Issues regarding the designation of seamless steel pipes
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I’ve just started working on piping, and I’m confused regarding the pipe designation codes: Can the wall thickness of metric pipe elbows be expressed in terms of wall thickness grades? For example: Is the notation 90E(L)65(B)-Sch40-20# GB/T12459-2005 correct? Additionally, regarding the selection of pipe fittings: is it correct to use 20# seamless steel pipes with dimensions Φ76×4, along with elbows of type 90E(L)65(B)-Sch40? Does Sch40 mean a elbow wall thickness of 5.16 mm? I would be extremely grateful for the guidance from those with more experience!
For DN65 fittings with an outer diameter of 76, the value is 4.5 for SCH20, 5 for SCH40, and 6 for SCH60; you can simply write T=4mm
What are you doing? Design, procurement, quality? For piping used in design, the wall thickness must be selected based on the pressure of the pipeline. Those in charge of procurement follow the requirements in the drawings; if they are not available, they ask the designers for them. Those in charge of quality also ask those in charge of technology for it; it should be included in the drawings. The identifier is correct. The wall thickness was also selected according to GB/T12459, which is correct as well.
If only 16-inch pipes are provided, how can one know the wall thickness of the pipes?