Archive for month: January, 2021

Ultra-high polymer pipes are called non-metallic pipes, which should belong to plastic products. The raw material of ultra-high polymer pipes is PE, but the molecular weight is much higher than ordinary molecular weight, and the performance is better than ordinary PE materials, such as: wear resistance and resistance Corrosion, impact resistance, yield strength and breaking strength, etc. In particular, its wear resistance is higher than that of materials such as polytetrafluoroethylene, nylon, and carbon steel. Ultra-high polymer pipes were used more abroad in the early days. After continuous research and development, the ultra-high polymer pipe technology has gradually matured in China, and the heavy industry has gradually adopted this type of pipe. It has become a new type of thermoplastic engineering pipe with moderate price and excellent performance. In terms of price and quality, it is a practical ideal pipe.

Ultra-polymer pipes can be used for the transportation of various highly corrosive and highly abrasive liquids or solid-liquid mixtures, such as various acid, lye, crude oil, tailings, mud, coal water slurry, and power plant ash and slag discharge and many more. Compared with seamless steel pipes, ultra-polymer pipes have significant advantages and increase service life. Under strong corrosive and high abrasive conditions, the service life can be increased several times or even dozens of times; due to the non-sticky inner wall of this pipe And the friction coefficient is small, which can reduce the conveying pressure or reduce the diameter of the conveying pipe, which is of great significance for long-distance conveying; because the thermal conductivity of this pipe is more than 10,000 times smaller than that of steel, it can greatly reduce the heat preservation cost of the conveying pipe. Transporting crude oil and other materials in cold regions and winter is of great significance.

It can be seen that ultra-high polymer pipes have excellent use characteristics and are used in the mining industry, coal industry, oil exploration, thermal power generation, chemical industry, river dredging and other industrial fields. With the continuous development of industrial technology, the fields in which ultra-polymer pipes will be used will become more and more extensive.

Decho is a professional supplier of ultra-high polymer pipes . If you need any for your project , pls feel free to contact us by email [email protected]

Due to the long pipeline construction period, it is generally required if the soil resistivity is less than 20Q. m, it is necessary to install a magnesium anode for temporary protection and connect it to the pipeline through a test pile. When the impressed current cathodic protection is put into use, the temporary protection is removed. The Cathodic Protection is very important to protect  pipes from corrosion .

what is cathodic protection?

It is a method of polarizing the protected metal into a cathode to prevent metal corrosion. This method has been used for ship anti-corrosion for more than 150 years; it was first used in pipelines in 1928, applying the principle that the cathode is not corroded but the anode is corroded in metal corrosion batteries to metal anti-corrosion technology. The externally applied current is used to force all the surface of the protected metal in the electrolyte to be catholic polarized, then corrosion will not occur. There are two indicators for judging whether a pipeline meets cathodic protection. One is the minimum protection potential, which is the potential of the metal in the electrolyte from cathodic polarization to the stop of the corrosion process; its value is related to environmental factors. The second is the maximum protection potential, which is the highest potential value that the metal surface to be protected can reach. When the cathodic polarization is too strong, hydrogen will evolve between the pipe surface and the coating, causing cathodic peeling of the coating. Therefore, the confluence point potential must be controlled within the allowable range to prevent the coating from being damaged.

Two methods to realize cathodic protection of underground pipelines

impressed current method

The impressed current method uses a DC power supply, with the negative pole connected to the protected pipeline and the positive pole connected to the anode bed. After the circuit is connected, the pipe is polarized cathode. When the pipeline’s ground potential reaches the minimum protection potential, complete cathodic protection is obtained. In order to determine the cathodic protection parameters and appraise the cathodic protection effect of the pipeline, it is necessary to set up inspection points and check sheets along the pipeline. The protection distance of a single station of impressed current cathodic protection is generally up to tens of kilometers, and this method is often used for cathodic protection of long-distance pipelines.

sacrificial anode method

The sacrificial anode method uses a metal with a more negative potential than the protected metal electrode to connect with the protected metal, and the two form a galvanic cell in the electrolyte. Metals with relatively negative potentials (such as magnesium, zinc, aluminum and their alloys) become anodes, which are gradually lost in the process of outputting current, and the protected pipe metal becomes cathodes to avoid corrosion. Therefore, metals with relatively negative potentials are called sacrifices anode.

Technical Requirement for applying cathodic protection .

To be economically reasonable and technically feasible on applying cathodic protection to the pipeline, certain conditions must be met, as follows:

①Ensure the conductivity of the longitudinal connection of the pipeline

②The covering layer of the pipeline must ensure sufficient resistance

③Ensure the electrical insulation between the pipeline and other low resistance grounding devices.

Decho is a professional supplier of 3lpe coated pipes , if you need any for your project , pls contact us by email [email protected]

As buried pipe delivering water, 3PE anti-corrosion coated pipes has been widely used in government projects in various countries. This is the first time for Decho to export 3PE coated pipes since its new establishment in 2018

The customer for this order is a steel distributor in Bangladesh. He has been engaged in steel pipe sales for nearly 20 years and has a good supply relationship with the Bangladesh government. After several email and telephone communications, the customer’s trust on Decho is more sufficient, and a full container quantity is finally confirmed as the trial order. Soon after order received, Decho sorted out the customer’s requirements. Although it is the most conventional seamless steel tube size, We implement each requirement in detail, no matter from the wall thickness to the thickness of the 3pe coatings, the packaging method to the marking. Because we firmly believe that the fulfillment of every small request is the cornerstone of continuous transactions in the future.

We received email that the customer intends to rush to the shipment date by December 20, at the same time ,we just received L/C from bank. We contacted the logistics department urgently to book a position on the 20th. And we purchased the seamless pipe from stock on the same day. After the processing bevel end on the two days, the bare pipe finally arrived at the coating mill . The production of 3PE coating started in the morning ,at noon , the container entered the factory. We make loading work as while as production.Until 21:00 in the evening,The loading work finished. Now,the customer’s order has been loaded and will be arrive to Bangladesh soon. The customer was informed that this order could be delivered to Bangladesh as his expectation. He highly affirmed the efficiency of Decho’s service and promised us that more new orders would be handed over to Decho in the future.

This order is small, but the original intention of serving customers has not changed. Regardless of how big the order is, Decho is a good partner for customers to be relied on

Building the world and striving the world, Decho is doing its best.

How are seamless steel pipes produced?

The production process of seamless steel pipes is mainly divided into two types: cold-drawn and hot-rolled. The production process of cold-rolled seamless steel pipes is more complicated than that of hot-rolled steel pipes. The pipe billet must firstly be under three-roll continuous rolling, and then sizing test after extrusion. If the surface does not respond to cracks, the pipe will be cut by a cutting machine about one meter length. Then entering into annealing process, the annealing should be pickled with acidic liquid. When pickling, pay attention to whether there is a lot of blistering on the surface. If there is a lot of blistering, it means that the quality of the steel pipe does not meet the corresponding standards.

Main production processes of hot-rolled seamless steel pipes (*main inspection processes):

Tube billet preparation and inspection*→tube billet heating→perforation→tube rolling→steel pipe reheating→fixed (reduced) diameter→heat treatment*→finished tube straightening→finishing→inspection* (non-destructive, physical and chemical, bench inspection) → warehousing

The main production process of cold rolled (drawn) seamless steel pipe:

Billets preparation → pickling and lubrication → cold rolling (drawing) → heat treatment → straightening → finishing → inspection

How to distinguish hot rolled pipes and cold rolled pipes ?

In length, cold-rolled seamless steel pipes are shorter than hot-rolled seamless steel pipes. The wall thickness of cold-rolled seamless steel pipes is generally thinner than that of hot-rolled seamless steel pipes, but the hot-rolled seamless steel pipes look brighter on the surface without much rough caliber and there are not too many burrs. The delivery conditions of hot-rolled seamless steel pipes is generally delivered after hot rolled or heat treatment. After the quality inspection, the hot-rolled seamless steel pipe must be strictly hand-selected by the inspectors. After the quality inspection, the surface should be oiled, and then followed by multiple experiments. After the hot-rolling treatment, the piercing experiment should be carried out. If the perforation is too large, it must be straightened. After straightening, it is transferred by the conveyor to the flaw detector for flaw detection experiment, and finally the label is affixed, the specification is arranged, and then it is placed in the warehouse.

Decho is able to supply various seamless steel pipes with different specifications and for different usages, if you are interested in our seamless steel pipes, please contact [email protected]