抄録
The failure of marine propeller shaft made by high strength α+β brass has been described. Metallurgical examination of failure part, measurement of stray current and electrolytic corrosion test have been carried out to determine the exact cause of failure. These tests led to the conclusions as follows: (1) The cause of the failure seems to be the combined effect of dezincification due to stray current and axial torsion stress of shaft. (2) The corrosion rate of shaft was more than 4 mm per year and is much more rapid than the usual dezincification rate. (3) The alternative effect of stray current and fracture of the dezincification layer by axial torsion increased the corrosion rate. (4) The shell pattern on fracture section and the Hartman’s pattern developed on the dezincification layer of shaft in dicate that the cause of failure of shaft is corrosion fatigue.
