What is fatigue strength

In material science, fatigue strength indicates the load limit, up to which a material can theoretically withstand an endless number of load changes, without being damaged. In practice, this is generally called operational stability, as many materials, including also high-strength steel grades, have to accept restrictions in strength even with low load characteristics due to very high numbers of vibrations.

In addition to the amount of load changes, the type is crucial as well. Here a distinction is made between pressure, tension, bending and torsion. Various types of vibrations and combinations can further reduce the longevity of materials. For loads that are significantly above fatigue strength, damage and breakage of the materials are to be quickly expected.

How to Increase Fatigue Strength?

Requirements for fatigue strength result from the construction. Constructions, in which low stress concentrations act on the affected components, reduce the demands on the fatigue strength of the materials used. However, a change of the construction is not always possible. A general way to increase fatigue strength are methods of surface hardening. When using stainless steel or rustproof steel in particular, the BORINOX® TREATMENT FOR STAINLESS STEEL HARDENING is an appropriate solution. This gas-based low-pressure process increases fatigue strength by means of the surface being harder up to 5 times. In this respect, positive properties of the stainless steel grades used, such as corrosive protection, are not lost.