Applications, Properties, and Manufacturing Process of 20G High-Pressure Boiler Steel Tubes

First. Definition and Applications of 20G High-Pressure Boiler Steel Tubes.

1. Definition: 20G high-pressure boiler steel tubes are seamless steel tubes specifically designed for manufacturing high-pressure boilers. They are made of high-quality carbon structural steel and possess high creep strength, high resistance to oxidation and corrosion, and good structural stability.

2. Applications: 20G high-pressure boiler steel tubes are mainly used to manufacture superheated steam tubes, boiling water tubes, and superheated steam tubes for locomotive boilers of various structures. In addition, they are widely used in high-temperature and high-pressure pipeline systems in the power, petrochemical, and aerospace industries.

Second. Chemical Composition and Physical-Mechanical Properties of 20G High-Pressure Boiler Steel Tubes.

1. Chemical Composition: The main chemical components of 20G boiler steel tubes include carbon ≤0.18%, silicon ≤0.30%, manganese ≤0.80%, phosphorus ≤0.045%, and sulfur ≤0.045%. In addition, depending on specific needs, trace amounts of alloying elements such as vanadium and niobium may be added to improve the strength or toughness of the steel.

2. Physical and Mechanical Properties of 20G High-Pressure Boiler Steel Tubes: 20G boiler steel tubes possess high tensile strength and yield strength, with a tensile strength ≥415MPa and a yield strength ≥245MPa (at 20℃). Simultaneously, it also exhibits good impact toughness, with an impact energy ≥27J at -20℃. Furthermore, its hardness is typically controlled within the range of HB180-230 to ensure good machinability and wear resistance.

Third, Production Process and Inspection Standards for 20G High-Pressure Boiler Steel Tubes.

1. Production Process of 20G High-Pressure Boiler Steel Tubes: The production process of 20G high-pressure boiler steel tubes includes multiple stages such as piercing, rolling, heat treatment, and non-destructive testing. During manufacturing, strict control of various process parameters is required to ensure that the product's dimensional accuracy, mechanical properties, and surface quality meet the requirements.

2. Inspection Standards for 20G High-Pressure Boiler Steel Pipes: Following relevant national standards such as GB/T 5310, inspection items include visual inspection, dimensional measurement, chemical composition analysis, mechanical property testing (such as tensile testing and impact testing), and non-destructive testing (such as ultrasonic testing and radiographic testing). These inspection items ensure that the quality of the 20G boiler steel pipes meets the standards and satisfies the requirements for high-pressure boiler use.

Fourth, Use and Maintenance of 20G High-Pressure Boiler Steel Pipes.

1. Precautions for Using 20G High-Pressure Boiler Steel Pipes: During use, attention should be paid to the requirements for material selection, installation, and maintenance. Avoid use beyond the specified temperature and pressure, and strictly follow the design parameters. At the same time, the pipeline should be regularly inspected for defects such as cracks and corrosion to ensure its safe and reliable operation.

2. Welding Requirements for 20G High-Pressure Boiler Steel Pipes: Welding of 20G boiler steel pipes requires appropriate preheating and post-weld heat treatment measures to reduce welding stress and cracking tendency. This helps ensure the quality and reliability of the welded joint.

In summary, 20G high-pressure boiler steel pipe is a high-performance, high-quality steel product with a wide range of applications and significant practical value. During use, strict control of various parameters and precautions is necessary to ensure its safe and reliable operation.