No.3（2000）15.Research on fatigue resistance in practical application of aluminum alloy bolts

Yoshihiro FUNAYAMA, Tomihiko OOKUBO,Takahiro TANAKA, Hiroshi IKEDA

The fatigue resistance of aluminum alloy bolts having both high joint strength and resistance to stress corrosion cracking was evaluated under conditions of low temperature (273K), normal temperature (293K),and high temperature (393K). As a result of the research, the following were found:

1. The fatigue strength of the bolt was the largest at low temperature and decreased in the order of normal and high temperatures.
2. The fatigue strength at high temperature sharply decreased as the number of cycles was increased ,and neared zero under high mean stress(360MPa).The fractured surface of the bolt was supposed to be intergranular fracture due to stress corrosion cracking.
3. The maximum fatigue strength was 24.7MPa at low temperature and under low mean stress(stress ratio：0.1), and also, it was found that the fatigue strength at normal temperature was a slightly inferior than the fatigue strength of the bolt with steel and stainless steel having the equivalent static strength to the aluminium alloy bolts.

Keywords
aluminium alloy bolt, fatigue strength, joint strength, stress corrosion craccking, intergranular fracture

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