Spring steel is a steel that has a higher strength compared to other
steels. There are many uses for spring steel, e.g. B. the springs in
the chassis of motor vehicles are made of spring steel, but also the
small spring that compresses the clothespins. Even modern
combat-ready battle-ready swords are made from spring steel.
Every component can be deformed up to a tension (elastic limit)
determined by the material, in order to then return elastically to
the initial state without permanent deformation. The material
property that makes this possible is elasticity. Any further
deformations lead to plastic deformation.
For example, the spring steel 38Si7 has an elastic limit of at least
1150 N / mm² (with a tensile strength of 1300 to 1600 N / mm²)
compared to 235 N / mm² for the structural steel S235JR (tensile
strength 360 N / mm²). The decisive difference here is the yield
strength ratio, i.e. the ratio of the yield strength to the tensile
strength of the material, which in the case of spring steels is
usually in the range> 85%.
Manufacturing
The elasticity as an outstanding property of a spring steel is
achieved by producing an alloy with the corresponding properties.
One alloy element that favors this is (among others) silicon. It is
also important to achieve a distribution of the carbon content that
is as even as possible.
For a component made of steel that is spring loaded, it is important
that the hardness of the material is correctly distributed over the
cross-section.
Industrial production processes aim to achieve the most uniform
possible distribution of the alloying elements directly in the
primary forming process.