1)
To determine the content and sequence of the new technological operations
and the type of appropriate technological equipment for performing these technological
operations.
2)
To determine the advantages of the new technology in comparison with the
known ones, that use the methods of heat hardening, methods of mechanical hardening
(including cold hardening) and thermomechanical hardening, by a number of the main
technological indicators and the quality of the steel products.
Based on the objective of this paper, first it is expedient to briefly review the
technologies for manufacturing hardened steel products, which use the most well-
known methods of hardening, emphasizing the following: hardening mechanism; basic
technological operations; basic parameters that enable this type of hardening; quality
of the manufactured hardened products by their geometry accuracy and the state of the
surface; a possibility of combining the hardening process with manufacturing a product
with the given geometry and surface roughness.
All known methods of the steel hardening are based on one principle that is
increasing the concentration of the crystal structure defects, but in different ways,
different types of defects in the crystal structure, and various conditions for the
possibility of increasing the concentration of crystal structure defects.
Heat hardening is based on the maintenance of the appropriate type phase
transformations in steel with a given chemical composition, which is one of the main
regulating parameters; the basic technological operations: heating, cooling, isothermal
equalizing (temperature, time) [1]. The main types of the used phase transformations
are: martensite transformation, bainite transformation, breakdown of the
supersaturated solid solutions. The main types of the crystal structure defects, increase
in the concentration of which creates the hardening, include: surface defects (two-
dimensional) and linear defects (dislocations during martensite and bainite
transformations) [1]. The synchronization of the technological operations of hardening
and manufacturing of the steel products with a given geometry is impossible; the
surface quality of a hardened steel product requires special machining, as well as the
finishing of a geometric form.
Mechanical hardening is most effective in the course of cold deformation, and
does not require special alloying (ordinary steel with carbon weight content up to
0.3%), and essentially can be effective in general for ingot iron and other metals
without any alloying. The mechanical hardening is associated with an increase in the
concentration of dislocations and disclinations. Technological operations are attributed
to maintaining the cold plastic deformation, and it is quite possible to combine the
technological hardening operation with the technological operation of manufacturing
a product of a given geometry with a low surface roughness. At the same time the
mechanical hardening of ordinary steel is associated with the danger of destruction of
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