A short tribute to the developers of the alloy that has raised the performance bar for metals in so many areas

August 2013 - Defining the moment when a substance 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. 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. Regardless, many have been celebrating the centenary this year with various events and visual content that look at how stainless steel has been used in buildings and structures across the world.

What is stainless steel?

In technical terms, stainless steel is defined as a steel alloy containing at least 10.5 percent to 11 percent of the element chromium. The standout feature of stainless steel, as the name suggests, is the fact that it is highly resistant to discoloration and corrosion. It can be exposed to moisture without rusting, for example, unlike carbon steel. These properties give stainless steel a huge number of applications across a broad range of industries. 

The invention of stainless steel

Pinpointing a single inventor of stainless steel or a single moment of invention is easier said than done. Several people have laid claim to the title of inventor over the years, from locations as disparate as the U.S., France, Poland, Germany and Britain. One of the factors that militates against making an exact judgment is the way in which stainless steel emerged via a process of ongoing modification, meaning that before the official definition was arrived at in 1913, various alloys existed that boasted some of the properties of stainless steel without the requisite levels of chromium.

It’s possible to trace the story back to the 1820s, when scientists such as Pierre Berthier, of France, and the U.K.’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 German scientist Hans Goldschmidt devised a method for the production of chromium which was free from carbon, a breakthrough that paved the way for the development of what we would recognize as stainless steel.

The next 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 percent chromium content was first put forth as the level at which corrosion stopped.

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. In 1912 he was asked by a gun manufacturer to develop a steel that would resist erosion. After a period of experimentation Brearley developed steel consisting of 12.8 percent chromium and 0.24 percent 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 August 13, 1913.

Upon noting the properties which this steel possessed, Brearley worked with a friend named Ernest Stuart, who was the cutlery manager at a company named Mosley’s. Stuart came up with the process for manufacturing hardened knife blades, while also persuading Brearley to replace his intended name, rustless steel, with the more attractive stainless steel.

It may seem surprising as we 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 used in a wide range of products and processes.

Today there are more than 150 grades of stainless steel, 15 of which are most common. As a rule of thumb, the higher the percentage of chromium, the greater the anti-corrosive properties of the steel, with levels of up to 26 percent 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 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, because it has been cleaned only 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 for storing and working with dangerous chemical substances such as nitric acid. 

From the knives and forks 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. FFJ

Ellie Foy is is the marketing executive of Castle Metals, a part of the A.M. Castle group. With a presence across the U.S., Europe, and Asia. Castle Metals specializes in stainless steel and is headquartered in Blackburn, Lancashire, U.K.

Infographic celebrating the Stainless Steel Centenary from Castle Metals - Stainless Steel Suppliers.