404 



APPLIED SCIENCE 



of ferromanganese, similar to spiegeleisen. The amount of 

 carbon left in the metal is ascertained by removing a small 

 quantity of metal in a ladle, cooling it, and then breaking 

 it up and testing it. If found satisfactory, the charge is 

 tapped and the metal run into the ingot molds. The ingot 

 is later reduced to a slab, called a bloom, by passing it back 



FIG. 194. Blooming Mill Showing Steel Ingot Reduced to Bloom. 



and forth between heavy rolls until it is reduced to the thick- 

 ness desired (Fig. 194). The operation is slower than the 

 Bessemer, but it enables the manufacturer to produce more 

 readily the desired grade of steel. It is the usual method of 

 producing steel of good and uniform quality at a low cost 

 and on a large scale; the product competes with Bessemer 

 steel in price. 



462. The Open-Hearth Process. In the open-hearth 

 process, a charge of material, consisting of wrought iron, 



