The most widely used method of steelmaking,
involving the blasting of oxygen at 
supersonic speed into molten pig iron.
Pig iron from a blast furnace, together
with steel scrap, is poured into a converter,
and a jet of oxygen is then projected into
the mixture. The excess carbon in the mix and
other impurities quickly burn out or form a
slag, and the converter is emptied by
tilting. It takes only about 45 minutes to
refine 350 tonnes/400 tons of steel. The
basic-oxygen process was developed in 1948 at
a steelworks near the Austrian towns of Linz
and Donawitz. It is a version of the Bessemer
process.