Quality test

The equipment is a RUMUL 150 kN high-frequency resonance test machine which keeps the normally long test times involved in Wöhler fatigue tests within a manageable scope. For example, a point on the Wöhler curve in the very high-cycle fatigue range with 10 million load cycles can be tested after just approx. 24 hours. Conventional servo-hydraulic machines require several days to do this.

The machine's extensive features mean that fasteners, components and material samples with a wide range of shapes and dimensions can be tested.
The dedicated evaluation program offers ongoing test planning and evaluation which helps the user obtain informative test results and evaluate statistics from Wöhler curves with a minimum of samples.

One of the main areas of application of the new fatigue testing machine is currently optimising the fatigue resistance of HELICOIL®. In addition, Böllhoff can now prove the fatigue strength of its customers' products relatively quickly.
Dynamic testing is also very relevant to screws. The continuously changing load borne by a threaded element is only around 5-10 % of the stress bearable under static load. It is conceivable that even a minor increase in fatigue strength can be of considerable benefit to the user. The effectiveness of measures intended to increase fatigue strength, such as improved surface quality, cannot be verified in a static tensile test, but rather only in a dynamic fatigue test.
Thanks to its own dynamic test machine, Böllhoff can now select or optimise products for its customers in terms of their fatigue strength.

The Böllhoff test laboratory, which is accredited to DIN EN ISO 17025, also offers testing services to non-Böllhoff customers according to availability. The laboratory specialises in the diverse testing and failure analysis of fasteners, but also undertakes destructive mechanical testing (including sample preparation) and the metallographic testing or corrosion testing of other products.