Understanding the steel pipe series in HG 20553
Thread Content
This post was last edited by hw197358 on 2009-7-9 21:16. In HG 20553, steel pipes are classified into Series Ia, Ib, and II; the outer diameters of these series vary, and the specifications provide rather vague explanations regarding these differences. Could any expert explain in detail what the distinctions are?
It–Imperial system; Ib–Rounded size of Ia; II–Metric system. Steel pipes of series II are cheaper than those of series I
There are instructions for HG20553; take a close look and you’ll understand.
The Ia series is the preferred series and serves as the basic series for steel pipes used in chemical piping in the future. The outer diameter of these pipes follows the standards of ISO4200, while the wall thickness is indicated by a \"Schedule Number\" (abbreviated as Sch.No.). The values for these schedule numbers are determined based on ASME B36.10, with rounding applied. The Ib series acts as a substitute for the Ia series; the outer diameter of pipes in this series is rounded to an integer value. The II series is a continuation of the existing standard with smaller outer diameters
I wonder why they created an Ib if they already have an Ia