What is elemental oxygen used for?
Oxy-fuel welding was invented in 1903 by French engineers Edmond Fouché and Charles Picard. Pure oxygen, instead of air, is used to increase the flame temperature: a common propane/air flame burns at about 2,000 °C (3,630 °F), a propane/oxygen flame burns at about 2,500 °C (4,530 °F), and an acetylene/oxygen flame burns at about 3,500 °C (6,330 °F).