--- title: "OLC25X — Quenched and tempered steels" description: "OLC25X in STAS: material number 1.0406, also listed as C25. Category: Quenched and tempered steels. Designations recorded for this grade: 58." canonical: https://steelequivalents.com/materials/stas/olc25x language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/stas/olc25x.md cs: https://steelequivalents.com/cs/materiály/stas/olc25x.md de: https://steelequivalents.com/de/werkstoffe/stas/olc25x.md es: https://steelequivalents.com/es/materiales/stas/olc25x.md fr: https://steelequivalents.com/fr/matériaux/stas/olc25x.md hu: https://steelequivalents.com/hu/anyagok/stas/olc25x.md it: https://steelequivalents.com/it/materiali/stas/olc25x.md nl: https://steelequivalents.com/nl/materialen/stas/olc25x.md pl: https://steelequivalents.com/pl/materiały/stas/olc25x.md pt: https://steelequivalents.com/pt/materiais/stas/olc25x.md ru: https://steelequivalents.com/ru/материалы/stas/olc25x.md tr: https://steelequivalents.com/tr/malzemeler/stas/olc25x.md zh: https://steelequivalents.com/zh/材料/stas/olc25x.md ja: https://steelequivalents.com/ja/材料/stas/olc25x.md ar: https://steelequivalents.com/ar/المواد/stas/olc25x.md ko: https://steelequivalents.com/ko/재료/stas/olc25x.md pt-br: https://steelequivalents.com/pt-br/materiais/stas/olc25x.md hi: https://steelequivalents.com/hi/सामग्री/stas/olc25x.md content_hash: sha256:aaff760c32351acdde112e8781b8b626bcfbe991de50855c67bb0b645e2fb799 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/stas/olc25x > Canonical URL: https://steelequivalents.com/materials/stas/olc25x > 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. STAS · Romania · 58 designations # OLC25X OLC25X is a designation in STAS for the material held under material number 1.0406, also listed as C25. It is a material in the category Quenched and tempered steels. We list 58 designations recorded for this grade, in the standards DIN / EN, UNS, AISI / SAE, BS, AFNOR, UNE, ISO, JIS, GB, GOST, UNI, SS, ČSN, COPANT, STN, PN, MSZ, STAS, BDS, NBN and KS. - [*Material no.* **1.0406**](/materials/material-no/1.0406 "Material no.: 1.0406") - [*Category* **Quenched and tempered steels · 133 grades**](/categories/quenched-and-tempered-steels "Category: Quenched and tempered steels · 133 grades") - *Designations* **58** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=855f3519-a7c8-4358-a987-627e92bfa890&designation=f0bc5fc3-0f6f-47ac-b36e-75b636719c7f "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/stas/olc25x.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN C25 This grade’s own name](/materials/din-en/c25 "DIN / EN C25") - [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 58 designations · 21 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 - [C25 This grade’s own name](/materials/din-en/c25 "DIN / EN C25") UNS United States · 1 - [G10250 This grade’s own name](/materials/uns/g10250 "UNS G10250") AISI / SAE United States · 4 - [1025 This grade’s own name](/materials/aisi-sae/1025 "AISI / SAE 1025") - [1026 Indicative](/materials/aisi-sae/1026 "AISI / SAE 1026") - [G10250 Indicative](/materials/uns/g10250 "AISI / SAE G10250") - [M1025 This grade’s own name](/materials/aisi-sae/m1025 "AISI / SAE M1025") BS United Kingdom · 5 - [070M26 Indicative](/materials/bs/070m26 "BS 070M26") - [1C25 Indicative](/materials/bs/1c25 "BS 1C25") - [C25 Indicative](/materials/din-en/c25 "BS C25") - [C25 C25E C25R Indicative](/materials/bs/c25-c25e-c25r "BS C25 C25E C25R") - [C25E Indicative](/materials/din-en/c25e "BS C25E") AFNOR France · 6 - [2C25 Indicative](/materials/afnor/2c25 "AFNOR 2C25") - [AF50C30 Indicative](/materials/afnor/af50c30 "AFNOR AF50C30") - [C25 Indicative](/materials/din-en/c25 "AFNOR C25") - [C25E Indicative](/materials/din-en/c25e "AFNOR C25E") - [FR28 Indicative](/materials/afnor/fr28 "AFNOR FR28") - [XC25 Indicative](/materials/afnor/xc25 "AFNOR XC25") UNE Spain · 4 - [C25E Indicative](/materials/din-en/c25e "UNE C25E") - [C25k Indicative](/materials/une/c25k "UNE C25k") - [F.1120 Indicative](/materials/une/f-1120 "UNE F.1120") - [F.221 Indicative](/materials/une/f-221 "UNE F.221") ISO International · 2 - [C25 Indicative](/materials/din-en/c25 "ISO C25") - [C25 C25E4 C25M2 Indicative](/materials/iso/c25-c25e4-c25m2 "ISO C25 C25E4 C25M2") JIS Japan · 3 - [S25C Indicative](/materials/jis/s25c "JIS S25C") - [S28C Indicative](/materials/jis/s28c "JIS S28C") - [SWRCH25K Indicative](/materials/jis/swrch25k "JIS SWRCH25K") GB China · 3 - [25 Indicative](/materials/gost/25 "GB 25") - [25Z Indicative](/materials/gb/25z "GB 25Z") - [ML25 Indicative](/materials/gb/ml25 "GB ML25") GOST Russia / CIS · 9 - [25 Indicative](/materials/gost/25 "GOST 25") - [25GS Indicative](/materials/gost/25gs "GOST 25GS") - [25GSL Indicative](/materials/gost/25gsl "GOST 25GSL") - [25KhGL Indicative](/materials/gost/25khgl "GOST 25KhGL") - [25KHGNMT Indicative](/materials/gost/25khgnmt "GOST 25KHGNMT") - [25KHGSА Indicative](/materials/gost/25khgsa "GOST 25KHGSА") - [25KHGT Indicative](/materials/gost/25khgt "GOST 25KHGT") - [25ps Indicative](/materials/gost/25ps "GOST 25ps") - [R2M5 Indicative](/materials/gost/r2m5 "GOST R2M5") UNI Italy · 5 - [C22E Indicative](/materials/din-en/c22e "UNI C22E") - [C22R Indicative](/materials/din-en/c22r "UNI C22R") - [C25 Indicative](/materials/din-en/c25 "UNI C25") - [C25E Indicative](/materials/din-en/c25e "UNI C25E") - [C25R Indicative](/materials/din-en/c25r "UNI C25R") SS Sweden · 1 - [1450 Indicative](/materials/ss/1450 "SS 1450") ČSN Czechia · 1 - [12030 Indicative](/materials/csn/12030 "ČSN 12030") COPANT Latin America · 1 - [1025 Indicative](/materials/aisi-sae/1025 "COPANT 1025") STN Slovakia · 1 - [12 030 Indicative](/materials/csn/12030 "STN 12 030") PN Poland · 2 - [20G Indicative](/materials/gb/20g "PN 20G") - [25 Indicative](/materials/gost/25 "PN 25") MSZ Hungary · 1 - [C25E Indicative](/materials/din-en/c25e "MSZ C25E") STAS Romania · 3 - [OLC25 Indicative](/materials/stas/olc25 "STAS OLC25") - [OLC25q Indicative](/materials/stas/olc25q "STAS OLC25q") - **OLC25X Indicative** BDS Bulgaria · 2 - [25 Indicative](/materials/gost/25 "BDS 25") - [C25E Indicative](/materials/din-en/c25e "BDS C25E") NBN Belgium · 1 - [C25-2 Indicative](/materials/nbn/c25-2 "NBN C25-2") KS South Korea · 2 - [SM25C Indicative](/materials/ks/sm25c "KS SM25C") - [SM28C Indicative](/materials/ks/sm28c "KS SM28C") 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 | 0.045 | | S | 0.045 | | 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 | 0,045 | 0.045 | 0.045 | Exact | | S | 0,045 | 0.045 | 0.045 | 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 | - (Cr+Mo+Ni)≤0,63 - (Cr+Mo+Ni)≤0,63 - (Cr+Mo+Ni)≤0,63 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 Transformation point Ac1 735 °C Exact Transformation point Ac3 835 °C Exact · Ac3(Acm) Transformation point Ar3 825 °C Exact · Ar3(Arcm) Transformation point Ar1 680 °C Exact Weldability readily weldable As published: without limitations. 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 · 62 values By delivery state**no delivery state stated** source `splav` | Delivery state | Rm N/mm² | A5% | Z% | HB | |---|---|---|---|---| | Rolled stock cold-worked , GOST 1050-88 | 540 | 7 | 40 | — | | Rolled stock annealed , GOST 1050-88 | 410 | 19 | 50 | — | | Band annealed , GOST 2284-79 | 340 – 590 | 18 | — | — | | Band cold-worked , GOST 2284-79 | 540 – 880 | — | — | — | | Sheet GOST 4041-71 | — | — | — | 138 | | Bar GOST 10702-78 | — | — | — | 156 | | Rolled stock GOST 1050-88 | — | — | — | 217 | | Sheet trick GOST 1577-93 | — | — | — | 170 | 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 | By dimension**no delivery state stated** source `splav` | Dimension mm | Rm N/mm² | A5% | |---|---|---| | 4 - 14 | 390 – 540 | 26 | By heat-treated condition**no delivery state stated** source `splav` | Heat-treated condition | Rm N/mm² | Z% | |---|---|---| | Bar cold-drawn , GOST 10702-78 | 540 | 50 | By dimension**Normalizing** source `splav` | Dimension mm | Rm N/mm² | Re N/mm² | A5% | Z% | |---|---|---|---|---| | to 80 | 450 | 275 | 23 | 50 | 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 | 7.82 | 198 | — | — | — | 169 | | 100 | — | 196 | 12.2 | 51 | 470 | 219 | | 200 | — | 191 | 13 | 49 | 483 | 292 | | 300 | — | 186 | 13.7 | 46 | — | 381 | | 400 | — | 163 | 14.3 | 43 | 521 | 488 | | 500 | — | — | 14.7 | 40 | 571 | 601 | | 600 | — | — | 15 | 36 | — | 758 | | 700 | — | — | 15.2 | 32 | — | 925 | | 800 | — | — | — | 26 | — | — | 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 1.0, 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. [1.0402 1.0402 Mn 0,40-0,70 · Si ≤0,40 - ΔMn 0.00 - ΔSi 0.00 - 94 designations](/materials/material-no/1.0402 "1.0402")[C26D 1.0415 Mn 0,50-0,80 · Si 0,10-0,30 - ΔMn 0.10 - ΔSi 0.00 - 8 designations](/materials/din-en/c26d "C26D")[1.0501 1.0501 Mn 0,50-0,80 · Si ≤0,40 - ΔMn 0.10 - ΔSi 0.00 - 123 designations](/materials/material-no/1.0501 "1.0501")[C35GPb 1.0502 Mn 0,50-0,80 · Si ≤0,40 - ΔMn 0.10 - ΔSi 0.00 - 2 designations](/materials/din-en/c35gpb "C35GPb")[1.0503 1.0503 Mn 0,50-0,80 · Si ≤0,40 - ΔMn 0.10 - ΔSi 0.00 - 93 designations](/materials/material-no/1.0503 "1.0503")[1.0511 1.0511 Mn 0,50-0,80 · Si ≤0,40 - ΔMn 0.10 - ΔSi 0.00 - 63 designations](/materials/material-no/1.0511 "1.0511") ## 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=855f3519-a7c8-4358-a987-627e92bfa890&designation=f0bc5fc3-0f6f-47ac-b36e-75b636719c7f "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/stas/olc25x.pdf "Datasheet as PDF")