What is the practical significance of the nominal thickness of steel pipes?
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This post was last edited by WANGJIABAO on 2026-1-20 at 17:15. The nominal thickness of pressure vessels is the thickness specified in the drawings; the thickness of the steel plates or coils supplied and after being formed should not be less than this nominal thickness. In contrast, the thickness of the steel pipes supplied for pressure pipelines is often less than the design thickness (due to a negative material tolerance). According to the relevant provisions of GB/T20801, the nominal thickness of steel pipes is the thickness specified in the material standards. However, there are various thicknesses available for steel pipes of the same nominal diameter in these standards. What practical meaning then does the nominal thickness of a steel pipe have? Also, can the thickness of the steel pipe supplied be less than the thickness specified in the drawings?
It is useful in the process engineering field; the nominal thickness is used for heat transfer calculations, and this value is fixed and incorporated into the calculations during the design phase, rather than using the actual thickness. There is also a common term such as the qualitative temperature, which is the average of the temperatures inside and outside the equipment.