Effect of surface parameters on anti-loosening performance of bolts for engineering machinery

Engineering machinery is characterized by high load frequency, large amplitude, and long continuous working time, which requires high anti-loosening performance of bolts. In this paper, based on DIN65151, a transverse vibration test is designed. By changing the surface roughness, hardness, and coating thickness of the connected parts, the specimens with different surface process parameters were obtained. Tightening and transverse vibra-tion experiments were carried out to monitor the changes in preload force and to study the surface process parameters of the connected parts to investigate their effect on the anti-loosening performance of threaded fas-teners. The research results show that the smaller the surface roughness, the higher the surface hardness, and the smaller the coating thickness, the better the anti-loosening performance of the bolt.