METHOD FOR INCREASING THE MECHANICAL PROPERTIES OF SURFACE LAYERS OF MACHINE PARTS WITH thermomechanical and chemical-thermal treatment to give submicron and nano-structured state diffusion layer

摘要

FIELD: machine building.;SUBSTANCE: invention relates to machine building, in particular, to the methods for the improvement of mechanic properties of near-surface layers of machine parts from iron-base alloys with obtaining submicro- or nanostructured state of diffused layers. The method involves assembling a package of alternating steel plates with different chemical composition, vacuumisation and heating of the package, hot deformation of the package in height under the temperature whose value falls between the temperature values of polymorphous transformation of both alloys, after the hot deformation the workpieces of parts are cut out of the package so that the direction of interlayer borders in the part workpiece coincides with the direction of the nitrogen diffusion flux during nitriding that follows, then nitriding is carried out to obtain submicro- and nanostructured state of diffused near-surface layer on the part surface.;EFFECT: method allows for the improvement of mechanical properties of material's near-surface layers formed in the course of nitriding and, respectively, longer service life of parts.;9 dwg, 1 ex