Cangzhou Spiral Steel Pipes Group Co.,Ltd.

                                                                              1. 2PE / 3PE anti-corrosion steel pipe
                                                                                Release date:2016-11-07
                                                                                2PE / 3PE anti-corrosion steel pipe
                                                                                3PE anti-corrosion steel pipe is a three-layer structure of polyolefin coating (MAPEC) outside the anti-corrosion steel pipe, is a commonly used anti-corrosion pipe. Generally refers to the outer wall of steel corrosion. There are other IPN8710, FBE epoxy powder, epoxy coal tar as anti-corrosion way.
                                                                                3PE anti-corrosion generally consists of three-tier structure:
                                                                                The first layer of epoxy powder (FBE> 100um)
                                                                                The second layer of adhesive (AD) 170 ~ 250um
                                                                                The third layer of polyethylene (PE) 2.5 ~ 3.7mm
                                                                                The actual operation will be three kinds of materials blend into one, after processing to make it firmly with the steel pipe to form an excellent coating. The processing methods are generally divided into two types of winding and round-type coated.
                                                                                2PE / 3PE anti-corrosion pipe It is suitable for coal mine water supply and drainage, underground shotcrete, positive and negative pressure ventilation, drainage gas, fire sprinkler and other pipe network. Thermal power plant process water waste, backwater pipeline. For the anti-spray, sprinkler system has excellent applicability of the water supply pipeline. Power, communications, highways and other cable protection casing. Suitable for high-rise building water supply, heating network heating, water works, gas transmission, buried water and other pipelines. Oil pipeline, chemical and pharmaceutical, printing and dyeing industries such as corrosive medium transport pipeline. Sewage treatment discharge pipe, sewage pipe and biological pool anti-corrosion project. Agricultural irrigation pipe, deep well pipe, drainage pipes and other purposes, it can be said 3PE corrosion-resistant steel pipe in the current construction is essential, and believe that through the extension of science and technology, the future of its still have more brilliant achievements.
                                                                                China Petroleum Engineering Research Institute in the introduction of 3PE coating technology in early April 1995 with reference to DIN30670-1991 and NFA49-710 (March 1988 edition) compiled the first 3PE coating construction acceptance criteria for Shaanxi Pipeline, reservoir construction pipeline. In the same year upgraded to the industry standard SY / T4013-1995, after several years of construction and summary of the practice, in 2001 revised SY / T0413-2002, and in August 1, 2002 implementation.
                                                                                At the beginning of the standard formulation, according to China's actual situation, polyethylene to high-density polyethylene-based Vicat softening point of not less than 110 ℃; outer coating thickness according to the low density polyethylene, German standard DIN30670-1991. Greatly improved the 3PE coating anti-impact strength, to ensure that the Shaanxi-Beijing pipeline and pipeline construction of the quality of the reservoir, SY / T0413-2002 3PE anti-corrosion layer peeling strength, the impact of a substantial increase in indicators and clearly defined According to some special materials carbon black content, to ensure that the 3PE coating mechanical strength and weather resistance, and increased the Fenkou peel strength (that is, thermal shrink sleeve, thermal tape with the stripping of steel peel strength) To ensure the quality of anti-corrosion coating outside the pipeline to make a contribution.
                                                                                3 reliable study
                                                                                For the use of 3PE coating in the domestic debate, CNPC Engineering Research Institute of Beijing Huayou Natural Gas Co., Ltd. commissioned to complete the "Shaanxi-Beijing gas pipeline outside the three-layer structure of polyethylene coating system security evaluation of the coating." The results of this study include the results of foreign pipeline inspection and non-excavation inspection conducted by Beijing Huayou Natural Gas Co., Ltd. from 2001 to 2003, and the unused open-air reservoirs in North China Petroleum Pipeline Plant 2 years and 6 years of 3PE anti-corrosion performance testing, the following conclusions:
                                                                                (1) the application of domestic and foreign anti-corrosion coating evaluation is very good, the use of defects in the report rarely. The main shortcomings of the report are dew point, stripping, cathodic stripping, cathodic protection shielding, stripping corrosion under the membrane corrosion, and most of the reports of defects still remain in theoretical speculation stage, such as the data mentioned cathode shielding problem, to There is no practical report on the actual cathodic protection of the coating. After many years of practice shows that with the increase in the use of life, the least defect coating system is FBE / extruded polyethylene 3-layer structure corrosion system.
                                                                                (2) through the European polyethylene coating 30 years of history review, although theoretically peeling under the corrosion layer corrosion or stress corrosion cracking, but there has not been peeling under the corrosion layer corrosion or stress cracking case . At the Mannesmann Institute in Germany, a long-term corrosion laboratory experiment was conducted to simulate the effect of the coating application. Corrosion test environment with soil and water, the main test test stress corrosion cracking problem, the experimental corrosion is to defective polyethylene coating corrosion and corrosion conditions placed under the conditions of the corrosion environment containing NaHCO3 sandy environment, temperature 70 ℃ , Pipe potential -430 ~ -460mV, steel pipe surface pretreatment in different ways, all with pressure cycle of steel pipe. End of the experiment, more or less around the coating defects are stripped, but the stripping area for the discovery of corrosion. The surface of the oxygen-free steel pipe to the emergence of stress cracking, there is oxide skin of the steel pipe cracking, the maximum depth of crack 0.2mm, may be caused by stress corrosion. It is concluded that a thorough surface treatment is an effective means of preventing stress cracking.
                                                                                (3) Shaanxi-Beijing pipeline excavation in 2003, 763m long pipe section, 3PE corrosion layer of a total of four points. By the damage point of the defect form can be seen, the coating damage are caused by scratching a hard object. 5 peel strength values ??were less than 70 N / cm, the minimum peeling strength was 120 N / cm, and the maximum peel strength was 200 N / cm. The peel strength of the three peeling tests was tested for 3 PE straight pipe and cold bend pipe. The reasons for the Shaanxi-Beijing pipeline is the first time using 3PE coating technology, coating the coating level is limited, the process control can be relatively poor legislation, may lead to improper coating process of individual pipes caused by corrosion coating layer of sticky Relay difference. Low peel strength of the coating is only individual parts, and as long as the coating is not damaged, it will not cause pipeline corrosion.
                                                                                (4) 1999 and 2003 on the North China Petroleum and Steel Pipe Plant open storage of Shaanxi-Beijing pipeline remaining anti-corrosion tube was tested, the performance of the basic anti-corrosion did not decline, especially Hualong company Qilu polyethylene production of anti-corrosion tube, stored for 6 years After the indicators are still in line with the current standard SY / T0413-2002 provides 3PE coating that does have excellent durability and anti-aging properties.
                                                                                Comprehensive research and Shaanxi-Beijing pipeline test results, 3PE coating the main drawback is the construction process of mechanical damage.

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