Nearly 110 years ago – in 1912 – Krupp’s German engineers patented austenitic stainless steel. The invention did not meet with a warm welcome from European industry straight away. Only when the English engineer Harry Brearley persuaded the cutler R. F. Mosley to use the material for cutlery did stainless steel begin to be used on a wider scale.
Over the following decades engineers around the world kept finding new uses for it. Today this remarkable material turns up in almost every branch of industry. Where does its popularity come from?
Properties of stainless steel
Stainless steels are a group of steels resistant to corrosion from dilute acids, alkaline solutions and the weather. The most common grade contains 18% chromium and 10% nickel. It is the chromium in the alloy that gives the steel its distinctive properties. Chromium particles react with the oxygen in the air, forming a film of chromium oxide on the surface that is invisible to the naked eye. That film is what prevents corrosion. Interestingly, this invisible shield is passive – it does not react chemically with other substances – which is why stainless steel products can be used in contact with food.
The chromium oxide film also repairs itself. That makes the material easy to work and gives engineers plenty of scope to reuse steel components that are no longer needed. Recycling matters in the context of the zero-emission economy the European Union is heading towards. Stainless steel products are also exceptionally strong and long-lived, so they need no costly or labour-intensive maintenance.
Applications of stainless steel
Almost 110 years after its invention, stainless steel is at work across many sectors of the economy. In recent decades it has become common in construction and architecture: lift cars, fittings, balustrades and columns are all made from it. Because it is so durable, it is increasingly used for street furniture too – benches, handrails and bicycle stands. Stainless steel products stand up well to vandalism and are not damaged by changing weather. They are also remarkably easy to keep clean: most detergents can be used for cleaning and disinfection without any risk that the steel will discolour or lose its properties. That matters particularly in public buildings, shopping centres and amusement parks.
Stainless steel products are used in the food, chemical, power and automotive industries. In the first of those it is an invaluable ally for customers and producers alike. Stainless steel is non-toxic and exceptionally hygienic, which is why it is used to store and transport food and why so many components of installations in food-processing plants are made from it. In the other sectors it is chosen mainly for its strength and resistance to high temperatures – and for the fact that it can be used in aggressive environments.
