--- title: "BM3 — composition, equivalents and standards" description: "BM3 is a designation in BS for the grade also listed as S6-5-3. Designations recorded for this grade: 5." canonical: https://steelequivalents.com/materials/bs/bm3 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/bs/bm3.md cs: https://steelequivalents.com/cs/materiály/bs/bm3.md de: https://steelequivalents.com/de/werkstoffe/bs/bm3.md es: https://steelequivalents.com/es/materiales/bs/bm3.md fr: https://steelequivalents.com/fr/matériaux/bs/bm3.md hu: https://steelequivalents.com/hu/anyagok/bs/bm3.md it: https://steelequivalents.com/it/materiali/bs/bm3.md nl: https://steelequivalents.com/nl/materialen/bs/bm3.md pl: https://steelequivalents.com/pl/materiały/bs/bm3.md pt: https://steelequivalents.com/pt/materiais/bs/bm3.md ru: https://steelequivalents.com/ru/материалы/bs/bm3.md tr: https://steelequivalents.com/tr/malzemeler/bs/bm3.md zh: https://steelequivalents.com/zh/材料/bs/bm3.md ja: https://steelequivalents.com/ja/材料/bs/bm3.md ar: https://steelequivalents.com/ar/المواد/bs/bm3.md ko: https://steelequivalents.com/ko/재료/bs/bm3.md pt-br: https://steelequivalents.com/pt-br/materiais/bs/bm3.md hi: https://steelequivalents.com/hi/सामग्री/bs/bm3.md content_hash: sha256:5dea95172745425d9f816a4eb5166800ece8759851c644839220f37195ed9dbf 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/bs/bm3 > Canonical URL: https://steelequivalents.com/materials/bs/bm3 > 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. BS · United Kingdom · 5 designations # BM3 BM3 is a designation in BS for the grade also listed as S6-5-3. We list 5 designations recorded for this grade, in the standards DIN / EN, ASTM, BS, ISO and GB. - *Designations* **5** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=f205683e-403b-4d91-9738-bfc0686340d4&designation=392d963e-de34-49e4-9920-100645811efd "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/bs/bm3.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [GB W6Mo5Cr4V3 This grade’s own name](/materials/gb/w6mo5cr4v3 "GB W6Mo5Cr4V3") ## 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 - [S6-5-3 Indicative](/materials/din-en/s6-5-3 "DIN / EN S6-5-3") ASTM United States · 1 - [M3-1 Indicative](/materials/astm/m3-1 "ASTM M3-1") BS United Kingdom · 1 - **BM3 Indicative** ISO International · 1 - [HS6-5-3 Indicative](/materials/din-en/hs6-5-3 "ISO HS6-5-3") GB China · 1 - [W6Mo5Cr4V3 This grade’s own name](/materials/gb/w6mo5cr4v3 "GB W6Mo5Cr4V3") 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 W Mo Cr Iron — the balance, never listed by a standard — 79.8 % W — 6.3 % Mo — 5 % Cr — 4.2 % Traces & impurities · 4.8 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 1.15–1.25 — Unusual | | Si | 0.2–0.45 | | Mn | 0.15–0.4 | | P | ≤ 0.03 | | S | ≤ 0.02 | | Cr | 3.8–4.5 | | Mo | 4.7–5.2 | | V | 2.7–3.2 — Unusual | | W | 5.9–6.7 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Molybdenum Vanadium Tungsten 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 | 1.15-1.25 | 1.150 | 1.250 | Range | | Si | 0.2-0.45 | 0.200 | 0.450 | Range | | P | ≤0.03 | — | 0.030 | Max | | S | ≤0.02 | — | 0.020 | Max | | V | 2.7-3.2 | 2.700 | 3.200 | Range | | Cr | 3.8-4.5 | 3.800 | 4.500 | Range | | Mn | 0.15-0.4 | 0.150 | 0.400 | Range | | Mo | 4.7-5.2 | 4.700 | 5.200 | Range | | W | 5.9-6.7 | 5.900 | 6.700 | 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 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 0 conditions · 0 values 3 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. ## Heat treatment **GB /T 9943-2025** In this order Test specimen 1. Preheating 800–900 °C 2. Quenching 1190–1210 °C Quenchant Oil, Salt bath or Nitrogen 3. Tempering 550 °C Supply condition - Annealing Supply condition - Annealing Supply condition - Quenching and Tempering Test specimen 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/azhlNWIxMTQ4NTQ_ "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=f205683e-403b-4d91-9738-bfc0686340d4&designation=392d963e-de34-49e4-9920-100645811efd "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/bs/bm3.pdf "Datasheet as PDF")