EN 1092-1 · Standard reference
EN 1092-1 material groups (1E0 to 16E0)
EN 1092-1 sorts flange steels into material groups rather than individual grades. A group collects materials with similar chemical and mechanical properties and similar corrosion resistance, so one pressure–temperature rating can be applied to any member of the group. The definitions are in informative Annex B, and the material selection table (Table 9) maps each group to EN forging, flat-product, casting and bar grades.
Group codes combine a family number, the letter E and a sub-index — 3E0, 6E1, 13E0 and so on. The numbering broadly follows the steel family described in Annex B (carbon, low-alloy, low-temperature, fine-grain, high-temperature ferritic or austenitic), and the trailing digit separates variants within that family. Confirm the group from the grade actually certified: an offered 1.4404 flange is group 13E0, not 14E0, even though both are molybdenum-bearing austenitic steels.
Two caveats matter for procurement. Table 9 is a selection for flange manufacture, not a list of every acceptable steel; Annex D adds materials, including ASME grades, that are widely used but not listed in EN standards, and those carry no presumption of conformity under the Pressure Equipment Directive. And a p/T rating quoted for a group is valid only for materials that genuinely belong to it — the certificate or material test report is the evidence.
- Groups
- 1E0 to 16E0
- Group definitions
- Annex B (informative)
- Material selection
- Table 9 (pp. 38–43)
- Additional materials
- Annex D (pp. 101–102)
- p/T ratings
- Annex G (selected groups)
Non-austenitic groups 1E0 to 9E1
The carbon, low-alloy, low-temperature, fine-grain and high-temperature ferritic groups as defined in Annex B, with representative EN grades from Table 9.
EN 1092-1 · EN 1092-1:2018
| Group | What the group covers (Annex B) | Typical EN grades (material number) | Notes |
|---|---|---|---|
| 1E0 | Unalloyed structural steels without guaranteed elevated-temperature properties; application range −10 °C to +100 °C. | GS-38 casting (1.0432, DIN 1681); VdTÜV C 21/1.0432 | Annex D additional material; no Annex G p/T table. |
| 1E1 | Unalloyed structural steels with elevated-temperature properties. | S235JR (1.0038) to EN 10025-2 | Annex D additional material; no Annex G p/T table. |
| 3E0 | Unalloyed steels with guaranteed elevated-temperature properties. | P250GH (1.0460) and P245GH (1.0352), EN 10222-2 forgings; P235GH (1.0345) and P265GH (1.0425), EN 10028-2 flats; GP240GH (1.0619) and GP280GH (1.0625), EN 10213 castings | p/T: Tables G.2–G.13 (calculated for P245GH). Default group for EN 1092-1 carbon-steel flanges. |
| 3E1 | Unalloyed steels with specified properties up to 400 °C and upper yield strength above 265 N/mm². | P280GH (1.0426), EN 10222-2; P295GH (1.0481), EN 10028-2 | p/T: Tables G.2–G.13 (P280GH). |
| 4E0 | Low-alloyed steels with 0,3 % molybdenum. | 16Mo3 (1.5415), EN 10222-2 / EN 10028-2; G20Mo5 (1.5419), EN 10213 | p/T: Tables G.2–G.13 (16Mo3). |
| 5E0 | Low-alloyed steels with 1 % chromium and 0,5 % molybdenum. | 13CrMo4-5 (1.7335), EN 10222-2 / EN 10028-2; G17CrMo5-5 (1.7357), EN 10213 | p/T: Tables G.2–G.13 (13CrMo4-5). |
| 6E0 | Low-alloyed steels with 2 % chromium and 1 % molybdenum. | 11CrMo9-10 (1.7383), EN 10222-2; 10CrMo9-10 (1.7380) and 12CrMo9-10 (1.7375), EN 10028-2; G17CrMo9-10 (1.7379), EN 10213 | p/T: Tables G.2–G.13 (11CrMo9-10). |
| 6E1 | Alloy steel with 5 % chromium and 0,5 % molybdenum. | X16CrMo5-1+NT (1.7366), EN 10222-2; GX15CrMo5 (1.7365), EN 10213 | p/T: Tables G.2–G.13 (X16CrMo5-1+NT). |
| 7E0 | Low-temperature-tough fine-grain steel with minimum yield strength 275 N/mm² at room temperature. | P275NL1 (1.0488) and P275NL2 (1.1104), EN 10028-3 flats; G17Mn5 (1.1131) and G20Mn5 (1.6220), EN 10213 castings | No separate Annex G p/T table. |
| 7E1 | Low-temperature-tough fine-grain steel with minimum yield strength 355 N/mm² at room temperature. | P355NL1 (1.0566) and P355NL2 (1.1106), EN 10028-3 | No separate Annex G p/T table. |
| 7E2 | Low-temperature nickel-alloyed steel with nickel ≤ 3 %. | 15NiMn6 (1.6228), EN 10222-3; 11MnNi5-3 (1.6212) and 13MnNi6-3 (1.6217), EN 10028-4; G9Ni10 (1.5636), EN 10213 | No separate Annex G p/T table. |
| 7E3 | Low-temperature nickel-alloyed steel with nickel > 3 %. | 12Ni14 (1.5637), X12Ni5 (1.5680), X8Ni9 (1.5662), EN 10222-3 / EN 10028-4; G9Ni14 (1.5638), EN 10213 | No separate Annex G p/T table. |
| 8E0 | Fine-grain steel with minimum yield strength 225 N/mm² at room temperature. | No grade listed in Table 9 for this group | Defined in Annex B; no grade or p/T table in the 2018 edition. |
| 8E2 | Fine-grain steel with minimum yield strength 285 N/mm² at room temperature. | P285NH (1.0477) and P285QH (1.0478), EN 10222-4; P275NH (1.0487), EN 10028-3 / EN 10273 | p/T: Tables G.2–G.13 (P285NH). |
| 8E3 | Fine-grain steel with minimum yield strength 355 N/mm² at room temperature. | P355NH (1.0565) and P355QH1 (1.0571), EN 10222-4; P355N (1.0562) and P355NH (1.0565), EN 10028-3; P355QH (1.8867), EN 10273 | p/T: Tables G.2–G.13 (P355NH). |
| 9E0 | High-temperature-tough ferritic steel with 12 % chromium, 1 % molybdenum and 0,5 % vanadium. | X20CrMoV11-1 (1.4922), EN 10222-2; GX23CrMoV12-1 (1.4931), EN 10213 | p/T: Tables G.2–G.13 (X20CrMoV11-1). |
| 9E1 | High-temperature-tough ferritic steel with 9 % chromium, 1 % molybdenum, 0,25 % vanadium and 0,1 % niobium. | X10CrMoVNb9-1 (1.4903), EN 10222-2 / EN 10028-2 | p/T: Tables G.2–G.13 (X10CrMoVNb9-1). |
Descriptions paraphrase informative Annex B. Grade and material-number examples are taken from Table 9 (forgings, flat products, castings and bars) and, for 1E0/1E1, from informative Annex D. One grade is enough to place a flange in a group; always confirm the group from the material certificate.
Austenitic and austenitic-ferritic groups 10E0 to 16E0
Annex B notes that groups 10E0 to 12E0 are not alloyed with molybdenum, while 13E0 to 15E0 are; 16E0 is the austenitic-ferritic (duplex) family.
EN 1092-1 · EN 1092-1:2018
| Group | What the group covers (Annex B) | Typical EN grades (material number) | Notes |
|---|---|---|---|
| 10E0 | LC-steel (low-carbon austenitic). | X2CrNi18-9 (1.4307), EN 10222-5 forgings; X2CrNi19-11 (1.4306) flat; GX2CrNi19-11 (1.4309), EN 10213 | p/T: Tables G.15–G.26 (1.4307). |
| 10E1 | LC-steel, nitrogen-alloyed. | X2CrNi18-10 (1.4311), EN 10222-5 | p/T: Tables G.15–G.26 (1.4311). |
| 11E0 | Austenitic, standard carbon content. | X5CrNi18-10 (1.4301) and X6CrNi18-10 (1.4948), EN 10222-5; GX5CrNi19-10 (1.4308), EN 10213 | p/T: Tables G.15–G.26 (1.4301, 1.4948). |
| 12E0 | Austenitic, standard carbon content, stabilised with Ti or Nb. | X6CrNiTi18-10 (1.4541), X6CrNiNb18-10 (1.4550) and X6CrNiTiB18-10 (1.4941), EN 10222-5; GX5CrNiNb19-11 (1.4552), EN 10213 | p/T: Tables G.15–G.26 (1.4541, 1.4550, 1.4941). |
| 13E0 | LC-steel with molybdenum. | X2CrNiMo17-12-2 (1.4404), X2CrNiMo17-12-3 (1.4432) and X2CrNiMo18-14-3 (1.4435), EN 10222-5; GX2CrNiMo19-11-2 (1.4409), EN 10213 | p/T: Tables G.15–G.26 (1.4404). |
| 13E1 | LC-steel with molybdenum, nitrogen-alloyed. | X2CrNiMoN17-13-3 (1.4429), X2CrNiMoN17-13-5 (1.4439) and X2CrNiMoN17-11-2 (1.4406) | No separate Annex G p/T table in this edition. |
| 14E0 | Austenitic, standard carbon content, alloyed with molybdenum. | X5CrNiMo17-12-2 (1.4401) and X3CrNiMo17-13-3 (1.4436); GX5CrNiMo19-11-2 (1.4408), EN 10213 | p/T: Tables G.15–G.26 (1.4401). |
| 15E0 | Austenitic, standard carbon content, alloyed with molybdenum, stabilised with Ti or Nb. | X6CrNiMoTi17-12-2 (1.4571) and X6CrNiMoNb17-12-2 (1.4580); GX5CrNiMoNb19-11-2 (1.4581), EN 10213 | p/T: Tables G.15–G.26 (1.4571). |
| 16E0 | Austenitic-ferritic (duplex) steel. | X2CrNiMoN22-5-3 (1.4462), X2CrNiMoN25-7-4 (1.4410) and X2CrNiN23-4 (1.4362), EN 10222-5; GX2CrNiMoN25-6-3-3 (1.4517), EN 10213 | p/T: Tables G.15–G.26 (1.4462). |
Descriptions paraphrase informative Annex B. Grades come from Table 9; the material number in brackets in the Notes column is the one used in the Annex G p/T tables (Table G.14, p. 125).
Which groups have pressure–temperature ratings?
Not every group in Annex B appears in the Annex G rating tables. The coverage is:
- Non-austenitic: 3E0, 3E1, 4E0, 5E0, 6E0, 6E1, 8E2, 8E3, 9E0 and 9E1, in Tables G.2 to G.13.
- Austenitic: the eleven materials listed in Table G.14 — 1.4307, 1.4311, 1.4301, 1.4541, 1.4550, 1.4404, 1.4401, 1.4571, 1.4462, 1.4948 and 1.4941 — in Tables G.15 to G.26.
- 1E0 and 1E1 appear only as additional materials in Annex D and have no Annex G p/T table.
- The 7E0 to 7E3 low-temperature groups are defined in Annex B but are not assigned separate p/T tables.
- 8E0 is defined in Annex B, but Table 9 lists no grade for it in the 2018 edition.
EN 1092-1 material groups — questions
Which material group is P250GH?
P250GH (1.0460, EN 10222-2) is group 3E0, the unalloyed steel group with guaranteed elevated-temperature properties. P245GH (1.0352) is also 3E0; P280GH (1.0426) is group 3E1.
Which group is 1.4301?
1.4301 (X5CrNi18-10) is group 11E0 — austenitic steel with standard carbon content and no molybdenum. The low-carbon variant 1.4307 (X2CrNi18-9) is group 10E0.
Which group is 1.4404?
1.4404 (X2CrNiMo17-12-2) is group 13E0 — low-carbon austenitic steel with molybdenum. The standard-carbon 1.4401 (X5CrNiMo17-12-2) is group 14E0.
Can I substitute one grade for another in the same group?
The grouping exists so that materials with similar properties can be treated equivalently for pressure, temperature and fluid service, and a group-level p/T rating is intended to cover its members. It does not make grades interchangeable in every detail — corrosion resistance, impact toughness and elevated-temperature strength can still differ. The material certificate and the project specification decide.