News

Common flange pressure-temperature rating standards are as follows:
ASME B16.5 (American System): Steel flanges are available in seven pressure ratings, Class150, 300, 400, 600, 900, 1500, and 2500. The standard establishes a table of pressure-temperature ratings based on different materials, nominal pressures, and temperature ranges. For example, a carbon steel flange of Class150 has a pressure capacity of approximately 270 PSIG at room temperature, 180 PSIG at 400°F (~204.4°C), 150 PSIG at 600°F (~315.6°C), and 75 PSIG at 800°F (~426.7°C).
EN 1092-1 (European System) : For butt-welding flanges with nominal pressures from PN2.5 to PN400. The relevant European component standard includes a table of specified pressure/temperature ratings or, at a minimum, rules for determining pressure/temperature ratings. For flanges of different materials and nominal pressures, there are corresponding pressure ratings at different temperatures, with the maximum non-shock working pressure of the flanges at working temperatures below 20°C being the same as for 20°C.
HG/T 20592 (China European system): specifies the non-shock working pressure of steel pipe flanges (European system) at working temperature. It covers a variety of materials and different nominal pressure levels, such as PN0.25MPa, PN0.6MPa, PN1.0MPa, etc. The working pressure of steel pipe flanges is the same as that at 20℃. Take PN0.25MPa as an example, for Q235 - A, B, C materials, the maximum allowable working pressure is different at different temperatures, 0.25MPa at ≤20℃, 0.25MPa at 100℃, 0.225MPa at 200℃, 0.20MPa at 300℃ and so on.
GB 9131: It stipulates the pressure-temperature ratings of steel pipe flanges, which are applicable to pipe flanges made of various materials, such as Q235-A, B, C, 20 steel, 16Mn and so on. Under different nominal pressures and temperatures, the maximum allowable working pressures of flanges of corresponding materials are given. For example, PN0.6MPa A3 steel flange, ≤ 20 ℃ when the maximum allowable working pressure of 0.60MPa, 100 ℃ for 0.60MPa, 150 ℃ for 0.54MPa, 200 ℃ for 0.48MPa.
JB / T 74 - 94: contains pipeline flange technical conditions, and its Appendix B gives the pipeline flange pressure - temperature rating. Flanges of various materials and different nominal pressures are involved, and the pressure values at different temperatures are clearly specified. For example, PN0.6MPa Q235 - A, B, C flanges are 0.60MPa at ≤20℃, 0.60MPa at 100℃, 0.54MPa at 200℃, and 0.48MPa at 300℃.
There are differences in flange pressure-temperature ratings under different standardized systems, and in actual application, it is necessary to select the flange pressure-temperature ratings correctly according to the specific engineering requirements, the piping system's working conditions, and the standard specifications adopted. In practical application, it is necessary to choose the correct pressure and temperature level of flanges according to the specific project requirements, working conditions of piping system and the standard specification adopted to ensure the safe and reliable operation of piping system.