--- title: "F.5123 — Unalloyed tool steels / carbon steels" description: "F.5123 in UNE: material number 1.1563, also listed as C125U. Category: Unalloyed tool steels / carbon steels. Designations recorded for this grade: 32." canonical: https://steelequivalents.com/materials/une/f-5123 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/une/f-5123.md cs: https://steelequivalents.com/cs/materiály/une/f-5123.md de: https://steelequivalents.com/de/werkstoffe/une/f-5123.md es: https://steelequivalents.com/es/materiales/une/f-5123.md fr: https://steelequivalents.com/fr/matériaux/une/f-5123.md hu: https://steelequivalents.com/hu/anyagok/une/f-5123.md it: https://steelequivalents.com/it/materiali/une/f-5123.md nl: https://steelequivalents.com/nl/materialen/une/f-5123.md pl: https://steelequivalents.com/pl/materiały/une/f-5123.md pt: https://steelequivalents.com/pt/materiais/une/f-5123.md ru: https://steelequivalents.com/ru/материалы/une/f-5123.md tr: https://steelequivalents.com/tr/malzemeler/une/f-5123.md zh: https://steelequivalents.com/zh/材料/une/f-5123.md ja: https://steelequivalents.com/ja/材料/une/f-5123.md ar: https://steelequivalents.com/ar/المواد/une/f-5123.md ko: https://steelequivalents.com/ko/재료/une/f-5123.md pt-br: https://steelequivalents.com/pt-br/materiais/une/f-5123.md hi: https://steelequivalents.com/hi/सामग्री/une/f-5123.md content_hash: sha256:6f97c9be9ae3a63f4ac640ffb71c23e6be94c222a4abf423d13d81d6ff7e52b8 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/une/f-5123 > Canonical URL: https://steelequivalents.com/materials/une/f-5123 > 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. UNE · Spain · 32 designations # F.5123 F.5123 is a designation in UNE for the material held under material number 1.1563, also listed as C125U. It is a material in the category Unalloyed tool steels / carbon steels. We list 32 designations recorded for this grade, in the standards DIN / EN, UNS, AISI / SAE, AFNOR, UNE, JIS, GOST, UNI, ČSN, SRPS, PN, MSZ, BDS and ÖNORM. - [*Material no.* **1.1563**](/materials/material-no/1.1563 "Material no.: 1.1563") - [*Category* **Unalloyed tool steels / carbon steels · 35 grades**](/categories/unalloyed-tool-steels-carbon-steels "Category: Unalloyed tool steels / carbon steels · 35 grades") - *Designations* **32** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=f997bb17-dbb6-47a5-b9e2-e3559b590f57&designation=710a9550-aaf3-499e-8415-ef815bc8089f "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/une/f-5123.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN C125U This grade’s own name](/materials/din-en/c125u "DIN / EN C125U") - [AISI / SAE W112 This grade’s own name · 2 grades on that route](/materials/aisi-sae/w112 "AISI / SAE W112") ## 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 32 designations · 14 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 - [C125U This grade’s own name](/materials/din-en/c125u "DIN / EN C125U") - [C125W This grade’s own name Withdrawn](/materials/din-en/c125w "DIN / EN C125W") UNS United States · 1 - [T72301 Indicative](/materials/uns/t72301 "UNS T72301") AISI / SAE United States · 4 - [T72301 Indicative](/materials/uns/t72301 "AISI / SAE T72301") - [W1-13 Indicative](/materials/aisi-sae/w1-13 "AISI / SAE W1-13") - [W112 This grade’s own name](/materials/aisi-sae/w112 "AISI / SAE W112") - [W1C 1,20% This grade’s own name](/materials/aisi-sae/w1c-1-20 "AISI / SAE W1C 1,20%") AFNOR France · 3 - [C120E3U Indicative](/materials/afnor/c120e3u "AFNOR C120E3U") - [C140E3U Indicative](/materials/afnor/c140e3u "AFNOR C140E3U") - [Y240 Indicative](/materials/afnor/y240 "AFNOR Y240") UNE Spain · 2 - [C120 Indicative](/materials/une/c120 "UNE C120") - **F.5123 Indicative** JIS Japan · 2 - [SK1 Indicative](/materials/jis/sk1 "JIS SK1") - [SK2 Indicative](/materials/jis/sk2 "JIS SK2") GOST Russia / CIS · 8 - [13GS Indicative](/materials/gost/13gs "GOST 13GS") - [13KhFA Indicative](/materials/gost/13khfa "GOST 13KhFA") - [13KhFYu Indicative](/materials/gost/13khfyu "GOST 13KhFYu") - [13ГС-У Indicative](/materials/gost/13gs-u "GOST 13ГС-У") - [PKG13 Indicative](/materials/gost/pkg13 "GOST PKG13") - [U13 Indicative](/materials/gost/u13 "GOST U13") - [ПКГ13-7.4 Indicative](/materials/gost/pkg13-7-4 "GOST ПКГ13-7.4") - [У13 Indicative](/materials/gost/u13 "GOST У13") UNI Italy · 2 - [C120KU Indicative](/materials/uni/c120ku "UNI C120KU") - [C140KU Indicative](/materials/uni/c140ku "UNI C140KU") ČSN Czechia · 1 - [19 255 Indicative](/materials/csn/19-255 "ČSN 19 255") SRPS Serbia · 1 - [Č.1943 Indicative](/materials/srps/c-1943 "SRPS Č.1943") PN Poland · 2 - [N12 Indicative](/materials/pn/n12 "PN N12") - [N13 Indicative](/materials/pn/n13 "PN N13") MSZ Hungary · 2 - [S131 Indicative](/materials/msz/s131 "MSZ S131") - [S132 Indicative](/materials/msz/s132 "MSZ S132") BDS Bulgaria · 1 - [U13 Indicative](/materials/gost/u13 "BDS U13") ÖNORM Austria · 1 - [K995 Indicative](/materials/onorm/k995 "ÖNORM K995") 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 — 98.2 % C — 1.3 % 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 | 1.2–1.35 | | 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 | 1,20-1,35 | 1.200 | 1.350 | 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 Transformation point Ac1 730 °C Exact Transformation point Ac3 830 °C Exact · Ac3(Acm) Transformation point Ar1 700 °C 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 3 conditions · 3 values By dimension**no delivery state stated** source `splav` | Dimension mm | Rm N/mm² | |---|---| | 0.08 - 3 | 900 | By delivery state**no delivery state stated** source `splav` | Delivery state | HB | |---|---| | (annealing) | 217 | At temperature**no delivery state stated** source `splav` | Temperature °C | Density g/cm³ | |---|---| | 20 | 7.8 | 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")[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")[C70W2 1.1620 Mn 0,10-0,35 · Si 0,10-0,30 - ΔMn 0.00 - ΔSi 0.00 - 26 designations](/materials/din-en/c70w2 "C70W2")[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=f997bb17-dbb6-47a5-b9e2-e3559b590f57&designation=710a9550-aaf3-499e-8415-ef815bc8089f "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/une/f-5123.pdf "Datasheet as PDF")