Anti-corrosion steel pipe manufacturers for gas pipelines

Cangzhou Tianze Pipeline Co., Ltd. is a large anti-corrosion steel pipe manufacturer in Hebei. Our factory specializes in the production of three-layer anti-corrosion steel pipes for natural gas and three-layer reinforced anti-corrosion steel pipes. Our factory processes high-quality seamless steel pipes, straight-seam steel pipes, and spiral steel pipes. Into three-layer anti-corrosion seamless steel pipes, three-layer anti-corrosion straight seam steel pipes, three-layer anti-corrosion spiral steel pipes, three-layer anti-corrosion steel pipes for gas pipelines. Our factory has a large number of pipes all year round. Welcome to discuss China Petroleum Engineering Technology Research Institute, which is sponsored by Beijing Huayou Natural Gas Co., Ltd. The company commissioned and completed the "Research on the Safety Evaluation of Polyethylene Coating for the External Anti-corrosion Layer Structure System of Gas Pipelines". The research includes collection from foreign literature, analysis of the results of excavation inspections and non-excavation inspections of pipeline outer anti-corrosion layers conducted by Beijing Huayou Natural Gas Co., Ltd., and analysis of the results of unused Shaanxi-Beijing pipelines stacked in the open at the North China Petroleum Steel Pipe Factory and After years of anti-corrosion performance testing, the following conclusions were drawn: At present, the application effect of anti-corrosion layers at home and abroad is very good, and there are few reports of defects caused by its use.
The main reported shortcomings include dew point, peeling, cathodic peeling, cathodic protection shielding, peeling corrosion under the anti-corrosion layer, etc., and most reports of defects are still in the stage of theoretical speculation. For example, the data mentions cathodic protection shielding. So far, there have been no reports on the occurrence of cathodic protection shielding in the actual operation of the anti-corrosion layer.
After years of practice, it has been shown that as the service life increases, the coating system with the fewest defects is the extruded polyethylene layer structure anti-corrosion system. A review of the annual application history of polyethylene anti-corrosion layers in Europe shows that although corrosion or stress corrosion cracking can theoretically occur under a peeled-off anti-corrosion layer, there has been no case of sub-film corrosion or stress cracking under a peeled-off anti-corrosion layer. At the Mannesmann Institute in Germany, long-term corrosion laboratory experiments have been conducted to simulate the effect of anti-corrosion layer application.
The corrosion experiment environment includes soil, water, and the test mainly examines the problem of stress corrosion cracking. The experimental anti-corrosion is to place the defective polyethylene anti-corrosion layer steel pipe under corrosion conditions and stress conditions. The corrosion environment is a sandy soil environment containing H , temperature ℃, pipe-to-ground potential ~m, the surface of the steel pipe is pretreated in different ways, and all steel pipes are circulated under pressure. At the end of the experiment, there was more or less peeling around the defects in the anti-corrosion layer, but no corrosion was found in the peeling area. Steel pipes without oxygen scale on the surface are prone to stress cracking. Steel pipes with oxide scale are cracked. The cracks are as deep as m, which may be caused by stress corrosion. It is concluded that thorough surface preparation is an effective means of preventing stress cracking.
The Shaanxi-Beijing Pipeline excavates m-long pipe sections every year, and there are four damage points in the anti-corrosion layer. It can be seen from the defective form of oil damage points that the damage to the anti-corrosion layer is caused by scratches by hard objects. After inspecting the pits of straight pipes and cold-bent pipes, the peel strength was detected in total. Among them, the peel strength value was lower than /m, the minimum peel strength/m, and the maximum peel strength/m. The reason is that the Shaanxi-Beijing pipeline is the first to adopt coating technology in China. The coating level of the coating company is limited and the control ability of the process engineering is relatively poor. This may lead to improper setting of the coating process of individual pipelines, resulting in the adhesion of the anti-corrosion layer. Poor strength. The peeling strength of the anti-corrosion layer is low only in certain parts, and as long as the anti-corrosion layer is not damaged, it will not cause pipeline corrosion.
Random tests were conducted on the remaining anti-corrosion pipes of the Shaanxi-Beijing pipeline stored in the open air at the North China Petroleum Steel Pipe Factory in 2018 and 2016. The results showed that their anti-corrosion performance has not declined at all. In particular, Hualong Company uses anti-corrosion pipes produced by Qilu Polyethylene. These indicators still comply with current standards/regulations, indicating that the anti-corrosion layer indeed has excellent durability and anti-aging properties. Based on the comprehensive investigation and inspection results of the Shaanxi-Beijing pipeline, the main defect of the anti-corrosion layer is mechanical damage during the construction process.