Steel can be made stainless by the adding of at least 10.5 per cent chromium to the melt. When cooled, the chromium protects the steel from rusting by providing an oxide layer on the surface to protect the steel.
As the chromium has very low levels of reactivity, it doesn’t rust, keeping your cutlery shining for years.
The origins of stainless steel are fairly complicated. As far back as 1821, scientists noticed that alloys of chromium and iron were resistant to rust, but it wasn’t until 1913 that the practise really took off.
Sheffield’s Harry Brearley, looking to create rifle barrels that didn’t corrode, discovered that steel-chromium alloys with at least six per cent chromium didn’t oxidise.
Further studies led him to create a steel product with 12.8 per cent chromium, which is widely considered the first stainless steel. Harry Brearley first displayed his invention to the public on 13 August 1913.