
The "
discovery" of stainless steel occured in the
1900 to 1915 time period. However, as with many discoveries, it was the accumulated efforts of several individuals that actually began in 1821. That year a Frenchman named Berthier found that iron when alloyed with chromium was resistant to some acids. Others studied the effects of chromium in an iron matrix, but using a low percentage of chromium. To be stainless steel, the chromium content needs to be at least 10.5%. In 1872, Messrs. Woods and Clark applied for a British patent for what they identified as an acid and weather resistant alloy containing 30 to 35% chromium and 1.5 to 2% tungsten. Then, in 1875, another Frenchman named Brustlein recognized the importance of carbon levels in addition to chromium. Stainless steels need to have a very low level of carbon at 0.15%. While many others investigated the chromium/iron composition, the difficulty in obtaining the low carbon levels persisted for many years until low carbon ferrochrome became commercially available.