--- title: "1.4951 — Heat resistant steels" description: "1.4951 is the material number of the grade also listed as X6CrNi25-20. Category: Heat resistant steels. Designations recorded for this grade: 34." canonical: https://steelequivalents.com/materials/material-no/1.4951 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/material-no/1.4951.md cs: https://steelequivalents.com/cs/materiály/číslo-materiálu/1.4951.md de: https://steelequivalents.com/de/werkstoffe/werkstoff-nr/1.4951.md es: https://steelequivalents.com/es/materiales/número-de-material/1.4951.md fr: https://steelequivalents.com/fr/matériaux/numéro-de-matériau/1.4951.md hu: https://steelequivalents.com/hu/anyagok/anyagszám/1.4951.md it: https://steelequivalents.com/it/materiali/numero-materiale/1.4951.md nl: https://steelequivalents.com/nl/materialen/materiaalnummer/1.4951.md pl: https://steelequivalents.com/pl/materiały/numer-materiału/1.4951.md pt: https://steelequivalents.com/pt/materiais/número-do-material/1.4951.md ru: https://steelequivalents.com/ru/материалы/номер-материала/1.4951.md tr: https://steelequivalents.com/tr/malzemeler/malzeme-numarası/1.4951.md zh: https://steelequivalents.com/zh/材料/材料编号/1.4951.md ja: https://steelequivalents.com/ja/材料/材料番号/1.4951.md ar: https://steelequivalents.com/ar/المواد/رقم-المادة/1.4951.md ko: https://steelequivalents.com/ko/재료/재료번호/1.4951.md pt-br: https://steelequivalents.com/pt-br/materiais/número-do-material/1.4951.md hi: https://steelequivalents.com/hi/सामग्री/सामग्री-संख्या/1.4951.md content_hash: sha256:d6a33f10afbbd91f1dee9317cc7ee7d6a79481dd861ff674269940d0e39bc7a3 generated: 2026-09-24 --- > **Machine-readable Markdown rendering.** This is a Markdown representation of a web page, > served for AI agents and crawlers as a token-efficient alternative to the full HTML. > Full interactive HTML version: https://steelequivalents.com/materials/material-no/1.4951 > Canonical URL: https://steelequivalents.com/materials/material-no/1.4951 > Available languages: en, cs, de, es, fr, hu, it, nl, pl, pt, ru, tr, zh, ja, ar, ko, pt-br, hi > Change detection: `content_hash` is the SHA-256 of this document's Markdown body — everything > below this block, whitespace-trimmed, excluding the front-matter. Compare it to detect a real > content change; `generated` moves on every render and is not a change signal. Material number · Europe · 34 designations # 1.4951 1.4951 is the material number of the grade also listed as X6CrNi25-20. It is a material in the category Heat resistant steels. We list 34 designations recorded for this grade, in the standards DIN / EN, UNS, AISI / SAE, ASTM, BS, ISO, SAE AMS, JIS and GB. - ***Material no.* **1.4951**** - [*Category* **Heat resistant steels · 64 grades**](/categories/heat-resistant-steels "Category: Heat resistant steels · 64 grades") - *Designations* **34** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=af88b470-1930-4637-9805-a4079be30077 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/material-no/1.4951.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN X6CrNi25-20 This grade’s own name](/materials/din-en/x6crni25-20 "DIN / EN X6CrNi25-20") - [UNS S31009 This grade’s own name](/materials/uns/s31009 "UNS S31009") - [AISI / SAE 310H This grade’s own name · 2 grades on that route](/materials/aisi-sae/310h "AISI / SAE 310H") ## About Heat resistant steels Heat resistant steels are alloyed materials designed to retain useful mechanical properties and resist oxidation or scaling during service at elevated temperatures. They are used for components in furnaces, boilers, heat exchangers and power-generation equipment exposed to hot gases or sustained heat. This describes the material class as a whole. Always confirm the individual grade against the standard before ordering. ## Also known as 34 designations · 9 standards · nothing hidden This grade’s own name recorded in our sources as this grade’s own designation under that standard. Indicative taken from a published cross-reference table; a close match, not a guarantee of interchangeability. Verify against the mill certificate before ordering. Withdrawn designation no longer current — a separate column from the two above, so a name can be same grade and withdrawn at once. DIN / EN Europe · 1 - [X6CrNi25-20 This grade’s own name](/materials/din-en/x6crni25-20 "DIN / EN X6CrNi25-20") UNS United States · 2 - [S31008 Indicative](/materials/uns/s31008 "UNS S31008") - [S31009 This grade’s own name](/materials/uns/s31009 "UNS S31009") AISI / SAE United States · 3 - [30310S Indicative](/materials/aisi-sae/30310s "AISI / SAE 30310S") - [310H This grade’s own name](/materials/aisi-sae/310h "AISI / SAE 310H") - [310S Indicative](/materials/aisi-sae/310s "AISI / SAE 310S") ASTM United States · 19 - [A1012 Indicative](/materials/astm/a1012 "ASTM A1012") - [A213 Indicative](/materials/astm/a213 "ASTM A213") - [A240 Indicative](/materials/astm/a240 "ASTM A240") - [A249 Indicative](/materials/astm/a249 "ASTM A249") - [A264 Indicative](/materials/astm/a264 "ASTM A264") - [A276 Indicative](/materials/astm/a276 "ASTM A276") - [A312 Indicative](/materials/astm/a312 "ASTM A312") - [A314 Indicative](/materials/astm/a314 "ASTM A314") - [A358 Indicative](/materials/astm/a358 "ASTM A358") - [A409 Indicative](/materials/astm/a409 "ASTM A409") - [A473 Indicative](/materials/astm/a473 "ASTM A473") - [A479 Indicative](/materials/astm/a479 "ASTM A479") - [A511 Indicative](/materials/astm/a511 "ASTM A511") - [A554 Indicative](/materials/astm/a554 "ASTM A554") - [A580 Indicative](/materials/astm/a580 "ASTM A580") - [A813 Indicative](/materials/astm/a813 "ASTM A813") - [A814 Indicative](/materials/astm/a814 "ASTM A814") - [A924 Indicative](/materials/astm/a924 "ASTM A924") - [A943 Indicative](/materials/astm/a943 "ASTM A943") BS United Kingdom · 1 - [310S31 Indicative](/materials/bs/310s31 "BS 310S31") ISO International · 1 - [X6CrNi25-21 Indicative](/materials/uni/x6crni25-21 "ISO X6CrNi25-21") SAE AMS United States / Aerospace · 5 - [5521 Indicative](/materials/ams/5521 "SAE AMS 5521") - [5572 Indicative](/materials/ams/5572 "SAE AMS 5572") - [5577 Indicative](/materials/ams/5577 "SAE AMS 5577") - [5651 Indicative](/materials/ams/5651 "SAE AMS 5651") - [7490 Indicative](/materials/ams/7490 "SAE AMS 7490") JIS Japan · 1 - [SUS310S Indicative](/materials/jis/sus310s "JIS SUS310S") GB China · 1 - [0Cr25Ni20 Indicative](/materials/gb/0cr25ni20 "GB 0Cr25Ni20") Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here. ## Chemical composition 8 elements on file · weight % What this alloy is Fe Cr Ni Mn Iron — the balance, never listed by a standard — 51.6 % Cr — 25 % Ni — 20.5 % Mn — 2 % Traces & impurities · 0.9 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.04–0.08 | | Si | ≤ 0.7 | | Mn | ≤ 2 | | P | 0.035 | | S | 0.015 | | Cr | 24–26 | | Ni | 19–22 | | N | 0.1 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Nickel Nitrogen 0.01 % 0.1 % 1 % 10 % 100 % The scale is logarithmic, not the element’s raw share of the alloy — the only honest way to fit 0.01 % and 100 % in one picture, and it means every value here can be compared with every other. | Element | As published source text, verbatim | Min% by weight | Max% by weight | Bound | |---|---|---|---|---| | C | 0,04-0,08 | 0.040 | 0.080 | Range | | N | 0,1 | 0.100 | 0.100 | Exact | | Si | ≤0,70 | — | 0.700 | Max | | P | 0,035 | 0.035 | 0.035 | Exact | | S | 0,015 | 0.015 | 0.015 | Exact | | Cr | 24,0-26,0 | 24.000 | 26.000 | Range | | Mn | ≤2,00 | — | 2.000 | Max | | Ni | 19,0-22,0 | 19.000 | 22.000 | Range | The published column is the source string byte-for-byte, decimal comma and all; Min and Max are the parsed bounds. Elements not listed have no value on file — they are omitted, never inferred. ## Predicted transformation temperatures Not enough recorded composition to predict a transformation temperature for this grade — missing: Mo. ## Physical & mechanical properties Density 7,85 g/cm³ Exact An absent property means we hold no value for it — it is left out rather than estimated, interpolated from a neighbouring grade, or filled from a handbook. It does not mean the property is undefined for the material. ## Properties by condition 2 conditions · 7 values By delivery state**no delivery state stated** source `steeljis` | Delivery state | Rm N/mm² | Re N/mm² | A% | HB | HRB | HV | |---|---|---|---|---|---|---| | Plate/Sheet Hot-rolled | 520 | 205 | 40 | — | — | — | | Hot-rolled | — | — | — | 187 | 90 | 200 | By delivery state**Soft annealed** source `steelnumber` | Delivery state | HB | |---|---| | Soft annealed | 192 | Every figure holds only for the condition on its own row. Values are never merged across conditions or across sources, never averaged, and never interpolated between two rows. An em dash means no value on file — never zero. Figures are converted to the unit in the column header; the source’s own wording is kept and shown where the two differ. ## Similar grades — and why Selection rule, stated so you can disagree with it: same number class 1.4, a shared category, and a published range for Cr / Ni that overlaps this grade’s. These are neighbours in composition space — they are not equivalents, and none is claimed to be interchangeable with this grade. [X15CrNiSi25-21 1.4841 Cr 24,0-26,0 · Ni 19,0-22,0 - ΔCr 0.00 - ΔNi 0.00 - 60 designations](/materials/din-en/x15crnisi25-21 "X15CrNiSi25-21")[1.4845 1.4845 Cr 24,0-26,0 · Ni 19,0-22,0 - ΔCr 0.00 - ΔNi 0.00 - 91 designations](/materials/material-no/1.4845 "1.4845") ## Looking for this grade under another name? Search the catalogue by designation, material number or composition — every name on this page is itself a way in. [Search](/search "Steel grade search")[Inquiry](/inquiry?material=af88b470-1930-4637-9805-a4079be30077 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/material-no/1.4951.pdf "Datasheet as PDF")