--- title: "400AAT — Weathering steels" description: "400AAT in CSA: material number 1.8963, also listed as WTSt 52-3. Category: Weathering steels. Designations recorded for this grade: 29." canonical: https://steelequivalents.com/materials/csa/400aat language: en robots: index, follow og_type: website type: material-detail language_alternates: en: https://steelequivalents.com/materials/csa/400aat.md cs: https://steelequivalents.com/cs/materiály/csa/400aat.md de: https://steelequivalents.com/de/werkstoffe/csa/400aat.md es: https://steelequivalents.com/es/materiales/csa/400aat.md fr: https://steelequivalents.com/fr/matériaux/csa/400aat.md hu: https://steelequivalents.com/hu/anyagok/csa/400aat.md it: https://steelequivalents.com/it/materiali/csa/400aat.md nl: https://steelequivalents.com/nl/materialen/csa/400aat.md pl: https://steelequivalents.com/pl/materiały/csa/400aat.md pt: https://steelequivalents.com/pt/materiais/csa/400aat.md ru: https://steelequivalents.com/ru/материалы/csa/400aat.md tr: https://steelequivalents.com/tr/malzemeler/csa/400aat.md zh: https://steelequivalents.com/zh/材料/csa/400aat.md ja: https://steelequivalents.com/ja/材料/csa/400aat.md ar: https://steelequivalents.com/ar/المواد/csa/400aat.md ko: https://steelequivalents.com/ko/재료/csa/400aat.md pt-br: https://steelequivalents.com/pt-br/materiais/csa/400aat.md hi: https://steelequivalents.com/hi/सामग्री/csa/400aat.md content_hash: sha256:b58fa962a4dbf7ad3fd1964ff4594a4533a6599f3aa8b828a47fe07d401e715f 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/csa/400aat > Canonical URL: https://steelequivalents.com/materials/csa/400aat > 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. CSA · Canada · 29 designations # 400AAT 400AAT is a designation in CSA for the material held under material number 1.8963, also listed as WTSt 52-3. It is a material in the category Weathering steels. We list 29 designations recorded for this grade, in the standards DIN / EN, UNS, AISI / SAE, BS, AFNOR, JIS, UNI, ČSN, STN and CSA. - [*Material no.* **1.8963**](/materials/material-no/1.8963 "Material no.: 1.8963") - [*Category* **Weathering steels · 27 grades**](/categories/weathering-steels "Category: Weathering steels · 27 grades") - *Designations* **29** [Search](/search "Steel grade search")[Inquiry](/inquiry?material=ef616ca4-b36b-4c09-80f6-8a7d09a71d22&designation=a0e585a5-f881-4048-8bbb-56217f662ac3 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/csa/400aat.pdf "Datasheet as PDF") ## If you came for one of these The most-used names for this grade. - [UNS K11430 This grade’s own name · 4 grades on that route](/materials/uns/k11430 "UNS K11430") ## About Weathering steels Weathering steels are structural steels designed to develop a protective patina when exposed to the atmosphere. This characteristic helps limit further corrosion and makes them suitable for bridges, building facades, rail vehicles and other outdoor structures where reduced coating maintenance is desirable. This describes the material class as a whole. Always confirm the individual grade against the standard before ordering. ## Also known as 29 designations · 10 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 · 7 - [A600C Indicative](/materials/din-en/a600c "DIN / EN A600C") - [Fe510D2KI Indicative](/materials/din-en/fe510d2ki "DIN / EN Fe510D2KI") - [S355J2G1W This grade’s own name Withdrawn](/materials/din-en/s355j2g1w "DIN / EN S355J2G1W") - [S355J2W This grade’s own name Withdrawn](/materials/din-en/s355j2w "DIN / EN S355J2W") - [S355J2W(+N) Indicative](/materials/din-en/s355j2w-n "DIN / EN S355J2W(+N)") - [WSt52.3 Indicative](/materials/din-en/wst52-3 "DIN / EN WSt52.3") - [WTSt 52-3 This grade’s own name Withdrawn](/materials/din-en/wtst-52-3 "DIN / EN WTSt 52-3") UNS United States · 11 - [K11430 This grade’s own name](/materials/uns/k11430 "UNS K11430") - [K11538 This grade’s own name](/materials/uns/k11538 "UNS K11538") - [K11541 This grade’s own name](/materials/uns/k11541 "UNS K11541") - [K11552 This grade’s own name](/materials/uns/k11552 "UNS K11552") - [K11567 This grade’s own name](/materials/uns/k11567 "UNS K11567") - [K12010 This grade’s own name](/materials/uns/k12010 "UNS K12010") - [K12032 This grade’s own name](/materials/uns/k12032 "UNS K12032") - [K12043 This grade’s own name](/materials/uns/k12043 "UNS K12043") - [K12044 This grade’s own name](/materials/uns/k12044 "UNS K12044") - [K12211 Indicative](/materials/uns/k12211 "UNS K12211") - [K12609 Indicative](/materials/uns/k12609 "UNS K12609") AISI / SAE United States · 4 - [A588Gr.A Indicative](/materials/aisi-sae/a588gr-a "AISI / SAE A588Gr.A") - [A600A Indicative](/materials/aisi-sae/a600a "AISI / SAE A600A") - [A600B Indicative](/materials/aisi-sae/a600b "AISI / SAE A600B") - [A600C Indicative](/materials/din-en/a600c "AISI / SAE A600C") BS United Kingdom · 1 - [WR50C Indicative](/materials/bs/wr50c "BS WR50C") AFNOR France · 1 - [E36WB4 Indicative](/materials/afnor/e36wb4 "AFNOR E36WB4") JIS Japan · 1 - [SMA570W Indicative](/materials/jis/sma570w "JIS SMA570W") UNI Italy · 1 - [Fe510D2K1 Indicative](/materials/uni/fe510d2k1 "UNI Fe510D2K1") ČSN Czechia · 1 - [15127 Indicative](/materials/csn/15127 "ČSN 15127") STN Slovakia · 1 - [15 127 Indicative](/materials/csn/15127 "STN 15 127") CSA Canada · 1 - **400AAT Indicative** Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here. ## Chemical composition 14 elements on file · weight % What this alloy is Fe Mn Ni Cr Iron — the balance, never listed by a standard — 96 % Mn — 1 % Ni — 0.7 % Cr — 0.6 % Traces & impurities · 1.8 % Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade. | Element | % by weight | |---|---| | C | ≤ 0.16 | | Si | ≤ 0.5 | | Mn | 0.5–1.5 | | P | 0.035 | | S | 0.035 | | Cr | 0.4–0.8 | | Mo | ≤ 0.3 | | Ni | 0.65 | | V | 0.02–0.12 | | Cu | 0.25–0.55 | | Al | ≥ 0.02 | | Ti | 0.02–0.1 | | Nb | 0.015–0.06 | | Zr | 0.15 | Carbon Silicon Manganese Phosphorus Sulfur Chromium Molybdenum Nickel Vanadium Copper Aluminium Titanium Niobium Zirconium 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 | ≤0,16 | — | 0.160 | Max | | Al | ≥0,020 | 0.020 | — | Min | | Si | ≤0,50 | — | 0.500 | Max | | P | 0,035 | 0.035 | 0.035 | Exact | | S | 0,035 | 0.035 | 0.035 | Exact | | Ti | 0,02-0,10 | 0.020 | 0.100 | Range | | V | 0,02-0,12 | 0.020 | 0.120 | Range | | Cr | 0,40-0,80 | 0.400 | 0.800 | Range | | Mn | 0,50-1,50 | 0.500 | 1.500 | Range | | Ni | 0,65 | 0.650 | 0.650 | Exact | | Cu | 0,25-0,55 | 0.250 | 0.550 | Range | | Zr | 0,15 | 0.150 | 0.150 | Exact | | Nb | 0,015-0,060 | 0.015 | 0.060 | Range | | Mo | ≤0,30 | — | 0.300 | 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 computed from composition · °C Predicted Ae3 814 °C Predicted Ae1 722 °C Predicted Acm 423 °C Predicted Bs 526 °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. ## Properties by condition 1 conditions · 16 values By thickness**no delivery state stated** source `steelnumber` | Thickness mm | ReH N/mm² | Rm N/mm² | A80% | A% | |---|---|---|---|---| | 1.5 – 2 | — | — | 16 | — | | 2 – 2.5 | — | — | 17 | — | | 2.5 – 3 | — | — | 18 | — | | ≤ 3 | — | 510 – 680 | — | — | | 3 – 100 | — | 470 – 630 | — | — | | 3 – 40 | — | — | — | 22 | | ≤ 16 | 355 | — | — | — | | 16 – 40 | 345 | — | — | — | | 40 – 63 | 335 | — | — | 21 | | 63 – 80 | 325 | — | — | — | | 63 – 100 | — | — | — | 20 | | 80 – 100 | 315 | — | — | — | | 100 – 150 | 295 | 450 – 600 | — | 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 1.8, a shared category, and a published range for Mn / Ni 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. [A709-50W 1.8959 Mn 0,50-1,50 · Ni (0,65) - ΔMn 0.00 - ΔNi 0.00 - 23 designations](/materials/din-en/a709-50w "A709-50W")[S355J2W 1.8965 Mn 0,50-1,50 · Ni (0,65) - ΔMn 0.00 - ΔNi 0.00 - 8 designations](/materials/din-en/s355j2w "S355J2W")[S355K2W(+N) 1.8966 Mn 0,50-1,50 · Ni 0,65 - ΔMn 0.00 - ΔNi 0.00 - 5 designations](/materials/din-en/s355k2w-n "S355K2W(+N)")[S355K2W 1.8967 Mn 0,50-1,50 · Ni (0,65) - ΔMn 0.00 - ΔNi 0.00 - 3 designations](/materials/din-en/s355k2w "S355K2W")[9CrNiCuP324 1.8945 Mn ≤1,00 · Ni (0,65) - ΔMn 0.50 - ΔNi 0.00 - 37 designations](/materials/din-en/9crnicup3-2-4 "9CrNiCuP324")[Fe510D1KI 1.8946 Mn ≤1,00 · Ni (0,65) - ΔMn 0.50 - ΔNi 0.00 - 7 designations](/materials/din-en/fe510d1ki "Fe510D1KI") ## 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=ef616ca4-b36b-4c09-80f6-8a7d09a71d22&designation=a0e585a5-f881-4048-8bbb-56217f662ac3 "Inquiry")[**Datasheet as PDF** Print-ready A4 document **Generating …** **Download started** **Try again**](/materials/csa/400aat.pdf "Datasheet as PDF")