Magnetic Analysis of Steel by Means of a New Method. II : On the Solubility of Chromium in Ferrite (α Iron) Contained in a Chromium Steel

摘要

A search coil is placed around a steel specimen put in a cylindrical heating furnace, and they are placed together in a magnetizing solenoid. Alternating current is passed through the solenoid, and the current induced in the search coil is measured by an alternating current galvanometer. The steel specimen containing 1.0% C and 1.5% Cr was taken, and the relations between the galvanometer reading and the temperature of the specimen were observed in the range 400℃--800℃. With this method, the following results have been obtained:-- (1) By quenching and tempering, the solubility of Cr in ferrite decreases with the increase of the tempering temperature, the Cr atoms diffusing into the carbide. (2) By austempering, the solubility of Cr in ferrite is higher when the isothermal transformation temperature is lower. (3) Therefore, the solubility of Cr in ferrite in a chromium steel varies with the temperature.