--- title: "ML40CrMo — composition, equivalents and standards" description: "ML40CrMo is a designation in GB for the grade also listed as 42CrMo4. Designations recorded for this grade: 5." canonical: https://steelequivalents.com/materials/gb/ml40crmo language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/gb/ml40crmo.md cs: https://steelequivalents.com/cs/materiály/gb/ml40crmo.md de: https://steelequivalents.com/de/werkstoffe/gb/ml40crmo.md es: https://steelequivalents.com/es/materiales/gb/ml40crmo.md fr: https://steelequivalents.com/fr/matériaux/gb/ml40crmo.md hu: https://steelequivalents.com/hu/anyagok/gb/ml40crmo.md it: https://steelequivalents.com/it/materiali/gb/ml40crmo.md nl: https://steelequivalents.com/nl/materialen/gb/ml40crmo.md pl: https://steelequivalents.com/pl/materiały/gb/ml40crmo.md pt: https://steelequivalents.com/pt/materiais/gb/ml40crmo.md ru: https://steelequivalents.com/ru/материалы/gb/ml40crmo.md tr: https://steelequivalents.com/tr/malzemeler/gb/ml40crmo.md zh: https://steelequivalents.com/zh/材料/gb/ml40crmo.md ja: https://steelequivalents.com/ja/材料/gb/ml40crmo.md ar: https://steelequivalents.com/ar/المواد/gb/ml40crmo.md ko: https://steelequivalents.com/ko/재료/gb/ml40crmo.md pt-br: https://steelequivalents.com/pt-br/materiais/gb/ml40crmo.md hi: https://steelequivalents.com/hi/सामग्री/gb/ml40crmo.md content_hash: sha256:169c8b66bee14b08ce7900df67628d4ab7ee87f9f878b029e5171b90a7d0cc33 generated: 2026-09-25 --- > **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/gb/ml40crmo > Canonical URL: https://steelequivalents.com/materials/gb/ml40crmo > 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. GB · China · 5 designations # ML40CrMo ML40CrMo is a designation in GB for the grade also listed as 42CrMo4. We list 5 designations recorded for this grade, in the standards DIN / EN, ASTM, ISO, JIS and GB. - *Designations* **5** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=253bfbae-c427-4c68-8cf6-5d4be41888d7&designation=7a4245d9-8a6b-4c75-bc6e-9e2dd3856740 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/gb/ml40crmo.pdf "Datasheet as PDF") ## Also known as 5 designations · 5 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 - [42CrMo4 Indicative](/materials/din-en/42crmo4 "DIN / EN 42CrMo4") ASTM United States · 1 - [4140 Indicative](/materials/aisi-sae/4140 "ASTM 4140") ISO International · 1 - [42CrMo4 Indicative](/materials/din-en/42crmo4 "ISO 42CrMo4") JIS Japan · 1 - [SCM440 Indicative](/materials/jis/scm440 "JIS SCM440") GB China · 1 - **ML40CrMo This grade’s own name** Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here. ## Chemical composition 7 elements on file · weight % What this alloy is Fe Cr Mn C Iron — the balance, never listed by a standard — 97.3 % Cr — 1.1 % Mn — 0.8 % C — 0.4 % Traces & impurities · 0.5 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.38–0.43 | | Si | 0.1–0.3 | | Mn | 0.6–0.9 | | P | ≤ 0.025 | | S | ≤ 0.025 | | Cr | 0.9–1.2 | | Mo | 0.15–0.3 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Molybdenum 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 | 0.38-0.43 | 0.380 | 0.430 | Range | | Si | 0.1-0.3 | 0.100 | 0.300 | Range | | P | ≤0.025 | — | 0.025 | Max | | S | ≤0.025 | — | 0.025 | Max | | Cr | 0.9-1.2 | 0.900 | 1.200 | Range | | Mn | 0.6-0.9 | 0.600 | 0.900 | Range | | Mo | 0.15-0.3 | 0.150 | 0.300 | 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 Rm ≤650 N/mm² Max 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 · 3 values By dimension**no delivery state stated** source `caishuku` | Specimen diameter mm | Rm N/mm² | Re N/mm² | A% | |---|---|---|---| | 25 – 25 | ≥ 1080 | ≥ 930 | ≥ 12 | 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 **GB /T 6478-2015** In this order Test specimen diameter d=25 1. Quenching 830–870 °C Cooling Oil 2. Tempering 500–600 °C Source: [www.caishuku.com](https://www.caishuku.com/detail/azhlNWIxMjMzMg__ "Source: www.caishuku.com") ## 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=253bfbae-c427-4c68-8cf6-5d4be41888d7&designation=7a4245d9-8a6b-4c75-bc6e-9e2dd3856740 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/gb/ml40crmo.pdf "Datasheet as PDF")