Archive for year: 2021

The wear-resistant pipe is manufactured by the self-propagating high-temperature synthesis-centrifugal method. That is, the seamless steel pipe is placed in the tube mold of the centrifuge, and a mixture of iron oxide powder and aluminum powder is added to the steel tube. This mixture is called the thermite in chemistry. After the centrifuge tube mold rotates to a certain speed, The spark ignites the thermite, the thermite immediately burns by itself, and the combustion wave spreads rapidly, and the following violent chemical reactions occur during the spread:
2Al+Fe2O3=Al2O3+2Fe+836KJ
3Fe3O4+8Al=4Al2O3+9Fe+3265KJ

After the thermite reacts, the product is stable α-Al2O3 (corundum) and iron, which emits a lot of heat at the same time. Such heat as under adiabatic conditions, the adiabatic temperature can reach 3753K and 3509K, it makes the original material in the steel pipe and the product after the reaction, even the corundum with a melting point of 2045 ℃ all become molten. Because the reaction is very rapid, only a few seconds, the molten reactant is quickly separated according to the specific gravity under the action of centrifugal force, the specific gravity of iron (7.85g/cm3) is twice that of Al2O3 (3.95g/cm3), the heavier iron Throwing to the inner wall of the steel pipe by centrifugal force, the lighter Al2O3 is distributed in the inner layer of iron.

Due to the rapid heat absorption and heat transfer of the steel pipe, Al2O3 and Fe quickly reach the freezing point and solidify in layers. The finally formed wear-resistant pipeline is composed of corundum porcelain layer, iron-based transition layer, and outer steel pipe layer. High-temperature molten iron and Al2O3 liquid contact with the inner wall of the steel pipe, making the inner wall of the steel pipe half outside. In the molten state, the iron layer and the steel pipe form a metallurgical bond, and the iron layer and the corundum porcelain layer also form a firm bond. The combined compressive shear strength (that is, the strength when the ceramic is laminated in the axial direction) ≥ 15MPa; the wear-resistant pipeline is crushed Strength (that is, the strength when the ceramic inside the tube is crushed from the outside of the tube) ≥ 350MPa;

The advantages of wear-resistant pipes compared with traditional pipes

Wear-resistant pipes are fundamentally different from traditional steel pipes, wear-resistant alloy cast steel pipes, cast stone pipes, steel-plastic and steel rubber pipes. The outer layer of the wear-resistant pipe is seamless steel pipe and the inner layer is corundum. The hardness of the corundum layer is as high as HV1100-1400, which is equivalent to tungsten-cobalt cemented carbide, and its wear resistance is more than 20 times higher than that of carbon steel pipes. The wear resistance of wear-resistant pipes is mainly based on the inner layer of corundum that is several millimeters thick. This is a qualitative leap in resistance to wear compared to wear-resistant alloy cast steel pipes and cast stone pipes not only by composition and structure, but also by thickness.
Wear-resistant pipes quickly occupy the market. In addition to high quality and good performance, it also has a higher cost performance than other wear-resistant, corrosion-resistant and heat-resistant pipes. In terms of wear-resistant pipes of the same specification and unit length, the weight of wear-resistant pipes is only about one-half of wear-resistant alloy cast steel pipes, and the project cost per meter is reduced by 20%-30%; only the weight of cast stone pipes is one-third. Reduce project cost by 5%-10% per meter; wear-resistant pipes used in corrosive or high-temperature situations are only a fraction of stainless steel pipes and nickel-titanium pipes.

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

There are two production processes for ceramic patch wear-resistant pipes for power plants: pasting process and inlay process

Ceramic chip type and thickness in ceramic chip wear-resistant tube:

Mutual pressure 60*40, 50*40, 30*25

Mosaic 10*10*10, 10*10*5, 17.7*17.5*5, 17.5*17.5*10

Purity: 92, 95, 97, 99

There are two types of ceramic adhesives for the inner wall of wear-resistant pipes for power plants: inorganic adhesives and organic adhesives. The difference is that inorganic adhesives can withstand temperatures within 500°C, while organic adhesives can withstand temperatures between 120°C and 380°C.

Performance introduction of ceramic patch wear-resistant pipe for power plant:

1. Wear resistance: The Al2O3 content in the inner ceramic layer of the ceramic composite steel pipe is greater than 90%, the microhardness is HV1000-1600, and the density is 3.8-3.97g/cm3, so it has extremely high wear resistance. The quenched medium carbon steel is ten times higher than the tungsten carbide carbide.
2. Corrosion resistance: ceramics are neutral materials with stable chemical properties, excellent corrosion resistance and acid resistance, resistance to various inorganic acids, organic acids, organic solvents, etc., and its corrosion resistance is more than ten times that of stainless steel .
3. Heat resistance: The ceramic layer is dense corundum with a linear expansion coefficient of 6-8×10-6/℃. Excellent heat resistance, can withstand temperatures above 2000℃, and can work for a long time in the range of -50℃～900℃.
4. Mechanical properties: It has excellent mechanical properties. Its crush strength is 300-600MPa, compressive shear strength is 20-30MPa, and the mechanical impact test has no obvious cracks under 50t energy impact for 15 times.
5. Easy to weld: The ceramic-lined composite steel pipe can be connected by welding the outer steel pipe.
6. The connection method of the product: Welding connection and flange connection of the transition section. If there is no transition section, the welding will be affected. If there is no transition section, the welding residual heat will affect the bonding of the ceramic patch while welding, which will melt the adhesive and make the bonded ceramic patch fall off, thereby reducing the adhesion. Therefore, the quality should be set aside for the transition period.

What are the contraindications of this product?

Inorganic glue can’t take water, organic glue has a higher temperature resistance than inorganic glue

Which industries does this product apply to?

Power plant pulverized coal, ash slag, mine powder, tailings, backfill, coal from coal mines, concentrators, coke particles from coking plants, and materials from sintering plants.

Decho is a professional supplier on Ceramic patch wear-resistant tube. If you need any for your project , pls feel free to contact us by email [email protected]

The forming principle of plastic-lined pipes used in water circulation transportation:

The steel-lined plastic pipe adopts the original steel body, electric furnace heating, plastic material inner filling centrifugal molding and external hot compress centrifugal processing, and the sealing surface of the connecting flange needs manual hot compress molding. All pipelines and water contact surfaces are all lined with plastic materials, the pipeline connection is convenient and fast, and it has reliable connection strength and anti-permeability. At the same time, all the connection joints are of detachable structure, coupled with the use of pipe fittings that can change direction at will, making maintenance more convenient.

Power pipeline and circulating water pipeline performance advantages:

1. Good corrosion resistance: It is an ideal pipeline for transporting corrosive gas media such as acid, alkali and salt.
2. Good permeability resistance: using rotomolding process or tight lining process, the inner lining is smooth and flat, the friction coefficient is small, and it is not easy to scale, so the permeability resistance is excellent.
3. High operating temperature: under the condition of strong corrosive medium, the applicable temperature range is -29℃—200℃
4. Vacuum resistant. In the range of -29°C to 150°C, it can be used under vacuum conditions. In chemical production, it is often caused by the backflow of local medium due to cooling, longitudinal discharge, and asynchronous operation of pumps and valves to produce a vacuum state.
5. Adopting standardized standard configuration, especially the pipes and fittings used in chemical pipelines are highly interchangeable, which provides great convenience for installation and spare parts.

The rotomolding process design is flexible and can be made into parts with different shapes and sizes. Application and plastic-lined pipes to save consumption costs will also develop in the direction of increasing output.

The plastic-lined pipe is lined with food-grade polypropylene, which can be used in the chemical, food, pharmaceutical and drinking water industries. Common plastic-lined pipes are: polypropylene steel pipes, polyvinyl chloride steel pipes, polyethylene steel pipes, polyolefin steel pipes and polytetrafluoroethylene steel pipes. Because the plastic-lined pipe has good corrosion resistance, weather resistance, soil and marine life, and physical properties, it has been widely used in agricultural production. At the same time, the use of plastic-lined tubes will not produce toxic side effects on agricultural products, and will not breed bacteria, so that the quality of crops can be guaranteed. From an operating point of view, the pipe wall of the plastic-lined pipe is smooth, and at the same time, it can improve transportation efficiency and have a longer life.

Decho is a professional supplier of plastic-lined steel pipe . If you need any for your project , pls feel free to contact us by email [email protected]

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]