Sheffield steel was steel made in Sheffield. The Fourth Doctor thought it was rather dependable. (AUDIO: Suburban Hell) According to Madame Vastra, "there [was] none finer". (AUDIO: A Photograph to Remember)
Sheffield was a notable producer of fine cutlery (PROSE: The Also People) made from Sheffield steel. (PROSE: Transit, Sky Pirates!)
Madame Vastra had a sword made from Sheffield steel. (AUDIO: A Photograph to Remember)
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) One recon Dalek also used local steel to forge a new shell. (TV: Resolution) Following the Thirteenth Doctor's regeneration, a dismayed Fourteenth Doctor noted the screwdriver's composition when it was destroyed by a Dalek at the Dalek Dome. (COMIC: Liberation of the Daleks)