--- title: "X40CrSiMo10-02 — Valve steels" description: "X40CrSiMo10-02 in UNE: material number 1.4731, also listed as X40CrSiMo10-2. Category: Valve steels. Designations recorded for this grade: 26." canonical: https://steelequivalents.com/materials/une/x40crsimo10-02 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/une/x40crsimo10-02.md cs: https://steelequivalents.com/cs/materiály/une/x40crsimo10-02.md de: https://steelequivalents.com/de/werkstoffe/une/x40crsimo10-02.md es: https://steelequivalents.com/es/materiales/une/x40crsimo10-02.md fr: https://steelequivalents.com/fr/matériaux/une/x40crsimo10-02.md hu: https://steelequivalents.com/hu/anyagok/une/x40crsimo10-02.md it: https://steelequivalents.com/it/materiali/une/x40crsimo10-02.md nl: https://steelequivalents.com/nl/materialen/une/x40crsimo10-02.md pl: https://steelequivalents.com/pl/materiały/une/x40crsimo10-02.md pt: https://steelequivalents.com/pt/materiais/une/x40crsimo10-02.md ru: https://steelequivalents.com/ru/материалы/une/x40crsimo10-02.md tr: https://steelequivalents.com/tr/malzemeler/une/x40crsimo10-02.md zh: https://steelequivalents.com/zh/材料/une/x40crsimo10-02.md ja: https://steelequivalents.com/ja/材料/une/x40crsimo10-02.md ar: https://steelequivalents.com/ar/المواد/une/x40crsimo10-02.md ko: https://steelequivalents.com/ko/재료/une/x40crsimo10-02.md pt-br: https://steelequivalents.com/pt-br/materiais/une/x40crsimo10-02.md hi: https://steelequivalents.com/hi/सामग्री/une/x40crsimo10-02.md content_hash: sha256:5f82f5c39b07fb0fb014f41d1f0a0254c5c6e0b1ebe5a0f8c328ca7b783ebdff 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/une/x40crsimo10-02 > Canonical URL: https://steelequivalents.com/materials/une/x40crsimo10-02 > 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. UNE · Spain · 26 designations # X40CrSiMo10-02 X40CrSiMo10-02 is a designation in UNE for the material held under material number 1.4731, also listed as X40CrSiMo10-2. It is a material in the category Valve steels. We list 26 designations recorded for this grade, in the standards DIN / EN, AISI / SAE, BS, AFNOR, UNE, JIS, GB, GOST, UNI, PN, MSZ, BDS and KS. - [*Material no.* **1.4731**](/materials/material-no/1.4731 "Material no.: 1.4731") - [*Category* **Valve steels · 14 grades**](/categories/valve-steels "Category: Valve steels · 14 grades") - *Designations* **26** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=b17f1a00-bb09-482b-9a79-67d0697084c8&designation=4b86f436-1644-4c60-afee-1f3db7d5cfc0 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/une/x40crsimo10-02.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN X40CrSiMo10-2 This grade’s own name](/materials/din-en/x40crsimo10-2 "DIN / EN X40CrSiMo10-2") - [AISI / SAE SUH3 This grade’s own name](/materials/jis/suh3 "AISI / SAE SUH3") - [JIS SUH3 This grade’s own name · 2 grades on that route](/materials/jis/suh3 "JIS SUH3") ## About Valve steels Valve steels are alloy steels developed for valve components exposed to heat, pressure, wear, and corrosive service conditions. They are characterised by combinations of strength, hardness, toughness, and resistance to oxidation or corrosion suited to the operating environment. Typical uses include engine valves and industrial valve parts where reliable performance and dimensional stability are required. This describes the material class as a whole. Always confirm the individual grade against the standard before ordering. ## Also known as 26 designations · 13 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 - [X40CrSiMo10-2 This grade’s own name](/materials/din-en/x40crsimo10-2 "DIN / EN X40CrSiMo10-2") AISI / SAE United States · 1 - [SUH3 This grade’s own name](/materials/jis/suh3 "AISI / SAE SUH3") BS United Kingdom · 2 - [0/4 Indicative](/materials/bs/0-4 "BS 0/4") - [X40CrSiMo10-2 Indicative](/materials/din-en/x40crsimo10-2 "BS X40CrSiMo10-2") AFNOR France · 1 - [Z40CSD10 Indicative](/materials/afnor/z40csd10 "AFNOR Z40CSD10") UNE Spain · 4 - [10-02 Indicative](/materials/une/10-02 "UNE 10-02") - [F.3221 Indicative](/materials/une/f-3221 "UNE F.3221") - [F.3221-X40CrSiMo Indicative](/materials/une/f-3221-x40crsimo "UNE F.3221-X40CrSiMo") - **X40CrSiMo10-02 Indicative** JIS Japan · 1 - [SUH3 This grade’s own name](/materials/jis/suh3 "JIS SUH3") GB China · 3 - [1Cr18Mn8Ni5N Indicative](/materials/gb/1cr18mn8ni5n "GB 1Cr18Mn8Ni5N") - [4Cr10Si2Mo Indicative](/materials/gb/4cr10si2mo "GB 4Cr10Si2Mo") - [S48140 Indicative](/materials/gb/s48140 "GB S48140") GOST Russia / CIS · 7 - [40Ch10S2M Indicative](/materials/gost/40ch10s2m "GOST 40Ch10S2M") - [40H10S2M Indicative](/materials/gost/40h10s2m "GOST 40H10S2M") - [40KH10S2M Indicative](/materials/gost/40kh10s2m "GOST 40KH10S2M") - [40Х10С2М Indicative](/materials/gost/40kh10s2m "GOST 40Х10С2М") - [4Х10С2М Indicative](/materials/gost/4kh10s2m "GOST 4Х10С2М") - [ЭИ107 Indicative](/materials/gost/ei107 "GOST ЭИ107") - [ЭЛ 107 Indicative](/materials/gost/el-107 "GOST ЭЛ 107") UNI Italy · 1 - [VM12D Indicative](/materials/uni/vm12d "UNI VM12D") PN Poland · 1 - [H10S2M Indicative](/materials/pn/h10s2m "PN H10S2M") MSZ Hungary · 1 - [SZ4 Indicative](/materials/msz/sz4 "MSZ SZ4") BDS Bulgaria · 2 - [4Ch10S2M Indicative](/materials/bds/4ch10s2m "BDS 4Ch10S2M") - [X40CrSiMo10-2 Indicative](/materials/din-en/x40crsimo10-2 "BDS X40CrSiMo10-2") KS South Korea · 1 - [STR3 Indicative](/materials/ks/str3 "KS STR3") 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 Si Mo Iron — the balance, never listed by a standard — 84.2 % Cr — 10.5 % Si — 2.5 % Mo — 1.1 % Traces & impurities · 1.8 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.35–0.45 | | Si | 2–3 — Unusual | | Mn | ≤ 0.8 | | P | 0.04 | | S | 0.03 | | Cr | 9.5–11.5 | | Mo | 0.8–1.3 | | Ni | 0.5 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Molybdenum Nickel 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 | 0,35-0,45 | 0.350 | 0.450 | Range | | Si | 2,00-3,00 | 2.000 | 3.000 | Range | | P | 0,04 | 0.040 | 0.040 | Exact | | S | 0,03 | 0.030 | 0.030 | Exact | | Cr | 9,50-11,5 | 9.500 | 11.500 | Range | | Mn | ≤0,80 | — | 0.800 | Max | | Ni | 0,5 | 0.500 | 0.500 | Exact | | Mo | 0,80-1,30 | 0.800 | 1.300 | 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 This grade's composition falls outside the published model's validated range (a low-alloy composition window), so no transformation temperature is predicted here. ## Physical & mechanical properties Density 7,85 g/cm³ Exact Transformation point Ac1 810 °C Exact Transformation point Ac3 950 °C Exact · Ac3(Acm) Transformation point Ar3 845 °C Exact · Ar3(Arcm) Transformation point Ar1 700 °C Exact Weldability difficult to weld As published: hard weldability. Flake sensitivity not susceptible As published: not predisposed Temper brittleness not susceptible As published: not predisposed 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 6 conditions · 49 values By delivery state**no delivery state stated** source `steeljis` | Delivery state | Rm N/mm² | Re N/mm² | A% | Z% | aK J/cm² | HB | |---|---|---|---|---|---|---| | Bars/Rods Quenching and tempering | 880 – 930 | 635 – 685 | 15 | 35 | 20 | — | | Quenched and tempered | — | — | — | — | — | 262 – 269 | By delivery state**Quenched and tempered** source `steelnumber` | Delivery state | HB | |---|---| | Quenched and tempered | 266 – 325 | By delivery state**Soft annealed** source `steelnumber` | Delivery state | HB | |---|---| | Soft annealed | 300 | By dimension**Quenching 1010 - 1050°C, air, Drawing 720 - 780°C, oil** source `splav` | Dimension mm | Rm N/mm² | Re N/mm² | A5% | Z% | KCU kJ/m² | |---|---|---|---|---|---| | Ø 60 | 930 | 735 | 10 | 35 | 200 | By delivery state**no delivery state stated** source `splav` | Delivery state | HB | |---|---| | 40KH10S2M ( 40Х10С2М ) (annealing) , Bar GOST 5949-75 | 197 – 269 | At temperature**no delivery state stated** source `splav` | Temperature °C | Density g/cm³ | Elastic modulus GPa | Thermal expansion coefficient 10^-6/K | Thermal conductivity W/(m·K) | Specific heat capacity J/(kg·K) | Electrical resistivity nΩ·m | |---|---|---|---|---|---|---| | 20 | 7.62 | 214 | — | 17 | — | — | | 100 | 7.61 | 211 | 10 | 18 | — | 906 | | 200 | — | 205 | 11 | 20 | — | 958 | | 300 | — | 202 | 11 | 22 | — | 1010 | | 400 | — | 196 | 11 | 22 | 532 | 1062 | | 500 | — | 187 | — | 24 | 561 | 1114 | | 600 | — | 172 | — | 25 | 586 | 1166 | | 700 | — | 151 | — | 26 | — | 1216 | | 800 | 7.43 | 129 | 11 | — | — | — | 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 / Si 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. [1.4718 1.4718 Cr 8,00-10,0 · Si 2,70-3,30 - ΔCr 1.50 - ΔSi 0.50 - 42 designations](/materials/material-no/1.4718 "1.4718") ## 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. 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