Process and apparatus for heat-treating carbon steel wires to obtain a fine pearlitic structure

摘要

Carbon steel wire, which has been maintained at a temperature above the Ac3 transformation temperature, is heat-treated to obtain a fine pearlitic structure by passing it through a tube containing a gas practically without forced ventilation and surrounded by a heat-exchange fluid. Certain relationships between the diameter of the wire, the diameter of the tube and the conductivity of the gas are to be satisfied to ensure cooling of the wire to a temperature below the Acl transformation temperature in a time prior to the time of the pearlitic nose and to effect pearlitization to completion under a nearly isothermal state.