The basic types of bearing wear and the forms, hazards and measures of wear in rolling bearings

wallpapers Environment 2020-10-27

Bearing wear is divided into three processes:

1. Running-in stage: new parts are generally in this stage when they are just put into use, and the wear rate is high

2. Stable wear stage: The wear rate is stable and low during normal use of parts

3. Severe wear stage: The wear rate rises sharply when the parts are about to be scrapped

Basic types of bearing wear:

1. Abrasive wear: also abbreviated as wear, the wear of external hard particles or hard protrusions on the friction surface causing the surface material to fall off during the friction process. (The condition to obtain a higher abrasive wear life is that the surface hardness of the material is at least 1.3 times the abrasive hardness)

2. Adhesive wear: also known as gluing, when the profile peaks of the friction surface are "cold welded" due to the instantaneous temperature rise and pressure at each point of interaction, the material migrates from one surface to another during relative movement. Adhesive wear is formed, which can cause the movement pair to seize in severe cases.

3. Fatigue wear: also known as pitting corrosion, it is mechanical wear caused by material fatigue caused by repeated deformation of the micro-volume of the friction surface material under the action of alternating friction.

4. Erosion wear: mechanical wear caused by hard objects or hard particles entrained in flowing liquid or gas impacting the surface of parts.

5. Corrosion wear: Corrosion caused by the chemical or electrochemical action of the environment where the friction surface material is located, and the wear caused by the relative movement of the friction pair is the corrosion wear.

6. Fretting wear: If two contact surfaces are macroscopically static, but under the influence of the environment, they move relative to each other with an amplitude of less than 100μm. Such contact surfaces will also experience wear, which is called fretting wear or fretting Corrosion wear. It is a compound type of wear.

Forms of wear in rolling bearings

a. Adhesive wear: In the case of poor lubrication, adhesive wear occurs on the friction surface of relative movement, and even surface burns occur

b. Abrasive wear: The seal is not tight, external dust and sand particles enter the mechanical impurities in the bearing lubricant, and the bearing is not cleaned, causing abrasive wear

c. Corrosion wear: Moisture, moisture and acid or alkali solution invades the bearing will cause corrosion and wear

d. Fretting wear: The wear on the contact surface that occurs when the bearing does not rotate and remains in a state of small vibration for a long time, may appear wear marks, accompanied by rust powder

e. Fatigue wear: fatigue peeling

The hazards of bearing wear:

(1) Roughen the working surface;

(2) Vibration and noise increase;

(3) The internal clearance of the bearing increases;

(4) Decreased rotation accuracy;

(5) Increased friction torque

The main measures to reduce bearing wear:

1. Keep the lubricant good

2. Reduce friction

3. Good sealing performance to prevent foreign matter from entering the bearing