Can a 20Ⅲ flange be used for containers holding highly hazardous media?
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I would like to ask everyone: (1) Can a 20Ⅲ flange be used for containers holding highly hazardous media? The tank is made of Q345R material; the design temperature ranges from 0 to 80°C, and the pressures are -0.1 MPa and 0.4 MPa. (2) What are the basic principles for selecting flanges in equipment design? Is it based on the shell material and design parameters, as long as the maximum operating temperature at that temperature and nominal pressure meets the design requirements, and then cost savings are taken into account?
The flange selection must also be at least as high as the lower limit of the operating temperature.
When the design pressure is not very high, 20 steel pipes are used for the nozzles, and 20 forged parts are used for other components. Strictly speaking, unless the forged parts are extremely large, there is no standard requirement stating that components in contact with highly hazardous media must use grade III forged parts.
The selection of the equipment flange must also be matched with the selection of gaskets and fasteners. 20III can certainly be used for highly hazardous media; the choice of forging grade is generally related to pressure.
Forgings with extreme and high toxicity for use in media, as well as those with a cross-sectional dimension greater than 300 mm, shall meet the requirements of Grade III or Grade IV. —HG/T20581 (P57) 6.4.3 We generally follow this provision
Sure, the 20# forgings are not bad at all
Yes, for some media, a 20Ⅲ quality level provides greater assurance