Principle of high current corrosion
When current (as shown in the figure below) flows from one bearing ring through rolling elements into another bearing ring, it will cause damage (a). The process of electric erosion on the contact surface of bearings is similar to arc welding, as there is a higher current density on the smaller contact surface (b). Electrocorrosion will heat the material to the temperature of tempering or even melting. This will cause the surface of the material to fade and vary in size due to tempering, secondary quenching, or melting. In addition, discharge marks may also appear at the melting point of the bearing material, and eventually fall off due to the rolling of the rolling elements (c). Excess material on the rolling element will also be worn off (d). Appearance: Discharge marks on the bearing raceway and rolling elements. Sometimes there may be "Z" shaped burn marks on the raceway of ball bearings. There will be visible local burn marks on the raceway and rolling elements.
The following figure shows a spherical roller bearing that can withstand high currents. From the figure, it can be seen that there are many large discharge marks on the rollers of the bearing. After magnification, the discharge marks and the surrounding molten material can be clearly observed.
High current corrosion on roller bearings
The following figure shows the damage caused by excessive current on the outer raceway and rollers of a deep groove ball bearing. Pay attention to the "Z" shaped burn marks on the raceway and rollers.
High current corrosion on the outer raceway and rollers of deep groove ball bearings
The current corrosion introduced in this article is extremely important in conductive applications. For more bearing usage cases and precautions, please contact us:
Email: jackengineer@blhbearing.com
WhatsApp：8613760352799
