Distinguishing between large outer diameter and small outer diameter
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Both American standards and European standards make a distinction between large outer diameter and small outer diameter. I would like to ask whether this distinction is applied to steel pipes, and why it is necessary to make such a distinction. Thank you all for your guidance~:handshake
Although there are many standard systems in use around the world, they can generally be divided into two main categories. Regarding the pipe series standards, one category is the so-called “large outer diameter” series, with corresponding outer diameter sizes of DN15-φ22mm, DN20-φ27mm, DN25-φ34mm, DN32-φ42mm, DN40-φ48mm, DN50-φ60mm, DN65-φ76 (73)mm, DN80-φ89mm, DN100-φ114mm, DN125-φ140mm, DN150-φ168mm, DN200-φ219mm, DN250-φ273mm, DN300-φ324mm, DN350-φ356mm, DN400-φ406mm, DN450-φ457mm, DN500-φ508mm, DN600-φ610mm, etc• ； The other category is the so-called “small outer diameter” series, with corresponding outer diameter sizes of DN15-φ18mm, DN20-φ25mm, DN25-φ32mm, DN32-φ38mm, DN40-φ45mm, DN50-φ57mm, DN65-φ73mm, DN80-φ89mm, DN100-φ108mm, DN125-φ133mm, DN150-φ159mm, DN200-φ219mm, DN250-φ273mm, DN300-φ325mm, DN350-φ377mm, DN400-φ426mm, DN450-φ480mm, DN500-φ530mm, DN600-φ630mm, etc.
Why separate them like this? Are they used in different fields respectively?
Originally, different standards led to the use of various diameter series; later, in order to accommodate these different standards, larger and smaller outer diameters were established
This is because different countries adopt different pipeline standards. Our country originally used Soviet standards, with pipelines of metric size, that is, small diameter, and these are still widely used to this day. Large diameter is the commonly used pipeline diameter internationally; it is widely adopted abroad, but due to its larger size, its price is slightly higher.
It’s caused by different standards for various **
I learned it, but I didn’t know there was such a difference; I’m sweating
Is it related to thin-walled pipes and thick-walled pipes? Non-materials major
Upstairs, those are two different concepts. The terms \"large outer diameter\" and \"small outer diameter\" refer to different standard systems used domestically and internationally; the assumption is that we’re talking about pipes of the same type. What you mentioned regarding thickness differences is a way of classifying pipes within China, similar to the distinction between welded and seamless pipes. To be more professional, could you tell me if what I said is correct? If not, please advise me...
For projects being carried out nowadays, Chinese standards are generally followed first, while also taking into account the owner’s **standards