--- title: "18NiCrMoS5 — Case hardening steels" description: "18NiCrMoS5 in UNI: material number 1.6569, also listed as 17NiCrMoS6-4. Category: Case hardening steels. Designations recorded for this grade: 2." canonical: https://steelequivalents.com/materials/uni/18nicrmos5 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/uni/18nicrmos5.md cs: https://steelequivalents.com/cs/materiály/uni/18nicrmos5.md de: https://steelequivalents.com/de/werkstoffe/uni/18nicrmos5.md es: https://steelequivalents.com/es/materiales/uni/18nicrmos5.md fr: https://steelequivalents.com/fr/matériaux/uni/18nicrmos5.md hu: https://steelequivalents.com/hu/anyagok/uni/18nicrmos5.md it: https://steelequivalents.com/it/materiali/uni/18nicrmos5.md nl: https://steelequivalents.com/nl/materialen/uni/18nicrmos5.md pl: https://steelequivalents.com/pl/materiały/uni/18nicrmos5.md pt: https://steelequivalents.com/pt/materiais/uni/18nicrmos5.md ru: https://steelequivalents.com/ru/материалы/uni/18nicrmos5.md tr: https://steelequivalents.com/tr/malzemeler/uni/18nicrmos5.md zh: https://steelequivalents.com/zh/材料/uni/18nicrmos5.md ja: https://steelequivalents.com/ja/材料/uni/18nicrmos5.md ar: https://steelequivalents.com/ar/المواد/uni/18nicrmos5.md ko: https://steelequivalents.com/ko/재료/uni/18nicrmos5.md pt-br: https://steelequivalents.com/pt-br/materiais/uni/18nicrmos5.md hi: https://steelequivalents.com/hi/सामग्री/uni/18nicrmos5.md content_hash: sha256:88987ee0429df8062e01af3564ae7a3dd4cc2288ba5c913e6dbfa97b1a8c3711 generated: 2026-09-22 --- > **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/uni/18nicrmos5 > Canonical URL: https://steelequivalents.com/materials/uni/18nicrmos5 > 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. UNI · Italy · 2 designations # 18NiCrMoS5 18NiCrMoS5 is a designation in UNI for the material held under material number 1.6569, also listed as 17NiCrMoS6-4. It is a material in the category Case hardening steels. We list 2 designations recorded for this grade, in the standards DIN / EN and UNI. - [*Material no.* **1.6569**](/materials/material-no/1.6569 "Material no.: 1.6569") - [*Category* **Case hardening steels · 60 grades**](/categories/case-hardening-steels "Category: Case hardening steels · 60 grades") - *Designations* **2** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=5b3366a5-088b-416b-b713-57c43bb0b0a5&designation=0f43ba64-91f4-4e4d-ae87-d66e0c6a9db4 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/uni/18nicrmos5.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN 17NiCrMoS6-4 This grade’s own name](/materials/din-en/17nicrmos6-4 "DIN / EN 17NiCrMoS6-4") ## About Case hardening steels Case hardening steels are steels designed to develop a hard, wear-resistant surface while retaining a tough and ductile core. They are used for components such as gears, shafts and other machine parts exposed to contact wear and cyclic loading. 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 - [17NiCrMoS6-4 This grade’s own name](/materials/din-en/17nicrmos6-4 "DIN / EN 17NiCrMoS6-4") UNI Italy · 1 - **18NiCrMoS5 Indicative** Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here. ## Chemical composition 8 elements on file · weight % What this alloy is Fe Ni Cr Mn Iron — the balance, never listed by a standard — 96.1 % Ni — 1.4 % Cr — 1 % Mn — 0.8 % Traces & impurities · 0.8 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.14–0.2 | | Si | ≤ 0.4 | | Mn | 0.6–0.9 | | P | 0.025 | | S | 0.02–0.04 | | Cr | 0.8–1.1 | | Mo | 0.15–0.25 | | Ni | 1.2–1.5 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Molybdenum Nickel 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 | 0,14-0,20 | 0.140 | 0.200 | Range | | Si | ≤0,40 | — | 0.400 | Max | | P | 0,025 | 0.025 | 0.025 | Exact | | S | 0,020-0,040 | 0.020 | 0.040 | Range | | Cr | 0,80-1,10 | 0.800 | 1.100 | Range | | Mn | 0,60-0,90 | 0.600 | 0.900 | Range | | Ni | 1,20-1,50 | 1.200 | 1.500 | Range | | Mo | 0,15-0,25 | 0.150 | 0.250 | 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 computed from composition · °C Predicted Ae3 795 °C Predicted Ae1 723 °C Predicted Acm 455 °C Predicted Bs 524 °C These four temperatures are a CALCULATION from this grade's own composition, using the published Li, Niebuhr, Meekisho & Atteridge (1998) model — never a measurement, and computed from the UPPER BOUND of each element's specified range, not a mid-range figure. Where this grade also has a measured transformation point (Ac1, Ac3, Ar1, Ar3) on file, it is shown separately, in Physical & mechanical properties, and is never replaced by the predicted figures here — Ae (predicted, equilibrium) and Ac/Ar (measured, on heating or cooling) are different physical quantities and can differ by tens of degrees; a mismatch between the two is not an error in either. ## 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 4 conditions · 4 values By delivery state**Treated to improve shearability** source `steelnumber` | Delivery state | HB | |---|---| | Treated to improve shearability | 255 | By delivery state**Soft annealed** source `steelnumber` | Delivery state | HB | |---|---| | Soft annealed | 229 | By delivery state**Treated to hardness range** source `steelnumber` | Delivery state | HB | |---|---| | Treated to hardness range | 179 – 229 | By delivery state**Treated to ferrite-pearlite structure and hardness range** source `steelnumber` | Delivery state | HB | |---|---| | Treated to ferrite-pearlite structure and hardness range | 149 – 201 | 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 1.6, a shared category, and a published range for Ni / Cr 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. [17NiCrMo6-4 1.6566 Ni 1,20-1,50 · Cr 0,80-1,10 - ΔNi 0.00 - ΔCr 0.00 - 11 designations](/materials/din-en/17nicrmo6-4 "17NiCrMo6-4")[20NiCrMoS6-4 1.6571 Ni 1,40-1,70 · Cr 0,60-0,90 - ΔNi 0.20 - ΔCr 0.20 - 1 designations](/materials/din-en/20nicrmos6-4 "20NiCrMoS6-4") ## 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=5b3366a5-088b-416b-b713-57c43bb0b0a5&designation=0f43ba64-91f4-4e4d-ae87-d66e0c6a9db4 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/uni/18nicrmos5.pdf "Datasheet as PDF")