Sheffield steel was steel made in Sheffield. The Fourth Doctor thought it was rather dependable. (AUDIO: Suburban Hell)
Sheffield was a notable producer of fine cutlery (PROSE: The Also People) made from Sheffield steel. (PROSE: Transit, Sky Pirates!)
The Thirteenth Doctor's handmade sonic screwdriver was partly made from Sheffield steel. She used actual spoons in the process of making it. (TV: The Woman Who Fell to Earth)