Improvement of mechanical properties of heat-resistant steels by activation of the nitriding process

Mechanical properties of hot-working steels after activization of cementation process

“…Metalographic studies prove strong (to 16 times) grinding of the initial coarse grained structure of sor bite [2]. Ferrite crystals preserving the crystallographic orientation of former martensite rods are ground into small fragments and assume the shape of new equiaxial grains with a size of 0.8 μm.…”

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322Considerable resources for the improvement of operational properties of a complex of important machine parts lie in the development of new technologies of thermal and chemicothermal treatment based on activization of diffuse saturation processes and providing a volume and surface fine dispersed state.The creation of a fine dispersed state of the surface layer in machine parts is achieved by using methods of intensive plastic deformation [1] and high performance processes of chemicothermal treatment [2]. Achieving a fine dispersed state with a considerable increase in the velocities for the diffuse saturation of a surface with carbon, nitrogen and other elements is observed and it can generate enormous change in the technology of chemicothermal treatment.

The main advantage of vacuum cementation concerns the formation of diffuse layers of high carrying capacity.

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“…The creation of a fine dispersed state of the surface layer in machine parts is achieved by using methods of intensive plastic deformation [1] and high performance processes of chemicothermal treatment [2]. Achieving a fine dispersed state with a considerable increase in the velocities for the diffuse saturation of a surface with carbon, nitrogen and other elements is observed and it can generate enormous change in the technology of chemicothermal treatment.…”

“…Samples of steel VKS 10 were hardened at 1010°C and high tempered at 570°C; the time of treat ment was also 3 hours. For the creation of a fine dispersed state of the surface diffuse layer, samples of steels VKS 7 and VKS 10 were exposed to intensive plastic deformation-sinkage (the level of deforma tion is 80%) at 700°C under conditions of multiaxis deformation [2].…”