---
title: "Weathering steels — 27 grades with composition"
description: "Weathering steels are structural steels designed to develop a protective patina when exposed to the atmosphere. This characteristic helps limit further…"
canonical: https://steelequivalents.com/categories/weathering-steels
language: en
robots: index, follow
og_type: website
type: category-detail
language_alternates:
  en: https://steelequivalents.com/categories/weathering-steels.md
  cs: https://steelequivalents.com/cs/kategorie/oceli-odolné-proti-povětrnostním-vlivům.md
  de: https://steelequivalents.com/de/kategorien/wetterfeste-baustähle.md
  es: https://steelequivalents.com/es/categorías/aceros-estructurales-resistentes-a-la-intemperie.md
  fr: https://steelequivalents.com/fr/catégories/aciers-de-construction-patinables.md
  hu: https://steelequivalents.com/hu/kategóriák/időjárásálló-szerkezeti-acélok.md
  it: https://steelequivalents.com/it/categorie/acciai-da-costruzione-patinabili.md
  nl: https://steelequivalents.com/nl/categorieën/weervaste-constructiestalen.md
  pl: https://steelequivalents.com/pl/kategorie/stale-konstrukcyjne-odporne-na-warunki-atmosferyczne.md
  pt: https://steelequivalents.com/pt/categorias/aços-estruturais-patináveis.md
  ru: https://steelequivalents.com/ru/категории/атмосферостойкие-конструкционные-стали.md
  tr: https://steelequivalents.com/tr/kategoriler/atmosferik-korozyona-dayanıklı-yapı-çelikleri.md
  zh: https://steelequivalents.com/zh/类别/耐候结构钢.md
  ja: https://steelequivalents.com/ja/カテゴリー/耐候性構造用鋼.md
  ar: https://steelequivalents.com/ar/الفئات/فولاذ-إنشائي-مقاوم-للعوامل-الجوية.md
  ko: https://steelequivalents.com/ko/분류/내후성-구조용강.md
  pt-br: https://steelequivalents.com/pt-br/categorias/aços-estruturais-patináveis.md
  hi: https://steelequivalents.com/hi/श्रेणियाँ/मौसमरोधी-संरचनात्मक-इस्पात.md
content_hash: sha256:d281cf1c6c4ad92b6757454c852c0e81598a1b1944eca653e35c82a08afc11ad
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/categories/weathering-steels
> Canonical URL: https://steelequivalents.com/categories/weathering-steels
> 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.

![Weathering steels](/images/uploads/f7f93554-147b-4918-af15-b6b46a768e24/weathering-steels-category-patina-panel-1920x1080.jpg)

Category · 27 grades

# 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.

| Grade | Material no. | C | Si | P | S | Cr | Mn |
|---|---|---|---|---|---|---|---|
| [SMA400AW](/materials/jis/sma400aw "SMA400AW") | — | max 0.18 | 0.15 - 0.65 | max 0.035 | max 0.035 | 0.45 - 0.75 | max 1.25 |
| [SMA400BP](/materials/jis/sma400bp "SMA400BP") | — | max 0.18 | max 0.55 | max 0.035 | max 0.035 | 0.3 - 0.55 | max 1.25 |
| [SMA490CW](/materials/jis/sma490cw "SMA490CW") | — | max 0.18 | 0.15 - 0.65 | max 0.035 | max 0.035 | 0.45 - 0.75 | max 1.4 |
| [SMA570W](/materials/jis/sma570w "SMA570W") | — | max 0.18 | 0.15 - 0.65 | max 0.035 | max 0.035 | 0.45 - 0.75 | max 1.4 |
| [SMA400AP](/materials/jis/sma400ap "SMA400AP") | — | max 0.18 | max 0.55 | max 0.035 | max 0.035 | 0.3 - 0.55 | max 1.25 |
| [SMA490BW](/materials/jis/sma490bw "SMA490BW") | — | max 0.18 | 0.15 - 0.65 | max 0.035 | max 0.035 | 0.45 - 0.75 | max 1.4 |
| [SMA490CP](/materials/jis/sma490cp "SMA490CP") | — | max 0.18 | max 0.55 | max 0.035 | max 0.035 | 0.3 - 0.55 | max 1.4 |
| [SPA-C](/materials/jis/spa-c "SPA-C") | — | max 0.12 | 0.2 - 0.75 | 0.07 - 0.15 | max 0.035 | 0.3 - 1.25 | max 0.6 |
| [SMA400CW](/materials/jis/sma400cw "SMA400CW") | — | max 0.18 | 0.15 - 0.65 | max 0.035 | max 0.035 | 0.45 - 0.75 | max 1.25 |
| [SMA490AW](/materials/jis/sma490aw "SMA490AW") | — | max 0.18 | 0.15 - 0.65 | max 0.035 | max 0.035 | 0.45 - 0.75 | max 1.4 |
| [SMA490BP](/materials/jis/sma490bp "SMA490BP") | — | max 0.18 | max 0.55 | max 0.035 | max 0.035 | 0.3 - 0.55 | max 1.4 |
| [SPA-H](/materials/jis/spa-h "SPA-H") | — | max 0.12 | 0.2 - 0.75 | 0.07 - 0.15 | max 0.035 | 0.3 - 1.25 | max 0.6 |
| [SMA400BW](/materials/jis/sma400bw "SMA400BW") | — | max 0.18 | 0.15 - 0.65 | max 0.035 | max 0.035 | 0.45 - 0.75 | max 1.25 |
| [SMA400CP](/materials/jis/sma400cp "SMA400CP") | — | max 0.18 | max 0.55 | max 0.035 | max 0.035 | 0.3 - 0.55 | max 1.25 |
| [SMA490AP](/materials/jis/sma490ap "SMA490AP") | — | max 0.18 | max 0.55 | max 0.035 | max 0.035 | 0.3 - 0.55 | max 1.4 |
| [SMA570P](/materials/jis/sma570p "SMA570P") | — | max 0.18 | max 0.55 | max 0.035 | max 0.035 | 0.3 - 0.55 | max 1.4 |
| [9CrNiCuP324](/materials/din-en/9crnicup3-2-4 "9CrNiCuP324") | [1.8945](/materials/material-no/1.8945 "1.8945") | ≤0,12 | ≤0,75 | 0,06-0,15 | 0,035 | 0,30-1,25 | ≤1,00 |
| [Fe510D1KI](/materials/din-en/fe510d1ki "Fe510D1KI") | [1.8946](/materials/material-no/1.8946 "1.8946") | ≤0,12 | ≤0,75 | 0,06-0,15 | 0,03 | 0,30-1,25 | ≤1,00 |
| [Fe360CKI](/materials/din-en/fe360cki "Fe360CKI") | [1.8958](/materials/material-no/1.8958 "1.8958") | ≤0,13 | ≤0,40 | 0,035 | 0,035 | 0,40-0,80 | 0,20-0,60 |
| [A709-50W](/materials/din-en/a709-50w "A709-50W") | [1.8959](/materials/material-no/1.8959 "1.8959") | ≤0,16 | ≤0,50 | 0,035 | 0,035 | 0,40-0,80 | 0,50-1,50 |
| [S235JRW](/materials/din-en/s235jrw "S235JRW") | [1.8960](/materials/material-no/1.8960 "1.8960") | ≤0,13 | 0,10-0,40 | 0,05 | 0,035 | 0,50-0,80 | 0,20-0,50 |
| [Fe360DKI](/materials/din-en/fe360dki "Fe360DKI") | [1.8961](/materials/material-no/1.8961 "1.8961") | ≤0,13 | ≤0,40 | 0,035 | 0,03 | 0,40-0,80 | 0,20-0,60 |
| [9CrNiCuP3-2-4](/materials/din-en/9crnicup3-2-4 "9CrNiCuP3-2-4") | [1.8962](/materials/material-no/1.8962 "1.8962") | ≤0,12 | 0,25-0,75 | 0,07-0,15 | 0,035 | 0,50-1,25 | 0,20-0,50 |
| [A600C](/materials/din-en/a600c "A600C") | [1.8963](/materials/material-no/1.8963 "1.8963") | ≤0,16 | ≤0,50 | 0,035 | 0,035 | 0,40-0,80 | 0,50-1,50 |
| [S355J2W](/materials/din-en/s355j2w "S355J2W") | [1.8965](/materials/material-no/1.8965 "1.8965") | ≤0,16 | ≤0,50 | 0,03 | 0,03 | 0,40-0,80 | 0,50-1,50 |
| [S355K2W(+N)](/materials/din-en/s355k2w-n "S355K2W(+N)") | [1.8966](/materials/material-no/1.8966 "1.8966") | ≤0,16 | ≤0,50 | 0,035 | 0,035 | 0,40-0,80 | 0,50-1,50 |
| [S355K2W](/materials/din-en/s355k2w "S355K2W") | [1.8967](/materials/material-no/1.8967 "1.8967") | ≤0,16 | ≤0,50 | 0,03 | 0,03 | 0,40-0,80 | 0,50-1,50 |

## Standards covering this category

 19

- [**JIS***21 grades*](/materials/jis "JIS — 21 grades in this category")
- [**DIN / EN***11 grades*](/materials/din-en "DIN / EN — 11 grades in this category")
- [**AISI / SAE***7 grades*](/materials/aisi-sae "AISI / SAE — 7 grades in this category")
- [**AFNOR***7 grades*](/materials/afnor "AFNOR — 7 grades in this category")
- [**UNS***6 grades*](/materials/uns "UNS — 6 grades in this category")
- [**UNI***6 grades*](/materials/uni "UNI — 6 grades in this category")
- [**BS***4 grades*](/materials/bs "BS — 4 grades in this category")
- [**ČSN***3 grades*](/materials/csn "ČSN — 3 grades in this category")
- [**ISO***2 grades*](/materials/iso "ISO — 2 grades in this category")
- [**GOST***2 grades*](/materials/gost "GOST — 2 grades in this category")
- [**STN***2 grades*](/materials/stn "STN — 2 grades in this category")
- [**CSA***2 grades*](/materials/csa "CSA — 2 grades in this category")
- [**GB***1 grade*](/materials/gb "GB — 1 grade in this category")
- [**SS***1 grade*](/materials/ss "SS — 1 grade in this category")
- [**ABNT NBR***1 grade*](/materials/abnt "ABNT NBR — 1 grade in this category")
- [**PN***1 grade*](/materials/pn "PN — 1 grade in this category")
- [**MSZ***1 grade*](/materials/msz "MSZ — 1 grade in this category")
- [**BDS***1 grade*](/materials/bds "BDS — 1 grade in this category")
- [**ÖNORM***1 grade*](/materials/onorm "ÖNORM — 1 grade in this category")

## Property ranges

 17

| Property | Unit | Min | Max | Grades |
|---|---|---|---|---|
| ReH | N/mm² | 195 | 355 | 7 |
| Rm | N/mm² | 350 | 720 | 23 |
| A80 | % | 16 | 21 | 7 |
| Re | N/mm² | 195 | 460 | 17 |
| A | % | 15 | 26 | 23 |
| A5 | % | 25 | 27 | 1 |
| KCU | kJ/m² | 640 | 690 | 1 |
| rho | g/cm³ | 7.49 | 7.87 | 11 |
| E | GPa | 165 | 211 | 1 |
| alpha | 10^-6/K | 12 | 13.85 | 1 |
| lambda | W/(m·K) | 38 | 57 | 1 |
| cp | J/(kg·K) | 486 | 703 | 1 |
| rho\_el | nΩ·m | 200 | 1219 | 1 |
| Ac1 | °C | 724 | 724 | 1 |
| Ac3 | °C | 860 | 860 | 1 |
| Ar3 | °C | 830 | 830 | 1 |
| Ar1 | °C | 676 | 676 | 1 |

Derived from 23 grades in this category with a recorded value.

## Composition range

 15

| Property | Unit | Min | Max | Grades |
|---|---|---|---|---|
| C | % | 0.12 | 0.18 | 27 |
| N | % | 0.009 | 0.009 | 4 |
| Al | % | 0.02 | 0.02 | 2 |
| Si | % | 0.1 | 0.75 | 27 |
| P | % | 0.03 | 0.15 | 27 |
| S | % | 0.03 | 0.035 | 27 |
| Ti | % | 0.02 | 0.1 | 2 |
| V | % | 0.02 | 0.12 | 2 |
| Cr | % | 0.3 | 1.25 | 27 |
| Mn | % | 0.2 | 1.5 | 27 |
| Ni | % | 0.05 | 0.65 | 19 |
| Cu | % | 0.2 | 0.55 | 27 |
| Zr | % | 0.15 | 0.15 | 5 |
| Nb | % | 0.015 | 0.06 | 2 |
| Mo | % | 0.3 | 0.3 | 5 |

Derived from 27 grades in this category with a recorded value.

## Related guides

 1

- [**Weathering Steels and Atmospheric Corrosion Design**](/wiki/steel-families/weathering-steels-and-atmospheric-corrosion-design "Weathering Steels and Atmospheric Corrosion Design")