This is a continuous open-hearth process, and seems destined to fill an important place in steel production. The furnace used embodies the same principle as the ordinary open-hearth furnace, but it is mounted on rockers so that any quantity of metal or slag may be poured out at will. Slag is poured from the charging side of the furnace and metal from the side opposite. When the charge is ready for tapping out, a part of the slag is first poured off and then only about one-third of the metal is poured out. That part of the charge which remains in the furnace is replenished with new stock to replace that poured out. In this way the process is continued from day to day, although it is necessary to empty the furnace about once a week for repairs to the hearth and the lining.

To the charge remaining in the furnace after each pour, there is added mill scale or ore, and limestone. These form a highly basic and a highly oxidizing slag, and when these materials are thoroughly fused, a quantity of molten pig iron is slowly poured into the furnace from the ladle. As this metal passes through the slag, a very vigorous reaction takes place between the iron oxide and the impurities in the metal, thus quickly burning out a large percentage of these impurities and thereby shortening the process.

The advantages of this process are as follows, viz.:

(1) A wider range is made possible in the grade of pig iron which can be used.

(2) The process is not dependent on steel scrap, which may be difficult to obtain.

(3) The wear and tear on the furnace hearth and lining are much reduced.

(4) A greater output of steel is obtained in a given time.

A tilting furnace, used in this process, has a capacity of 200 tons or slightly more.