Short answers, pulled from the story.
Harry Brearley invented stainless steel in 1913 while testing chromium-iron alloys at the Brown-Firth research laboratory in Sheffield, England. He discovered the material that did not rust, which was initially called rustless steel before becoming known as stainless steel.
Stainless steel must contain at least 10.5% chromium to form a self-healing passive film that protects the underlying metal from oxidation. This chromium threshold is critical for the alloy's protective capabilities and distinguishes it from ordinary carbon steel.
The New York Times announced the development of stainless steel in January 1915, two years after its discovery. The metal was first used for the new entrance canopy of the Savoy Hotel in London in 1929 under the Staybrite brand by Firth Vickers.
Stainless steel is classified into five families: austenitic, ferritic, martensitic, duplex, and precipitation hardening. Austenitic stainless steel is the largest family, making up about two-thirds of all stainless steel production.
Over 25,000 tons of stainless steel were manufactured and sold in the US annually in 1929 before the Great Depression. The average carbon footprint of stainless steel is estimated to be 2.90 kg of CO2 per kg of stainless steel produced.
Stainless steel is generally considered biologically inert with no established connection between cookware and cancer. However, welding stainless steel produces carcinogenic fumes from cadmium oxides, nickel, and chromium, which were classified as a Group 1 carcinogen in 2017.