Cause analysis of pump shaft fracture
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This post was last edited by lxq700918 on 2009-5-11 20:02. Please help analyze the reasons for the pump shaft breaking: The material of the pump shaft is 2Cr13, and breaks often occur at the nut connecting the upper impeller. What factors could be responsible for this?
Is the broken pump shaft a product from the same supplier? If so, it may be a product quality issue; it is recommended to work with the manufacturer to find out the cause. If not, it may be caused by improper or unreasonable pump installation, etc.; it is necessary to look for the problems within the device itself.
Physical and chemical tests such as fracture analysis, chemical composition analysis, and metallographic analysis are carried out on the shaft fracture site to verify the shaft’s strength.
This post was last edited by Fan Zhou Wu Hu on 2009-5-12 09:21. The fracture at the back nut of the pump shaft is mainly due to issues in the processing technique used for the pump shaft; the threads on the back nut are generally manufactured using lathes, which results in reduced strength in those areas. Using extruded threads is relatively better; nowadays, high-pressure bolts are generally produced by the extrusion method.
How many such pumps are there in total? Is it only this one unit that keeps having problems, or do the others have the same issues as well? If it’s the only one, then not only the quality of the pump shaft needs to be considered, but also the installation aspects.
It’s possible that the end of the pump shaft is too thin, resulting in excessive pre-tensioning force on the impeller, which damages the shaft
First, check the alignment of the pump body and the motor, as well as whether the outlet check valve malfunctioned due to tripping and resulting in liquid backflow. Also, examine the quality of the spare parts
In addition to the reasons analyzed above, I believe there are the following reasons: 1. The thread specification of the back cap is too small. 2. The thread’s clearance groove is too deep and too wide. 3. Increase the diameter of the shaft journal and the locking thread at the interface between the impeller and the shaft.
First, check the alignment of the pump body and the motor, as well as whether the outlet check valve malfunctioned due to tripping and resulting in liquid backflow. Also, examine the quality of the spare parts.