INFLUENCE OF STEEL SPECIMEN ELECTRIC POTENTIAL ON DEFECT FORMATION IN SURFACE LAYER UNDER ACTION OF FACTORS RELATED TO PULSED DISCHARGE IN AIR

摘要

A study has been made of the manner in which an electrical potential on the surface of steel St40KhN affects the character of deformation and alters the structure of the near-surface layer when it is acted upon by a pulsed discharge in air. The absence of a galvanic connection between the source of the controlled potential and the metal surface being treated made it possible to detect appearance of light-colored acicular structures about 0.1 mm long, which extended into the interior of the metal. The results of the these experiments lead to the supposition that vapor phase particles move into the interior of the solidifying melt, acquiring a negative charge that interacts with the space charge field at the melt surface. The layer by layer changes in microhardness and electrical conductivity duplicate the distribution density of the acicular structures and the depth to which they penetrate the metal.