Motivation I have a few outdoor designs which I am working on, I am writing this blog with the aim to better understand weathering steel and it’s advantages and limitations.
Intro So weathering steel is often known by one of it’s brand name’s “Corten”. This material can be cut, bent, drilled etc and then left in it’s raw state (No painting or surface treatment) then used for it’s intended purpose.
Availability – Australia So far I have found a supplier that stocks 3mm sheet form only. At time of this blog a 3m x 1.2m sheet is $330, as opposed to a mild steel sheet which is $135.
How it works Basically the weathering steel is similar to stock mild steel but classed as an alloy steel due to its additional properties of Chromium, Copper & Nickel. These elements assist in forming an oxide layer on the material surface which in effect allows the material to continually rust to a limited depth which increases the materials resistance to atmospheric corrosion.
Comparison This material was developed as a cheaper substitute for “Stainless steel” which is one of the best materials to use in corrosive environments.
Applications Weathering steel is often chosen A; Because of its corrosion resistant properties and B; Because of its aesthetic appearance. It is popular for use in outdoor sculptures, marine environments, Bridge piling & Exterior facades on buildings to project a rustic theme.
Disadvantages Using weathering steel in construction presents several challenges. Weathering steel is not rustproof in itself. If water is allowed to accumulate in pockets, those areas will experience higher corrosion rates, so provision for drainage must be made. Weathering steel is sensitive to humid subtropical climates. In such environments, it is possible that the protective patina may not stabilize but instead continue to corrode; in this case Stainless steel would be the preferred option.
Weathering of the material can result in discoloration of the surrounding environment, IE; city sidewalks, as well as other nearby buildings. Staining can be prevented if the structure can be designed so that water does not drain from the steel onto concrete where stains would be visible.
Welding I- Contact your local welding supplier to find out what welding electrodes should be used. Challenges that exist are ensuring that weld-points weather at the same rate as the Weathering steel.
Freestyle Metal (FMA) Artis - Glen Jones Designer and Fabricator of unique metal products..