I’m a beginner; please give me some guidance, experts
Thread Content
In American standards, the pipe wall thickness grades such as Sch20, Sch40, etc. – what do the numbers 20, 40, 60, 80, and so on represent? It shouldn’t refer to the pressure rating in kilograms, right?
In my opinion, it’s a matter of grade differentiation – pipes of different grades vary, with larger and thicker ones being used; generally, Sch40 represents the standard thickness.
The pipe designation is the value obtained by multiplying the ratio of the pipe’s design pressure to the allowable stress of the material at the design temperature by 1000, and then rounding it off. The Sch value is equal to 1000×P/S; for Sch40, this means that when the allowable stress of the material is 100 MPa, the pressure-bearing capacity of the steel pipe is 40 bar.
The answer on the 3rd floor is great – simple and thorough! SCH stands for schedule, which means specifications. In practical applications, data is usually selected by looking up tables.
Steel pipes with the same outer diameter come in different wall thickness specifications. SCH denotes the wall thickness grade for British standard steel pipes, with grades ranging from lowest to highest as SCH 5, SCH 10S, SCH 10, etc. The letter S indicates that it is applicable only to stainless steel; the standard grade is SCH STD 40
For wall thickness grades, you can refer to the Quick Reference Manual for the Installation Design of Petrochemical Pipelines, which provides detailed explanations; check it to see the thicknesses corresponding to different wall thickness grades.