Journal is generally the place on the shaft where the bearing is mounted. A section of the shaft of the same diameter on the shaft or an unequal diameter but a uniform cylindrical surface is a uniform continuous cylindrical surface. The outer circular surface must be uniform and continuous, and no shoulder or groove can be broken.
In industrial production, there are many mechanical equipments. When used, due to various reasons, such as improper cooperation between the shaft and the pulley or the coupling, long-term overload operation, the journal of the sliding bearing is poorly lubricated, and the iron in the lubricating oil is iron. Impurities such as chips and sand, or because of the low manufacturing quality, the heat treatment does not meet the requirements, or the shaft is worn by external force and the like, causing the journal to wear, and even causing the journal to break.
A. Return to the factory for turning
Advantages: There is no change in the material of the journal surface of the turning part, and the finish is high.
Disadvantages: 1, returning to the factory for a long time and cost is relatively high.
2. After the journal is turned, it must be equipped with a non-standard tile. If the rotor is pulled again, there is a danger of scrapping.
B. Electroplating repair
Advantages: 1. On-site repair, easy to operate.
2. The repair period is shorter.
3. The temperature rise of the workpiece during plating is low, no deformation, the residual stress of the coating is small, and the surface metallographic structure is unchanged.
Disadvantages: 1. The bonding strength is lower than that of cold welding and laser welding.
2. Man-made damage to the rotor journal. The groove below 7~8mm must be widened, and the small groove on the journal must be twisted into a U-shaped shape with a file.
3, low hardness, poor wear resistance, can only repair non-bearing parts.
4, improper operation of the plating will fall off the whole piece.
C. Laser welding repair
Advantages: 1. On-site repair.
2, metallurgical combination, never fall off.
3. The repair layer has good wear resistance. Only the worn parts are repaired, and no artificial damage is caused to the surface of the journal.
Disadvantages: 1. The equipment is large and not easy to operate.
2. The repair time is longer and the efficiency is lower.
3. The laser welding repair process needs to be improved and the price is high.
4. Laser welding and arc welding types. Long-time welding is likely to cause deformation of the workpiece, high residual stress level, and easy cracking.
D. Micro arc cold welding repair
Advantages: 1. On-site repair, easy to operate.
2, metallurgical combination, never fall off.
3. The journal supplement material is a bismuth-based alloy welding wire with a material similar to that of the base metal and high wear resistance.
4. The temperature rise of the workpiece during welding is low, no deformation, no thermal stress, and the repaired part is within 60 °C.
5. The groove repair only repairs the worn parts of the weld and does not cause artificial damage to the surface of the journal.
Disadvantages: Repairing wide face is less efficient.
