The attenuation law and compensation measures of the buckle pressure of the spring clip
- What are the manifestations of the attenuation law of elastic clip clamping force?
The initial attenuation is fast, and the clamping force may decrease by 10% - 15% within 3 months after installation, because the elastic deformation of the elastic clip gradually stabilizes, which is common in 60Si2MnA elastic clips in ordinary railways. The medium - term attenuation is gentle, with a decrease of 5% - 8% within 3 - 12 months, mainly affected by material fatigue. The attenuation is slightly faster (2% - 3% more) when the environmental humidity is high. The long - term attenuation accelerates, and the clamping force may decrease by 20% - 25% after 2 years of use. Due to large loads, the attenuation amplitude of heavy - haul railways is 5% - 10% higher than that of ordinary railways, requiring early maintenance. The attenuation of elastic clips in different parts is different. The attenuation of elastic clips in curve sections is 10% - 15% faster than that in straight sections, because the lateral force acts more frequently.
- What environmental factors affect the attenuation of elastic clip clamping force?
High temperature environment (≥35℃) will relax the elastic clip material, and the attenuation rate of clamping force will increase by 20% - 30%. The detection cycle needs to be shortened in summer in the south. Humid environment will accelerate the rusting of elastic clips, and the surface rust layer will reduce elasticity, with the clamping force attenuating by 3% - 5% more every year. Anti - corrosion treatment needs to be strengthened in coastal areas. In mining railways with much dust, the friction between elastic clips and rails increases, and the clamping force attenuates 15% - 20% faster than in clean environment, so the contact surface needs to be cleaned every month. Strong ultraviolet areas (such as plateaus) will accelerate the aging of elastic clip materials, and the clamping force attenuation can reach 30% in 2 years. Elastic clip materials resistant to ultraviolet rays need to be selected.
- How to monitor the attenuation of elastic clip clamping force?
Regularly use a clamping force tester for detection, once every 6 months for ordinary railways and once every 3 months for high - speed railways. During the test, the clamping force value of each elastic clip must be recorded, and the attenuation rate is calculated by comparing with the initial value. Install wireless sensing elastic clips in key parts (such as turnout areas) to monitor the change of clamping force in real time. When the attenuation exceeds 15%, an alarm is automatically given to facilitate timely treatment. Indirectly judge by observing rail displacement. If the gauge deviation exceeds ±1mm, it may be that the elastic clip clamping force is insufficient, and the elastic clips in this area need to be tested pertinently. Compare the clamping force of adjacent elastic clips. If the difference exceeds 10%, it indicates uneven attenuation. The cause needs to be checked and adjusted to avoid unbalanced stress on the rail.
- What are the specific measures to compensate for the attenuation of elastic clip clamping force?
Regularly retighten the elastic clips, and re - tighten them with a torque wrench according to the specified torque (such as 300 - 350N·m for 8.8 grade bolts), which can restore the clamping force to more than 90% of the initial value. Ordinary railways are retightened once every six months. Replace elastic clips with serious attenuation. When the clamping force is lower than 75% of the design value, the elastic clips in this area must be replaced as a whole. Select elastic clips of the same model with high elasticity, such as 60Si2MnA elastic clips to replace the attenuated 65Mn elastic clips. Install thin gaskets (thickness 0.3 - 0.5mm) between the elastic clip and the pressing plate, which can compensate for the decrease of clamping force caused by elastic clip deformation, increase the clamping force by 5% - 10%, and the temporary emergency effect is significant. For elastic clips of heavy - haul railways, the pre - tension installation method is adopted. During installation, the elastic clips are pre - loaded with 5% - 10% tension to delay later attenuation, and the 2 - year retention rate of clamping force can reach more than 85%.
- What are the differences in clamping force compensation cycles of different types of elastic clips?
The compensation cycle of 60Si2MnA elastic clips is long, about 12 months for ordinary railways and 8 - 10 months for high - speed railways, because of their good elasticity, slow attenuation and long - lasting effect after retightening. 65Mn elastic clips attenuate faster, and the compensation cycle needs to be shortened to 6 - 8 months. Heavy - haul railways need to be inspected and retightened every 4 - 6 months to avoid insufficient clamping force. The compensation cycle of 55SiCrA elastic clips in cold areas is similar to that of 60Si2MnA, but in high - temperature areas, compensation is needed every 8 months, because high temperature has a great impact on their elasticity. The compensation cycle of composite material elastic clips is the shortest (4 - 6 months), and the retightening effect is limited. It is recommended to replace them directly when the attenuation exceeds 20%, which is suitable for temporary use in light - load lines.