--- title: "1.7709 — Heat-resistant structural steels" description: "1.7709 is the material number of the grade also listed as 21CrMoV5-7. Category: Heat-resistant structural steels. Designations recorded for this grade: 14." canonical: https://steelequivalents.com/materials/material-no/1.7709 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/material-no/1.7709.md cs: https://steelequivalents.com/cs/materiály/číslo-materiálu/1.7709.md de: https://steelequivalents.com/de/werkstoffe/werkstoff-nr/1.7709.md es: https://steelequivalents.com/es/materiales/número-de-material/1.7709.md fr: https://steelequivalents.com/fr/matériaux/numéro-de-matériau/1.7709.md hu: https://steelequivalents.com/hu/anyagok/anyagszám/1.7709.md it: https://steelequivalents.com/it/materiali/numero-materiale/1.7709.md nl: https://steelequivalents.com/nl/materialen/materiaalnummer/1.7709.md pl: https://steelequivalents.com/pl/materiały/numer-materiału/1.7709.md pt: https://steelequivalents.com/pt/materiais/número-do-material/1.7709.md ru: https://steelequivalents.com/ru/материалы/номер-материала/1.7709.md tr: https://steelequivalents.com/tr/malzemeler/malzeme-numarası/1.7709.md zh: https://steelequivalents.com/zh/材料/材料编号/1.7709.md ja: https://steelequivalents.com/ja/材料/材料番号/1.7709.md ar: https://steelequivalents.com/ar/المواد/رقم-المادة/1.7709.md ko: https://steelequivalents.com/ko/재료/재료번호/1.7709.md pt-br: https://steelequivalents.com/pt-br/materiais/número-do-material/1.7709.md hi: https://steelequivalents.com/hi/सामग्री/सामग्री-संख्या/1.7709.md content_hash: sha256:aa347bf7dcdeea21987427a29c37c74bb3654ffb82233fbea91190e0228f302f 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/1.7709 > Canonical URL: https://steelequivalents.com/materials/material-no/1.7709 > 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 · 14 designations # 1.7709 1.7709 is the material number of the grade also listed as 21CrMoV5-7. It is a material in the category Heat-resistant structural steels. We list 14 designations recorded for this grade, in the standards DIN / EN, AFNOR, GOST, ČSN, STN, PN and MSZ. - ***Material no.* **1.7709**** - [*Category* **Heat-resistant structural steels · 62 grades**](/categories/heat-resistant-structural-steels "Category: Heat-resistant structural steels · 62 grades") - *Designations* **14** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=1cf96e02-dcd5-4b95-8280-878670397d97 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/material-no/1.7709.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN 21CrMoV5-7 This grade’s own name](/materials/din-en/21crmov5-7 "DIN / EN 21CrMoV5-7") ## About Heat-resistant structural steels Heat-resistant structural steels are structural steels designed to retain useful strength and dimensional stability at elevated temperatures. They are used for load-bearing components in hot-service equipment where mechanical performance must be maintained during heating. This describes the material class as a whole. Always confirm the individual grade against the standard before ordering. ## Also known as 14 designations · 7 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 - [21CrMoV5-7 This grade’s own name](/materials/din-en/21crmov5-7 "DIN / EN 21CrMoV5-7") AFNOR France · 1 - [20CDV5-07 Indicative](/materials/afnor/20cdv5-07 "AFNOR 20CDV5-07") GOST Russia / CIS · 8 - [21Kh1M1F Indicative](/materials/gost/21kh1m1f "GOST 21Kh1M1F") - [25Ch1M1F Indicative](/materials/gost/25ch1m1f "GOST 25Ch1M1F") - [25KH1M1F Indicative](/materials/gost/25kh1m1f "GOST 25KH1M1F") - [25KH1MF Indicative](/materials/gost/25kh1mf "GOST 25KH1MF") - [25Х1М1Ф Indicative](/materials/gost/25kh1m1f "GOST 25Х1М1Ф") - [25Х1М1ФА Indicative](/materials/gost/25kh1m1fa "GOST 25Х1М1ФА") - [25Х1МФ Indicative](/materials/gost/25kh1mf "GOST 25Х1МФ") - [ЭИ10 Indicative](/materials/gost/ei10 "GOST ЭИ10") ČSN Czechia · 1 - [15320 Indicative](/materials/csn/15320 "ČSN 15320") STN Slovakia · 1 - [15 320 Indicative](/materials/csn/15320 "STN 15 320") PN Poland · 1 - [21HMF Indicative](/materials/pn/21hmf "PN 21HMF") MSZ Hungary · 1 - [MCrMoV Indicative](/materials/msz/mcrmov "MSZ MCrMoV") 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 Mo Mn Iron — the balance, never listed by a standard — 95.8 % Cr — 1.4 % Mo — 0.7 % Mn — 0.6 % Traces & impurities · 1.6 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.17–0.25 | | Si | ≤ 0.4 | | Mn | 0.4–0.8 | | P | 0.025 | | S | 0.03 | | Cr | 1.2–1.5 | | Mo | 0.55–0.8 | | Ni | 0.6 | | V | 0.2–0.35 | | Al | ≤ 0.03 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Molybdenum Nickel Vanadium Aluminium 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 | 0,17-0,25 | 0.170 | 0.250 | Range | | Al | ≤0,030 | — | 0.030 | Max | | Si | ≤0,40 | — | 0.400 | Max | | P | 0,025 | 0.025 | 0.025 | Exact | | S | 0,03 | 0.030 | 0.030 | Exact | | V | 0,20-0,35 | 0.200 | 0.350 | Range | | Cr | 1,20-1,50 | 1.200 | 1.500 | Range | | Mn | 0,40-0,80 | 0.400 | 0.800 | Range | | Ni | 0,6 | 0.600 | 0.600 | Exact | | Mo | 0,55-0,80 | 0.550 | 0.800 | 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 803 °C Predicted Ae1 747 °C Predicted Acm 514 °C Predicted Bs 502 °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 Transformation point Ac1 760 °C Exact Transformation point Ac3 840 °C Exact · Ac3(Acm) Transformation point Ar3 760 °C Exact · Ar3(Arcm) Transformation point Ar1 680 °C Exact Weldability difficult to weld As published: hard 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 · 43 values By delivery state**no delivery state stated** source `splav` | Delivery state | HB | |---|---| | 25Kh1MF ( 25Х1МФ ) (quenching, tempering) | 241 – 321 | | 25Kh1MF ( 25Х1МФ ) (hot-rolled, annealing) , GOST 20072-74 | 229 | By delivery state**Annealed to achieve spheroidization of the carbides** source `steelnumber` | Delivery state | HB | |---|---| | Annealed to achieve spheroidization of the carbides | 229 | By delivery state**Treated to improve shearability** source `steelnumber` | Delivery state | HB | |---|---| | Treated to improve shearability | 255 | By dimension**Quenching 880 - 900°C, oil, Drawing 640 - 660°C,Cooling air** source `splav` | Dimension mm | Rm N/mm² | Re N/mm² | A5% | Z% | KCU kJ/m² | |---|---|---|---|---|---| | max thickness 25 | 880 | 735 | 14 | 50 | 590 | By heat-treated condition**no delivery state stated** source `splav` | Heat-treated condition | Rm N/mm² | Re N/mm² | A5% | Z% | KCU kJ/m² | |---|---|---|---|---|---| | Bar, band, GOST 20072-74 | 780 | 665 | 16 | 50 | 590 | At temperature**no delivery state stated** source `splav` | Temperature °C | Density g/cm³ | Elastic modulus GPa | Thermal expansion coefficient 10^-6/K | Thermal conductivity W/(m·K) | Specific heat capacity J/(kg·K) | Electrical resistivity nΩ·m | |---|---|---|---|---|---|---| | 20 | 7.84 | 217 | — | — | — | — | | 100 | — | 211 | 11.3 | 39.8 | 462 | 312 | | 200 | 7.79 | 206 | 11.7 | 37.9 | — | 396 | | 300 | — | 198 | 12.8 | 36.9 | — | 475 | | 400 | 7.72 | 191 | 13.9 | 35.9 | — | 574 | | 500 | — | 180 | 14.2 | 34.8 | — | 680 | | 600 | 7.65 | 167 | 14.4 | — | — | 826 | 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 1.7, a shared category, and a published range for Cr / Mo 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. [24CrMoV5-5 1.7733 Cr 1,20-1,50 · Mo 0,50-0,60 - ΔCr 0.00 - ΔMo 0.13 - 31 designations](/materials/din-en/24crmov5-5 "24CrMoV5-5")[13CrMoSi5-5 1.7336 Cr 1,00-1,50 · Mo 0,45-0,65 - ΔCr 0.10 - ΔMo 0.13 - 12 designations](/materials/din-en/13crmosi5-5 "13CrMoSi5-5")[10CrMo5-5 1.7338 Cr 1,00-1,50 · Mo 0,45-0,65 - ΔCr 0.10 - ΔMo 0.13 - 3 designations](/materials/din-en/10crmo5-5 "10CrMo5-5")[40CrMoV4-6 1.7711 Cr 0,90-1,20 · Mo 0,50-0,65 - ΔCr 0.30 - ΔMo 0.10 - 8 designations](/materials/din-en/40crmov4-6 "40CrMoV4-6") ## 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=1cf96e02-dcd5-4b95-8280-878670397d97 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/material-no/1.7709.pdf "Datasheet as PDF")