GB/T 17395 Pipe Dimensions

What GB/T 17395 Governs

GB/T 17395-2008 is a dimensional standard for seamless steel pipe: a flat list of permitted outside diameters, the wall thicknesses allowed at each, and the mass per metre that follows. It sets no steel grade and no pressure rating — those belong to the product standards that reference it, such as GB/T 8163 for fluid piping.

Two things about the size designation matter before any number on this page is useful. First, GB/T 17395 publishes no DN column. It is a list of diameters, and the DN values quoted in the trade are a convention applied on top of it, exactly as they are for GOST pipe dimensions. Second, the diameter itself is printed twice, and the two printings do not mean the same thing.

Region: China. The country table compiled for this site maps China to this family, and it is one of the 16 entries in that table checked against the country’s own standard rather than inferred from bloc membership.

The Number in Brackets Is Not the Size

GB/T 17395 prints its Series 1 diameters in the form 21(21.3), 27(26.9), 60(60.3), 325(323.9). The bracketed figure is the corresponding imperial specification, and the standard states plainly that the nominal size is normally used and the imperial size is not recommended. English-language pipe charts reproduce the bracketed number and drop the other one, which is the standard exactly backwards.

The dataset behind this page settles it without needing to read the sentence at all. The published mass columns were re-derived from the formula, and they agree with the un-bracketed integer — which is why these are the diameters that appear in the compiled list:

So the Chinese nominal outside diameter of what the trade calls DN 50 seamless is 60 mm. 60.3 mm is a cross-reference the standard tells you not to use, and it is not a diameter this standard publishes.

The 100 Outside Diameters

3,547 wall thicknesses in total, from 0.25 mm to 120 mm. The evidence column is per diameter: what could be confirmed about the walls published at that size.

The ID is not tabulated: it is the diameter minus twice the wall, and it changes with every wall at that size.

A Series, B Series, and What a Buyer Receives

China runs two diameter conventions at once, and the difference is not a rounding. The A series follows the international values; the B series is the domestic legacy list, and it is what a seamless-pipe mill quotes by default. The B series is not a rival standard — every one of its diameters is a member of GB/T 17395’s own list, selected out of the tiers the standard does not prefer.

19 of the 19 domestic diameters are published in this standard. 5 of the 19 American ones are. That asymmetry is the practical warning on this page: a Chinese mill quoting a familiar trade size is quoting a diameter your fittings were not bored for, and the pipe and its own fittings can default to different series within China as well.

Where GB/T 17395 Parts From ASME and From Europe

13 of the 100 Chinese diameters appear in ASME B36.10M: 73, 273, 457, 508, 610, 660, 711, 762, 813, 864, 914, 965, 1016 mm. Against EN 10220 Series 1 the overlap is 9 of 35. In both cases the agreement is concentrated at the large end, where every system has settled on the same round numbers, and absent through the middle of the range where most pipe is bought.

The one place China lands on the American value rather than the international one is worth knowing about. 73 mm — the diameter at which ASME is the odd one out worldwide, everyone else being near 76 — is in the Chinese list, and so is 76. Chinese industry treats the resulting mismatch as a known trap rather than a settled question, and this site does not pick a winner between them. EN 10220 pipe dimensions covers the European side of the same argument.

What We Could Verify, and What We Could Not

Of the 3,547 rows on this page, 2,930 are verified and 617 rest on a single publisher and are labelled single source in the evidence column above. None had to be marked as could not be verified, and no published mass had to be suppressed.

This is the best-evidenced of the non-American standards on this site, for one reason: all 3,547 rows carry a published mass, so every row could be tested against M = (OD - t) * t * C rather than merely compared with another website. A mistyped diameter or wall breaks that agreement immediately. Where a standard prints no mass column, as EN 10220 does not here, that check cannot run at all.

The same check found an error inside the standard. At 402 mm with a 24 mm wall the published mass reads 233.72 kg/m, where the formula gives 223.73. The neighbouring rows show why 233.72 cannot be right: mass rises with wall thickness at a fixed diameter, and 233.72 kg/m would make a 24 mm wall heavier than the 25 mm row beside it at 232.44 kg/m.

One gap is open and cannot be closed for free. A 2024 edition of GB/T 17395 exists and changed the diameter and wall range, but its tables are unreadable: the pages carry private-use glyphs with no character map, and the official source serves encrypted image tiles. Everything here is therefore GB/T 17395-2008, named on every table, and the 2024 lists are absent rather than guessed at. How this data was verified lists the other standards in the same position.

The Same Sizes Under Other Standards

GOST pipe dimensions

Russia and the CIS — the same integers, and no DN column either

EN 10220 pipe dimensions

Europe — 114.3 and 168.3 where China has 114 and 168

JIS G3452 and G3454 pipe dimensions

Japan — a third answer again at every small size

ASME B36.10M pipe dimensions

the American series, in inches, with schedules

For all of them side by side, see the pipe standards compared by country. For the American dimensions with wall thicknesses and weights, steel pipe sizes.

Frequently Asked Questions

What outside diameter is DN 50 pipe in China?

Three numbers compete, and two of them are in this standard. The Series 1 nominal is 60 mm. The domestic B series, which is what a seamless-pipe mill quotes by default, is 57 mm — and 57 mm is itself a member of this same diameter list. The ISO and American value, 60.3 mm, is not in the list at all. Asking for DN 50 in China without naming the series leaves the diameter genuinely undecided.

Why does GB/T 17395 print two numbers for each size?

The bracketed number is the corresponding imperial or ISO specification, and the standard tells you not to use it: normally the nominal size is used, and the imperial size is not recommended. English-language pipe charts almost universally reproduce only the bracketed figure, which inverts the standard. The published mass columns settle it — they were re-derived from the un-bracketed integer, and they agree with it.

Is GB/T 17395 the same as ASME B36.10M?

Barely. 13 of the 100 Chinese diameters appear in ASME B36.10M — 73, 273, 457, 508, 610, 660, 711, 762, 813, 864, 914, 965, 1016 mm — and almost all of them are large-diameter sizes where both systems converge on the same round figures. Everything a building or a process plant actually uses is a different number: 114 against 114.3, 168 against 168.3, 219 against 219.1.

Which edition of GB/T 17395 is this?

GB/T 17395-2008. A 2024 edition exists and changed the diameter and wall range, but its tables could not be read: the pages are encoded with private-use glyphs and no character map, and the official source serves encrypted image tiles. Rather than mix editions or guess, this page publishes the 2008 lists and names the edition on every table.

How much does GB/T 17395 pipe weigh per metre?

Every one of the 3,547 rows carries a published mass, and every one re-derives from M = (OD - t) * t * C with C = 0.02466 kg per metre for carbon steel. That arithmetic is what proved the un-bracketed diameter is the real one, and it also caught a misprint inside the standard itself at a 402 mm diameter with a 24 mm wall.