Question

Write two properties of open-hearth furnaces.

Answer 1

In manufacturing of steel, a particular furnace is used to remove carbon and other impurities out of pig iron. Normal furnaces are not sufficient to tolerate the high temperature required in steel production.

Complete Solution:
We have studied about the various processes used for the purification of metals from our lower classes. Now let us see what open – hearth furnace is and its properties.
- In the manufacturing process, the furnace is first charged with scrap such as sheet metals, shredded vehicles or other waste material. The furnace is then heated using burning gas. Once all this is melted, heavier material like construction or steel milling scrap is added.
-Once all the steel gets melted, limestone is added as a slag forming agent. Impurities are removed by excess burning and pure steel is obtained.
- Open hearth furnaces were developed in order to overcome the issue with extreme high temperature required for steel manufacturing.

Some of the properties are:
- In an open hearth furnace the heat of combustion of fuel is used to convert a charge of scrap and liquid blast furnace iron to liquid steel.
-In an open hearth furnace, the steel is not exposed to excessive nitrogen which can make it brittle.
- Open hearth furnace permits refining and melting of a large amount of scrap iron and steel
The process of an open-hearth furnace is very slow and hence easy to control.

Additional information: Open hearth furnace was developed in 1865. However, now most of these furnaces are replaced by basic oxygen furnaces or electric arc furnaces.

Note: Various types of furnaces are used in manufacturing of various substances which is depending on the requirement of the substance and its physical properties, type of furnace changes.