--- title: "Ck 25 — Quenched and tempered steels" description: "Ck 25 in DIN / EN: material number 1.1158, also listed as C25E. Category: Quenched and tempered steels. Designations recorded for this grade: 19." canonical: https://steelequivalents.com/materials/din-en/ck-25 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/din-en/ck-25.md cs: https://steelequivalents.com/cs/materiály/din-en/ck-25.md de: https://steelequivalents.com/de/werkstoffe/din-en/ck-25.md es: https://steelequivalents.com/es/materiales/din-en/ck-25.md fr: https://steelequivalents.com/fr/matériaux/din-en/ck-25.md hu: https://steelequivalents.com/hu/anyagok/din-en/ck-25.md it: https://steelequivalents.com/it/materiali/din-en/ck-25.md nl: https://steelequivalents.com/nl/materialen/din-en/ck-25.md pl: https://steelequivalents.com/pl/materiały/din-en/ck-25.md pt: https://steelequivalents.com/pt/materiais/din-en/ck-25.md ru: https://steelequivalents.com/ru/материалы/din-en/ck-25.md tr: https://steelequivalents.com/tr/malzemeler/din-en/ck-25.md zh: https://steelequivalents.com/zh/材料/din-en/ck-25.md ja: https://steelequivalents.com/ja/材料/din-en/ck-25.md ar: https://steelequivalents.com/ar/المواد/din-en/ck-25.md ko: https://steelequivalents.com/ko/재료/din-en/ck-25.md pt-br: https://steelequivalents.com/pt-br/materiais/din-en/ck-25.md hi: https://steelequivalents.com/hi/सामग्री/din-en/ck-25.md content_hash: sha256:2243cc2c75a03845cc7913ec31182ec289e22957a13efd9f76d10e17952cc2a5 generated: 2026-09-22 --- > **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/din-en/ck-25 > Canonical URL: https://steelequivalents.com/materials/din-en/ck-25 > 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. DIN / EN · Europe · 19 designations # Ck 25 Ck 25 is a designation in DIN / EN for the material held under material number 1.1158, also listed as C25E. It is a material in the category Quenched and tempered steels. We list 19 designations recorded for this grade, in the standards DIN / EN, UNS, AISI / SAE, BS, AFNOR, UNE, ISO, JIS, GB, GOST, ČSN, STN and AS / NZS. - [*Material no.* **1.1158**](/materials/material-no/1.1158 "Material no.: 1.1158") - [*Category* **Quenched and tempered steels · 133 grades**](/categories/quenched-and-tempered-steels "Category: Quenched and tempered steels · 133 grades") - *Designations* **19** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=2d3a8a59-638f-4c99-aeba-cf8b6da241c7&designation=e132bd36-5726-4af2-a5ba-e90f7dd31b69 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/din-en/ck-25.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN C25E This grade’s own name](/materials/din-en/c25e "DIN / EN C25E") - [UNS G10250 This grade’s own name · 6 grades on that route](/materials/uns/g10250 "UNS G10250") - [AISI / SAE 1025 This grade’s own name · 6 grades on that route](/materials/aisi-sae/1025 "AISI / SAE 1025") ## About Quenched and tempered steels Quenched and tempered steels are heat-treated steels designed to combine high strength with useful toughness and ductility. They are used for heavily loaded components such as shafts, gears, fasteners and structural machine parts where resistance to mechanical stress is required. This describes the material class as a whole. Always confirm the individual grade against the standard before ordering. ## Also known as 19 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 · 3 - [1.1158 Indicative](/materials/material-no/1.1158 "DIN / EN 1.1158") - [C25E This grade’s own name](/materials/din-en/c25e "DIN / EN C25E") - **Ck 25 This grade’s own name Withdrawn** UNS United States · 1 - [G10250 This grade’s own name](/materials/uns/g10250 "UNS G10250") AISI / SAE United States · 1 - [1025 This grade’s own name](/materials/aisi-sae/1025 "AISI / SAE 1025") BS United Kingdom · 2 - [070M26 Indicative](/materials/bs/070m26 "BS 070M26") - [C25 C25E C25R Indicative](/materials/bs/c25-c25e-c25r "BS C25 C25E C25R") AFNOR France · 2 - [C25E Indicative](/materials/din-en/c25e "AFNOR C25E") - [XC25 Indicative](/materials/afnor/xc25 "AFNOR XC25") UNE Spain · 2 - [F.1120 Indicative](/materials/une/f-1120 "UNE F.1120") - [F.1120-C 25 k Indicative](/materials/une/f-1120-c25k "UNE F.1120-C 25 k") ISO International · 2 - [C25 C25E4 C25M2 Indicative](/materials/iso/c25-c25e4-c25m2 "ISO C25 C25E4 C25M2") - [C25E4 Indicative](/materials/iso/c25e4 "ISO C25E4") JIS Japan · 1 - [S25C Indicative](/materials/jis/s25c "JIS S25C") GB China · 1 - [25 Indicative](/materials/gost/25 "GB 25") GOST Russia / CIS · 1 - [25 Indicative](/materials/gost/25 "GOST 25") ČSN Czechia · 1 - [12030 Indicative](/materials/csn/12030 "ČSN 12030") STN Slovakia · 1 - [12 030 Indicative](/materials/csn/12030 "STN 12 030") AS / NZS Australia / New Zealand · 1 - [1025 Indicative](/materials/aisi-sae/1025 "AS / NZS 1025") 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 Mn Si Cr Iron — the balance, never listed by a standard — 97.8 % Mn — 0.6 % Si — 0.4 % Cr — 0.4 % Traces & impurities · 0.8 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.22–0.29 | | Si | ≤ 0.4 | | Mn | 0.4–0.7 | | P | 0.035 | | S | 0.035 | | Cr | ≤ 0.4 | | Mo | ≤ 0.1 | | Ni | ≤ 0.4 | 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 | 0,22-0,29 | 0.220 | 0.290 | Range | | Si | ≤0,40 | — | 0.400 | Max | | P | 0,035 | 0.035 | 0.035 | Exact | | S | 0,035 | 0.035 | 0.035 | Exact | | Cr | ≤0,40 | — | 0.400 | Max | | Mn | 0,40-0,70 | 0.400 | 0.700 | Range | | Ni | ≤0,40 | — | 0.400 | Max | | Mo | ≤0,10 | — | 0.100 | Max | 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 computed from composition · °C Predicted Ae3 803 °C Predicted Ae1 725 °C Predicted Acm 503 °C Predicted Bs 572 °C These four temperatures are a CALCULATION from this grade's own composition, using the published Li, Niebuhr, Meekisho & Atteridge (1998) model — never a measurement, and computed from the UPPER BOUND of each element's specified range, not a mid-range figure. Where this grade also has a measured transformation point (Ac1, Ac3, Ar1, Ar3) on file, it is shown separately, in Physical & mechanical properties, and is never replaced by the predicted figures here — Ae (predicted, equilibrium) and Ac/Ar (measured, on heating or cooling) are different physical quantities and can differ by tens of degrees; a mismatch between the two is not an error in either. ## 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 1 conditions · 8 values By thickness**Normalized** source `steelnumber` | Thickness mm | Rm N/mm² | A% | |---|---|---| | ≤ 100 | 440 | 23 | | 100 – 250 | 420 | 23 | | 250 – 500 | 400 | 23 | | 500 – 1000 | 390 | 22 | 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 1.1, a shared category, and a published range for Mn / 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. [C22R 1.1149 Mn 0,40-0,70 · Si ≤0,40 - ΔMn 0.00 - ΔSi 0.00 - 11 designations](/materials/din-en/c22r "C22R")[C22E 1.1151 Mn 0,40-0,70 · Si ≤0,40 - ΔMn 0.00 - ΔSi 0.00 - 27 designations](/materials/din-en/c22e "C22E")[C25R 1.1163 Mn 0,40-0,70 · Si ≤0,40 - ΔMn 0.00 - ΔSi 0.00 - 8 designations](/materials/din-en/c25r "C25R")[C26D2 1.1139 Mn 0,50-0,70 · Si 0,10-0,30 - ΔMn 0.05 - ΔSi 0.00 - 7 designations](/materials/din-en/c26d2 "C26D2")[C32D2 1.1143 Mn 0,50-0,70 · Si 0,10-0,30 - ΔMn 0.05 - ΔSi 0.00 - 9 designations](/materials/din-en/c32d2 "C32D2")[C40D2 1.1153 Mn 0,50-0,70 · Si 0,10-0,30 - ΔMn 0.05 - ΔSi 0.00 - 10 designations](/materials/din-en/c40d2 "C40D2") ## 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=2d3a8a59-638f-4c99-aeba-cf8b6da241c7&designation=e132bd36-5726-4af2-a5ba-e90f7dd31b69 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/din-en/ck-25.pdf "Datasheet as PDF")