--- title: "20CrMo — composition, equivalents and standards" description: "20CrMo is a designation in GB for the grade also listed as 18CrMo4. We list 2 designations recorded for this grade, in the standards AFNOR and GB." canonical: https://steelequivalents.com/materials/gb/20crmo language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/gb/20crmo.md cs: https://steelequivalents.com/cs/materiály/gb/20crmo.md de: https://steelequivalents.com/de/werkstoffe/gb/20crmo.md es: https://steelequivalents.com/es/materiales/gb/20crmo.md fr: https://steelequivalents.com/fr/matériaux/gb/20crmo.md hu: https://steelequivalents.com/hu/anyagok/gb/20crmo.md it: https://steelequivalents.com/it/materiali/gb/20crmo.md nl: https://steelequivalents.com/nl/materialen/gb/20crmo.md pl: https://steelequivalents.com/pl/materiały/gb/20crmo.md pt: https://steelequivalents.com/pt/materiais/gb/20crmo.md ru: https://steelequivalents.com/ru/материалы/gb/20crmo.md tr: https://steelequivalents.com/tr/malzemeler/gb/20crmo.md zh: https://steelequivalents.com/zh/材料/gb/20crmo.md ja: https://steelequivalents.com/ja/材料/gb/20crmo.md ar: https://steelequivalents.com/ar/المواد/gb/20crmo.md ko: https://steelequivalents.com/ko/재료/gb/20crmo.md pt-br: https://steelequivalents.com/pt-br/materiais/gb/20crmo.md hi: https://steelequivalents.com/hi/सामग्री/gb/20crmo.md content_hash: sha256:09601218797bd93b96a2df789f963b39e224269603f80d5f7b12a70c2a8ca4a5 generated: 2026-09-23 --- > **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/20crmo > Canonical URL: https://steelequivalents.com/materials/gb/20crmo > 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 · 2 designations # 20CrMo 20CrMo is a designation in GB for the grade also listed as 18CrMo4. We list 2 designations recorded for this grade, in the standards AFNOR and GB. - *Designations* **2** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=4812feb1-1d21-41bd-bdb0-0abaa8d31e20&designation=2a7f2abf-cc9d-4d87-add3-ba8fac45f848 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/gb/20crmo.pdf "Datasheet as PDF") ## Also known as 2 designations · 2 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. AFNOR France · 1 - [18CrMo4 Indicative](/materials/din-en/18crmo4 "AFNOR 18CrMo4") GB China · 1 - **20CrMo 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 9 elements on file · weight % What this alloy is Fe Cr Mn Ni Iron — the balance, never listed by a standard — 97.2 % Cr — 1 % Mn — 0.6 % Ni — 0.3 % Traces & impurities · 1 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.17–0.24 | | Si | 0.17–0.37 | | Mn | 0.4–0.7 | | P | ≤ 0.03 | | S | ≤ 0.02 | | Cr | 0.8–1.1 | | Mo | 0.15–0.25 | | Ni | ≤ 0.3 | | Cu | ≤ 0.3 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Molybdenum Nickel Copper 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 | 0.17-0.24 | 0.170 | 0.240 | Range | | Si | 0.17-0.37 | 0.170 | 0.370 | Range | | P | ≤0.03 | — | 0.030 | Max | | S | ≤0.02 | — | 0.020 | Max | | Cr | 0.8-1.1 | 0.800 | 1.100 | Range | | Mn | 0.4-0.7 | 0.400 | 0.700 | Range | | Ni | ≤0.3 | — | 0.300 | Max | | Cu | ≤0.3 | — | 0.300 | Max | | Mo | 0.15-0.25 | 0.150 | 0.250 | 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 computed from composition · °C Predicted Ae3 811 °C Predicted Ae1 743 °C Predicted Acm 494 °C Predicted Bs 546 °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 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 · 7 values At temperature**no delivery state stated** source `caishuku` | Temperature °C | Elastic modulus GPa | Specific heat capacity J/(kg·K) | G GPa | |---|---|---|---| | 20 | 205 | 461 | 79 | | 100 | 200 | — | 74 | | 200 | 188 | — | 72 | 4 further values are held for this grade under a condition the source did not name — a bound with no quantity attached. They are withheld rather than shown against a guessed condition. 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 3077-2015** In this order 1. Quenching 860–870 °C Cooling Oil 2. Tempering 690–700 °C Cooling Furnace Supply condition - Quenching and Tempering d=15 - Annealing and Tempering and Normalizing Supply condition - Spheroidize annealing Plate and Strip 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/azhlNWIxMjYyMDE_ "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=4812feb1-1d21-41bd-bdb0-0abaa8d31e20&designation=2a7f2abf-cc9d-4d87-add3-ba8fac45f848 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/gb/20crmo.pdf "Datasheet as PDF")