--- title: "UD12 — Tool steels for hot work" description: "UD12 in UNI: material number 1.2343, also listed as X37CrMoV5-1. Category: Tool steels for hot work. Designations recorded for this grade: 42." canonical: https://steelequivalents.com/materials/uni/ud12 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/uni/ud12.md cs: https://steelequivalents.com/cs/materiály/uni/ud12.md de: https://steelequivalents.com/de/werkstoffe/uni/ud12.md es: https://steelequivalents.com/es/materiales/uni/ud12.md fr: https://steelequivalents.com/fr/matériaux/uni/ud12.md hu: https://steelequivalents.com/hu/anyagok/uni/ud12.md it: https://steelequivalents.com/it/materiali/uni/ud12.md nl: https://steelequivalents.com/nl/materialen/uni/ud12.md pl: https://steelequivalents.com/pl/materiały/uni/ud12.md pt: https://steelequivalents.com/pt/materiais/uni/ud12.md ru: https://steelequivalents.com/ru/материалы/uni/ud12.md tr: https://steelequivalents.com/tr/malzemeler/uni/ud12.md zh: https://steelequivalents.com/zh/材料/uni/ud12.md ja: https://steelequivalents.com/ja/材料/uni/ud12.md ar: https://steelequivalents.com/ar/المواد/uni/ud12.md ko: https://steelequivalents.com/ko/재료/uni/ud12.md pt-br: https://steelequivalents.com/pt-br/materiais/uni/ud12.md hi: https://steelequivalents.com/hi/सामग्री/uni/ud12.md content_hash: sha256:41ef65016491a4b811870698c7af405ddb3f1f8aabecc5d2123cbc659092a358 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/uni/ud12 > Canonical URL: https://steelequivalents.com/materials/uni/ud12 > 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. UNI · Italy · 42 designations # UD12 UD12 is a designation in UNI for the material held under material number 1.2343, also listed as X37CrMoV5-1. It is a material in the category Tool steels for hot work. We list 42 designations recorded for this grade, in the standards DIN / EN, UNS, AISI / SAE, BS, AFNOR, UNE, ISO, SAE AMS, JIS, GB, GOST, UNI, ČSN, STN, HRN, SRPS, PN, STAS, BDS, ÖNORM and KS. - [*Material no.* **1.2343**](/materials/material-no/1.2343 "Material no.: 1.2343") - [*Category* **Tool steels for hot work · 37 grades**](/categories/tool-steels-for-hot-work "Category: Tool steels for hot work · 37 grades") - *Designations* **42** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=c4cb69a9-c75e-46eb-83ec-1c64c7f6bdab&designation=3279262a-9d2c-4cc8-aacc-b1db74d2e2c0 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/uni/ud12.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN X37CrMoV5-1 This grade’s own name](/materials/din-en/x37crmov5-1 "DIN / EN X37CrMoV5-1") - [UNS T20811 This grade’s own name · 3 grades on that route](/materials/uns/t20811 "UNS T20811") - [AISI / SAE H11 This grade’s own name · 2 grades on that route](/materials/aisi-sae/h11 "AISI / SAE H11") ## About Tool steels for hot work Tool steels for hot work are alloy steels designed for tooling that operates in contact with heated metal. They are characterised by hot hardness, wear resistance, toughness and resistance to thermal fatigue, making them suitable for dies, moulds, punches and other forging, extrusion and die-casting tools. This describes the material class as a whole. Always confirm the individual grade against the standard before ordering. ## Also known as 42 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 · 2 - [X37CrMoV5-1 This grade’s own name](/materials/din-en/x37crmov5-1 "DIN / EN X37CrMoV5-1") - [X38CrMoV5-1 This grade’s own name Withdrawn](/materials/din-en/x38crmov5-1 "DIN / EN X38CrMoV5-1") UNS United States · 2 - [T20811 This grade’s own name](/materials/uns/t20811 "UNS T20811") - [T20813 Indicative](/materials/uns/t20813 "UNS T20813") AISI / SAE United States · 3 - [H11 This grade’s own name](/materials/aisi-sae/h11 "AISI / SAE H11") - [H13 Indicative](/materials/aisi-sae/h13 "AISI / SAE H13") - [T20811 Indicative](/materials/uns/t20811 "AISI / SAE T20811") BS United Kingdom · 2 - [2343 Indicative](/materials/bs/2343 "BS 2343") - [BH11 Indicative](/materials/bs/bh11 "BS BH11") AFNOR France · 4 - [X37CrMoV51KU Indicative](/materials/afnor/x37crmov5-1ku "AFNOR X37CrMoV51KU") - [X38CrMoV5 Indicative](/materials/afnor/x38crmov5 "AFNOR X38CrMoV5") - [Z38CDV5 Indicative](/materials/afnor/z38cdv5 "AFNOR Z38CDV5") - [Z38CDV5-1 Indicative](/materials/afnor/z38cdv5-1 "AFNOR Z38CDV5-1") UNE Spain · 3 - [F.5317X37CrMoV5 Indicative](/materials/une/f-5317x37crmov5 "UNE F.5317X37CrMoV5") - [F.5318 Indicative](/materials/une/f-5318 "UNE F.5318") - [X37CrMoV5 Indicative](/materials/une/x37crmov5 "UNE X37CrMoV5") ISO International · 3 - [35CrMoV5 Indicative](/materials/iso/35crmov5 "ISO 35CrMoV5") - [X37CrMoV5-1 Indicative](/materials/din-en/x37crmov5-1 "ISO X37CrMoV5-1") - [X40CrMoV5-1 Indicative](/materials/din-en/x40crmov5-1 "ISO X40CrMoV5-1") SAE AMS United States / Aerospace · 3 - [6485 Indicative](/materials/ams/6485 "SAE AMS 6485") - [6487 Indicative](/materials/ams/6487 "SAE AMS 6487") - [6488 Indicative](/materials/ams/6488 "SAE AMS 6488") JIS Japan · 1 - [SKD6 Indicative](/materials/jis/skd6 "JIS SKD6") GB China · 2 - [4Cr5MoSiV Indicative](/materials/gb/4cr5mosiv "GB 4Cr5MoSiV") - [SM4Cr5MoSiV Indicative](/materials/gb/sm4cr5mosiv "GB SM4Cr5MoSiV") GOST Russia / CIS · 3 - [4Ch5MFS Indicative](/materials/gost/4ch5mfs "GOST 4Ch5MFS") - [4KH5MFS Indicative](/materials/gost/4kh5mfs "GOST 4KH5MFS") - [4Х5МФС Indicative](/materials/gost/4kh5mfs "GOST 4Х5МФС") UNI Italy · 2 - **UD12 Indicative** - [X37CrMoV5-1KU Indicative](/materials/afnor/x37crmov5-1ku "UNI X37CrMoV5-1KU") ČSN Czechia · 2 - [19552 Indicative](/materials/csn/19552 "ČSN 19552") - [19553 Indicative](/materials/csn/19553 "ČSN 19553") STN Slovakia · 1 - [19 552 Indicative](/materials/csn/19552 "STN 19 552") HRN Croatia · 1 - [Č 4751 Indicative](/materials/srps/c-4751 "HRN Č 4751") SRPS Serbia · 1 - [Č.4751 Indicative](/materials/srps/c-4751 "SRPS Č.4751") PN Poland · 2 - [WCL Indicative](/materials/pn/wcl "PN WCL") - [WCLV Indicative](/materials/pn/wclv "PN WCLV") STAS Romania · 1 - [39VSiMoCr52 Indicative](/materials/stas/39vsimocr52 "STAS 39VSiMoCr52") BDS Bulgaria · 1 - [X37CrMoV5-1 Indicative](/materials/din-en/x37crmov5-1 "BDS X37CrMoV5-1") ÖNORM Austria · 2 - [BOHLERW300 Indicative](/materials/onorm/bohlerw300 "ÖNORM BOHLERW300") - [W300 Indicative](/materials/onorm/w300 "ÖNORM W300") KS South Korea · 1 - [STD6 Indicative](/materials/ks/std6 "KS STD6") 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 Cr Mo Si Iron — the balance, never listed by a standard — 91.4 % Cr — 5.2 % Mo — 1.3 % Si — 1 % Traces & impurities · 1.2 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.33–0.41 | | Si | 0.8–1.2 | | Mn | 0.25–0.5 | | P | 0.03 | | S | 0.02 | | Cr | 4.8–5.5 | | Mo | 1.1–1.5 | | V | 0.3–0.5 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Molybdenum Vanadium 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 | 0,33-0,41 | 0.330 | 0.410 | Range | | Si | 0,80-1,20 | 0.800 | 1.200 | Range | | P | 0,03 | 0.030 | 0.030 | Exact | | S | 0,02 | 0.020 | 0.020 | Exact | | V | 0,30-0,50 | 0.300 | 0.500 | Range | | Cr | 4,80-5,50 | 4.800 | 5.500 | Range | | Mn | 0,25-0,50 | 0.250 | 0.500 | Range | | Mo | 1,10-1,50 | 1.100 | 1.500 | 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. ## Physical & mechanical properties Density 7,8 g/cm³ Exact Transformation point Ac1 840 °C Exact Transformation point Ac3 870 °C Exact · Ac3(Acm) Transformation point Ar3 810 °C Exact · Ar3(Arcm) Transformation point Ar1 735 °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 5 conditions · 28 values By delivery state**no delivery state stated** source `steeljis` | Delivery state | HB | HRC | |---|---|---| | Annealed | 229 | — | | Quenched and tempered | — | 48 | By delivery state**Soft annealed** source `steelnumber` | Delivery state | HB | |---|---| | Soft annealed | 229 | By dimension**Quenching 1000 - 1020°C,Drawing 530 - 560°C,Drawing 500 - 520°C** source `splav` | Dimension mm | Rm N/mm² | Re N/mm² | KCU kJ/m² | |---|---|---|---| | 10 | 1750 | 1480 | 570 | By delivery state**no delivery state stated** source `splav` | Delivery state | HB | |---|---| | (annealing) , GOST 5950-2000 | 241 | At temperature**no delivery state stated** source `splav` | Temperature °C | Density g/cm³ | Thermal conductivity W/(m·K) | Electrical resistivity nΩ·m | |---|---|---|---| | 20 | 7.75 | 29 | 480 | | 100 | 7.724 | 30 | — | | 200 | 7.697 | 30 | — | | 300 | 7.67 | 31 | — | | 400 | 7.641 | 33 | — | | 500 | 7.6 | 31 | — | | 600 | 7.573 | 30 | — | | 700 | 7.546 | 28 | — | | 800 | 7.52 | 26 | — | | 900 | 7.495 | 27 | — | 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. ## Heat treatment Supply condition - Quenching Test specimen - Annealing Supply condition Conditions the standard permits on delivery. No temperature or medium is published for these, so no order and no alternation is implied. Source: [www.caishuku.com](https://www.caishuku.com/detail/azhlNWIxMzUyNDM_ "Source: www.caishuku.com") ## Similar grades — and why Selection rule, stated so you can disagree with it: same number class 1.2, a shared category, and a published range for Cr / Mo 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. [1.2344 1.2344 Cr 4,80-5,50 · Mo 1,20-1,50 - ΔCr 0.00 - ΔMo 0.05 - 49 designations](/materials/material-no/1.2344 "1.2344")[X35CrWMoV5 1.2605 Cr 4,75-5,50 · Mo 1,25-1,60 - ΔCr 0.03 - ΔMo 0.13 - 7 designations](/materials/din-en/x35crwmov5 "X35CrWMoV5")[X50CrMoV5-1 1.2345 Cr 4,80-5,20 · Mo 1,25-1,45 - ΔCr 0.15 - ΔMo 0.05 - 4 designations](/materials/din-en/x50crmov5-1 "X50CrMoV5-1")[X37CrMoW5-1 1.2606 Cr 5,00-5,60 · Mo 1,30-1,60 - ΔCr 0.15 - ΔMo 0.15 - 11 designations](/materials/din-en/x37crmow5-1 "X37CrMoW5-1")[X35CrMoV5-1-1 1.2342 Cr 4,50-5,50 · Mo 1,00-1,20 - ΔCr 0.15 - ΔMo 0.20 - 1 designations](/materials/din-en/x35crmov5-1-1 "X35CrMoV5-1-1") ## 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=c4cb69a9-c75e-46eb-83ec-1c64c7f6bdab&designation=3279262a-9d2c-4cc8-aacc-b1db74d2e2c0 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/uni/ud12.pdf "Datasheet as PDF")