From 1964 to the present, many works have been devoted to studying bimetallic wire with a heat-resistant jacket of nickel or corrosion-resistant steel and a core of a metal with a high electrical conductivity such as copper or silver. This wire retains its operating capacity up to 700~ and is widely used as a high-temperatur~ conductor in various fields of engineering. The present paper is devoted to a comparative analysis of thn structure and electrical properties of bimetallic conductors with a copper core and a heat-resistant jacket ol chromal alloy Kh23Yu5T or corrosion-resistant steel 12Kh 18N9T.In studying a bimetallic conductor most attention is devoted to two characteristics, namely, the electrical resistivity and its stability in a hold at an elevated (up to 900~ temperature. The electrical resistivity P2o of a bimetallic wire at 20~ is close to the value calculated using the model of parallel-connected continuously contacting components of the bimetal (see, for example, [1]). The stability of the resistivity is evaluated from the relative change in the resistivity of specimens of the bimetallic wire at a temperature t in a given period of time [1, 2]:where Ohm, Pl, 132 are the values of P20 for the bimetal as a whole and its first and second components, respectively, and x is the volume fraction of the second component.The dependences of the electrical resistivity of heat-resistant bimetals on the temperature in continuous heating and cooling in a wide (20-1000~ temperature range in an air medium, the mechanisms that determine the behavior of these experimental dependences, and their deviation from the values calculated from the additive model of parallel-connected continuously contacting components remain virtually unstudied.In order to investigate the interaction of the components of high-temperature bimetallic conductors in the 20 -1000~ range and its effect on the properties of these materials and to create heat-resistant conductors with a high (at least 900~ operating temperature, we studied specimens of bimetallic wire with diameters ranging from 8.0 to 0.45 mm with a jacket of heat-resistant alloy Kh23Yu5T [3] melted in a vacuum induction furnace or corrosion-resistant steel 12Khl8N9T [4] and a core of copper of grade M1 (Table 1).The bimetallic specimens were fabricated by forging and rolling composite cylindrical preforms 29.0 mm in diameter into rods 8.0 mm in diameter at 950~ and by cold drawing to a diameter of 0.45 mm with an intermediate heat trealment that consisted in hardening in water or air atter heating in a through furnace in a hydrogen atmosphere. In accordance with the recommendations of [5] the temperature of heating for hardening was chosen the same as for a single-metal wire made of the material of the jacket of the bimetal, namely, thard = 800--850~ for bimetals 1 and 2 and thard = 900-950~ for bimetals 3 and 4.The electrical resistance was measured in a four-contact circuit on a U309 installation for specimens 3.0 mm in di~ ameter or by an Sh34 precision ohmmeter for specimen...

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