--- title: "1.6355 — Special steels for aviation and aerospace" description: "1.6355 is the material number of the grade also listed as X2NiCoMo18-12. It is a material in the category Special steels for aviation and aerospace." canonical: https://steelequivalents.com/materials/material-no/1.6355 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/material-no/1.6355.md cs: https://steelequivalents.com/cs/materiály/číslo-materiálu/1.6355.md de: https://steelequivalents.com/de/werkstoffe/werkstoff-nr/1.6355.md es: https://steelequivalents.com/es/materiales/número-de-material/1.6355.md fr: https://steelequivalents.com/fr/matériaux/numéro-de-matériau/1.6355.md hu: https://steelequivalents.com/hu/anyagok/anyagszám/1.6355.md it: https://steelequivalents.com/it/materiali/numero-materiale/1.6355.md nl: https://steelequivalents.com/nl/materialen/materiaalnummer/1.6355.md pl: https://steelequivalents.com/pl/materiały/numer-materiału/1.6355.md pt: https://steelequivalents.com/pt/materiais/número-do-material/1.6355.md ru: https://steelequivalents.com/ru/материалы/номер-материала/1.6355.md tr: https://steelequivalents.com/tr/malzemeler/malzeme-numarası/1.6355.md zh: https://steelequivalents.com/zh/材料/材料编号/1.6355.md ja: https://steelequivalents.com/ja/材料/材料番号/1.6355.md ar: https://steelequivalents.com/ar/المواد/رقم-المادة/1.6355.md ko: https://steelequivalents.com/ko/재료/재료번호/1.6355.md pt-br: https://steelequivalents.com/pt-br/materiais/número-do-material/1.6355.md hi: https://steelequivalents.com/hi/सामग्री/सामग्री-संख्या/1.6355.md content_hash: sha256:b12f012397be6c35e509549a3a0a59277fe07eecd89877589c8c0d60aab60b57 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/material-no/1.6355 > Canonical URL: https://steelequivalents.com/materials/material-no/1.6355 > 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. Material number · Europe · 2 designations # 1.6355 1.6355 is the material number of the grade also listed as X2NiCoMo18-12. It is a material in the category Special steels for aviation and aerospace. We list 2 designations recorded for this grade, in the standards DIN / EN and UNS. - ***Material no.* **1.6355**** - [*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* **2** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=a18326d9-904f-4a76-a9f3-c9b524377547 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/material-no/1.6355.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN X2NiCoMo18-12 This grade’s own name](/materials/din-en/x2nicomo18-12 "DIN / EN X2NiCoMo18-12") - [UNS K93540 This grade’s own name · 2 grades on that route](/materials/uns/k93540 "UNS K93540") ## 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 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. DIN / EN Europe · 1 - [X2NiCoMo18-12 This grade’s own name](/materials/din-en/x2nicomo18-12 "DIN / EN X2NiCoMo18-12") UNS United States · 1 - [K93540 This grade’s own name](/materials/uns/k93540 "UNS K93540") 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 Ni Co Mo Iron — the balance, never listed by a standard — 63.6 % Ni — 18 % Co — 12 % Mo — 5.2 % Traces & impurities · 1.3 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | ≤ 0.03 | | Si | ≤ 0.1 | | Mn | ≤ 0.1 | | P | 0.01 | | S | 0.01 | | Mo | 4.8–5.5 — Unusual | | Ni | 17–19 | | Co | 11–13 | | Al | 0.05–0.15 | | Ti | 0.75–1.1 | Carbon Silicon Manganese Phosphorus Sulfur Molybdenum Nickel Cobalt Aluminium Titanium 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 | ≤0,03 | — | 0.030 | Max | | Al | 0,05-0,15 | 0.050 | 0.150 | Range | | Si | ≤0,10 | — | 0.100 | Max | | P | 0,01 | 0.010 | 0.010 | Exact | | S | 0,01 | 0.010 | 0.010 | Exact | | Ti | 0,75-1,10 | 0.750 | 1.100 | Range | | Mn | ≤0,10 | — | 0.100 | Max | | Co | 11,0-13,0 | 11.000 | 13.000 | Range | | Ni | 17,0-19,0 | 17.000 | 19.000 | Range | | Mo | 4,80-5,50 | 4.800 | 5.500 | 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: Cr. ## 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. ## Similar grades — and why Selection rule, stated so you can disagree with it: same number class 1.6, a shared category, and a published range for Ni / Co 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. [X2NiCoMoTi18-12-4 1.6356 Ni 17,0-18,5 · Co 11,5-13,5 - ΔNi 0.25 - ΔCo 0.50 - 2 designations](/materials/din-en/x2nicomoti18-12-4 "X2NiCoMoTi18-12-4") ## 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=a18326d9-904f-4a76-a9f3-c9b524377547 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/material-no/1.6355.pdf "Datasheet as PDF")