What Is Corten Steel?
Sep 14, 2023
Corten steel is a type of chromium-copper alloy weathering steel that relies on a wet/dry cycle to build up a protective layer of rust. As the surface develops it changes color over time, beginning with a red-orange hue, and ending with a purplish patina. While most people have a negative association with rust, in this case, it’s what is needed to develop the right look and seal, developing a layer protecting the rest of the material from corroding over time.
As mentioned previously, Corten steel is a weather resistant steel that can also be called ‘Atmospheric Corrosion Resistant Steel’, and it is its alloying elements of copper and chromium that provide this level of atmospheric resistance.
Corten steel has a distinctive orange color, which is caused by the chemical composition forming a protective rust layer when exposed to extreme environments. There are two main grades of Corten steel; Corten A and Corten B.
Corten A has added phosphorous, which makes it suitable for aesthetic facias and gas flue applications, while Corten B is better suited for heavy and load-bearing structures.
| GRADE | THICKNESS (MM) STRIP PRODUCTS |
PLATE PRODUCTS | YIELD STRENGTH REL N/MM² MINIMUM |
TENSILE STRENGTH RM N/MM² MINIMUM |
ELONGATION A50 % MINIMUM |
|---|---|---|---|---|---|
| Corten A | 2-12 | 6-12 | 345 | 485 | 20 |
Corten A Chemical Composition
| C | 0.15 |
| Si | 0.25/0.75 |
| Mn | 0.20/0.50 |
| P | 0.07/0.15 |
| S | 0.030 |
| Al | 0.015/0.06 |
| Cu | 0.25/0.55 |
| Cr | 0.50/1.25 |
| Ni | 0.65 |
| GRADE | THICKNESS (MM) STRIP PRODUCTS |
PLATE PRODUCTS | YIELD STRENGTH REL N/MM² MINIMUM |
TENSILE STRENGTH RM N/MM² MINIMUM |
ELONGATION A50 % MINIMUM |
|---|---|---|---|---|---|
| Corten B | 2-13 | 6-40 | 345 | 485 | 19 |
Corten B Chemical Composition
| C | 0.19 |
| Si | 0.30/0.65 |
| Mn | 0.80/1.25 |
| P | 0.035 |
| S | 0.030 |
| Al | 0.020/0.06 |
| V | 0.02/0.10 |
| Cu | 0.25/0.40 |
| Cr | 0.40/0.65 |
| Ni | 0.40 |
