The zone of stable immiscibility of liquid phases during the smelting of a copper alloy with 20% wt. Fe is obtained by using steel with 0.2% C; the research method is agree with the features of the state diagrams of Cu–Fe and Cu–Fe–C systems in the zone of low concentrations of C. In the induction crucible furnace, primary melting of steel is carried out with gradual saturation of the melt with copper with small solid additives in insignificant overheating of the melt above the liquidus temperature (up to 25 K) and laminar motion of metal. This ensures its constant presence in the state of pre-stratification (emulsion nucleuses that continuously nucleate and dissolve), which is characteristic of Cu–Fe melts. In the melt layers that surround the copper additives during their dissolution, the Cu content increases and they enter into the immiscibility zone of the Cu–Fe system alloyed with C. There spontaneous emulsification and acquisition of a stable structure by dispersed phases took place. During their subsequent transition to the mixing zone, the inherited constancy of the structure restrains the dissolution process of globularized formations. The cooling of the metal liquid is accompanied by competition between the processes of globularization and dendrites’ formation. This manifests itself in the sizes of the melt volumes, which are characterized by the predominance of one of the types of phases or their parity depending on the temperature, concentration and time conditions, as well as the features of their nucleation and development. In the structure of the sheet obtained by casting in a roll crystallizer (cooling rate of $\cong$ 1000 K/s), 19 types of globularized formations (0.2–250 $\mu$m) are found, three of which (0.2–1.0 $\mu$m) are frozen microemulsions. Prospective directions for the application of sheet products made of copper–steel alloys with a microemulsified structure (manufacture of products by additive technologies for responsible equipment, shields from electromagnetic and thermal influences, and inserts in sliding bearings) are determined.