Benjamin Huntsman
An English clockmaker, born in 1704, credited with the invention of cast steel, which was far more consistent and reliable than the laminated steel that preceded it.
Borrowing techniques from glass blowers, Huntsman was able to heat the steel to a much higher temperature, paving the way for superior quality springs and other steelwork for horological purposes, among myriad other applications both within and beyond the borders of England.
Image source Crucible Steel Company of America Share Certificate