The metallurgy of weathering steel (corten steel)
The basic difference that you would be able to find between ordinary structural steel and weathering steel would be the inclusion of copper, chromium, and nickel alloying elements. This would help to give the corten steel its enhanced resistance to corrosion. On the other hand, when ordinary structural steel and materials standards for weathering steel would be compared, it has been found that all the other elements seem to be more or less similar.
ASTM A 242
Also known as the original A 242 alloy, this would have a yield strength of 50 ksi (340 Mpa) and the ultimate tensile strength would be of 70 ksi (480 Mpa) for light-medium rolled shapes. As for the plates, that would be up to 0.75 inches thick. In addition, it would have ultimate strength of 67 ksi and yield strength of 46 ksi, with the plates ranging from 0.75-1 inch in terms of thickness.
The rolled plates and sections which would be the most thickly rolled would have ultimate strength of 63 ksi and yield strength of 42 ksi.
As for its categories, you would be able to find it in Types 1 and 2. Just like the name suggests, both of them would be used for different applications, depending upon its thickness. In the case of Type 1, it would most normally be used in the construction industry, housing structures, and freight cars. As for Type 2 steel, also known as Corten B, this would mostly be used in passenger cranes or ships, and urban furnishings.
ASTM A 588
With ultimate tensile strength of 70 ksi and a yield strength of at least 50 ksi, you would be able to find this kind of weathered steel in all rolled shapes. In terms of plate thickness, that would be up to 4 inches thick. As for plates that would be at least 4 to 5 inches, the ultimate tensile strength would be at least 67 ksi. For plates that would range between 5 and 8 inches, the ultimate tensile strength would be at least 63 ksi and yield strength would be at least 42 ksi.
Chemical Composition For Corten Steel ASTM A242 Type 1 Plate & Sheet
| Corten – A | ASTM 588 Grade A | ASTM 242 TYPE -1 | IRSM 41 -97 | |
| Carbon, Max | 0.12 | 0.19 | 0.15 | 0.10 |
| Manganese | 0.20-50 | 0.80-1.25 | 1.00 | 0.25-0.45 |
| Phosphorus | 0.07-0.15 | 0.04 | 0.15 | 0.07-0.11 |
| Sulphur, max | 0.030 | 0.05 | 0.05 | 0.030 |
| Silicon | 0.25-0.75 | 0.30-0.65 | 0.25-0.40 | 0.28-0.72 |
| Nickel, max | 0.65 | 0.40 | – | 0.20-0.49 |
| Chromium | 0.50-1.25 | 0.40-065 | – | 0.30-0.50 |
| Molybdenum, max | – | – | – | – |
| Copper | 0.25-0.55 | 0.25-0.40 | 0.20 min | 0.30-0.39 |
| Vanadium | – | 0.02-0.10 | – | 0.050 |
| Aluminimum | – | … | – | 0.030 |
Mechanical properties of corten steel ASTM A242 Type 1 plates & Sheets
| Tensile Strength | Min. Yield Point | Elongation | |
| CORTEN A | [470 – 630 MPa] | [355 MPa] | 20 % min |
| ASTM 588 GR. A | [485 MPa] | [345 MPa] | 21% min |
| ASTM 242 TYPE -1 | [480 MPa] | [345 MPa] | 16% min |
| IRSM 41- 97 | [480 MPa] | [340 MPa] | 21% min |
Company profile
Founded in 2008, Gnee (Tianjin) Supply Chain Group Co., Ltd. specializes in the global trade and processing of Corten steel products.
• We handle all kinds of Corten engineering projects, such as bridges, gardens, hotels, and facade systems.
• Compliant with ASTM, EN, and other international standards; third-party inspection supported.
• Exported to over 200 countries and regions worldwide.
• 8 subsidiaries across China and overseas, ensuring global service coverage.
Application Fields: Architecture, landscaping, gardening, cladding, and urban infrastructure.
