--- title: "NW6621 — High-temperature steels" description: "NW6621 in ISO: material number 2.4951, also listed as NiCr20Ti. Category: High-temperature steels. Designations recorded for this grade: 16." canonical: https://steelequivalents.com/materials/iso/nw6621 language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/iso/nw6621.md cs: https://steelequivalents.com/cs/materiály/iso/nw6621.md de: https://steelequivalents.com/de/werkstoffe/iso/nw6621.md es: https://steelequivalents.com/es/materiales/iso/nw6621.md fr: https://steelequivalents.com/fr/matériaux/iso/nw6621.md hu: https://steelequivalents.com/hu/anyagok/iso/nw6621.md it: https://steelequivalents.com/it/materiali/iso/nw6621.md nl: https://steelequivalents.com/nl/materialen/iso/nw6621.md pl: https://steelequivalents.com/pl/materiały/iso/nw6621.md pt: https://steelequivalents.com/pt/materiais/iso/nw6621.md ru: https://steelequivalents.com/ru/материалы/iso/nw6621.md tr: https://steelequivalents.com/tr/malzemeler/iso/nw6621.md zh: https://steelequivalents.com/zh/材料/iso/nw6621.md ja: https://steelequivalents.com/ja/材料/iso/nw6621.md ar: https://steelequivalents.com/ar/المواد/iso/nw6621.md ko: https://steelequivalents.com/ko/재료/iso/nw6621.md pt-br: https://steelequivalents.com/pt-br/materiais/iso/nw6621.md hi: https://steelequivalents.com/hi/सामग्री/iso/nw6621.md content_hash: sha256:fb7683c41fc280607de93fb44200e5d3621252c8e961c09ad7a4e893d86328ab 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/iso/nw6621 > Canonical URL: https://steelequivalents.com/materials/iso/nw6621 > 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. ISO · International · 16 designations # NW6621 NW6621 is a designation in ISO for the material held under material number 2.4951, also listed as NiCr20Ti. It is a material in the category High-temperature steels. We list 16 designations recorded for this grade, in the standards DIN / EN, UNS, ASTM, BS, ISO, SAE AMS and GOST. - [*Material no.* **2.4951**](/materials/material-no/2.4951 "Material no.: 2.4951") - [*Category* **High-temperature steels · 40 grades**](/categories/high-temperature-steels "Category: High-temperature steels · 40 grades") - *Designations* **16** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=bf156392-ddd8-433e-a1d7-4ff5d263e045&designation=b636dc33-bf8d-4bdf-a530-36d70f3bdc0c "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/iso/nw6621.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [DIN / EN NiCr20Ti This grade’s own name · 2 grades on that route](/materials/din-en/nicr20ti "DIN / EN NiCr20Ti") - [UNS N06075 This grade’s own name · 2 grades on that route](/materials/uns/n06075 "UNS N06075") ## About High-temperature steels High-temperature steels are steels designed to retain useful strength and structural stability during exposure to elevated temperatures. Their alloying systems provide resistance to oxidation, creep and loss of mechanical properties during prolonged heating, making them suitable for furnace components, heat exchangers, boilers and other hot-service equipment. This describes the material class as a whole. Always confirm the individual grade against the standard before ordering. ## Also known as 16 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 - [NiCr20Ti This grade’s own name](/materials/din-en/nicr20ti "DIN / EN NiCr20Ti") UNS United States · 3 - [N06075 This grade’s own name](/materials/uns/n06075 "UNS N06075") - [N06076 This grade’s own name](/materials/uns/n06076 "UNS N06076") - [N06617 This grade’s own name](/materials/uns/n06617 "UNS N06617") ASTM United States · 2 - [B 166 Indicative](/materials/astm/b166 "ASTM B 166") - [B637 Indicative](/materials/astm/b637 "ASTM B637") BS United Kingdom · 3 - [2HR 504 Indicative](/materials/bs/2hr-504 "BS 2HR 504") - [HR 203 Indicative](/materials/bs/hr203 "BS HR 203") - [HR 403 Indicative](/materials/bs/hr403 "BS HR 403") ISO International · 2 - [NiCr20Ti Indicative](/materials/din-en/nicr20ti "ISO NiCr20Ti") - **NW6621 Indicative** SAE AMS United States / Aerospace · 3 - [5887 Indicative](/materials/ams/5887 "SAE AMS 5887") - [5888 Indicative](/materials/ams/5888 "SAE AMS 5888") - [5889 Indicative](/materials/ams/5889 "SAE AMS 5889") GOST Russia / CIS · 2 - [ChN78T Indicative](/materials/gost/chn78t "GOST ChN78T") - [ХН78Т Indicative](/materials/gost/khn78t "GOST ХН78Т") Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here. ## Chemical composition 13 elements on file · weight % What this alloy is Fe Cr Co Si Iron — the balance, never listed by a standard — 72.1 % Cr — 19.5 % Co — 5 % Si — 1 % Traces & impurities · 2.4 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | 0.08–0.15 | | Si | ≤ 1 | | Mn | ≤ 1 | | P | 0.02 | | S | 0.015 | | Cr | 18–21 | | Ni | Balance | | Co | ≤ 5 | | Cu | ≤ 0.5 | | Al | ≤ 0.3 | | Ti | 0.2–0.6 | | B | ≤ 0.006 | | Fe | ≤ 5 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Nickel Cobalt Copper Aluminium Titanium Boron Iron 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 | |---|---|---|---|---| | B | ≤0,006 | — | 0.006 | Max | | C | 0,08-0,15 | 0.080 | 0.150 | Range | | Al | ≤0,30 | — | 0.300 | Max | | Si | ≤1,00 | — | 1.000 | Max | | P | 0,02 | 0.020 | 0.020 | Exact | | S | 0,015 | 0.015 | 0.015 | Exact | | Ti | 0,20-0,60 | 0.200 | 0.600 | Range | | Cr | 18,0-21,0 | 18.000 | 21.000 | Range | | Mn | ≤1,00 | — | 1.000 | Max | | Fe | ≤5,00 | — | 5.000 | Max | | Co | ≤5,00 | — | 5.000 | Max | | Ni | Rest/Bal. | 65.409 | 81.685 | Balance | | Cu | ≤0,50 | — | 0.500 | 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: Ni, Mo. ## 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. ## Similar grades — and why Selection rule, stated so you can disagree with it: same number class 2.4, 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. [NiCr20TiAl 2.4952 Ni ≥65,0 · Cr 18,0-21,0 - ΔNi 8.55 - ΔCr 0.00 - 7 designations](/materials/din-en/nicr20tial "NiCr20TiAl") ## 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=bf156392-ddd8-433e-a1d7-4ff5d263e045&designation=b636dc33-bf8d-4bdf-a530-36d70f3bdc0c "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/iso/nw6621.pdf "Datasheet as PDF")