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                         It has been found that the nanocrystalline surface layer serves as a barrier for

                  hydrogen penetration into the bulk material. The surface layer with nanocrystalline

                  structure formed on the 45 steel by mechanical-pulse treatment is characterized by

                  lower hydrogen  permeability (hydrogen diffusion coefficient  is in  1.3–4 times

                  lower) and higher in 1.5–4.4 times efficiency of hydrogen trapping in comparison

                  with the untreated steel. Therefore, it serves as a barrier for hydrogen penetration

                  into the bulk material. It has been established that nanostructurization of the steel

                  surface using mechanical-pulse treatment by multidirectional deformation in an oil

                  technological  medium  provides the  highest  resistance of the  steel to hydrogen

                  embrittlement.

                         It  has been shown  that  adding  nickel, boron  and  nitrogen-containing

                  substances into technological  environment  during  mechanical-pulse treatment  of

                  the carbon steels 35 and 45 increases their resistance to corrosion and can offset

                  the negative influence of intensive plastic deformation on corrosion resistance of

                  these steels in a corrosiion environment.

                         Friction coefficient  and temperature in friction contact zone  decreases

                  significantly after mechanical pulse treatment of surface of carbon and low-alloyed

                  steels.  The surface layer  of  the 35 steel  with nanocrystalline structure in a

                  tribological  pair  with  the  ШХ15  steel  is  characterzed  by  8%  lower  friction

                  coefficient under dry friction in comparison with that of the untreated 35 steel. It is

                  decreased in almost 4 times for the 45 steel with surface nanocrystalline structure

                  under oil wear. The decrease in the coefficient of friction after mechanical pulse

                  treatment of steels correlates with the decrease in crystallite size on the surface.

                  Temperature in the zone of friction contact of a friction pair of the 40X steel with a

                  surface nanocrystalline structure is lower than that of a friction pair of  the  40X

                  steel without  a nanocrystalline structure,  which  has  a positive effect on  wear

                  resistance.

                         The  nanocrystalline  surface layer  is characterized by high wear resistance

                  under oil  and oil-abrasive  wear,  as  well  as,  under  the action  of  the  corrosive-

                  hydrogenating  medium  of diethyl glycol.  The  highest wear resistance  of  the
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