duplex process[′dü‚pleks ‚präs·əs]
in metallurgy, a steel-making process that is carried out in two successive steel-melting units (the process is sometimes also used to smelt cast iron, beginning in a cupola furnace and ending in an electric furnace).
The duplex process, which was first used in the second half of the 19th century, makes possible more efficient use of various units. For example, the duplex process using a basic open hearth furnace and an arc furnace or a converter and an arc furnace is used to increase the output of the electric furnace (that is, to increase the output of high-quality steel) and to reduce the specific consumption of electric power, which is accomplished by removing from the electric furnace such operations as the melting of the charge and the partial refining of the metal; in the duplex process, only the final refining and deoxidation of the steel are carried out in the arc furnace. The application of the duplex process is limited.