Jacob Mayer
Jacob Mayer (born 1 May 1813 in Dunningen, Germany, died 30 July 1875 in Bochum) was a German steel manufacturer and inventor.
Mayer, the son of a farmer, completed an apprenticeship as a watchmaker with his uncle in Cologne before going to work in England. His uncle had experimented with steel crucible casting, and in England Mayer sought to gain knowledge of this process. Back in Germany, he first carried out experiments on steel crucible casting at his father's farm in Dunningen, which were probably successful on a small scale around 1836.
1854 discovered a mould material suitable for casting steel, composed of calcined fire-clay, with only a small quantity of new clay to make it plastic.
See German Wikipedia entry for more information.