Questions regarding the calculation of pipe fitting wall thickness
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Dear teachers, recently when calculating the wall thickness grades for pipes, I referred to two methods: SHT3059 and the formula “Sch = design pressure / allowable stress * 1000”. The method outlined in SHT3059 is quite detailed; although the resulting wall thickness values are on the low side, it can still serve as a theoretical basis. My question is: Can the formula “Sch = design pressure / allowable stress * 1000” be used as a calculation method for determining wall thicknesses? If so, what should be done if the specified grade for a stainless steel pipe is Sch160S, but according to HGT20553, the maximum allowable wall thickness grade for stainless steel pipes is only Sch80S? I might be asking a naive question; I hope everyone can help clarify it. Thank you
That formula is not used to determine the wall thickness of pipes and fittings. . . The thickness of pipeline fittings is specified in the design and manufacturing standards. .
Thank you for your answer. I would like to ask further: if, using the calculation formula in B31.3, the wall thickness for a DN40 stainless steel pipe is 5.2 mm, which exceeds the maximum wall thickness allowed for DN40 stainless steel pipes of grade Sch80S (5.08 mm), then what should be chosen? Can I choose XXS? What is the basis for this? Thank you
This post was last edited by xxj19810407 on 2016-2-28 17:20, in accordance with Sch160 and B36.10
Generally, for stainless steel, the one with an S is the choice. . . But in reality, there are also mixed ones. Only pipes of that specification are available. For his DN40 version, the calculated wall thickness is 5.2. . It’s easy to imagine that the pressure is very high. It’s too rare. . . It might be difficult to find this Sch160 stainless steel pipe. .