--- title: "1.1203 — Quenched and tempered steels" description: "1.1203 is the material number of the grade also listed as C55E. Category: Quenched and tempered steels. Designations recorded for this grade: 32." canonical: https://steelequivalents.com/materials/material-no/1.1203 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/material-no/1.1203.md cs: https://steelequivalents.com/cs/materiály/číslo-materiálu/1.1203.md de: https://steelequivalents.com/de/werkstoffe/werkstoff-nr/1.1203.md es: https://steelequivalents.com/es/materiales/número-de-material/1.1203.md fr: https://steelequivalents.com/fr/matériaux/numéro-de-matériau/1.1203.md hu: https://steelequivalents.com/hu/anyagok/anyagszám/1.1203.md it: https://steelequivalents.com/it/materiali/numero-materiale/1.1203.md nl: https://steelequivalents.com/nl/materialen/materiaalnummer/1.1203.md pl: https://steelequivalents.com/pl/materiały/numer-materiału/1.1203.md pt: https://steelequivalents.com/pt/materiais/número-do-material/1.1203.md ru: https://steelequivalents.com/ru/материалы/номер-материала/1.1203.md tr: https://steelequivalents.com/tr/malzemeler/malzeme-numarası/1.1203.md zh: https://steelequivalents.com/zh/材料/材料编号/1.1203.md ja: https://steelequivalents.com/ja/材料/材料番号/1.1203.md ar: https://steelequivalents.com/ar/المواد/رقم-المادة/1.1203.md ko: https://steelequivalents.com/ko/재료/재료번호/1.1203.md pt-br: https://steelequivalents.com/pt-br/materiais/número-do-material/1.1203.md hi: https://steelequivalents.com/hi/सामग्री/सामग्री-संख्या/1.1203.md content_hash: sha256:ae8582214d07b67cd369cb02bea092d6338af6a221d62e354323d8e7b273c96a 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/1.1203 > Canonical URL: https://steelequivalents.com/materials/material-no/1.1203 > 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 · 32 designations # 1.1203 1.1203 is the material number of the grade also listed as C55E. It is a material in the category Quenched and tempered steels. We list 32 designations recorded for this grade, in the standards DIN / EN, UNS, AISI / SAE, BS, AFNOR, UNE, ISO, JIS, GB, GOST, UNI, ČSN, ABNT NBR, STN, PN and MSZ. - ***Material no.* **1.1203**** - [*Category* **Quenched and tempered steels · 133 grades**](/categories/quenched-and-tempered-steels "Category: Quenched and tempered steels · 133 grades") - *Designations* **32** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=40036c5e-d8d0-44c1-b1cd-3ed867191af3 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/material-no/1.1203.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN C55E This grade’s own name](/materials/din-en/c55e "DIN / EN C55E") - [UNS G10550 This grade’s own name · 10 grades on that route](/materials/uns/g10550 "UNS G10550") - [AISI / SAE 1055 This grade’s own name · 10 grades on that route](/materials/aisi-sae/1055 "AISI / SAE 1055") ## 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 32 designations · 16 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 - **1.1203 Indicative** - [C55E This grade’s own name](/materials/din-en/c55e "DIN / EN C55E") - [Ck 55 This grade’s own name Withdrawn](/materials/din-en/ck55 "DIN / EN Ck 55") UNS United States · 2 - [G10550 This grade’s own name](/materials/uns/g10550 "UNS G10550") - [G10600 Indicative](/materials/uns/g10600 "UNS G10600") AISI / SAE United States · 2 - [1055 This grade’s own name](/materials/aisi-sae/1055 "AISI / SAE 1055") - [1060 Indicative](/materials/aisi-sae/1060 "AISI / SAE 1060") BS United Kingdom · 3 - [060A57 Indicative](/materials/bs/060a57 "BS 060A57") - [070M55 Indicative](/materials/bs/070m55 "BS 070M55") - [CS50 Indicative](/materials/bs/cs50 "BS CS50") AFNOR France · 6 - [C50RR Indicative](/materials/afnor/c50rr "AFNOR C50RR") - [C55E Indicative](/materials/din-en/c55e "AFNOR C55E") - [XC 50 Indicative](/materials/afnor/xc50 "AFNOR XC 50") - [XC54 Indicative](/materials/afnor/xc54 "AFNOR XC54") - [XC55 Indicative](/materials/afnor/xc55 "AFNOR XC55") - [XC55H1 Indicative](/materials/afnor/xc55h1 "AFNOR XC55H1") UNE Spain · 3 - [C55K Indicative](/materials/une/c55k "UNE C55K") - [F.1150-C 55 k Indicative](/materials/une/f-1150-c-55-k "UNE F.1150-C 55 k") - [F1150 Indicative](/materials/une/f1150 "UNE F1150") ISO International · 1 - [C55E4 Indicative](/materials/iso/c55e4 "ISO C55E4") JIS Japan · 1 - [S55C Indicative](/materials/jis/s55c "JIS S55C") GB China · 1 - [55 Indicative](/materials/bds/55 "GB 55") GOST Russia / CIS · 1 - [55 Indicative](/materials/bds/55 "GOST 55") UNI Italy · 2 - [C50 Indicative](/materials/din-en/c50 "UNI C50") - [C55 Indicative](/materials/din-en/c55 "UNI C55") ČSN Czechia · 1 - [12060 Indicative](/materials/csn/12060 "ČSN 12060") ABNT NBR Brazil · 1 - [1055 Indicative](/materials/aisi-sae/1055 "ABNT NBR 1055") STN Slovakia · 1 - [12 060 Indicative](/materials/csn/12060 "STN 12 060") PN Poland · 3 - [55 Indicative](/materials/bds/55 "PN 55") - [60 Indicative](/materials/bds/60 "PN 60") - [gat. 55 Indicative](/materials/pn/gat-55 "PN gat. 55") MSZ Hungary · 1 - [C 55 Indicative](/materials/din-en/c55 "MSZ C 55") 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 C Si Iron — the balance, never listed by a standard — 97.3 % Mn — 0.8 % C — 0.6 % Si — 0.4 % Traces & impurities · 1 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.52–0.6 | | Si | ≤ 0.4 | | Mn | 0.6–0.9 | | 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 | 0,52-0,60 | 0.520 | 0.600 | 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 | 0,60-0,90 | 0.600 | 0.900 | 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 744 °C Predicted Ae1 723 °C Predicted Acm 687 °C Predicted Bs 547 °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 7 conditions · 16 values By thickness**Normalized** source `steelnumber` | Thickness mm | Rm N/mm² | A% | |---|---|---| | ≤ 16 | 680 | 11 | | 16 – 100 | 640 | 12 | | 100 – 250 | 620 | 12 | | 250 – 500 | 600 | — | | 500 – 1000 | 590 | — | By thickness**Soft annealed** source `steelnumber` | Thickness mm | Rm N/mm² | A80% | |---|---|---| | 0.3 – 3 | 600 | 17 | By thickness**Quenched and tempered** source `steelnumber` | Thickness mm | Rm N/mm² | |---|---| | 0.3 – 3 | 1100 – 1700 | By delivery state**Treated to improve shearability** source `steelnumber` | Delivery state | HB | |---|---| | Treated to improve shearability | 255 | By delivery state**Soft annealed** source `steelnumber` | Delivery state | HB | HV | |---|---|---| | Soft annealed | 229 | 185 | By delivery state**Cold rolled** source `steelnumber` | Delivery state | HV | |---|---| | Cold rolled | 300 | By delivery state**Quenched and tempered** source `steelnumber` | Delivery state | HV | |---|---| | Quenched and tempered | 340 – 520 | 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. [C50E 1.1206 Mn 0,60-0,90 · Si ≤0,40 - ΔMn 0.00 - ΔSi 0.00 - 33 designations](/materials/din-en/c50e "C50E")[1.1221 1.1221 Mn 0,60-0,90 · Si ≤0,40 - ΔMn 0.00 - ΔSi 0.00 - 38 designations](/materials/material-no/1.1221 "1.1221")[C60R 1.1223 Mn 0,60-0,90 · Si ≤0,40 - ΔMn 0.00 - ΔSi 0.00 - 6 designations](/materials/din-en/c60r "C60R")[C30E 1.1178 Mn 0,50-0,80 · Si ≤0,40 - ΔMn 0.10 - ΔSi 0.00 - 19 designations](/materials/din-en/c30e "C30E")[C30R 1.1179 Mn 0,50-0,80 · Si ≤0,40 - ΔMn 0.10 - ΔSi 0.00 - 11 designations](/materials/din-en/c30r "C30R")[C35 1.1180 Mn 0,50-0,80 · Si ≤0,40 - ΔMn 0.10 - ΔSi 0.00 - 17 designations](/materials/din-en/c35 "C35") ## 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=40036c5e-d8d0-44c1-b1cd-3ed867191af3 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/material-no/1.1203.pdf "Datasheet as PDF")