An Evaluation Test for Influences of the Paint-Film Upon Self-loosening of Fasteners
Yasuo SATOH, Takafumi NAGATOMO,
Engineer, Metallic Materials Group, Materials Technology Development Division, Technological Development Department
Hiroto MACHIDA, Saburoh ENDOH, Takafumi ENARI,
Engineer, Organic Materials Group, Materials Technology Development Division, Technological Development Department
Katsuya KIRIMURA,
General Manager, Materials Technology Development Division, Technological Development Department
Takehiko KIGAWA, Dr.Eng.,
Materials Technology Development Division, Technological Development Department
Experiments are carried out for evaluating the influence of the paint-film upon self-loosening of fasteners. Two kinds of paint, i.e. alkyd paint system and etching primer, are used in the test. The evaluation was carried out in terms of the relationship between the rotation angle and the axial tension from the onset of tightening stage to the end of vibrating stage of the tightening specimen. A thicker paint-film of alkyd paint system gives rise to a remarkable reduction of axial tension after tightening. Furthermore, the vibration accelerates this reduction causing a considerable self-rotation. Paint-film of etching primer brings about less reduction of axial tension and the self-rotation is not observed at all even in the vibrating stage.