Fishplate Connection Strength and Installation Process
- What factors determine the connection strength of fishplates?
The material strength of the fishplate itself is the foundation, and fishplates made of high - strength steel have higher connection strength. The geometric dimensions of the fishplate, such as thickness, bolt hole position and quantity, will also affect the connection strength. Reasonable size design can better disperse stress. The strength and tightening torque of bolts are also important. High - strength bolts with appropriate tightening torque can ensure that the fishplate is closely connected with the rail, improving the overall connection strength. In addition, the degree of fit between the fishplate and the rail, the closer the fit, the more uniform the stress distribution, and the more guaranteed the connection strength.
- What are the differences in connection strength between fishplates of different specifications?
The fishplate matched with 50kg/m rail has relatively low connection strength, which is suitable for medium and low load lines and can meet the connection needs of ordinary passenger and freight transportation. The fishplate matched with 60kg/m rail has larger thickness and size, and the steel used has higher strength, so the connection strength is greater, which can bear larger train load and is suitable for trunk railways and heavy - haul railways. Foreign standard fishplates, such as those matched with UIC60 rails, are designed with connection strength in line with international heavy - haul standards, can adapt to higher axle load and running speed, and their connection strength is better than some ordinary national standard fishplates.
- What preparations are needed before installing fishplates?
Before installation, check the appearance quality of the fishplate, check for cracks, deformation and other defects to ensure that it is in good condition. Clean the rust, oil and debris at the rail joint to ensure that the contact surface between the fishplate and the rail is clean and flat. Check whether the rail bolt holes are aligned with the fishplate bolt holes, and whether there are debris in the holes. If necessary, clean and trim them. Prepare bolts, nuts and washers that meet the specifications, and check their quality to ensure that they can meet the installation requirements.
- What impact does the installation sequence of fishplates have on connection strength?
If the installation sequence is improper, tightening the bolts at one end first and then at the other end will cause uneven stress on the fishplate, local stress concentration, reduce the connection strength, and may even deform or damage the fishplate or bolts. The correct installation sequence should be to tighten the bolts symmetrically and evenly from the middle to both ends, and apply torque step by step for many times. This can make the fishplate bear force evenly, closely fit with the rail, and the stress distribution is uniform, thus ensuring the connection strength and avoiding potential safety hazards caused by uneven stress.
- How to check whether the connection strength of fishplates meets the standard?
A torque wrench can be used to check the tightening torque of the bolts to ensure that the torque of each bolt is within the specified range, which is the basis for ensuring the connection strength. Observe the state of the fishplate and bolts after the train passes. If there is no loosening, deformation or displacement, it indicates that the connection strength basically meets the standard. Static load tests can also be carried out. Apply a certain load to the fishplate connection part and detect the deformation of the joint. If the deformation is within the allowable range, the connection strength meets the requirements.