Alloy Steel Pipes And Tubes Pipeline Three PE Anti-corrosion Structure

Alloy Steel Pipes And Tubes Pipeline three PE anti-corrosion structure

Pipeline three PE anti-corrosion structure:

The i-th layer of epoxy powder (FBE> 100um)

The second layer of adhesive (AD) 170 ~ 250um,

The third layer of polyethylene (PE) 2.5 ~ 3.7mm.

Three materials into one, and firmly combined with the formation of steel pipe to form an excellent coating. Diameter range Φ60 ~ Φ1420

Through the European polyethylene coating 30 years of application history review, although theoretically peeled under the corrosion layer will be corrosion or stress corrosion cracking, but there is no peeling off the coating under the film corrosion or stress cracking cases. At the Mannesmann Institute in Germany, a long-term corrosion laboratory experiment was conducted to simulate the effect of coating applications. Corrosion test environment with soil, water, test the main test of stress corrosion cracking problem, the experimental anti-corrosion is the defective polyethylene coating steel pipe placed under the conditions of corrosion and stress conditions, corrosion environment containing NaHCO3 sand environment, temperature 70 ℃ , Tube potential -430 ~ -460mV, steel pipe surface pretreatment in different ways, all steel pipe with pressure cycle.

At the end of the experiment, there was more or less stripping around the defect in the coating, but the stripping zone was found to be corrosive. Surface oxygen-free gasification of the steel pipe for the emergence of stress cracking, there are cracks in the steel pipe cracks, the largest crack depth of 0.2mm, may be caused by stress corrosion. It follows that a thorough surface treatment is an effective means of preventing stress cracking.

Three-layer structure Polyethylene coating (TPEP) combines the excellent properties of two kinds of sintered epoxy powder coating and extruded polyethylene. The interfacial properties and chemical resistance of the sintered epoxy powder coating are The mechanical protection properties of the pressure-resistant polyethylene coating, and the like, thereby remarkably improving the respective properties. So the outer protective layer as a buried pipeline is very superior. According to the information, three PE can make the life of buried pipes to 50 years, at present, in the international community is considered the most advanced anti-corrosion technology outside the pipeline. In China, the three-tier PE has been the first in the oil and gas systems have been applied. China has completed the Shaanxi-Beijing natural gas pipeline and Ku Shan oil pipeline, the recent national key projects West Gas nearly 4,000 km pipeline are used three layers of PE anti-corrosion coating. In Tianjin, Shaanxi gas into the 67 km high-pressure pipeline, the outer ring 30 km high-pressure natural gas pipeline, Shaanxi and Beijing line underground gas storage 122 km pipeline is also used in three-tier PE.

TPEP anti-corrosion steel pipe base material including seamless steel pipe, spiral steel pipe and straight seam steel pipe. Three-layer structure of polyethylene (TPEP) anti-corrosion coating with its good corrosion resistance, water vapor permeability and mechanical properties, in the oil pipeline industry has been widely used. TPEP anti-corrosion steel pipe a coating for the life of the pipeline is essential, the same material pipeline, and some buried in the ground for decades without corrosion, and some years there have been leaked. It is because they use a different outer coating.

In the long-term point of view, with the steel prices, steel pipe per ton of steel profit profit tens of dollars, a slight increase in production power. At the same time, the level of overseas mining shipments gradually increased, while the steel mills on the purchase of high ore prudent, import ore prices do not have the trend of rising conditions. In addition, the domestic monetary policy is still stable mainly in the first quarter, "days" is not sustainable, the second quarter of the economic downward pressure is still large. After the end-user recharge library, the steel supply and demand in March or return to the weak balance of the situation, steel prices were mixed, narrow fluctuations in the run. This year the infrastructure investment is still to force, the author expected the traffic investment plan nearly 3 trillion yuan, the role of the price of steel, or difficult to decline in the trend.