Engineering Tools · Flange Quick Reference
DN25 Flange Weight & Dimension Quick Reference
DN25 Flange Dimension Parameters (PN16, unit mm)
Letters correspond to the series dimensional codes in GB/T 9124.1-2019 (which has superseded GB/T 9115-2010): D outside diameter, K bolt circle diameter, L bolt hole diameter, n number of holes, C flange thickness, d4 raised face (RF) outside diameter, f raised face height, H weld neck length, N1 neck outside diameter; Plate Slip-On PLF has no raised face/neck dimension columns.
Weld Neck WNF (GB/T 9124.1-2019)
| OD D | 115 |
| Bolt Circle K | 85 |
| Bolt Holes n×L | 4×14 |
| Stud Size | M12 |
| Flange Thickness C | 18 |
| Raised Face OD d4 | 68 |
| Raised Face Height f | 2 |
| Weld Neck Length H | 40 |
| Neck OD N1 | 46 |
Plate Slip-On PLF (GB/T 9124.1-2019)
| OD D | 115 |
| Bolt Circle K | 85 |
| Bolt Holes n×L | 4×14 |
| Stud Size | M12 |
| Flange Thickness C | 16 |
Pipe OD 33.7 / Bore 28.5 mm
Weld neck WNF and plate slip-on PLF (GB/T 9124.1-2019) on one page: full dimension columns for DN25 D/K/bolt holes/thickness/sealing face, unit weight in kg or lb for carbon steel/304/316L, PN10/PN16 toggle on page (default PN16), nominal size and source fully disclosed.
Full PDF
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Other Sizes
Unit Weight (DN25 · PN16, kg/pc)
| Type | Carbon Steel | 304 Stainless Steel | 316L Stainless Steel |
|---|---|---|---|
| Weld Neck WNF (GB/T 9124.1-2019) | 1.3 | 1.31 | 1.32 |
| Plate Slip-On PLF (GB/T 9124.1-2019) | 1.11 | 1.12 | 1.12 |
Cell shows unit weight (kg/pc): WNF/PLF × carbon steel/304/316L. PN10/PN16 column values differ where applicable, calculated cell by cell; theoretical estimate, settlement subject to actual measurement.
References
- GB/T 9124.1-2019 Steel Pipe Flanges Part 1: PN Series (replaces GB/T 9115-2010 / GB/T 9119-2010; National Standard Information Public Service Platform)
- EN 1092-1 PN series flange dimension/weight published tables (hsflange / marcelforged / tesco dual-source, row-by-row archived in catalog spec)
- Dimensions and weights cross-checked against 60 flange SKU spec_json in product catalog (same source as product pages)
Material Density Conversion
Table values are for carbon steel (7.85 g/cm³); other materials converted by density ratio: weight × factor.
| Material | Density (g/cm³) | Conversion Factor |
|---|---|---|
| Carbon Steel | 7.85 | ×1.000 |
| 304 Stainless Steel | 7.93 | ×1.010 |
| 316L Stainless Steel | 7.98 | ×1.017 |
Data Basis and Source Disclosure
Data basis
- Dimensions and unit weights are taken directly from the spec values of flange SKUs in the product catalog — the same source as the WNF/PLF product pages under /products/pipe-flanges-and-gaskets/.
- Dimensions follow GB/T 9124.1-2019 Steel Pipe Flanges Part 1: PN Series — weld neck WN per Table 29/30, plate slip-on PL per Table 52/53.
- The small-bore sharing rule comes from the footnotes of that standard’s tables: for PN10, DN10–DN40 uses the PN40 size series and DN50–DN150 uses the PN16 size series, and the PN10 dedicated series starts at DN200 — this chart follows it size by size, so PN10 and PN16 are identical in dimensions and weight from DN15 to DN150.
- The carbon steel 7.85 g/cm³ figures are the catalog values; 304/316L are converted by the density ratio 7.93/7.98 ÷ 7.85 (estimate).
Scope & limits
- Theoretical unit weight estimates (gaskets/bolts/nuts and coating allowance excluded) for quotation, freight and lifting budgets.
- Actual values for the same DN×PN vary with the manufacturing standard edition, sealing face type (RF/FF etc.) and material tolerance; use measured values for trade settlement.
Cite this chart
YAXIIO. DN25 Flange Weight & Dimension Quick Reference. https://www.yaxiio.com/en/tools/flange-weight-chart/dn25 (accessed 2026-10-29).
Free to cite and embed — attribution required: “YAXIIO” + a link to this page.
FAQ
What is the weight difference between PN10 and PN16 flanges?
Whether PN10 and PN16 have the same weight depends on size. Per footnotes to Table 52/53 of GB/T 9124.1-2019, for Plate Slip-On PLF in DN15–DN150 PN10 directly uses the PN16 size series, so the two classes are the same flange (identical dimensions and unit weight); the same rule applies to Weld Neck WNF (footnotes to Table 29/30: for PN10 DN10–DN40 takes the PN40 size series and DN50–DN150 takes the PN16 size series). Differences start from DN200: PN16 has greater thickness/bolt circle and is generally heavier. Taking DN25 as an example: Weld Neck WNF approx. 1.3 kg (PN10) / 1.3 kg (PN16); Plate Slip-On PLF approx. 1.11 kg (PN10) / 1.11 kg (PN16).
How many bolt holes and what size for DN25 flange? What studs to use?
For PN16 class: weld neck WNF 4×Φ14 mm (bolt circle K=85 mm), plate slip-on PLF 4×Φ14 mm, both with M12 stud bolts + hex nuts (hole diameter ≈ stud diameter + 2~3 mm). See cross-reference table at page bottom for matching stud/nut dimensions and weights.
How to choose between weld neck flange (WNF) and plate slip-on flange (PLF)?
Weld neck flange has tapered hub and butt-welded connection, better load bearing and fatigue resistance, suitable for medium/high pressure, temperature fluctuation, frequent assembly piping (e.g., PN16, DN200+ process piping); plate slip-on flange is directly fillet welded on pipe end, saves material and labor, lower cost, suitable for low-pressure ambient water/gas etc. For same DN×PN, WNF is usually heavier than PLF.
What are D, K, C, d4, f in the flange dimension table?
D = flange outside diameter, K = bolt circle diameter, C = flange thickness, d4 = raised face (RF) sealing face outside diameter, f = raised face height; bolt holes are denoted as n×L (n = number of holes, L = hole diameter). For DN25 see the dimensional parameter table at the top of the page; toggle PN10/PN16 to compare the two classes: DN15–DN150 share the same dimensions and weight for both classes (footnote to Table 52/53 of GB/T 9124.1-2019), differences start from DN200.
Next: work out your order, or pick the size by standard
Related References
Weld Neck Flange (WNF) Product Category
GB/T 9124.1-2019 PN10/PN16 weld neck flange catalog: DN15–DN300 × carbon steel/304/316L, with inquiry and drawing customization.
Plate Slip-On Flange (PLF) Product Category
GB/T 9124.1-2019 PN10/PN16 plate slip-on flange catalog: DN15–DN300 × carbon steel/304/316L, economical choice for low-pressure piping.
M12 Stud Bolt / Threaded Rod Weight Quick Reference
Matching flange fasteners: same-size stud bolt/threaded rod weight per meter and unit weight by length class, same nominal size as flange table.
M12 Hex Nut Weight Quick Reference
Matching flange fasteners: same-size hex nut unit weight and kg per thousand pieces (GB/T 6170 nominal size).
Industrial Pipe Flanges
Industrial pipe flange selection and purchasing essentials: type, pressure rating and sealing face coordination.
Disclaimer: This table is engineering estimate data for selection, quotation and freight estimation reference only, not a design basis or acceptance standard.