Weathering steel
Weathering steel (also known by the trademark COR-TEN steel) is a form of high-strength, low alloy steel originally developed in the 1930's by United States Steel. It is a steel alloy, chemically composed to form a stable rust-like appearance that can resist corrosion and abrasion, by forming a protective surface layer, or patina.
The protective layer’s increased resistance is produced by the alloying elements and their particular distribution and concentration. When subjected to the influence of the weather, the protective surface layer continuously develops and regenerates, allowing the rust to form.
Weathering steel is often used in external sculptures, the most iconic of which is the Angel of the North in Gateshead. It can be used in bridges and other large structural applications, such as the New River Gorge Bridge, and it is becoming an increasingly popular design choice for buildings, often used alongside materials such as glass and terracotta. An example of such a building is the distinctive Broadcasting Tower in Leeds (see top image).
The advantages of weathering steel are that because it is already weathered and ‘rusted’, there are very low maintenance costs, it can be installed easily, and the need for a protective paint system is removed. Studies have found that bridges fabricated from unpainted weathering steel can achieve a design life of 120 years with only nominal maintenance, due to the low corrosion rate.
However, there are several challenges to weathering steel. It is unsuitable for use in marine or coastal environments, and in humid subtropical climates the patina may continue to corrode instead of stabilising into a protective layer. In addition, interface details require careful design as run-off water from wet rusted steel may negatively impact on other materials, such as staining glass. This is a particular problem in the first years after installation.
Special welding techniques or materials may be needed to ensure that weld-points weather at the same rate as the other materials.
[edit] Related articles on Designing Buildings
Featured articles and news
Amendment to the GB Energy Bill welcomed by ECA
Move prevents nationally-owned energy company from investing in solar panels produced by modern slavery.
Gregor Harvie argues that AI is state-sanctioned theft of IP.
Heat pumps, vehicle chargers and heating appliances must be sold with smart functionality.
Experimental AI housing target help for councils
Experimental AI could help councils meet housing targets by digitising records.
New-style degrees set for reformed ARB accreditation
Following the ARB Tomorrow's Architects competency outcomes for Architects.
BSRIA Occupant Wellbeing survey BOW
Occupant satisfaction and wellbeing tool inc. physical environment, indoor facilities, functionality and accessibility.
Preserving, waterproofing and decorating buildings.
Many resources for visitors aswell as new features for members.
Using technology to empower communities
The Community data platform; capturing the DNA of a place and fostering participation, for better design.
Heat pump and wind turbine sound calculations for PDRs
MCS publish updated sound calculation standards for permitted development installations.
Homes England creates largest housing-led site in the North
Successful, 34 hectare land acquisition with the residential allocation now completed.
Scottish apprenticeship training proposals
General support although better accountability and transparency is sought.
The history of building regulations
A story of belated action in response to crisis.
Moisture, fire safety and emerging trends in living walls
How wet is your wall?
Current policy explained and newly published consultation by the UK and Welsh Governments.
British architecture 1919–39. Book review.
Conservation of listed prefabs in Moseley.
Energy industry calls for urgent reform.