--- title: "K71340 — Low-temperature structural steels" description: "K71340 in UNS: material number 1.5662, also listed as X8Ni9. Category: Low-temperature structural steels. Designations recorded for this grade: 18." canonical: https://steelequivalents.com/materials/uns/k71340 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/uns/k71340.md cs: https://steelequivalents.com/cs/materiály/uns/k71340.md de: https://steelequivalents.com/de/werkstoffe/uns/k71340.md es: https://steelequivalents.com/es/materiales/uns/k71340.md fr: https://steelequivalents.com/fr/matériaux/uns/k71340.md hu: https://steelequivalents.com/hu/anyagok/uns/k71340.md it: https://steelequivalents.com/it/materiali/uns/k71340.md nl: https://steelequivalents.com/nl/materialen/uns/k71340.md pl: https://steelequivalents.com/pl/materiały/uns/k71340.md pt: https://steelequivalents.com/pt/materiais/uns/k71340.md ru: https://steelequivalents.com/ru/материалы/uns/k71340.md tr: https://steelequivalents.com/tr/malzemeler/uns/k71340.md zh: https://steelequivalents.com/zh/材料/uns/k71340.md ja: https://steelequivalents.com/ja/材料/uns/k71340.md ar: https://steelequivalents.com/ar/المواد/uns/k71340.md ko: https://steelequivalents.com/ko/재료/uns/k71340.md pt-br: https://steelequivalents.com/pt-br/materiais/uns/k71340.md hi: https://steelequivalents.com/hi/सामग्री/uns/k71340.md content_hash: sha256:b871495a9a2add33a9eccc253410b20ad4fd3c3cb7731cfb7f6dda87a820ae40 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/uns/k71340 > Canonical URL: https://steelequivalents.com/materials/uns/k71340 > 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. UNS · United States · 18 designations # K71340 K71340 is a designation in UNS for the material held under material number 1.5662, also listed as X8Ni9. It is a material in the category Low-temperature structural steels. We list 18 designations recorded for this grade, in the standards DIN / EN, UNS, AISI / SAE, ASTM, BS, AFNOR, UNE, UNI and ČSN. - [*Material no.* **1.5662**](/materials/material-no/1.5662 "Material no.: 1.5662") - [*Category* **Low-temperature structural steels · 55 grades**](/categories/low-temperature-structural-steels "Category: Low-temperature structural steels · 55 grades") - *Designations* **18** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=68eab8f1-0e4b-474e-856d-99ed7c5739c1&designation=83496360-9e0b-4f67-bc1b-c3b27422bb0d "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/uns/k71340.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN X8Ni9 This grade’s own name · 2 grades on that route](/materials/din-en/x8ni9 "DIN / EN X8Ni9") - [UNS K81340 This grade’s own name · 2 grades on that route](/materials/uns/k81340 "UNS K81340") ## About Low-temperature structural steels Low-temperature structural steels are structural steels designed to retain toughness and reliable load-bearing performance in cold service. Their resistance to brittle fracture at low temperatures makes them suitable for structures, pressure-containing equipment and other components exposed to severe cold. This describes the material class as a whole. Always confirm the individual grade against the standard before ordering. ## Also known as 18 designations · 9 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 · 3 - [1.5662 Indicative](/materials/material-no/1.5662 "DIN / EN 1.5662") - [X8Ni9 This grade’s own name](/materials/din-en/x8ni9 "DIN / EN X8Ni9") - [Z8N09 Indicative](/materials/din-en/z8n09 "DIN / EN Z8N09") UNS United States · 2 - **K71340 This grade’s own name** - [K81340 This grade’s own name](/materials/uns/k81340 "UNS K81340") AISI / SAE United States · 2 - [A353 Indicative](/materials/aisi-sae/a353 "AISI / SAE A353") - [ASTM A353 Indicative](/materials/aisi-sae/astm-a353 "AISI / SAE ASTM A353") ASTM United States · 1 - [A353 Indicative](/materials/aisi-sae/a353 "ASTM A353") BS United Kingdom · 3 - [1501-509 Indicative](/materials/bs/1501-509 "BS 1501-509") - [1501-509-510 Indicative](/materials/bs/1501-509-510 "BS 1501-509-510") - [510 Indicative](/materials/bs/510 "BS 510") AFNOR France · 3 - [9Ni490 Indicative](/materials/afnor/9ni490 "AFNOR 9Ni490") - [Z8N09 Indicative](/materials/din-en/z8n09 "AFNOR Z8N09") - [Z8N9 Indicative](/materials/afnor/z8n9 "AFNOR Z8N9") UNE Spain · 2 - [F.2645 Indicative](/materials/une/f-2645 "UNE F.2645") - [XBNi09 Indicative](/materials/une/xbni09 "UNE XBNi09") UNI Italy · 1 - [X10Ni9 Indicative](/materials/din-en/x10ni9 "UNI X10Ni9") ČSN Czechia · 1 - [17501VN Indicative](/materials/csn/17501vn "ČSN 17501VN") 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 Mn Si Iron — the balance, never listed by a standard — 89.6 % Ni — 9.3 % Mn — 0.6 % Si — 0.4 % Traces & impurities · 0.3 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | ≤ 0.1 | | Si | ≤ 0.35 | | Mn | 0.3–0.8 | | P | 0.02 | | S | 0.01 | | Mo | ≤ 0.1 | | Ni | 8.5–10 — Unusual | | V | ≤ 0.05 | Carbon Silicon Manganese Phosphorus Sulfur Molybdenum Nickel Vanadium 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 | ≤0,10 | — | 0.100 | Max | | Si | ≤0,35 | — | 0.350 | Max | | P | 0,02 | 0.020 | 0.020 | Exact | | S | 0,01 | 0.010 | 0.010 | Exact | | V | ≤0,05 | — | 0.050 | Max | | Mn | 0,30-0,80 | 0.300 | 0.800 | Range | | Ni | 8,50-10,0 | 8.500 | 10.000 | Range | | Mo | ≤0,10 | — | 0.100 | Max | 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. ## Properties by condition 3 conditions · 6 values By thickness**Normalized** source `steelnumber` | Thickness mm | ReH N/mm² | Rm N/mm² | |---|---|---| | ≤ 30 | 490 | — | | 30 – 50 | 480 | — | | ≤ 50 | — | 640 – 840 | By thickness**Quenched and tempered** source `steelnumber` | Thickness mm | ReH N/mm² | |---|---| | ≤ 30 | 490 – 585 | | 30 – 50 | 480 – 575 | By thickness**no delivery state stated** source `steelnumber` | Thickness mm | A% | |---|---| | ≤ 50 | 18 | 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 1.5, a shared category, and a published range for Ni / Mn 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. [X7Ni9 1.5663 Ni 8,50-10,0 · Mn 0,30-0,80 - ΔNi 0.00 - ΔMn 0.00 - 2 designations](/materials/din-en/x7ni9 "X7Ni9")[X10Ni9 1.5682 Ni 8,50-9,50 · Mn 0,30-0,80 - ΔNi 0.25 - ΔMn 0.00 - 1 designations](/materials/din-en/x10ni9 "X10Ni9")[1.5662 1.5662 Ni 8,50-9,50 · Mn 0,50-0,70 - ΔNi 0.25 - ΔMn 0.05 - 16 designations](/materials/material-no/1.5662 "1.5662") ## 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=68eab8f1-0e4b-474e-856d-99ed7c5739c1&designation=83496360-9e0b-4f67-bc1b-c3b27422bb0d "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/uns/k71340.pdf "Datasheet as PDF")