--- title: "170H20 — Quenched and tempered steels" description: "170H20 in BS: material number 1.5530, also listed as 20MnB5. Category: Quenched and tempered steels. Designations recorded for this grade: 5." canonical: https://steelequivalents.com/materials/bs/170h20 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/bs/170h20.md cs: https://steelequivalents.com/cs/materiály/bs/170h20.md de: https://steelequivalents.com/de/werkstoffe/bs/170h20.md es: https://steelequivalents.com/es/materiales/bs/170h20.md fr: https://steelequivalents.com/fr/matériaux/bs/170h20.md hu: https://steelequivalents.com/hu/anyagok/bs/170h20.md it: https://steelequivalents.com/it/materiali/bs/170h20.md nl: https://steelequivalents.com/nl/materialen/bs/170h20.md pl: https://steelequivalents.com/pl/materiały/bs/170h20.md pt: https://steelequivalents.com/pt/materiais/bs/170h20.md ru: https://steelequivalents.com/ru/материалы/bs/170h20.md tr: https://steelequivalents.com/tr/malzemeler/bs/170h20.md zh: https://steelequivalents.com/zh/材料/bs/170h20.md ja: https://steelequivalents.com/ja/材料/bs/170h20.md ar: https://steelequivalents.com/ar/المواد/bs/170h20.md ko: https://steelequivalents.com/ko/재료/bs/170h20.md pt-br: https://steelequivalents.com/pt-br/materiais/bs/170h20.md hi: https://steelequivalents.com/hi/सामग्री/bs/170h20.md content_hash: sha256:93bda674b8e4b2ac51628c83ed88716f439b48564b4247334a1896883e34595d generated: 2026-09-24 --- > **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/170h20 > Canonical URL: https://steelequivalents.com/materials/bs/170h20 > 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 # 170H20 170H20 is a designation in BS for the material held under material number 1.5530, also listed as 20MnB5. It is a material in the category Quenched and tempered steels. We list 5 designations recorded for this grade, in the standards DIN / EN, BS and AFNOR. - [*Material no.* **1.5530**](/materials/material-no/1.5530 "Material no.: 1.5530") - [*Category* **Quenched and tempered steels · 133 grades**](/categories/quenched-and-tempered-steels "Category: Quenched and tempered steels · 133 grades") - *Designations* **5** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=b48e9e9c-c730-4003-9286-a5b68acadff6&designation=0b0ece01-cfc7-4493-90ff-3b60aa84364e "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/bs/170h20.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN 20MnB5 This grade’s own name · 2 grades on that route](/materials/din-en/20mnb5 "DIN / EN 20MnB5") ## About Quenched and tempered steels Quenched and tempered steels are heat-treated steels designed to combine high strength with useful toughness and ductility. They are used for heavily loaded components such as shafts, gears, fasteners and structural machine parts where resistance to mechanical stress is required. This describes the material class as a whole. Always confirm the individual grade against the standard before ordering. ## Also known as 5 designations · 3 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 · 3 - [19MnB4 Indicative](/materials/din-en/19mnb4 "DIN / EN 19MnB4") - [20MnB5 This grade’s own name](/materials/din-en/20mnb5 "DIN / EN 20MnB5") - [21MnB5 This grade’s own name Withdrawn](/materials/din-en/21mnb5 "DIN / EN 21MnB5") BS United Kingdom · 1 - **170H20 Indicative** AFNOR France · 1 - [20MB5 Indicative](/materials/afnor/20mb5 "AFNOR 20MB5") Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here. ## Chemical composition 6 elements on file · weight % What this alloy is Fe Mn Si C Iron — the balance, never listed by a standard — 98.1 % Mn — 1.3 % Si — 0.4 % C — 0.2 % Traces & impurities · 0.1 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.17–0.23 | | Si | ≤ 0.4 | | Mn | 1.1–1.4 | | P | 0.025 | | S | 0.035 | | B | 0.0008–0.005 | Carbon Silicon Manganese Phosphorus Sulfur Boron 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 | |---|---|---|---|---| | B | 0,0008-0,0050 | 0.001 | 0.005 | Range | | C | 0,17-0,23 | 0.170 | 0.230 | Range | | Si | ≤0,40 | — | 0.400 | Max | | P | 0,025 | 0.025 | 0.025 | Exact | | S | 0,035 | 0.035 | 0.035 | Exact | | Mn | 1,10-1,40 | 1.100 | 1.400 | 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 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 · 2 values By thickness**Quenched and tempered · round products** source `steelnumber` | Thickness mm | A% · Lo = 5,65 √So | |---|---| | ≤ 16 | 14 | | 16 – 40 | 15 | 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 1.5, 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. [30MnB5 1.5531 Mn 1,15-1,45 · Si ≤0,40 - ΔMn 0.05 - ΔSi 0.00 - 7 designations](/materials/din-en/30mnb5 "30MnB5")[38MnB5 1.5532 Mn 1,15-1,45 · Si ≤0,40 - ΔMn 0.05 - ΔSi 0.00 - 3 designations](/materials/din-en/38mnb5 "38MnB5") ## 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=b48e9e9c-c730-4003-9286-a5b68acadff6&designation=0b0ece01-cfc7-4493-90ff-3b60aa84364e "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/bs/170h20.pdf "Datasheet as PDF")