outer wall of pipeline anticorrosion coating can increase the loop resistance, reduce erosion, current and dc power supply, make the steel pipe to soil forming negative potential, cathodic protection, can eliminate the anode potential, is fundamentally very process of Yin and Yang, anticorrosive coating table under the rule of law, cathode to maintain the rule of law, but once the anticorrosive coating damage, leakage of local iron will speed up the part, so the anti-corrosion coating and cathodic maintenance is severely, the method of combining economic and useful.
Commonly used for anti-corrosion steel pipe, vinyl, epoxy phenolic anticorrosive coatings, such as construction technology, generally require steel tube surface is nearly white level (Sa2.5). Verified by research institutions and the life of the coating depends on the quality of coating types, coating and construction environment factors, such as anti-corrosion of steel pipe surface treatment effect on the service life of coating accounts for about 50%, should be strictly in accordance with the coating specification requirement for anti-corrosion steel pipe surface error and summary, keep improving steel pipe surface treatment. Sampling test should be continuously mixed abrasive in the operation, according to the particle size distribution, to the derusting machine mixing into new abrasive, and mixing in a new abrasive, the number of steel shot to account for the main.
About the use of anti-corrosion steel pipe top place, underground coal used in coal mine drainage, shotcrete, positive negative pressure ventilation, drainage, gas, such as fire sprinkler pipe network. Power plant, thermal power plant process water slag, backwater walks. Walked oil, oil pipelines, chemical pharmaceutical, printing and dyeing industries walks the process piping of corrosive medium. Sewage disposal, sewage discharge pipe, sewage pipe and biological pond anti-corrosion engineering. Agriculture, agriculture irrigation pipe, deep well pipe and drainage pipe network. Fire, about the sprinkler, sprinkler system water supply pipe has outstanding usability. Highway, electric power, communication, highway cable casing maintenance, etc. Municipal engineering, used in high-rise building water supply, heat supply network heating, water engineering, gas walks, buried water pipe, etc.
Anti-corrosion steel pipe refers to the antiseptic technology processing, which can effectively prevent or slow down in the transport and use of chemical or electrochemical reaction occurred in the process of corrosion phenomenon of steel pipe. According to the statistics, every year the domestic steel tube corrosion direct economic loss of more than $2800, the world due to steel corrosion losses as high as $500 billion a year. The anti-corrosion steel pipe can effectively prevent or slow down the corrosion.
Epoxy coal tar anti-corrosion structure: made of epoxy resin, coal tar pitch and packing in steel pipe anticorrosion coating on the surface with glass cloth as strengthening coating anticorrosive coating formation, commonly used in the outer wall of pipeline corrosion. Normally the thickness of 0.5 ~ 1.0 mm.
Epoxy powder anticorrosive FBE structure adopts electrostatic spraying technology in the steel pipe surface coating epoxy powder, a film. The coating has a coating easy operation, no pollution, impact resistance and good resistance to bending performance coating, high temperature resistance, etc.
High density polyethylene coat anticorrosive structure: package of high-density polyethylene material outside the steel pipe surface, has high mechanical strength and good corrosion resistance, can protect the steel pipe in the process of transportation, installation and use to avoid the damage caused by external factors. Manufacturing outside casing should be adding antioxidants, ultraviolet stabilizer, carbon black and so on. Polyethylene outer casing is easy to aging, such as appropriate is used in open air tarpaulin cover, stacking area should be far away from the high heat and fire, made the anti-corrosion steel pipe, it is prohibited to insolate, quenching, or polyethylene outer casing is easy craze, affect the product performance and service life.
2 PE / 3 PE anticorrosion structure: in the steel pipe surface electrostatic spraying epoxy powder and lateral winding dope, lateral winding polyethylene anticorrosive layer, in combination with the three excellent properties, significantly improve the overall quality of anti-corrosion pipeline. Chemical corrosion resistance, resistance to cathodic stripping, mechanical damage performance.
Epoxy powder was coated by electrostatic spraying technology. Due to epoxy powder jinsu processing by adhesion problems, epoxy powder jinsu always failed to promote. In recent years, along with three special coconut epoxy powder jinsu phosphating liquid development success, for the first time the adhesive force of epoxy powder jinsu processing to overcome the difficulties, began to appear jinsu this emerging technology of epoxy powder.
Anti-corrosion steel pipe material including spiral pipe, straight seam pipe, seamless tube, etc., in our country are widely used in petroleum, chemical, natural gas, heating, sewage treatment, water supply, Bridges, steel structures, ocean water conveyance pipeline engineering area, such as piling.
3 PE anticorrosive steel pipe refers to the three layers structure of polyolefin coating (MAPEC) anti-corrosion steel pipe, is commonly used one kind of anticorrosive pipe in China. There are other IPN8710, FBE epoxy powder, such as epoxy coal tar anti-corrosion way.
In the early 1980 s, 3 PE anticorrosive steel pipes are widely used in Europe first, well received by users, is the most used pipeline coating system. China national petroleum corporation was decided in the summer of 1994 the introduction of 3 PE coating and coating technology, used in the construction to the shanxi-beijing gas pipeline and the ku-shan oil pipeline anticorrosion coating. In December, by petrochina pipeline bureau, construction bureau, sichuan petroleum institute, northwest pipe joint group headquarters experts to the United States, Italy, Turkey and other countries of 3 PE coating production line. In May 1995, the liaohe YouJian a company is responsible for the bidding root pain from Canada company introduced our country the first 3 PE coating production line. In early 1996 into normal operation. 1996 Italian surname Sam it is mined here of the construction of the plastic factory of joint venture company and the Harbin preservation plant was put into normal production in May. Northwest pipe command joint venture with hong kong-invested 3 PE coating production line imported from the Netherlands, in 1996 completed and put into operation in baoji dongya anti-corrosion company.
3 PE anticorrosive pipe domestic executive SY/T0413-2002 standard. Main specification standard polyethylene and high density polyethylene, vicat softening point was not less than 110 ℃; Outside the thickness of the coating is given priority to with low, medium density polyethylene German standard to determine DIN30670-1991. Greatly improve the impact strength of 3 PE anticorrosive coating. SY/T0413-2002 will be 3 PE anticorrosive layer of the peel strength, impact resistant index increase, according to some special material and specified by carbon black content, ensure the 3 PE coating and weather resistance, mechanical strength and increased the repairing peel strength (i.e., heat shrinkable sleeve, heat shrinkable belt of peel strength) of primer for steel of parking frequency.
3 PE anticorrosive for attention and application in China. Since acerbity NingLan pipeline construction, by means of bid invitation, together with all 3 PE anticorrosion material localization, 3 PE anticorrosive prefabricated prices have fallen sharply, began the age of 3 PE anticorrosion are widely used, so far, 20000 km of buried steel pipe anticorrosion USES 3 PE anticorrosive coating. At present domestic dozens of 3 PE coating production line, has the processing Φ 25-2800 - mm steel pipe of 3 PE coating capability.
