Effect of the initial structure of steels on the deterioration of their contact layers in dry sliding against quenched steel under alternating electric current of a density higher than 100 A/cm2

Abstract

Dry sliding of a number of alloy steels against a quench-hardened steel was tested at a high-density alternating electric current. The aim of these tests was to determine the factors decreasing the wear. The sliding contact layers were observed to undergo plastic deformation due to the formation of certain transfer layers in the contact zone. It was shown that these layers contain more than 75 vol% FeO and also some initial phases. The transfer layers contained signs of melt formation. This phenomenon was described at a qualitative level. Melt appearance is conditioned by occurrence of a displacement current in FeO containing medium. This displacement current provided energy to the FeO ions for their transition to the melt. A low ductility of the doped initial phases caused an increase in wear intensity of the transfer layers. These effects were manifested due to a low ability of the material to relax the mechanical stresses in the contact zone of the alloy steels. This meant that a low ductility was among the main factors contributing to severe wear. A relationship between low wear resistance and low electrical conductivity of the contact was shown.