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APPLIED SCIENCE 



nearly free from these ingredients can be used. The product 

 of this process is more reliable than that of the Bessemer 

 process, because it is more homogeneous and is therefore 

 less likely to show unexpected or inexplicable weaknesses. 

 For these reasons it is used very much more than the 

 Bessemer steel. 



FIG. 196. Drawing Steel from Open-Hearth Furnaces. 



463. Crucible Steel. Crucible steel is made by rolling a 

 pure grade of wrought iron into flat bars. These bars are cut 

 up and placed in piles in a crucible with layers of pounded 

 charcoal between them. The piles are then subjected to a 

 high temperature for several days. When withdrawn from 

 the furnace the steel is found to have absorbed some of the 

 carbon and to be hard and fusible. As its surface is covered 

 with small bubbles, it is called blister steel. When the bars 

 are heated with a flux, it is called shear steel, because this 

 grade of steel is most suitable for making shears, scissors, etc. 



