Page:Popular Science Monthly Volume 90.djvu/454

 Electric Steel from Electric Furnaces

We were forced by the exigencies of war to develop our own crucible-steel industry. Now we lead the world

��ELECTRIC steel is now a commercial success, and the United States leads the world in its production. Until it became possible to melt and refine steel by the use of electricity as a source of heat, instead of gas or oil, nearly all steel was made either in crucibles or small pots, or in large coal or oil furnaces. Large furnaces, known as open- hearth, today still make the majority of the steel produced in the world, but it is the electric steel furnace which now makes the best and purest steel, rapidly displacing that made. in small crucibles, hitherto the best for tools, razors, etc.

The unusual qualities possessed by electric steel are not bestowed on it by the electricity itself. This should be clearly under- stood. The conditions are responsible rather than the agent itself. In other furnaces where oil or gas and air are the heat- producing mediums, there is more or less contamina- tion from impurities, such as sulphur, as well as from the oxygen of the air itself, too much of which is often harmful to steel. But in the furnace, electricity is an even and very intense source of heat; the conditions can be so regulated that the air or oxygen has but little effect on the steel. Practically no contamination is possible. Also the temperature is so high that more refining is attainable than in any other furnace. In other words, certain chemical reactions can take place so as to remove objectionable elements — an impossibility in other steel-making furnaces.

One of the qualities that distinguishes electric steel is its greater purity. Hence it is stronger than other steels. Compare it with any steel made by any other proc- ess and of the same composition, and the electric steel will show greater strength. Many steels are susceptible to change from

��Tapping molten metal from an electric furnace. Steel flows from it like water from a tub

��frequent shocks. Some give out and break down before others under such conditions. Again, electric steel is superior to others in this respect and is now used in many places where shocks must be withstood, as for automobile axles, springs, etc. Electric steel is also very uniform in composition and is denser than other steel — both im- portant qualities. Steel made by the usual and older processes also con- tains varying amounts of certain gases included in them, strange as this may seem. Electric steel, however, is very free from these objec- tionable constituents.

Europe and particu- larly Germany had al- ways led in the use of electric furnaces for mak- ing steel until the war started. Development in this country had been very slow partly because electricity was high and partly because there was not a large demand for such a high grade steel. The actual need was sup- plied by importations from Europe. As the war progressed and electric steel could not be imported when needed we were forced to develop our own electric steel industry. In addition plumbago crucibles, with which crucible steels, then the high grade steel, were made, advanced so in price and became so expensive and hard to get that crucible steel makers were driven to the electric furnace. Today in this country all but two or three crucible steel castings makers are now using electric fur- naces instead of crucibles and would not change back to the old process if they could. Their product is better and more easily made. Tons are made at a time where formerly it took over twenty crucibles to make one ton.

The expansion in this branch of the steel industry in the last six years in the world and in this country is astonishing.

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