What is a high-pressure boiler tube?
High-pressure boiler tubes are a type of steel tube with specific uses and strict requirements, mainly used for equipment working in high-temperature and high-pressure environments. It is usually used to manufacture pressure-bearing components of high-pressure boilers, such as water-cooled walls, superheaters, reheaters, etc., as well as other piping systems that need to withstand high temperatures and high pressures.
1. Material requirements
High-pressure boiler tubes are extremely strict in the selection of materials because they need to withstand high-temperature and high-pressure environments and erosion by high-temperature flue gas and water vapor for a long time. First of all, high-pressure boiler tubes need to have high durability, that is, the material is not easy to plastically deform or break under long-term high temperature and high pressure to ensure the long-term stable operation of the pipeline. Secondly, high oxidation resistance is another key characteristic of high-pressure boiler tubes to resist oxidation in high-temperature environments and prevent thinning or perforation of the tube wall. In addition, the structural stability of the material is equally important to reduce the risk of structural changes and stress corrosion cracking in high temperature environments.
Specifically, high-pressure boiler tubes are often made of high-quality carbon structural steel, alloy structural steel, and stainless heat-resistant steel. These materials not only have good mechanical properties, but also have high heat and corrosion resistance. Common steel grades include 20G, 20MnG, 15CrMoG, 12Cr2MoG, etc. These steel grades have improved the comprehensive performance of the material through alloying design, and meet the stringent requirements of high-pressure boiler tubes for material performance.
High-quality carbon steel has high toughness and plasticity, and is suitable for manufacturing general-purpose high-pressure boiler tubes; alloy steel adds a small amount of alloy elements to carbon steel, has higher strength and heat resistance, and is suitable for manufacturing high-pressure boiler tubes working in higher temperature and pressure environments; stainless steel has excellent corrosion resistance and is suitable for manufacturing high-pressure boiler tubes working in strong corrosive environments.
2. Manufacturing process
The manufacturing process of high-pressure boiler tubes is similar to that of seamless steel tubes, mainly including hot rolling, cold drawing and hot expansion processes. The hot rolling process softens the steel billet by high temperature heating, and then passes through the rolling mill for multiple rolling to form the required size and shape. The cold drawing process is to draw the hot-rolled tube at room temperature or low temperature to improve the precision and surface quality of the tube. The hot expansion process is to further expand the tube diameter to meet the needs of specific sizes.
During the manufacturing process, the quality of the raw steel billet is strictly controlled, including chemical composition, mechanical properties and surface quality. At the same time, the tube needs to be inspected and tested in multiple processes, such as water pressure test, expansion test, flattening test, etc., to ensure the reliability and safety of the tube.
3. Performance characteristics
High-pressure boiler tubes have a series of excellent performance characteristics, which enable them to adapt to complex and harsh working environments. First, high-pressure boiler tubes have high lasting strength, that is, they can still maintain sufficient strength under high temperature and pressure to withstand the fluid pressure and temperature stress in the pipeline. Secondly, its high oxidation and corrosion resistance enables the tube to maintain good performance in a long-term high-temperature environment, extending its service life. In addition, high-pressure boiler tubes also have good organizational stability, can maintain a stable microstructure at high temperatures, and reduce the risk of stress corrosion cracking.
In terms of mechanical properties, high-pressure boiler tubes have high tensile strength and yield strength, as well as good elongation and toughness. These performance indicators ensure the safety and reliability of the tubes under complex stress conditions. At the same time, through process means such as heat treatment, the mechanical properties and service life of the tubes can be further improved.
4. Application areas
High-pressure boiler tubes are mainly used in key parts such as superheater tubes, reheater tubes, gas guide tubes, and main steam pipes of high-pressure and ultra-high-pressure boilers. These pipes not only withstand high-temperature and high-pressure fluid media, but also directly participate in the heat exchange process of the boiler, which has an important impact on the overall performance and efficiency of the boiler. Therefore, the quality and performance of high-pressure boiler tubes are directly related to the safe operation and economic benefits of the boiler.
5. Standards and specifications
High-pressure boiler tubes follow a series of national and international standards, such as China's national standards GB3087-2008, GB5310-2008, the US boiler and pressure vessel specifications ASME SA210, ASME SA213, and the Federal German Industrial Standard DIN17175.
In terms of specifications, high-pressure boiler tubes have a wide range of sizes, ranging from 8-1240mm outer diameter and 1-200mm wall thickness. High-pressure boiler tubes are also called 20G high-pressure boiler tubes, 15CrMoG high-pressure boiler tubes, and 12Cr1MoVG high-pressure boiler tubes. High-pressure boiler tubes manufactured by HSCO support cutting and blanking.
In summary, high-pressure boiler tubes are a type of steel pipe with specific uses and strict requirements. Their materials, manufacturing processes, performance characteristics, uses, standards and specifications are carefully designed and strictly controlled to ensure that they can meet the working requirements under high temperature and high pressure environments.
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