--- title: "EN355 — Case hardening steels" description: "EN355 in BS: material number 1.6587, also listed as 18CrNiMo7-6. Category: Case hardening steels. Designations recorded for this grade: 41." canonical: https://steelequivalents.com/materials/bs/en355 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/bs/en355.md cs: https://steelequivalents.com/cs/materiály/bs/en355.md de: https://steelequivalents.com/de/werkstoffe/bs/en355.md es: https://steelequivalents.com/es/materiales/bs/en355.md fr: https://steelequivalents.com/fr/matériaux/bs/en355.md hu: https://steelequivalents.com/hu/anyagok/bs/en355.md it: https://steelequivalents.com/it/materiali/bs/en355.md nl: https://steelequivalents.com/nl/materialen/bs/en355.md pl: https://steelequivalents.com/pl/materiały/bs/en355.md pt: https://steelequivalents.com/pt/materiais/bs/en355.md ru: https://steelequivalents.com/ru/материалы/bs/en355.md tr: https://steelequivalents.com/tr/malzemeler/bs/en355.md zh: https://steelequivalents.com/zh/材料/bs/en355.md ja: https://steelequivalents.com/ja/材料/bs/en355.md ar: https://steelequivalents.com/ar/المواد/bs/en355.md ko: https://steelequivalents.com/ko/재료/bs/en355.md pt-br: https://steelequivalents.com/pt-br/materiais/bs/en355.md hi: https://steelequivalents.com/hi/सामग्री/bs/en355.md content_hash: sha256:15e977ae99e2293fa85cedd953dedeecc1b1ae60fec057ad5101bb235e919331 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/bs/en355 > Canonical URL: https://steelequivalents.com/materials/bs/en355 > 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 · 41 designations # EN355 EN355 is a designation in BS for the material held under material number 1.6587, also listed as 18CrNiMo7-6. It is a material in the category Case hardening steels. We list 41 designations recorded for this grade, in the standards DIN / EN, UNS, AISI / SAE, BS, AFNOR, UNE, ISO, JIS, GB, GOST, UNI, ČSN, PN, COPANT, SRPS and SFS. - [*Material no.* **1.6587**](/materials/material-no/1.6587 "Material no.: 1.6587") - [*Category* **Case hardening steels · 60 grades**](/categories/case-hardening-steels "Category: Case hardening steels · 60 grades") - *Designations* **41** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=7a457feb-713a-4f70-a5f1-8b5036421463&designation=9ca6e4ac-07a4-4e89-a47d-a5f6d247c61f "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/bs/en355.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN 18CrNiMo7-6 This grade’s own name](/materials/din-en/18crnimo7-6 "DIN / EN 18CrNiMo7-6") - [BS 22H17 This grade’s own name](/materials/bs/22h17 "BS 22H17") ## 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 41 designations · 16 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 · 4 - [1.6587 Indicative](/materials/material-no/1.6587 "DIN / EN 1.6587") - [17CrNiMo6 This grade’s own name Withdrawn](/materials/din-en/17crnimo6 "DIN / EN 17CrNiMo6") - [17CrNiMo7 Indicative](/materials/din-en/17crnimo7 "DIN / EN 17CrNiMo7") - [18CrNiMo7-6 This grade’s own name](/materials/din-en/18crnimo7-6 "DIN / EN 18CrNiMo7-6") UNS United States · 1 - [G48200 Indicative](/materials/uns/g48200 "UNS G48200") AISI / SAE United States · 5 - [4320 Indicative](/materials/aisi-sae/4320 "AISI / SAE 4320") - [4320H Indicative](/materials/aisi-sae/4320h "AISI / SAE 4320H") - [4820 Indicative](/materials/aisi-sae/4820 "AISI / SAE 4820") - [G43200 Indicative](/materials/uns/g43200 "AISI / SAE G43200") - [H43200 Indicative](/materials/uns/h43200 "AISI / SAE H43200") BS United Kingdom · 6 - [22H17 This grade’s own name](/materials/bs/22h17 "BS 22H17") - [817M17 This grade’s own name](/materials/bs/817m17 "BS 817M17") - [820A16 Indicative](/materials/bs/820a16 "BS 820A16") - [822A17 This grade’s own name](/materials/bs/822a17 "BS 822A17") - [822M17 Indicative](/materials/bs/822m17 "BS 822M17") - **EN355 This grade’s own name** AFNOR France · 2 - [18NCD6 Indicative](/materials/afnor/18ncd6 "AFNOR 18NCD6") - [18NiCrMo6 Indicative](/materials/afnor/18nicrmo6 "AFNOR 18NiCrMo6") UNE Spain · 3 - [14NiCrMo13 Indicative](/materials/une/14nicrmo13 "UNE 14NiCrMo13") - [F.1560 Indicative](/materials/une/f-1560 "UNE F.1560") - [F.1560-14NiCrMo13 Indicative](/materials/une/f-1560-14nicrmo13 "UNE F.1560-14NiCrMo13") ISO International · 1 - [18CrNiMo7 Indicative](/materials/iso/18crnimo7 "ISO 18CrNiMo7") JIS Japan · 4 - [SNCM415 Indicative](/materials/jis/sncm415 "JIS SNCM415") - [SNCM420 Indicative](/materials/jis/sncm420 "JIS SNCM420") - [SNCM420H Indicative](/materials/jis/sncm420h "JIS SNCM420H") - [SNCM815 Indicative](/materials/jis/sncm815 "JIS SNCM815") GB China · 1 - [17Cr2Ni2Mo Indicative](/materials/gb/17cr2ni2mo "GB 17Cr2Ni2Mo") GOST Russia / CIS · 6 - [12ChN4A Indicative](/materials/gost/12chn4a "GOST 12ChN4A") - [18KH2N4VА Indicative](/materials/gost/18kh2n4va "GOST 18KH2N4VА") - [18Х2Н4ВА Indicative](/materials/gost/18kh2n4va "GOST 18Х2Н4ВА") - [20KHN2M Indicative](/materials/gost/20khn2m "GOST 20KHN2M") - [20ХН2М Indicative](/materials/gost/20khn2m "GOST 20ХН2М") - [20ХНМ Indicative](/materials/gost/20khnm "GOST 20ХНМ") UNI Italy · 1 - [18NiCrMo7 Indicative](/materials/uni/18nicrmo7 "UNI 18NiCrMo7") ČSN Czechia · 2 - [16326 Indicative](/materials/csn/16326 "ČSN 16326") - [16326PH Indicative](/materials/csn/16326ph "ČSN 16326PH") PN Poland · 2 - [17HGM Indicative](/materials/pn/17hgm "PN 17HGM") - [17HNM Indicative](/materials/pn/17hnm "PN 17HNM") COPANT Latin America · 1 - [4820 Indicative](/materials/aisi-sae/4820 "COPANT 4820") SRPS Serbia · 1 - [Č.4520 Indicative](/materials/srps/c-4520 "SRPS Č.4520") SFS Finland · 1 - [511 Indicative](/materials/sfs/511 "SFS 511") 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 Cr Ni Mn Iron — the balance, never listed by a standard — 95.2 % Cr — 1.7 % Ni — 1.5 % Mn — 0.7 % Traces & impurities · 0.9 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.15–0.21 | | Si | ≤ 0.4 | | Mn | 0.5–0.9 | | P | 0.025 | | S | 0.035 | | Cr | 1.5–1.8 — Unusual | | Mo | 0.25–0.35 | | Ni | 1.4–1.7 | 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 | 0,15-0,21 | 0.150 | 0.210 | Range | | Si | ≤0,40 | — | 0.400 | Max | | P | 0,025 | 0.025 | 0.025 | Exact | | S | 0,035 | 0.035 | 0.035 | Exact | | Cr | 1,50-1,80 | 1.500 | 1.800 | Range | | Mn | 0,50-0,90 | 0.500 | 0.900 | Range | | Ni | 1,40-1,70 | 1.400 | 1.700 | Range | | Mo | 0,25-0,35 | 0.250 | 0.350 | 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 789 °C Predicted Ae1 737 °C Predicted Acm 480 °C Predicted Bs 492 °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 7,77 g/cm³ Exact Transformation point Ac1 720 °C Exact Transformation point Ac3 825 °C Exact · Ac3(Acm) Weldability weldable with restrictions As published: limited weldability. Flake sensitivity susceptible As published: predisposed Temper brittleness not susceptible As published: not predisposed 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 6 conditions · 10 values By dimension**Quenching and drawing** source `splav` | Dimension mm | Rm N/mm² | Re N/mm² | A5% | Z% | KCU kJ/m² | |---|---|---|---|---|---| | Ø 15 | 880 | 685 | 11 | 50 | 780 | 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 | 159 – 207 | At temperature**no delivery state stated** source `steelnumber` | Temperature °C | Rm N/mm² | |---|---| | 200 | 1200 | 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. ## 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=7a457feb-713a-4f70-a5f1-8b5036421463&designation=9ca6e4ac-07a4-4e89-a47d-a5f6d247c61f "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/bs/en355.pdf "Datasheet as PDF")