Numerical Simulation and Experimental Verification of Cu \ Ni Dissimilar Metal Wire Deep Penetration Brazing

Low-temperature radiant heating technology of heating cable has the advantages of cleanliness, safety, high efficiency, energy saving and environmental protection. It is an internationally recognized advanced heating method. The key technology is the manufacture of heating cable core. The core of the heating cable is made of Cu wire (Cold line, Φ0.4~1.13mm) with different diameters and Ni base alloy hot wire (Hot line, Φ0.3~0.85mm). The heating cable is made of Ag base filler metal through deep brazing. Deep penetration brazing of cable core is a special welding method between thermal conductivity brazing and common brazing. The contact resistance between the copper electrode and the hole graphite welding pool is used to generate heat to melt the Ag base solder, then realize the brazing of Cu/Ni hot wire in the hole graphite welding pool. It is the key to obtain good welding effect and high quality welding joints to study the heat transfer characteristics of graphite and Ag-based solder in deep penetration brazing of Cu\Ni dissimilar metal wires. In this article, the contact resistance model between copper electrode and cylindrical graphite welding pool was established, and the finite element model of deep penetration brazing of Cu/Ni dissimilar metal wires was established based on the specific heat capacity and thermal conductivity coefficient of materials measured. The thermal field distribution of graphite welding pool and Ag base filler metal was simulated and calculated. The temperature of the calibration point of the graphite welding pool measured by experiment is basically consistent with the temperature at the same position in the simulation calculation.