A contribution to the study of the magnetic properties of manganese and of some special manganese steels

Abstract

The object of this research has been to find a connection between the magnetic susceptibility per unit mass (called the mass susceptibility) of different manganese steels and their chemical constitution. All measurements were made with the help of the magnetic balance of P. Curie and C. Chéneveau. In this instrument the body to be tested is attached to one arm of a torsion balance. A horseshoe magnet can be moved horizontally, so that the direction of motion is at right angles to the line joining the poles, and the body is gradually brought into a stronger and stronger field. The observed deflection of the torsion balance increases at first, then diminishes, and becomes zero when the body lies between the poles of the magnet. If the magnet be moved still further, a deflection in the opposite direction is observed, which again passes through a maximum at the point where the variation of the field of force is greatest. Fig. 1 illustrates the deflections observed in a particular case. The difference between the readings of the torsion balance when the deflections are greatest on either side is proportional to the mass susceptibility, so that this quantity may be determined by comparison with a specimen whose susceptibility is known. Throughout the paper the mass susceptibility is denoted by the symbol X .