关键词: 微动；转动微动；微动磨损；试验装置

Abstract:

Rotational fretting tests in a configuration of ball-on-flat were successfully realized by developing a new fretting device based on an ultra-low-speed reciprocating rotational driver. The rotational fretting tests of LZ50 steel flats against GCr15 steel balls were performed under different testing parameters. The results show that the rotational fretting behavior of the LZ50 is strongly dependent upon the angular displacement amplitude and the normal load. Friction force-angular displacement (Ft-θ) curves can be used to characterize the rotational fretting running behavior, which exhibits three basic types of the parallelogram, elliptical and linear cycles by varying the angular displacement amplitudes or the normal loads. The rotational fretting is characterized by elastic deformation coordination at the contact interface when run in the regime of partial slip. With the increase of the angular displacement amplitude and the decrease of normal load, the fretting running state transfers from the partial slip to the gross slip. The micro-examinations indicate that the plastic deformation, abrasive wear, oxidative wear and delamination are the main damage mechanism for LZ50 steel under the gross slip conditions. A special phenomenon which is different from that observed in the tests of the normal reciprocating fretting(tangential fretting), i.e. wear debris generated is accumulated in the centre zone of the wear scar under the condition of gross slip, is observed and analyzed herein.

Key words: fretting, rotational fretting, fretting wear, testing apparatus