Open Hearth Process

: The Working Of Steel

The open hearth furnace consists of a big brick room with a low

arched roof. It is charged with pig iron and scrap through doors

in the side walls.

Through openings at one end of the furnace come hot air and gas,

which burn in the furnace, producing sufficient heat to melt the

charge and refine it of its impurities. Lime and other nonmetallic

substances are put in the furnace. These melt, fo
ming a slag

which floats on the metal and aids materially in the refining


In the bessemer process air is forced through the metal. In the

open-hearth furnace the metal is protected from the flaming gases

by a slag covering. Therefore it is reasonable to suppose that

the final product will not contain so much gas.

A diagram of a modern regenerative furnace is shown in Fig. 3.

Air and gas enter the hearth through chambers loosely packed with

hot fire brick, burn, and exit to the chimney through another pair

of chambers, giving to them some of the heat which would otherwise

waste. The direction is reversed about every twenty minutes by

changing the position of the dampers.