Celebrating 100 years of Stainless Steel
2013 marks 100 years since the discovery of a super-steel that was to have an enduring impact on everyday life. Here, Ancon explains what makes stainless steel different to other materials and why it is often preferred to carbon or galvanised steels in structural applications.
What is Stainless Steel?
A common misconception is that stainless steel is a single specific material. It is actually the name given to a group of corrosion-resistant steel alloys which contain a minimum of 10.5% chromium.
Corrosion is a naturally occurring phenomenon. It is the deterioration of a metal due to a chemical reaction with its environment. When left exposed to the air and unprotected by a coating, corrosion is easily identified on carbon steel as a layer of brown rust.
The chromium in a stainless steel reacts with oxygen to produce a very thin, inert, chromium-rich oxide film on the surface of the steel. It is the presence of this passive film which provides the inherent corrosion resistant properties of the material. The layer is unlike an applied coating on plain carbon steel, such as paint or galvanising, in one very important way. If it is damaged by abrasion or mechanical means such as cutting, it re-forms immediately and continues to protect the steel.
Other elements can be added to the alloy to improve the material’s properties such as nickel and molybdenum.
Who Discovered Stainless Steel and When?
Many countries and individuals lay claim to the discovery of stainless steel, but it was probably a combined effort of many scientists and metallurgists around the world. The key developments are summarised below.
- The corrosion resistance of iron-chromium alloys was first recognised in 1821 by French metallurgist Pierre Berthier, who noted their resistance against acid attack and suggested their use in cutlery.
- Between 1904 and 1911 several researchers, particularly Leon Guillet in France, studied the performance of different iron-chromium alloys that would today be considered stainless steel.
- In 1911, Philip Monnartz and W. Borchers of Germany observed the relationship between chromium content and corrosion resistance, stating that there was a significant improvement in corrosion resistance when at least 10.5% chromium was present.
- In 1912, Harry Brearley of the Brown-Firth research laboratory in Sheffield, England, began experimenting with steel alloys while trying to solve high temperature erosion in gun barrels. Brearley created a steel with 12.8% chromium and 0.24% carbon, which he called ‘rustless steel’.
- In Germany, employees of the Krupp works, Eduard Maurer and Benno Strauss, worked from 1912-1914 on developing austenitic steels.
- In the US, Elwood Haynes developed a martensitic stainless steel during 1911, and two other Americans, Frederick Becket and Christian Dantsizen, worked on the development of ferritic stainless steel between 1911 and 1914.
It is generally acknowledged by the global stainless steel industry that 1912-1913 marks the ‘discovery’ of the material and 2013 rightly celebrates 100 years since it was patented and produced commercially.
The term ‘Stainless Steel’ was first used by the cutlery industry to describe the non-corroding surface of the metal, despite contact with food acids, and it was quickly adopted as a generic name.
Where is Stainless Steel Used?
Today, the high strength, corrosion resistance, aesthetics and high/low temperature properties of stainless steel means it is not only standard in cutlery production but is widely used for washing machine drums, sinks, surgical blades, oxygen tanks, solar panels, tools, sculptures etc. The list is endless, with more applications being found all the time.
The use of stainless steel in the Construction Industry continues to increase as its benefits, especially those relating to sustainability, are more widely recognised. It comprises 65-90% recycled material content (limited only by the availability of scrap), offers low thermal conductivity and is 100% recyclable at the end of a long, often maintenance-free, service life.
How and Why does Ancon Use Stainless Steel?
Ancon has been fabricating steel in Sheffield, England , for over 130 years and was one of the first companies to recognise the potential for stainless steel in building applications, when it began developing its range of construction fixings in the 1960s.
It has been working with a range of stainless steels at its manufacturing operations in Switzerland since 1983.
Today, the Ancon product range includes stainless steel engineered reinforcing bar and accessories, shear load connectors, balcony connectors, cavity wall ties, brick support systems and masonry reinforcement. Typically, these products provide a critical connection within a building or structure, are invisible once installed and are permanently under load.
Inspection, maintenance or replacement of these products is either impossible due to inaccessibility or impractical due to cost and inconvenience. Therefore it is stainless steel that is preferred to carbon or galvanised steels in these structural applications as it provides the necessary integrity and assurance required by most designers and asset owners.
Over the years, Ancon has firmly established a reputation for quality and innovation. Whilst we continually consider new materials for structural applications), stainless steel still provides the platform for many of our latest new products e.g. Lightning Wire, Acoustic Dowels.
Ancon is a member of the Australian Stainless Steel Development Association , Swiss Inox and the British Stainless Steel Association.
Ancon is exhibiting at the 2016 NZ Bridges Summit on 1st - 2nd November in Auckland. The conference is endorsed by the NZ Transport Agency (NZTA) and we will be showcasing our BT range of threaded reinforcement couplers, our MBT range of bolted couplers and various Lifting Systems including our brand new EdjPro Narrow Anchor system.
Having recently identified issues with the performance of some batches of reinforcing steel supplied to us, we have introduced batch testing for all reinforcement used in combination with our BT coupler system in New Zealand to ensure compatibility.