Harry Brearley
The first true stainless steel, a 0.24wt% C, 12.8wt% Cr ferrous alloy, was produced by Brearley in an electric furnace on 13 August 1913. He was subsequently awarded the Iron and Steel Institute's Bessemer Gold Medal in 1920.  The American Society for Metals gives the date for Brearley's creation of casting number 1008 (12.8% chromium, 0.44% manganese, 0.2% silicon, 0.24% carbon and 85.32% iron) as 20 August 1913.