IMPROVING THE PROPERTIES OF SPRING AND SPRING STEELS BY CHANGING THEIR STRUCTURE

A large number of various spring alloys are
used in industry, since depending on the service conditions
of the elastic elements, as well as their shape and size, they
must differ in mechanical, physicochemical and
technological properties. Therefore, spring alloys have
different chemical composition and structure and are
subjected to various types of heat treatment. Classification
of spring alloys can be carried out according to a number
of features. Firstly, alloys can be divided by the main
methods of strengthening. Steels and alloys, strengthened
by cold plastic deformation and subsequent lowtemperature
heating (tempering or annealing). This group
includes steels with an increased carbon content (0.4-
1.3%), subjected to strengthening by cold plastic
deformation (after preliminary heat treatment), and after
cold working - low tempering. In this case, preliminary
heat treatment makes a certain, and in some cases, a very
significant contribution to the overall strengthening.
Depending on the structure obtained during heat treatment,
the absolute degree of strengthening in the process of cold
plastic deformation also changes. During the cold working
process, the phase state of the steel remains practically
unchanged, but only the fine structure changes due to an
increase in the dislocation density. As a result of additional
tempering (aging), residual stresses are removed,
dislocations are redistributed, segregations are formed on
them, which causes a strong increase in the elastic limit,
relaxation resistance and other properties of the steel.