What is the difference between GB5310 25MnG steel pipe and 20G steel pipe
Both 25MnG steel pipe and 20G steel pipe in GB5310 are seamless steel pipes for high-pressure boilers, but they have some differences in chemical composition, mechanical properties and application areas:
Chemical composition:
25MnG: Contains a higher manganese content (about 1.2%-1.6% manganese), which helps to improve the strength and toughness of steel.
20G: The main components are carbon and manganese, with a lower carbon content, good plasticity and welding properties.
Mechanical properties:
25MnG: The specified yield strength is ≥784MPa, the tensile strength is ≥319MPa, the impact value is 22J, the elongation is 13%, and the cross-sectional shrinkage is 21%.
20G: Generally has excellent welding performance, but the specific yield strength and tensile strength are slightly lower than 25MnG.
Heat treatment:
25MnG: Heat treatment includes normalizing, annealing, quenching and tempering processes to improve the mechanical properties and endurance of the material.
20G: Usually hot rolled or normalized, suitable for high temperature and high pressure environments.
Application areas:
25MnG: Due to its high strength and toughness, it is often used to manufacture heating surface tubes, economizers, superheaters and reheaters of high-pressure boilers.
20G: Widely used to manufacture tube sheets and structural parts of various types of boilers, especially in medium and low pressure boilers.
In summary, 25MnG steel pipes have better strength and toughness than 20G steel pipes due to their high manganese content and specific heat treatment, and are suitable for environments with higher pressures and temperatures. 20G steel pipes are widely used in the manufacture of medium and low pressure boilers due to their good weldability and moderate mechanical properties.