Abstract
Effects of C, Mn, Ni, Si, and N on structural changes and magnetic properties of cold-worked and heat-treated high manganese non-magnetic steels were studied by means of optical and transmission-electron microscopy, X ray diffraction, magnetic measurement, and Mossbauer spectroscopy.
Additions of C, Mn, Ni, and Si restrain increase in permeability with cold working. Additions of C and Si accelerate increase in permeability with isothermal annealing at 600°C, and those of Mn and Ni restrain this increase. The increase of the permeability with cold working corresponds to the appearance of strain-induced martensite. The increase of the permeability with isothermal annealing at 600°C is considered to be caused mainly by the ferrite among the pearlitic constituent precipitates. When the amount of ferrite is over 2%, the permeability is above 1.1.
From these results, it is found that the permeability of steels containing optimum alloying elements such as 0.65%C, 14%Mn, 2%Cr, and 2%Ni remains at a low level under cold working and heat treatment.
