Effect of anaerobic threadlockers on the fatigue strength of threaded connections

The paper deals with the fatigue behaviour of threaded connections bonded with anaerobic threadlockers. Fatigue tests are described involving rolled ISO M10 bolts of property class 10.9 loaded under constant amplitude at the load levels 11+/- 10 kN and 8.8 +/- 8 kN. The number of cycles to failure consequent to treatment with anaerobics is significantly longer than without treatment, the ratio between the corresponding lives being about 3.5 at the higher load (11 +/- 10 kN) and about 2 at the lower load (8.8 +/- 8 kN). The reduced effect with the lower load discloses a common endurance limit. The behaviour is attributed to elimination of fretting damage between the contacting threads of the bonded connections. This interpretation suggests an important role of the mean test load and fosters further investigation.