About the wear failure analysis of imported bearings during use

The temperature of the bearing can generally be inferred from the temperature of the outside of the bearing. It is more appropriate if the oil hole can be used to directly measure the temperature of the outer ring of the imported bearing.

Generally, the temperature of the bearing starts to rise slowly as the bearing runs, and reaches a steady state after 1-2 hours. The normal temperature of the bearing varies with the heat capacity, heat dissipation, speed and load of the machine. If the lubrication and installation parts are proper, the bearing temperature will rise sharply and abnormally high temperature will occur. At this time, the operation must be stopped and necessary precautions must be taken.

The use of thermal sensors can monitor the operating temperature of the bearing at any time, and automatically alarm or stop when the temperature exceeds the specified value to prevent combustion shaft accidents.

High temperature often indicates that the bearing is in an abnormal condition. High temperature is also harmful to the lubricant of the bearing. Sometimes bearing overheating can be attributed to the lubricant of the bearing. Long-term continuous rotation of the bearing at a temperature exceeding 125°C will reduce the life of the bearing. Causes of high temperature bearings include: insufficient or excessive lubrication, lubricants. Containing impurities, excessive load, bearing ring damage, insufficient clearance, and high friction caused by oil seals, etc.

Therefore, it is necessary to continuously monitor the temperature of the bearing, whether it is measuring the bearing itself or other important parts. If the operating conditions remain unchanged, any temperature change can indicate that a malfunction has occurred.

The bearing temperature can be measured regularly with the help of a thermometer, such as a digital thermometer, which can accurately measure the bearing temperature and display it in units of °C or Fahrenheit. The important bearing means that when it is damaged, it will cause the shutdown of the equipment, so it is best to install a temperature detector for this type of bearing. Under normal circumstances, the bearing will have a natural temperature rise just after lubrication or relubrication and it will last for one to two days.

Generally, the bearing used at a working temperature above 150° is called a high-temperature bearing. When the service temperature of chromium bearing steel exceeds 150°, its hardness will drop sharply, the size will be unstable, and the bearing will not work normally. Therefore, for bearings that work at a working temperature of 150° to 350°, if the rings and rolling elements are still made of ordinary high-carbon chromium bearing steel, the bearing parts must be subjected to special tempering treatment, which should generally be higher than the working temperature Tempering at 50°. The bearing steel that has been tempered according to the above requirements can be used normally at working temperature. However, due to the decrease in hardness after tempering, the life of the bearing is reduced.

Newly built and remodeled bearings are shipped with protective coating, usually in a protective cover paper or other packaging, and shipped in a carton or wooden box. When receiving a new or remanufactured bearing, do not remove it from the packaging until it is ready to be installed in the application.

Do not store directly on the concrete floor, where condensate can be collected and bearing. Pallets or bearings on store shelves are areas where the bearings will not be subject to high humidity or sudden and severe temperature changes that may cause condensation to form.

Abrasive wear of a bearing refers to the wear caused by foreign hard particles or hard foreign matter or metal surface wear debris between the working surface of the bearing and the relative movement of the contact surface. It often causes furrow-like scratches on the working surface of the bearing. Hard particles or foreign matter may come from the inside of the main engine or from other adjacent parts of the main engine system and are fed into the bearing by the lubricating medium. Adhesive wear refers to the uneven force on the friction surface due to microscopic protrusions or foreign objects on the friction surface. When the lubrication conditions are severely deteriorated, local friction generates heat, which can easily cause local deformation of the friction surface and friction microscopic welding. At this time, the surface metal may be partially melted, and the force on the contact surface tears the local friction welded joints from the substrate and increases the plastic deformation. This adhesion-tear-adhesion cycle process constitutes adhesive wear. Generally speaking, slight adhesive wear of the bearing is called abrasion, and severe adhesive wear is called seizure.