Metals That Build New Worlds 179 



remove sulphur and oxygen. If the sulphur were not removed 

 it would cause the steel to become brittle. (Manganese like- 

 wise is used to harden aluminum.) 



Steel as well as iron rusts when exposed to air. So 12 to 18 

 per cent of chromium is added to make a "stainless steel" 

 which resists corrosion. Chrome steel, containing smaller 

 amounts of chromium, is very hard and elastic and is valuable 

 for armor plate and for bearings. 



Nickel steel is resistant to corrosion and tough enough for 

 armor plate, guns, and bridges. 



Tungsten steel is used by machine tools to cut and shape 

 other metals. A tungsten-steel tool does not lose its cutting 

 edge even when heated red-hot by long use at high speeds. 

 Tungsten sees to it that our fighting men get enough weapons 

 on time. The tungsten filament in Mazda lamps provides much 

 of the world with light. 



Molybdenum steel matches tungsten steel in its resistance 

 to heat; hence it can be used for cutting tools, and for axles 

 and other equipment where toughness is demanded. 



Vanadium steel has high tensile strength and elasticity, 

 which make it valuable in the production of axles, crank- 

 shafts, and gears. 



Precious Common Metals 



When war came, we were faced with the fact that the 

 nation's industry depended largely upon imports for five of 

 the six metals listed above. Only molybdenum, 85 per cent of 

 which is produced in the United States, was abundant. But it 

 also got short because great amounts were used to replace 

 nickel, chromium, and tungsten in high-grade steels. 



Seeking to solve our shortage problems, metallurgists have 

 yanked a lot of rabbits out of hats. Metallurgical magic is pro- 

 ducing N.E., or national emergency, steels, which pare down 



