Common causes and control of spring clip pressure decay
1.What are the common causes of elastic clip clamping force attenuation?
Fatigue of the elastic clip material is the main cause. Under long - term train vibration loads, micro - damage occurs inside the material, the elasticity gradually decreases, and the clamping force attenuates accordingly, which is more obvious in heavy - haul lines. Insufficient preload during installation, the initial clamping force does not reach the design value, and obvious attenuation will occur within a short time after use. Wear at the contact part between the elastic clip and the rail leads to a decrease in the actual deformation, and the clamping force is reduced, especially in curve sections, where the wear speed is faster.
2.How to monitor the attenuation of elastic clip clamping force?
Use a clamping force tester for regular detection, place the sensor between the elastic clip and the rail, directly read the clamping force value, compare it with the initial value, and calculate the attenuation rate. Observe the state of the elastic clip during daily inspection. If obvious deformation or inclination occurs, it may be accompanied by clamping force attenuation. Combined with changes in track geometric parameters, such as increased gauge deviation, it may be caused by insufficient clamping force, requiring further detection.
3.What are the differences in the attenuation rate of clamping force among elastic clips of different materials?
For ordinary carbon steel elastic clips (such as 60Si2Mn) in heavy - haul lines, the clamping force attenuation can reach 15% - 20% within 1 - 2 years. Alloy spring steel elastic clips (such as 55SiCr) have better fatigue resistance, and the attenuation rate is usually less than 10% within 3 years under the same conditions. Elastic clips with surface treatment (such as galvanizing) have a slower attenuation rate than untreated ones by 5% - 8% due to reduced corrosion, especially in humid environments, the difference is more obvious.
4.What measures can be taken to slow down the attenuation of elastic clip clamping force?
Use high - strength alloy materials to make elastic clips to improve their fatigue resistance and delay attenuation from the material aspect. Strictly control the installation preload to ensure it reaches the design value (such as 10kN ± 1kN), and use a calibrated torque wrench for operation. Regularly maintain the elastic clips, clean surface debris, apply grease to reduce wear, and correct slightly deformed elastic clips.
5.To what extent must elastic clips be replaced when their clamping force attenuates?
When the clamping force attenuation rate exceeds 20% (such as the design value is 10kN, and the actual value is less than 8kN), even if there is no obvious deformation, the elastic clip must be replaced to avoid rail loosening. When the elastic clip has cracks, fractures or serious deformation, it must be replaced immediately regardless of the clamping force, as such elastic clips have lost their safe bearing capacity and continued use will endanger driving safety.