--- title: "OSC7 — Unalloyed tool steels / carbon steels" description: "OSC7 in STAS: material number 1.1620, also listed as C70W2. Category: Unalloyed tool steels / carbon steels. Designations recorded for this grade: 26." canonical: https://steelequivalents.com/materials/stas/osc7 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/stas/osc7.md cs: https://steelequivalents.com/cs/materiály/stas/osc7.md de: https://steelequivalents.com/de/werkstoffe/stas/osc7.md es: https://steelequivalents.com/es/materiales/stas/osc7.md fr: https://steelequivalents.com/fr/matériaux/stas/osc7.md hu: https://steelequivalents.com/hu/anyagok/stas/osc7.md it: https://steelequivalents.com/it/materiali/stas/osc7.md nl: https://steelequivalents.com/nl/materialen/stas/osc7.md pl: https://steelequivalents.com/pl/materiały/stas/osc7.md pt: https://steelequivalents.com/pt/materiais/stas/osc7.md ru: https://steelequivalents.com/ru/материалы/stas/osc7.md tr: https://steelequivalents.com/tr/malzemeler/stas/osc7.md zh: https://steelequivalents.com/zh/材料/stas/osc7.md ja: https://steelequivalents.com/ja/材料/stas/osc7.md ar: https://steelequivalents.com/ar/المواد/stas/osc7.md ko: https://steelequivalents.com/ko/재료/stas/osc7.md pt-br: https://steelequivalents.com/pt-br/materiais/stas/osc7.md hi: https://steelequivalents.com/hi/सामग्री/stas/osc7.md content_hash: sha256:7b0880c6e16d14d83d5263022184b49571383aa4996c6f21095bd8c30053794b generated: 2026-09-21 --- > **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/osc7 > Canonical URL: https://steelequivalents.com/materials/stas/osc7 > 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 · 26 designations # OSC7 OSC7 is a designation in STAS for the material held under material number 1.1620, also listed as C70W2. It is a material in the category Unalloyed tool steels / carbon steels. We list 26 designations recorded for this grade, in the standards DIN / EN, AISI / SAE, AFNOR, ISO, JIS, GB, GOST, UNI, ČSN, SRPS, PN, MSZ, STAS, BDS and ÖNORM. - [*Material no.* **1.1620**](/materials/material-no/1.1620 "Material no.: 1.1620") - [*Category* **Unalloyed tool steels / carbon steels · 35 grades**](/categories/unalloyed-tool-steels-carbon-steels "Category: Unalloyed tool steels / carbon steels · 35 grades") - *Designations* **26** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=6e95f90b-071c-44fe-ba62-2cebccf9ff7d&designation=5a7cf165-bb35-4289-bf10-e520bd95f06c "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/stas/osc7.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN C70W2 This grade’s own name · 2 grades on that route](/materials/din-en/c70w2 "DIN / EN C70W2") ## About Unalloyed tool steels / carbon steels Unalloyed tool steels are carbon steels whose working properties are developed primarily through carbon content and heat treatment. They are characterised by high attainable hardness and wear resistance, and are used for cutting tools, punches, dies, gauges and other tooling where edge retention and resistance to deformation are important. This describes the material class as a whole. Always confirm the individual grade against the standard before ordering. ## Also known as 26 designations · 15 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 - [C70W2 This grade’s own name](/materials/din-en/c70w2 "DIN / EN C70W2") AISI / SAE United States · 2 - [C 0.70 Indicative](/materials/aisi-sae/c-0-70 "AISI / SAE C 0.70") - [W 1 Indicative](/materials/aisi-sae/w1 "AISI / SAE W 1") AFNOR France · 3 - [C70E2U Indicative](/materials/afnor/c70e2u "AFNOR C70E2U") - [XC65 Indicative](/materials/afnor/xc65 "AFNOR XC65") - [Y1-70 Indicative](/materials/afnor/y1-70 "AFNOR Y1-70") ISO International · 2 - [C70U Indicative](/materials/din-en/c70u "ISO C70U") - [C70W1 Indicative](/materials/din-en/c70w1 "ISO C70W1") JIS Japan · 3 - [SK6 Indicative](/materials/jis/sk6 "JIS SK6") - [SK65 Indicative](/materials/jis/sk65 "JIS SK65") - [SK7 Indicative](/materials/jis/sk7 "JIS SK7") GB China · 1 - [T7 Indicative](/materials/gb/t7 "GB T7") GOST Russia / CIS · 3 - [U7 Indicative](/materials/bds/u7 "GOST U7") - [U7A Indicative](/materials/gost/u7a "GOST U7A") - [У7 Indicative](/materials/bds/u7 "GOST У7") UNI Italy · 1 - [C70KU Indicative](/materials/uni/c70ku "UNI C70KU") ČSN Czechia · 2 - [19 132 Indicative](/materials/csn/19132 "ČSN 19 132") - [19133 Indicative](/materials/csn/19133 "ČSN 19133") SRPS Serbia · 1 - [Č.1740 Indicative](/materials/srps/c-1740 "SRPS Č.1740") PN Poland · 2 - [N7 Indicative](/materials/pn/n7 "PN N7") - [N7E Indicative](/materials/pn/n7e "PN N7E") MSZ Hungary · 2 - [S71 Indicative](/materials/msz/s71 "MSZ S71") - [S72 Indicative](/materials/msz/s72 "MSZ S72") STAS Romania · 1 - **OSC7 Indicative** BDS Bulgaria · 1 - [U7 Indicative](/materials/bds/u7 "BDS U7") ÖNORM Austria · 1 - [K970 Indicative](/materials/onorm/k970 "ÖNORM K970") Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here. ## Chemical composition 5 elements on file · weight % What this alloy is Fe C Mn Si Iron — the balance, never listed by a standard — 98.8 % C — 0.7 % Mn — 0.2 % Si — 0.2 % Traces & impurities · 0.1 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.65–0.74 | | Si | 0.1–0.3 | | Mn | 0.1–0.35 | | P | 0.03 | | S | 0.03 | Carbon Silicon Manganese Phosphorus Sulfur 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 | 0,65-0,74 | 0.650 | 0.740 | Range | | Si | 0,10-0,30 | 0.100 | 0.300 | Range | | P | 0,03 | 0.030 | 0.030 | Exact | | S | 0,03 | 0.030 | 0.030 | Exact | | Mn | 0,10-0,35 | 0.100 | 0.350 | 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 Not enough recorded composition to predict a transformation temperature for this grade — missing: Ni, Cr, Mo. ## 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 · 2 values By delivery state**no delivery state stated** source `steeljis` | Delivery state | HB | HRC | |---|---|---| | ( SK7 ) Annealed | 183 | — | | ( SK7 ) Quenched and tempered | — | 56 | 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. [C110U 1.1554 Mn 0,10-0,35 · Si 0,10-0,30 - ΔMn 0.00 - ΔSi 0.00 - 9 designations](/materials/din-en/c110u "C110U")[C125U 1.1563 Mn 0,10-0,35 · Si 0,10-0,30 - ΔMn 0.00 - ΔSi 0.00 - 32 designations](/materials/din-en/c125u "C125U")[C135U 1.1573 Mn 0,10-0,35 · Si 0,10-0,30 - ΔMn 0.00 - ΔSi 0.00 - 3 designations](/materials/din-en/c135u "C135U")[C80W2 1.1625 Mn 0,10-0,35 · Si 0,10-0,30 - ΔMn 0.00 - ΔSi 0.00 - 27 designations](/materials/din-en/c80w2 "C80W2")[C105W2 1.1645 Mn 0,10-0,35 · Si 0,10-0,30 - ΔMn 0.00 - ΔSi 0.00 - 45 designations](/materials/din-en/c105w2 "C105W2")[1.1620 1.1520 Mn 0,10-0,40 · Si 0,10-0,30 - ΔMn 0.03 - ΔSi 0.00 - 21 designations](/materials/material-no/1.1620 "1.1620") ## 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=6e95f90b-071c-44fe-ba62-2cebccf9ff7d&designation=5a7cf165-bb35-4289-bf10-e520bd95f06c "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/stas/osc7.pdf "Datasheet as PDF")