Specifications for Corten Steel
The primary trademark product is COR-TEN. However, ASTM has also laid down specifications as follows:
A588 (structural panels, shapes, plates, and bars)
A242 (steel plate up to 1.5 inches thick)
A606-4 (corten steel sheet and coil)
A847 (tube and pipe)
A871-65 (plate with 65ksi yield strength)
A709-50W (steel plate for bridges)
Corten A vs Corten B
Weathering steel is available in two main grades: Corten A and Corten B.
Corten A (ASTM A242) is mainly used in architectural applications. Its higher phosphorus content enhances patina formation and gives a more uniform, aesthetic finish.
Corten B (ASTM A588) is preferred for structural and heavy-duty applications. It offers higher strength but has lower phosphorus content, making it ideal for bridges and load-bearing structures.
Both grades develop a protective rust layer, but their chemical compositions are optimised for different needs.
Welding on Weathering Steel
Welding on corten steel is relatively similar to low-carbon steel. The only precaution the welders need to take is regarding the filler or electrode, which is different from mild steel.
When welding corten steel, it's critical to select the right electrode that preserves the base metal's corrosion-resistant properties.
Recommended Electrode: AWS E7018
When choosing a welding electrode for weathering steel, AWS E7018 is most suitable. The choice of electrode depends on two factors: required strength and code requirements.
At D&H Sécheron, we recommend Lotherme 7018 and similar low-hydrogen electrodes that maintain joint strength and match the patina's corrosion behaviour.
Best Welding Techniques for Corten Steel
When it comes to welding corten steel, the method should match the material thickness and end-use.
Stick Welding (SMAW): Reliable and economical for structural joints.
TIG Welding (GTAW): Clean and precise, suitable for fine applications.
MIG Welding Corten Steel (GMAW): Fast and efficient for thin sheets.
For MIG welding corten steel, shielding gases like CO₂ and Ar-CO₂ mixtures help ensure smoother arcs and less spatter while using weathering steel-compatible filler wire.
Common Challenges When Welding Corten Steel
Despite its benefits, welding corten steel comes with some challenges:
Heat-induced distortion or cracking
Loss of corrosion resistance near the heat-affected zone
Difficulty in matching the patina formation post-weld
However, with the right expertise and materials, these can be addressed. The necessary knowledge and experience in welding already exist. Hence, welders should be able to use it without any hassles.
Post-Weld Treatment and Maintenance Tips
To retain the steel's integrity and look:
Clean the weld area to remove slag and spatter
Use weathering accelerators to match the patina faster
Avoid stagnant water and ensure drainage in structural designs
This ensures that the weathering finish evolves consistently across welded and unwelded sections.
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.
