Evaluation of white metal adhesion (conventional casting and thermal wire arc spraying) by ultrasonic non-destructive method

Slide bearings can be classified (as follows): bearing shells, radial and axial segments, used for turbogenerators and hydrogenerators. Slide bearings work in heavy operating conditions including their size of load, middle peripheral velocity, number of revolutions and operating temperature. Causes of the slide bearing damage is possible to divide into these types: casting defects, adhesion defects, steel substrate break, assembling defects, operating defects on the white metal surface (scribbling), insufficiency of lubricating oil, dynamic overload of the bearing, cavitation and corrosion [V. Ševčík, M. Knotek, Segmentová ložiska, SNTL Praha, 1985]. The article presents that adhesion defects can be depended on used technology for the deposition of the white metal on the steel substrate. Two types of deposition technology, conventional casting and thermal spraying, are compared by help of ultrasonic and penetrant method, metallography and X-ray diffraction.