--- title: "S99 — composition, equivalents and standards" description: "S99 is a designation in BS for the grade also listed as 5S99D. We list 4 designations recorded for this grade, in the standards BS." canonical: https://steelequivalents.com/materials/bs/s99 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/bs/s99.md cs: https://steelequivalents.com/cs/materiály/bs/s99.md de: https://steelequivalents.com/de/werkstoffe/bs/s99.md es: https://steelequivalents.com/es/materiales/bs/s99.md fr: https://steelequivalents.com/fr/matériaux/bs/s99.md hu: https://steelequivalents.com/hu/anyagok/bs/s99.md it: https://steelequivalents.com/it/materiali/bs/s99.md nl: https://steelequivalents.com/nl/materialen/bs/s99.md pl: https://steelequivalents.com/pl/materiały/bs/s99.md pt: https://steelequivalents.com/pt/materiais/bs/s99.md ru: https://steelequivalents.com/ru/материалы/bs/s99.md tr: https://steelequivalents.com/tr/malzemeler/bs/s99.md zh: https://steelequivalents.com/zh/材料/bs/s99.md ja: https://steelequivalents.com/ja/材料/bs/s99.md ar: https://steelequivalents.com/ar/المواد/bs/s99.md ko: https://steelequivalents.com/ko/재료/bs/s99.md pt-br: https://steelequivalents.com/pt-br/materiais/bs/s99.md hi: https://steelequivalents.com/hi/सामग्री/bs/s99.md content_hash: sha256:d8d600cef9fe9e15b80425bfcfa044b380adadf6a3bfd9363ce4333048b8379f 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/s99 > Canonical URL: https://steelequivalents.com/materials/bs/s99 > 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 · 4 designations # S99 S99 is a designation in BS for the grade also listed as 5S99D. We list 4 designations recorded for this grade, in the standards BS. - *Designations* **4** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=9bbcd10f-c6d7-4a0b-ac4a-1b730f3b55c1&designation=cb090700-8b5f-4d7c-91e4-8289d42463a0 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/bs/s99.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [BS 5S99D This grade’s own name](/materials/bs/5s99d "BS 5S99D") ## Also known as 4 designations · 1 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. BS United Kingdom · 4 - [5S99D This grade’s own name](/materials/bs/5s99d "BS 5S99D") - [5S99G Indicative](/materials/bs/5s99g "BS 5S99G") - [826M40 Indicative](/materials/bs/826m40 "BS 826M40") - **S99 Indicative** Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here. ## Predicted transformation temperatures Not enough recorded composition to predict a transformation temperature for this grade — missing: C, Mn, Si, Ni, Cr, Mo. ## 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. ## 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=9bbcd10f-c6d7-4a0b-ac4a-1b730f3b55c1&designation=cb090700-8b5f-4d7c-91e4-8289d42463a0 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/bs/s99.pdf "Datasheet as PDF")