--- title: "S191 — Special steels for aviation and aerospace" description: "S191 in BS: material number 1.4933, also listed as S64152. Category: Special steels for aviation and aerospace. Designations recorded for this grade: 8." canonical: https://steelequivalents.com/materials/bs/s191 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/bs/s191.md cs: https://steelequivalents.com/cs/materiály/bs/s191.md de: https://steelequivalents.com/de/werkstoffe/bs/s191.md es: https://steelequivalents.com/es/materiales/bs/s191.md fr: https://steelequivalents.com/fr/matériaux/bs/s191.md hu: https://steelequivalents.com/hu/anyagok/bs/s191.md it: https://steelequivalents.com/it/materiali/bs/s191.md nl: https://steelequivalents.com/nl/materialen/bs/s191.md pl: https://steelequivalents.com/pl/materiały/bs/s191.md pt: https://steelequivalents.com/pt/materiais/bs/s191.md ru: https://steelequivalents.com/ru/материалы/bs/s191.md tr: https://steelequivalents.com/tr/malzemeler/bs/s191.md zh: https://steelequivalents.com/zh/材料/bs/s191.md ja: https://steelequivalents.com/ja/材料/bs/s191.md ar: https://steelequivalents.com/ar/المواد/bs/s191.md ko: https://steelequivalents.com/ko/재료/bs/s191.md pt-br: https://steelequivalents.com/pt-br/materiais/bs/s191.md hi: https://steelequivalents.com/hi/सामग्री/bs/s191.md content_hash: sha256:9cec31386eee019fbc0dbe3451aa4b45c38be53de4d9c7342cb06537be228606 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/s191 > Canonical URL: https://steelequivalents.com/materials/bs/s191 > 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 · 8 designations # S191 S191 is a designation in BS for the material held under material number 1.4933, also listed as S64152. It is a material in the category Special steels for aviation and aerospace. We list 8 designations recorded for this grade, in the standards UNS, AISI / SAE, BS and SAE AMS. - [*Material no.* **1.4933**](/materials/material-no/1.4933 "Material no.: 1.4933") - [*Category* **Special steels for aviation and aerospace · 39 grades**](/categories/special-steels-for-aviation-and-aerospace "Category: Special steels for aviation and aerospace · 39 grades") - *Designations* **8** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=a990db3a-c9d4-4dce-9369-8a2a8f9afd84&designation=00e333f0-59d9-49c3-ac04-4413bd4a6e63 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/bs/s191.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [UNS S64152 This grade’s own name · 2 grades on that route](/materials/uns/s64152 "UNS S64152") - [AISI / SAE XM-32 This grade’s own name · 2 grades on that route](/materials/aisi-sae/xm-32 "AISI / SAE XM-32") ## About Special steels for aviation and aerospace Special steels for aviation and aerospace are engineered steels designed to provide controlled mechanical properties and reliable performance in demanding service. Their alloying and heat-treatment capabilities support components that require a combination of strength, toughness and fatigue resistance, including aircraft structures and engine parts. This describes the material class as a whole. Always confirm the individual grade against the standard before ordering. ## Also known as 8 designations · 4 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. UNS United States · 1 - [S64152 This grade’s own name](/materials/uns/s64152 "UNS S64152") AISI / SAE United States · 1 - [XM-32 This grade’s own name](/materials/aisi-sae/xm-32 "AISI / SAE XM-32") BS United Kingdom · 5 - [S151 Indicative](/materials/bs/s151 "BS S151") - [S159 Indicative](/materials/bs/s159 "BS S159") - [S159A Indicative](/materials/bs/s159a "BS S159A") - [S159D Indicative](/materials/bs/s159d "BS S159D") - **S191 Indicative** SAE AMS United States / Aerospace · 1 - [5719 Indicative](/materials/ams/5719 "SAE AMS 5719") Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here. ## Chemical composition 10 elements on file · weight % What this alloy is Fe Cr Ni Mo Iron — the balance, never listed by a standard — 82.4 % Cr — 11.8 % Ni — 2.5 % Mo — 1.8 % Traces & impurities · 1.6 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.08–0.13 | | Si | ≤ 0.35 | | Mn | 0.5–0.9 | | P | 0.03 | | S | 0.025 | | Cr | 11–12.5 | | Mo | 1.5–2 | | Ni | 2–3 | | V | 0.25–0.4 | | N | 0.02–0.04 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Molybdenum Nickel Vanadium Nitrogen 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 | 0,08-0,13 | 0.080 | 0.130 | Range | | N | 0,02-0,040 | 0.020 | 0.040 | Range | | Si | ≤0,35 | — | 0.350 | Max | | P | 0,03 | 0.030 | 0.030 | Exact | | S | 0,025 | 0.025 | 0.025 | Exact | | V | 0,25-0,40 | 0.250 | 0.400 | Range | | Cr | 11,0-12,5 | 11.000 | 12.500 | Range | | Mn | 0,50-0,90 | 0.500 | 0.900 | Range | | Ni | 2,00-3,00 | 2.000 | 3.000 | Range | | Mo | 1,50-2,00 | 1.500 | 2.000 | 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 This grade's composition falls outside the published model's validated range (a low-alloy composition window), so no transformation temperature is predicted here. ## 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. ## 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=a990db3a-c9d4-4dce-9369-8a2a8f9afd84&designation=00e333f0-59d9-49c3-ac04-4413bd4a6e63 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/bs/s191.pdf "Datasheet as PDF")