100 Years of Stainless Steel
As we’ll come to see, actually defining the moment when a substance such as stainless steel is ‘discovered’ can be a complicated and somewhat less than precise business. Although popular imagination tends to assume that scientific discoveries revolve around a single ‘Eureka’ moment, the truth is usually much more mundane and rather more complicated.
A breakthrough like the invention of stainless steel is something which comes along as a result of multiple smaller discoveries and developments, and is usually the culmination of contemporaneous work by different scientists and technicians scattered around the world. In the case of stainless steel itself, several names have, over the years, been put forward as being the ‘inventor’, with varying levels of authenticity.
What is Stainless Steel?
Before examining its discovery or invention, it would perhaps be useful to give a brief overview of what stainless steel actually is. In technical terms, stainless steel is defined as a steel alloy containing at least 10.5 to 11% of the chemical element chromium, an alloy being a metal consisting of at least two elements.
The standout feature of stainless steel, as the name suggests, is the fact that it is highly resistant to discolouration and corrosion, being able to stand exposure to moisture without rusting, for example, unlike carbon steel. It is this property which means that stainless steel has a huge number of applications across a broad range of industries.
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The Invention of Stainless Steel
As stated previously, pinpointing a single inventor of stainless steel or an actual moment of invention is easier said than done. There are several different people who’ve laid claim to the title of Inventor over the years, from locations as disparate and varied as the U.S.A., France, Poland, Germany and Britain.
One of the factors which militate against making an exact judgement is the way in which stainless steel emerged via a process of on-going modification, meaning that before the official definition was arrived at in 1913, various alloys existed which boasted some of the properties of stainless steel without containing the requisite levels of chromium.
It’s possible, indeed, to trace the story back to the 1820’s, when scientists such as Pierre Berthier of France and the UK’s Stoddard and Faraday were working with chromium alloys to investigate their resistance to attack from acids. The chromium content of these alloys was low, however, since scientists had yet to grasp the importance of having low carbon content in the iron.
Small advances were made over the years, but it wasn’t until 1895 that the German scientist Hans Goldschmidt devised a method for the production of chromium which was free from carbon, a breakthrough which paved the way for the development of what we would recognise as stainless steel.
The next big breakthrough came in 1911, when the Germans P. Monnartz and W. Borchers noted the link between high chromium content and a resistance to corrosion. It was at this point that the figure of at least 10.5% chromium content was first mooted as being the level at which corrosion began to be successfully resisted.
At this stage in the development we come across one Harry Brearley, of Sheffield, who, in 1908, became the head researcher at Brown Firth laboratories. More than any other individual it is Brearley who can reasonably claim to have ‘invented’ stainless steel (originally called ‘rustless steel’).
In 1912 he was asked by a gun manufacturer to develop a steel which would resist erosion. After a period of experimentation Brearley developed steel which consisted of 12.8% chromium and 0.24% carbon and which is widely regarded as marking the creation of stainless steel as we know it. The date upon which this breakthrough came is generally accepted as being the 13th August 1913.
Upon noting the properties which this steel possessed, Brearley worked with a friend of his named Ernest Stuart, who was the cutlery manager at a company named Mosley’s. It was Stuart who came up with the process for manufacturing hardened knife blades, whilst also persuading Brearley to replace his intended name ‘Rustless Steel’ with the more attractive Stainless Steel.
It may seem surprising as we prepare to celebrate its centenary, but stainless steel was not an instant success. Indeed, in the early days, stainless steel cutlery was branded as ‘the knife that won’t cut’. As manufacturers became more aware of its properties, however, it began to be utilised in a wide range of products and processes.
Stainless Steel in 2013
Today there are over a hundred and fifty different grades of stainless steel, with fifteen which are the most commonly utilised. As a basic rule of thumb, the higher the percentage of chromium present, the greater the anti-corrosive properties of the steel, with levels of up to 26% being used in extremely harsh environments.
Put simply, the chromium present forms a microscopically thin layer of chromium oxide on the surface of the metal. Although so thin as to be invisible, this layer has the effect of protecting the metal beneath from contact with water and air, thus maintaining its lustrous appearance.
It’s for this reason that stainless steel is often utilised for its decorative effect, over the entrance of the Savoy Hotel London, for example, or the highest levels of the Chrysler building in New York. The latter is an extremely useful demonstration of the durability of stainless steel, since it has only ever been cleaned twice since it was built in 1929 and yet still maintains its aesthetic appeal and gleaming brightness.
The fact that stainless steel is also immune to effects of corrosion from the likes of acid, for example, makes it highly versatile and able to be used for storing and working with dangerous chemical substances such as nitric acid.
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From the knives and forks which we use every day to the gleaming exterior of a building like the European Court Of Human Rights, stainless steel is all around us and helps us to perform a multitude of different tasks each and every day.