Technical requirements for 90-degree ceramic wear-resistant elbows
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Technical requirements for 90-degree ceramic wear-resistant elbows: I. Equipment design and operating conditions, medium parameters: gas and ash mixture. II. Technical requirements for ceramic-resistant elbows 1. Type: Ceramic-lined 2. Technical performance and parameters: Design pressure for the pipe fitting structure: 0.8 MPa (g); Operating temperature of the pipe fitting structure: 400°C; Medium: Two-phase flow of coal powder and air; Coal powder concentration (for the designed coal type): 0.485 kg/kg; Flow velocity of the gas-solid two-phase flow: 6–18 m/s; Flow velocity of the gas-solid two-phase flow: 32 m/s; Dimensions of the connected pipes: See diagram; Elbow material: The outer steel structure is made of seamless carbon steel tubes, grade #20; wall thickness: See diagram ； The lining is made of ceramic with an Al2O3 content of over 95%, and it is sintered using the centrifugal casting method. The thickness of the ceramic layer is not less than 5 mm. A protective cover is attached to the outside of the elbow, and this cover contains wear-resistant filling material to ensure that the entire area of the elbow is covered. The pipe elbows in contact with ash should be made of ceramic material. A straight pipe section with a length of not less than 1000 mm should be provided in the outlet direction of the wear-resistant elbow, and a straight pipe section with a length of not less than 500 mm should be provided in the inlet direction of the same elbow. The bending radius of the wear-resistant elbow should be at least 5 times the diameter of the ash transport pipe. The hardness of the inner surface of the wear-resistant elbow should be at least HRC55. The normal service life of all wear-resistant fittings and elbows should be greater than 15,000 hours.
Ceramic wear-resistant elbows are generally divided into two types: one is the self-igniting ceramic elbow produced using high-temperature self-igniting centrifugal composite technology, and the other is the ceramic tile-mounted wear-resistant elbow.
Introduction to the properties and technical parameters of ceramic sheets used in wear-resistant elbows in power plants 1. Technical requirements for the ceramic material: Aluminum oxide content: ≥95%; Volume density: ≥3.64 g/m³; Mohs hardness: ≥9.0; Vickers hardness: ≥1150; Rockwell hardness (HRA): ≥80; Cold compressive strength: ≥850 MPa; Ceramic thickness: 15 mm; Bending strength: ≥290 MPa; Temperature resistance: ≥350°C℃
The ceramic blocks used as the lining for wear-resistant components feature an interlocking ceramic structure; that is, they consist of male and female grooved ceramic tiles designed to prevent detachment. The ceramic blocks are fitted together in a 360° mechanical self-supporting structure through a unique male-female groove design along the circumferential direction, ensuring face-to-face contact between various sections of the elbow component. There is no direct contact between the individual ceramic blocks – they are pressed tightly against the inner wall of the wear-resistant component. The ceramic tiles are connected to one another in a ring-like fashion to form a single unit. The edges of the contact surfaces of all ceramic blocks are designed to be conical, which helps to prevent them from falling off.
Ceramic-lined elbows and ceramic pipes: Ceramic wear-resistant pipes can be divided into alumina ceramic pipes and silicon carbide ceramic pipes. Ceramic wear-resistant pipes can be classified into self-igniting ceramic pipes and ceramic-coated wear-resistant pipes based on their structural design. Thanks to their wear resistance, corrosion resistance, and heat resistance, these pipes can be widely used in industries such as power generation, metallurgy, mining, coal processing, and chemicals for transporting abrasive particles such as sand, stones, coal powder, ash, and aluminum melt, as well as corrosive fluids; they represent an ideal choice for wear-and-corrosion resistance in piping applications.
Ceramic wear-resistant pipes are increasingly widely used due to their excellent wear resistance and low weight. They are suitable for transporting materials containing solid particles and corrosive substances, as well as high-temperature corrosive gases and sulfur-containing hot spring water. They find extensive application in industries such as steel plants for dust removal pipelines, power plants for ash removal pipelines, cement factories, the metallurgical industry, mines, coal industries, chemical industries, and the aviation sector, where they are used to transport abrasive granular materials and corrosive substances such as sand and gravel, coal powder, ash, molten aluminum, and powders. A detailed introduction as a manufacturer of ceramic wear-resistant pipes. Ceramic wear-resistant pipes are manufactured using a world-class self-propagating reaction process, via a chemical reaction and centrifugal casting technique. The ceramic layer is formed at temperatures above 2200°C to create dense corundum porcelain (AL2O3), which forms a strong bond with the steel pipe through an intermediate layer. Composite pipes take full advantage of the high strength, good toughness, impact resistance, and excellent weldability of steel pipes, as well as the high hardness, high wear resistance, corrosion resistance, and heat resistance of corundum ceramics, thereby overcoming the shortcomings of steel pipes such as low hardness and poor wear resistance, as well as the poor toughness of ceramics. The ceramic-lined steel pipe has a diameter of DN125; it features a straight section made of wear-resistant ceramic, with both ends connected by welding (using reverse flanges, bolts, and gaskets). The thickness of the wear-resistant ceramic lining is 4 mm, while the thickness of the steel pipe itself is 8 mm. The steel pipe is made of carbon steel, and the ceramic lining is made of aluminum oxide ceramic. One piece is 6 meters long. Ceramic-lined elbow, specified as DN125*12mm, 90° with large radius (1250mm); the lining is made of wear-resistant ceramic (thickness 4mm), while the outer part is cement cast. It features an air supply pipe at the rear end, and is connected at both ends via flanges (complete with reverse flanges, bolts, and gaskets). It is a 90-degree butt-welded seamless elbow with a ceramic lining | 90E(L) DN100*4 GB/T12459|20; the material is steel grade 20#, with an inner diameter of 100mm and a wall thickness of 4mm
When air is conveyed through pipes in coal washing plants, the high speed of the airflow causes significant wear on the outer wall of the wear-resistant elbows. Reducing the speed at which the material impacts these walls can help minimize wear. If the walls are worn through, it is necessary to stop the operation of the pipes involved and carry out welding work, which is time-consuming and labor-intensive; it also leads to interruptions in production. Wear-resistant ceramic patches for pipes provide impact resistance, wear resistance, and corrosion resistance. Ceramic wear-resistant pipes effectively protect the pipe walls from wear, serving as a substitute product for coal washing plants. What wear-resistant pipe fittings are needed in coal washing plants? 1. Wear-resistant straight pipes, with a corundum ceramic lining and flanges; the specifications range from 125 to 530, and these pipes are fitted with wear-resistant ceramic sheets. Wear-resistant ceramic tubes for coal washing plants. 2. Wear-resistant pipe fittings, including wear-resistant elbows, wear-resistant tees, wear-resistant crosses, and wear-resistant reducers, all require flanges; the typical pressure rating is 1.0 kilogram per square centimeter. Ceramic wear-resistant tee joint. 3. Special adhesive for ceramic tiles, with a compressive strength of >65 MPa, a steel-to-steel tensile bonding strength of >30 MPa, and a shear strength of >18 MPa for bonding wear-resistant ceramic tiles. Special adhesive for wear-resistant ceramic sheets. 4. Corundum linings, Al2O3. Ceramic materials have a close-packed hexagonal structure composed of oxygen ions, with aluminum ions filling two-thirds of the octahedral interstices; this is the same stable α-Al2O3 structure as that found in natural corundum. As a result, ceramics possess a high melting point and high hardness, as well as excellent wear resistance. The hardness of ceramic patches is ≥ HRA85, second only to that of diamond, and they have a smooth surface with a low friction coefficient.
Corrosion-resistant and wear-resistant ceramic elbows are used in primary air duct elbows, coal powder pipelines, and dust removal pipelines. Product description: I. Product structure – These wear-resistant ceramic elbows utilize a special high-temperature resistant adhesive developed by our company to attach special corundum ceramic sheets to the interior of steel pipe elbows. This solution addresses the severe wear problems that occur in the elbows used for material transport in industries such as thermal power, metallurgy, steel manufacturing, and cement production. By combining steel pipe elbows with wear-resistant ceramic sheets, it is possible to facilitate quick replacement and easier installation. Depending on the working conditions, the manufacturing process varies; the direct bonding method, bolt clamping method, or one-piece molding method can be used. Among them, the pipe integral molding method (RHS) involves using selected alumina particles to fire a lined pipe through various molding techniques, and then pouring a special filler into the interior of the steel pipe to form the integral pipe. The pipes formed by this method differ from the ceramic composite pipes produced using the self-igniting combustion technique, as their inner ceramic crystals are exactly the same as those in the ceramic coatings. Its advantage is a smooth inner wall of the pipeline and excellent wear resistance, making it suitable for slag transfer and ash removal systems that have high requirements for pipeline material. The bolt clamping method is a ceramic assembly technique that employs triple fixation through adhesive bonding, mutual pressing and interlocking of ceramic pieces, and bolt clamping. Thanks to the triple fixation method, the ceramic and the equipment have become one; even when operating at high temperatures above 1000°C, the ceramic does not come loose.
Production process of ceramic-lined elbows: Ceramic-lined elbows are manufactured using a centrifugal self-propagating process, based on a chemical reaction-driven centrifugal casting technique. The ceramic layer is formed at temperatures above 2200°C to create dense corundum porcelain (AL2O3), which then forms a strong bond with the steel pipe through an intermediate layer. Ceramic-lined elbows take full advantage of the high strength, good toughness, impact resistance, and excellent weldability of steel pipes, as well as the high hardness, superior wear resistance, corrosion resistance, and heat resistance of corundum ceramics, thereby overcoming the weaknesses of steel pipes such as low hardness and poor wear resistance, as well as the poor toughness of ceramics.
90° ceramic-lined wear-resistant elbow, with a bending radius of 800 mm and DN100; it consists of no less than 7 sections. Explanation: The angle of the ceramic-lined wear-resistant elbow is 90 degrees. The bending radius of the elbow, 800 mm, refers to R in the diagram; there are 7 sections, although some requirements specify 5 sections – it depends on the specific needs of the customer. As shown in the figure below, this is a wear-resistant elbow with an inner diameter of 100 mm; for the outer diameter, a steel pipe of 121*8 is required.