Steel-high chromium bimetal wear-resisting compound pipe exterior wall uses the ordinary seamless steel tube, through the centrifugal forming process forms the high chromium cast steel lining compound. The outer wall of the elbow is heated and the inner layer is made of high chromium cast steel, which has the wear-resisting property of high alloy cast steel, and can withstand pressure and has higher mechanical properties.

The wear resistance of the pulverized coal conveying pipeline of the boiler of the thermal power plant must be designed for leakproof, anti-corrosion, rain-proof, anti-freeze and other factors. The key points are anti-wear and anti-corrosion. It has always been the key part of power plant maintenance. The comprehensive performance of the pipeline system, especially the wear resistance, is directly related to the operating cost and the economic benefit of the entire power plant, and is a key issue that must be considered in the construction and maintenance of new power plants.

• Bimetal wear-resistant composite elbow material grade: KMTBCr26

• Working temperature: 150℃

• Working pressure: 0.4Mpa

• Working medium: pulverized coal, air two-phase flow

• Maximum flow velocity of gas-solid two-phase flow: 28m/s

Technical requirements

• The overall performance of the bimetal wear-resistant composite elbow must meet the following requirements; the flexural strength must be greater than 610MN/M2, the tensile strength must be greater than 415MN/M2, the impact toughness must be greater than 15J/CM2, and the hardness of the wear-resistant layer must be greater than 50.

• The inner and outer surfaces of the bimetal wear-resistant composite elbow should be smooth and clean, without burrs, burrs, cracks, porosity, pores or air bubbles, no cracks are allowed, the pipe has good compactness, and the flow direction of the medium should be marked in obvious parts. The inner lining of each elbow must be formed at one time, and it is strictly prohibited to weld the folded line after it is produced in sections.

• The dimensional deviation of pipe fittings shall comply with the provisions of GB3092, GB8162 and GB8163, and shall comply with the requirements of product drawings and order agreements. Thickness deviation of inner lining ≤+1.2mm. The weight of each elbow cannot exceed the design weight. And mark the weight in the obvious place.

• The steel pipe used in the composite pipe adopts seamless steel pipe, and its performance shall comply with the relevant agreement.

• The bimetal wear-resistant composite elbow is installed by direct welding, with good welding performance, and the outer welded pipe is made of 16MnR# steel.

• Each inlet and outlet of the bimetal wear-resistant composite elbow has a straight section of a certain length. The straight section (L1/L2) should be consistent with the material and wall thickness of the elbow body, and a 100mm transition section is added outside the straight section to be welded to the powder feeding pipeline. There should be no special requirements for on-site welding of products to ensure good welding performance when products are welded at room temperature on site.

• The life of the bimetal wear-resistant composite elbow is not less than 10 years (8000 hours of operation per year).

• During the service life of the bimetal wear-resistant composite elbow and under the abnormal conditions of spontaneous combustion of the powder feeding pipeline, the product should ensure that the lining wear-resistant layer does not crack or peel off; when the pipeline is partially blocked, it should ensure that it can knock , cutting, it should be convenient for unloading, installation and maintenance.

• The sealing performance test of the bimetal wear-resistant composite elbow shall be carried out before leaving the factory, and the test shall be carried out according to the relevant standards. When the quality and performance of the products provided by the supplier do not meet the specified standards, they shall not leave the factory.

• The product should meet the “DL/T 680-1999 Technical Conditions Standard for Wear-Resistant Pipelines”.

Technical requirements parameter table

Special Corundum ceramics made of rare metal oxides as solvents and sintered at high temperature by 1730 ℃ through bonding, welding, mosaic, riveting and socket technology, a variety of wear-resistant ceramic pieces, block brick materials in the pipe wear surface, so as to form a surface with excellent wear resistance, and the matrix is still using the composite pipe of ordinary metal.

Main technical parameters of bimetal composite wear-resistant elbow:

• Thickness of bimetal wear-resistant composite elbow: inner arc: 22 outer arc: 32

• Eccentricity: 5mm

• Thickness deviation of inner lining: ≤+1.2mm

• Design pressure: 1.6Mpa, hydraulic test pressure: 5.6-19MPa:

• Design temperature: 350℃