--- title: "15423 — Hydrogen resistant steels" description: "15423 in ČSN: material number 1.7779, also listed as 20CrMoV13-5. Category: Hydrogen resistant steels. 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Compare it to detect a real > content change; `generated` moves on every render and is not a change signal. ČSN · Czechia · 3 designations # 15423 15423 is a designation in ČSN for the material held under material number 1.7779, also listed as 20CrMoV13-5. It is a material in the category Hydrogen resistant steels. We list 3 designations recorded for this grade, in the standards DIN / EN and ČSN. - [*Material no.* **1.7779**](/materials/material-no/1.7779 "Material no.: 1.7779") - [*Category* **Hydrogen resistant steels · 8 grades**](/categories/hydrogen-resistant-steels "Category: Hydrogen resistant steels · 8 grades") - *Designations* **3** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=41c745c8-6058-47f5-b2a3-a4a7889f5027&designation=8952f779-0219-44e3-b289-4d341cf5578a "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/csn/15423.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN 20CrMoV13-5-5 This grade’s own name](/materials/din-en/20crmov13-5-5 "DIN / EN 20CrMoV13-5-5") ## About Hydrogen resistant steels Hydrogen resistant steels are steels designed to withstand hydrogen-related damage, including hydrogen embrittlement and hydrogen attack. They are used for pressure vessels, piping and process equipment exposed to hydrogen-containing environments, where resistance to hydrogen ingress and loss of toughness is important. This describes the material class as a whole. Always confirm the individual grade against the standard before ordering. ## Also known as 3 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 Withdrawn designation no longer current — a separate column from the two above, so a name can be same grade and withdrawn at once. DIN / EN Europe · 2 - [20CrMoV13-5 This grade’s own name Withdrawn](/materials/din-en/20crmov13-5 "DIN / EN 20CrMoV13-5") - [20CrMoV13-5-5 This grade’s own name](/materials/din-en/20crmov13-5-5 "DIN / EN 20CrMoV13-5-5") ČSN Czechia · 1 - **15423 Indicative** Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here. ## Chemical composition 11 elements on file · weight % What this alloy is Fe Cr Mo V Iron — the balance, never listed by a standard — 94.3 % Cr — 3.2 % Mo — 0.6 % V — 0.5 % Traces & impurities · 1.5 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.17–0.23 | | Si | 0.15–0.35 | | Mn | 0.3–0.5 | | P | 0.025 | | S | 0.02 | | Cr | 3–3.3 | | Mo | 0.5–0.6 | | Ni | 0.3 | | V | 0.45–0.55 | | Cu | ≤ 0.3 | | Al | ≤ 0.04 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Molybdenum Nickel Vanadium Copper 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 | 0,17-0,23 | 0.170 | 0.230 | Range | | Al | ≤0,040 | — | 0.040 | Max | | Si | 0,15-0,35 | 0.150 | 0.350 | Range | | P | 0,025 | 0.025 | 0.025 | Exact | | S | 0,02 | 0.020 | 0.020 | Exact | | V | 0,45-0,55 | 0.450 | 0.550 | Range | | Cr | 3,00-3,30 | 3.000 | 3.300 | Range | | Mn | 0,30-0,50 | 0.300 | 0.500 | Range | | Ni | 0,3 | 0.300 | 0.300 | Exact | | Cu | ≤0,30 | — | 0.300 | Max | | Mo | 0,50-0,60 | 0.500 | 0.600 | 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 811 °C Predicted Ae1 796 °C Predicted Acm 528 °C Predicted Bs 465 °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. ## 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=41c745c8-6058-47f5-b2a3-a4a7889f5027&designation=8952f779-0219-44e3-b289-4d341cf5578a "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/csn/15423.pdf "Datasheet as PDF")