Some High Lights in the Use of Electricity in Steel Mills

Approximately one tenth of the investment in the American steel industry is in electrical plant. The power consumption of steel mills is increasing. About two thirds of the power used is generated within the plants but there is a trend toward increased purchase of power. Electricity is gaining a foothold in the field of transportation through the Diesel-electric locomotive. D-c motors are being used more for main-roll drives. Synchronous motors are also gaining favor. Reversing drives have developed interesting ramifications. There is a trend toward subdivision of main roll drives. The combination of reduction gears and mill pinions into a single unit is of interest. The use of new types of bearings affects power requirements. The concentration of d-c power associated with the main-roll drives of wide strip mills has introduced problems concerning interrupting capacity of circuit breakers and strength of bus installations. In the field of auxiliary drives, the increased application of small individual induction motors is notable. Electrical precipitation finds greater acceptance in the field of gas cleaning. Electric melting furnaces supply a small but growing increment of total steel production. High-frequency heating is finding some uses. New types of electric furnaces are being installed for heat treating and annealing operations.