Problems regarding pipe test pressure and allowable stress.
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Pipes, designed for a temperature of 265°C, grade 20#. Question 1: The allowable stress values specified in the Industrial Metal Pipe Design Code differ from those given in 20801. Which set are you all using? Question 2: Allowable stresses are only available at 250°C and 300°C. Is it allowed to use interpolation for 265℃ as specified in the standards? Is this linear? I directly used the allowable stress at 300°C for the calculations. The hydrostatic test pressure turned out to be a bit high. Is this acceptable?
1: The design specifications for industrial metal pipelines are GB standards, which are mandatory **standards； 20802 is a GB/T standard, and it is a recommended **standard. 2: Using the stress required at 300°C for calculation is acceptable from a safety perspective; however, from an economic point of view, the investment cost may be higher.
According to Table 20801.2, use 300 degrees directly
It’s definitely not linear, but the specifications state that interpolation can be used. The hydraulic test stress verification shall be carried out according to the test pressure you select.