Common Problems in NACHI Bearing Parts Processing

Writer: Eric Bearing Limited

In order to ensure the service life of NACHI bearings, it is necessary to process the bearings, such as forging processes; in order to obtain evenly distributed residual carbides in the finished parts of the bearing, and to ensure the wear resistance of the bearings, an annealing process is required; The carbon layer ensures the hardness of the finished bearing parts and requires a turning process; in order to maintain the core performance of the material and provide the final outline of the surface hardness of the material, the cage is light and wear resistance, and the bearing cage needs to be heat treated.

In order to allow NACHI bearings to get good performance and improve the working efficiency of the bearings, processing technology is the only way to go. What are some common problems when processing bearing parts? Eric Bearing Limited will give you the following explanation on this problem.

1. Common quality problems of cage heat treatment

(1) Low hardness:

Reasons: the quenching temperature is too low (underheating); the decarburized layer is not turned off; severe overheating.

(2) Unqualified metallographic organization:

Tissue underheating: the quenching temperature is low.

Organization overheating: the quenching temperature is too high.

2. Common problems in outer ring grinding

(1) Common problems in grinding end faces

a. Grinding burns, resulting in a decrease in surface hardness;

b. The uneven grinding at both ends causes the raceway to be misaligned and the ribs cannot be ground;

c. The parallelism is poor, the size is too poor, and the ribs cannot be worn out;

(2) Common problems of rough grinding/outer diameter

a. The surface roughness is too bad, and the fine grinding process is not easy to correct.

b. Out-of-poor roundness will inevitably lead to out-of-poor raceway roundness when the raceway is finely ground.

c. The vertical difference is out of tolerance, which leads to insufficient grinding when grinding the raceway, and it is scrapped.

(3) Common problems of fine grinding outer diameter

a. The surface roughness is too bad, and the final grinding process is not easy to correct.

b. Out-of-poor roundness will inevitably lead to out-of-poor roundness of the raceway during final grinding.

c. The vertical difference is out of tolerance, which leads to insufficient grinding when grinding the raceway, and it is scrapped.

(4) Common problems of grinding ribs

a. Grinding burns, causing micro-cracks in the ferrule, greatly reducing the service life of the bearing;

b. The raceway width is out of tolerance, resulting in out of tolerance in the axial clearance of the complete set of bearings, reducing the service life of the bearing;

(5) Common problems of rough grinding raceway

Grinding burns cause micro-cracks in the ferrule, which greatly reduces the service life of NACHI bearings;

(6) Common problems of fine grinding raceway

a. Grinding burns, resulting in a decrease in the surface hardness of the raceway of the ring or micro-cracks, which greatly reduces the service life of NACHI bearings;

b. The roundness and surface roughness of the raceway make it difficult to correct the super-precision raceway. The roundness and surface roughness are too bad: the NACHI bearing vibration value is too bad, the noise increases, and the bearing life is reduced;    NACHI 6804 ball bearings on line ,pls click here :

c. Because the width of the grinding wheel is not enough or the vibration amplitude is not enough, steps are generated on the raceway surface, which causes the bearing to have no clearance and cannot be used;

d. The raceway surface is concave, reducing the service life of NACHI bearings.

(7) Common problems of fine grinding raceway

The raceway roundness and surface roughness are too bad to cause the surface roughness to be too bad: the NACHI bearing vibration value is too bad, the noise increases, and the service life is reduced;

(8) Common problems of final grinding outer diameter

a. The roundness is too poor, which makes it difficult or impossible for users to assemble the bearing.

b. The vertical difference is out of tolerance, which causes the center of the outer ring to be out of concentricity with the shaft after the bearing is assembled, which reduces the service life of NACHI bearings.

3. Common problems in inner ring grinding

(1) Common problems in grinding end faces

a. Grinding burns, resulting in a decrease in surface hardness;

b. The abrasion at both ends is uneven, causing the ribs to be worn out;

c. Poor parallelism and ultra-tolerance in size, causing the ribs to be worn out;

(2) Common problems of grinding ribs

a. Grinding burns, causing micro-cracks in the ferrule, greatly reducing the service life of the bearing;

b. The raceway width is out of tolerance, resulting in out of tolerance in the axial clearance of the complete set of bearings, reducing the service life of NACHI bearings;

c. The angle between the rib surface and the raceway bus bar is less than 90°, which reduces the service life of NACHI bearings;

d. There are waste parts of car processing materials.

(3) Rough ground raceway

a. Grinding burns cause micro cracks in the ferrule, which greatly reduces the service life of the bearing.

b. The roundness and surface roughness are too bad, which makes it difficult to control the roundness of the fine grinding raceway, the surface roughness is too bad, or even cannot be ground, and it is scrapped.

c. The vertical difference is out of tolerance, which causes the subsequent processes to be worn out and scrapped.

4. Common problems of fine grinding raceway

(1) Grinding burns cause micro-cracks in the ferrule, which greatly reduces the service life of NACHI bearings.

(2) The roundness and surface roughness are too bad, which makes it difficult to control the roundness of the finely ground raceway, the surface roughness is too bad, or even cannot be ground, and it is scrapped.

(3) The vertical difference is out of tolerance, which causes the inner ring center of the NACHI bearing to be non-concentric with the shaft after assembly, resulting in the NACHI bearing without clearance, reducing the bearing life or not working properly.

5. Common problems of rough grinding inner diameter

(1) The roundness and surface roughness are too bad, which makes it difficult to control the roundness of the finely ground raceway, the surface roughness is too bad, or even cannot be ground, and it is scrapped.

(2) The vertical difference is out of tolerance, which causes the subsequent processes to be worn out and scrapped.

6. Common problems of fine grinding inner diameter

(1) The roundness is too poor, which makes it difficult or impossible for users to assemble NACHI bearings.

(2) The vertical difference is excessive, which causes the inner ring center and the shaft to be non-concentric after NACHI bearing assembly, which reduces the bearing life.

7. Common problems of fine grinding raceway

The roundness and surface roughness of the raceway lead to the excessive surface roughness: the vibration value of the NACHI bearing is excessively poor, the noise increases, and the service life is reduced.