THE MAKING AND WORKING OF STEEL 405 



cast iron, steel scrap, and other ores, is melted on the hearth 

 of a reverberatory furnace and heated by gas, as in the Sie- 

 mens-Martin or regenerative system. Sometimes the mol- 

 ten metal from the blast furnace is poured directly into 

 the open-hearth steel furnace, as shown in Fig. 195. The 

 carbon is thus partially burned out, much as in the wrought 



FIG. 195. Pouring Molten Iron into Open-Hearth Steel Furnace. 



iron process, and its proportion is brought down to the de- 

 sired point or somewhat below. A charge of spiegeleisen 

 is then added, in order that the manganese may act on 

 any oxide of iron slag which remains in the bath, and which 

 would make the steel red-short (brittle when hot) if allowed 

 to form a part of the charge. The manganese separates 

 the iron from the oxide, returns it to the bath, and the 

 carbon joins with that already present. 



In the open-hearth, as in the Bessemer process, there is 

 no removal of sulphur or phosphorus, and only materials 



