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There are five important reasons for angular contact ball bearing fracture to understand

Update:04-07-2022
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There are five important reasons for the fracture of an […]

There are five important reasons for the fracture of angular contact ball bearings to understand. The high-power observation of the fractured part by scanning electron microscope shows that its characteristics are as follows:

 

①Observed by magnification, it can be seen that there are many fan-shaped patterns in the micro area.

 

② There is a fatigue arc at the front of the crack and a large number of corrosion pits.

 

③ The shape of the fan-shaped pattern is different when observed from different angles. The fan-shaped pattern is formed by the connection of different plane cracks in the angular contact ball bearing. Observing the crack propagation area under high magnification, typical fatigue cracks are found; low magnification scans at the crack source, it can be found that the beach pattern surrounds the crack source, there are a large number of corrosion pits in the crack source area, and some corrosion pits are connected into lines, showing a mud-like pattern appearance.

 

 

④The receiving stress is high, and the place is the contact point between the water jacket and the hot rib of the cylinder liner. The stress at B is smaller. TIMKEN bearing water jacket is mainly subjected to three kinds of stress, namely explosion stress, assembly stress and thermal stress. The larger stress of the water jacket is the hoop stress, and its value is about 128MPa. It belongs to the oil-containing angular contact ball. The ignition is a random abnormal phenomenon. The abnormal ignition and burn defects of the workpiece often seriously affect the appearance quality and product performance of the workpiece, and even cause the workpiece. Unqualified failure is scrapped, especially for precision workpieces or important workpiece surfaces with high surface quality requirements.

 

⑤ Observations in production found that in induction heating, the workpiece and the sensor are often not in contact with each other for ignition, and the noise generated by the angular contact ball bearing is very sensitive. Therefore, in order to maintain the smooth operation of the bearing, sintered bronze oil-impregnated bearings with high reliability are generally used, and some measures must be taken, such as appropriate control of the sintering conditions, so that the structure of the alloy is a single a-phase, and anti-corrosion process measures can be adopted; One way is to generate compressive stress on the surface of the workpiece to offset the tensile stress in the service of the water jacket.

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