Ash transfer wear-resistant elbow
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Technical requirements for ceramic elbows in ash transfer wear-resistant pipelines: Ceramic elbows used in ash transfer pipelines in power plants are employed frequently. Coal used in power plants, both domestically and internationally, contains a high amount of impurities including stones, and its quality is poor; as a result, wear-resistant elbows used for ash transfer in power plants suffer from severe wear and have a short lifespan. The use of ceramic wear-resistant pipes yields significant results. 1. The ceramic composite pipe used for ash transport features a male-female interlocking ceramic patch structure to prevent detachment; it is employed in ash transport systems, with the steel pipe thickness being no less than 5 mm and the ceramic layer thickness being less than 8 mm. 2. To reduce the resistance to flow within the pipe, the ceramic outer tube of each elbow should adopt an integral or heat-bent elbow design; shrimp-shaped elbows or spliced elbows cannot be used for individual elbows. 3. To reduce the incidence of leaks, the length of each fitting in a straight pipe should be no less than 6 meters. The ceramic outer tube must be manufactured from a single seamless steel pipe; straight pipes cannot be made by joining multiple sections together. 4. The inner diameter of all pipes must be consistent; the ceramic lining pieces should fit together tightly without any gaps, and the surface must be smooth. Adhesives or other substances shall not be used for filling purposes. After the ceramic pipes are formed, any debris inside them must be removed, and the lining should appear in a pure ceramic white color. 5. Adhesive: A high-temperature and low-temperature resistant inorganic adhesive is used as the bonding agent between the ceramic tiles and the cylinder body; its thickness should be ≥1 mm. The adhesive must have stable properties and strong impact resistance, enabling it to function over a long period of time at temperatures ranging from -30°C to +600°C, with full filling.
Production process: Self-igniting ceramic composite steel is manufactured using a high-tech production method—the self-igniting high-temperature centrifugal synthesis process. The tube is composed of three layers from the inside out: corundum ceramic, a transition layer, and steel pipe. The ceramic layer is dense corundum porcelain (AL2O3) formed at high temperatures above 2200°C, and it forms a strong bond with the steel pipe through the transition layer. Wear-resistant ceramic tubes are composite tubes that combine ceramics and metal-organic compounds using the thermite centrifugation method. The thermite tube centrifugation method utilizes the high temperature generated by the reaction itself to melt the reaction products; under the action of centrifugal force, these products are separated, thereby producing ceramic-lined steel tubes that feature a low-energy-consuming alumina ceramic lining. Manufacturers of wear-resistant ceramic elbows have improved their manufacturing processes by adding whiskers and silica to enhance the wear resistance of the ceramics. As the speed of the self-igniting ceramic machine increases, the bonding strength rises ； The coating thickness increases, to around 5-8 mm.
The inner surface of the ceramic wear-resistant elbow in the ash transfer pipeline should be smooth and even, with a surface roughness of Ra 0.8. This ensures that the flow rate and output of the transported medium are not affected, and operational resistance is low. Moreover, no deposits, scaling, ash accumulation, or blockages occur on the inner surface. There are no cracks, nor any defects that could affect performance such as inclusions, sand inclusions, cold shuts, pores, shrinkage cavities, shrinkage porosity, lack of material, burrs, rough edges, or sand adhesion.