--- title: "C30R — Quenched and tempered steels" description: "C30R: 11 equivalent designations across 9 standards, with the recorded chemical composition shown next to the source text." canonical: https://steelequivalents.com/materials/din-en/c30r language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/din-en/c30r.md cs: https://steelequivalents.com/cs/materiály/din-en/c30r.md de: https://steelequivalents.com/de/werkstoffe/din-en/c30r.md es: https://steelequivalents.com/es/materiales/din-en/c30r.md fr: https://steelequivalents.com/fr/matériaux/din-en/c30r.md hu: https://steelequivalents.com/hu/anyagok/din-en/c30r.md it: https://steelequivalents.com/it/materiali/din-en/c30r.md nl: https://steelequivalents.com/nl/materialen/din-en/c30r.md pl: https://steelequivalents.com/pl/materiały/din-en/c30r.md pt: https://steelequivalents.com/pt/materiais/din-en/c30r.md ru: https://steelequivalents.com/ru/материалы/din-en/c30r.md tr: https://steelequivalents.com/tr/malzemeler/din-en/c30r.md zh: https://steelequivalents.com/zh/材料/din-en/c30r.md ja: https://steelequivalents.com/ja/材料/din-en/c30r.md ar: https://steelequivalents.com/ar/المواد/din-en/c30r.md ko: https://steelequivalents.com/ko/재료/din-en/c30r.md pt-br: https://steelequivalents.com/pt-br/materiais/din-en/c30r.md hi: https://steelequivalents.com/hi/सामग्री/din-en/c30r.md content_hash: sha256:50feb4cc26c4ba2a4257268a64192b4ce1fa1b9479251ab2186d045ad4eeb789 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/c30r > Canonical URL: https://steelequivalents.com/materials/din-en/c30r > 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 · 11 designations # C30R Cm 30 is a material in the category [Quenched and tempered steels](/categories/quenched-and-tempered-steels "Quenched and tempered steels"), held under material number 1.1179. We list 10 designations recorded for this grade, in the standards DIN / EN, UNS, AISI / SAE, BS, AFNOR, ISO, JIS, GB and ČSN. Its recorded composition includes C 0.27–0.34%, Si ≤ 0.4%, Cr ≤ 0.4%, Mn 0.5–0.8% and Ni ≤ 0.4%. Its recorded density is 7.85 g/cm³. - [*Material no.* **1.1179**](/materials/material-no/1.1179 "Material no.: 1.1179") - [*Category* **Quenched and tempered steels · 133 grades**](/categories/quenched-and-tempered-steels "Category: Quenched and tempered steels · 133 grades") - *Designations* **11** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=4b10c96f-a983-4e46-9faf-8888faf13804&designation=27809c4f-99de-4267-8f81-4a1a1bbf3e51 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/din-en/c30r.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [UNS G10300 This grade’s own name · 6 grades on that route](/materials/uns/g10300 "UNS G10300") - [AISI / SAE 1030 This grade’s own name · 7 grades on that route](/materials/aisi-sae/1030 "AISI / SAE 1030") ## 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 11 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 · 2 - **C30R This grade’s own name Withdrawn** - [Cm 30 This grade’s own name Withdrawn](/materials/din-en/cm-30 "DIN / EN Cm 30") UNS United States · 1 - [G10300 This grade’s own name](/materials/uns/g10300 "UNS G10300") AISI / SAE United States · 1 - [1030 This grade’s own name](/materials/aisi-sae/1030 "AISI / SAE 1030") BS United Kingdom · 2 - [060A30 Indicative](/materials/bs/060a30 "BS 060A30") - [C30 C30E C30R Indicative](/materials/bs/c30-c30e-c30r "BS C30 C30E C30R") AFNOR France · 1 - [XC32 Indicative](/materials/afnor/xc32 "AFNOR XC32") ISO International · 1 - [C30 C30E4 C30M2 Indicative](/materials/iso/c30-c30e4-c30m2 "ISO C30 C30E4 C30M2") JIS Japan · 1 - [S30C Indicative](/materials/jis/s30c "JIS S30C") GB China · 1 - [30 Indicative](/materials/pn/30 "GB 30") ČSN Czechia · 1 - [12031 Indicative](/materials/csn/12031 "ČSN 12031") 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 — 97.7 % Mn — 0.7 % Si — 0.4 % Cr — 0.4 % Traces & impurities · 0.9 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.27–0.34 | | Si | ≤ 0.4 | | Mn | 0.5–0.8 | | P | 0.035 | | S | 0.02–0.04 | | 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 | 0,27-0,34 | 0.270 | 0.340 | Range | | Si | ≤0,40 | — | 0.400 | Max | | P | 0,035 | 0.035 | 0.035 | Exact | | S | 0,020-0,040 | 0.020 | 0.040 | Range | | Cr | ≤0,40 | — | 0.400 | Max | | Mn | 0,50-0,80 | 0.500 | 0.800 | 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 792 °C Predicted Ae1 724 °C Predicted Acm 539 °C Predicted Bs 566 °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. ## 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. [C30E 1.1178 Mn 0,50-0,80 · Si ≤0,40 - ΔMn 0.00 - ΔSi 0.00 - 19 designations](/materials/din-en/c30e "C30E")[C35 1.1180 Mn 0,50-0,80 · Si ≤0,40 - ΔMn 0.00 - ΔSi 0.00 - 17 designations](/materials/din-en/c35 "C35")[C35E 1.1181 Mn 0,50-0,80 · Si ≤0,40 - ΔMn 0.00 - ΔSi 0.00 - 36 designations](/materials/din-en/c35e "C35E")[C40E 1.1186 Mn 0,50-0,80 · Si ≤0,40 - ΔMn 0.00 - ΔSi 0.00 - 25 designations](/materials/din-en/c40e "C40E")[C40R 1.1189 Mn 0,50-0,80 · Si ≤0,40 - ΔMn 0.00 - ΔSi 0.00 - 14 designations](/materials/din-en/c40r "C40R")[1.1191 1.1191 Mn 0,50-0,80 · Si ≤0,40 - ΔMn 0.00 - ΔSi 0.00 - 39 designations](/materials/material-no/1.1191 "1.1191") ## 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=4b10c96f-a983-4e46-9faf-8888faf13804&designation=27809c4f-99de-4267-8f81-4a1a1bbf3e51 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/din-en/c30r.pdf "Datasheet as PDF")