Metallurgy 487 Heat treatment 171 Steel 150 Metals 96 Powder metallurgy 95 Physical metallurgy 91 Aluminum alloys 79 Petroleum 62 Geology 51 Mathematical models 51 Petroleum engineering 50 Prospecting 46 Titanium alloys 45 Mines and mineral resources 39 Alloys 37 Natural gas 36 Oil reservoir engineering 34 Aluminum 32 Design and construction 32 Mechanical alloying 31 Equipment and supplies 30 Materials 30 Oil fields 29 Sintering 28 Standards 28 Steel alloys 27 Injection molding of metals 26 Testing 25 Mining engineering 24 Corrosion and anti-corrosives 22