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%.
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.