Each month, Stainless Solutions from IMOA covers a different stainless steel issue with tips on design and specification, and links to technical resources. This month the organization is highlighting duplex stainless steel resources.
Duplex Stainless Steel Resources
There is a growing interest in using duplex stainless steels as a building and construction design material because of their unique characteristics: higher strength than carbon steel and a high level of corrosion resistance for the price relative to austenitic (300-series) stainless steels. Duplex stainless steels are not a new material but they have primarily been used in demanding industrial applications. The first large construction project for this family of unique steels may have been the new structural framing for the Statue of Liberty where alloy 255 was used when it was restored in the 1980s.
The most common building and construction application for duplexes have been spectacular pedestrian bridges like The Helix bridge in Singapore, San Diego’s Harbor Drive Bridge, and the new Lusail Pedestrian Bridges in Qatar. The duplex alloy 2205 has been used for all of these projects because it provides significantly higher corrosion resistance and twice the strength of Type 316/316L stainless steel.
Other applications have included handrails in corrosive locations like the Canary Islands and the Four Freedoms Park in New York. High strength tension bars and spiders are being used in low profile glass curtain wall structural supports. Stainless steel curtain wall projects are also in development. Finish options for panels include polished, rolled-on dull roofing, and linen. Relative to austenitic (300-series) stainless steels the finish choices are more limited, a larger bend radius is required, and the higher strength must be considered during fabrication. Duplex gauges can often be reduced which minimizes these fabrication factors.
IMOA’s website provides duplex stainless steel fabrication assistance including resources like the recently released 3rd version of the brochure, Practical Guidelines for the Fabrication of Duplex Stainless Steels.
Information on codes, design guides, projects, research and technical papers related to duplex and other stainless steels can be found on the IMOA Structural Design Resource Page, in the downloadable Library, and in the September 2014 issue of Stainless Solutions.