Investigation of Heat-treatment Effect of Magnetic Wires by means of Current-carrying Heating

Abstract

In recent years, magnetic wires, which have magnetic properties comparable to those of the electrical steel sheets, have been commercialized and their application to electrical equipment as an iron core is being explored. The conventional electrical steel sheets are generally thin sheets less than 0.5 mm thickness to reduce eddy current losses. The magnetic wires have also small cross-sectional area and can easily processes to be any structure. It is therefore necessary to anneal the magnetic wires after processing to remove residual-strain. However, the conventional heat treatment in an electric furnace is time-consuming and then inefficient. In this study, we paid attention to the current-carrying heating method, in which an electric current is applied directly to the magnetic wires. Due to the Joule loss, effective heat treatment can be therefore performed in a very short time. This paper reports results of a comparative study of magnetic properties of one of the magnetic wires heat-treated by means of the current-carrying heating method.