THE AGE OF STEEL 



furnaces, which, however, must not be situated at 

 any very great distances from the furnaces. This ac- 

 counts partly for the grouping together of blast-fur- 

 naces, rolling mills, and machine shops, the economical 

 feature of this arrangement being so great that segre- 

 gated establishments find it next to impossible to 

 compete in the open market with such "communities" 

 under the conditions prevailing in the steel industry. 



ALLOY STEELS 



The introduction of Krupp steel, or nickel, for 

 armor plates, a few years ago, called attention in a 

 popular way to the fact that for certain purposes pure 

 steel that is, iron plus a certain quantity of carbon- 

 was not as useful as an alloy of steel with some other 

 metal. An alloy was a great improvement over ordi- 

 nary steel or iron plates used in warfare; but in the 

 more peaceful pursuits, as well as in warfare, certain 

 alloyed steels, such as chrome steel, tungsten steel, 

 and manganese steel play a very important part. 



Chrome steel, for example, in the form of projec- 

 tiles, is the most dreaded enemy of nickel-steel armor 

 plates, because of the hardness and elasticity of armor- 

 piercing projectiles made of it. Such a steel contains 

 about two per cent, of chromium with about one or 

 two per cent, of carbon, which when suddenly cooled 

 is extremely hard and tough. This kind of steel and 

 manganese steel are the best guards against the 

 burglar and safe-blower, as they resist even very highly 

 tempered and hardened drills. As this steel is rela- 



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