Fishplate Machining Precision and Connection Performance
- What impact does the thickness tolerance of fishplates have on the connection performance?
Excessive thickness tolerance of fishplates will lead to poor fit with rails. Under the action of train load, large gaps will be generated at the connection parts, making the fishplates and rails stressed unevenly and aggravating wear. If the thickness is too thin, it will reduce the bearing capacity of the fishplate, which is easy to deform or even break when stressed. Strictly controlling the thickness tolerance within the design allowable range (generally ±0.3mm) can ensure that the fishplate is in close contact with the rail, evenly transmit the load, and ensure stable connection performance.
- How does the position accuracy of bolt holes affect the installation and use of fishplates?
Excessive deviation in the position of bolt holes will make the fishplate unable to accurately align with the bolt holes on the rail. Forced adjustment during installation is easy to cause additional stress on the fishplate and bolts, reducing the connection strength. Under the vibration of train operation, position deviation will aggravate the wear and loosening of bolts, affecting the reliability of the connection. The position accuracy of bolt holes should be controlled within ±0.2mm to ensure smooth installation, uniform stress on bolts, and prolong service life.
- What harm does the flatness error of fishplates do to the connection?
Fishplates with large flatness errors have uneven fitting surfaces with rails, which will form local contact stress concentration. Under the repeated load of trains, plastic deformation and cracks are easy to occur at the contact parts, leading to early damage of fishplates. At the same time, flatness error will increase the vibration of the connection part, accelerate the wear of rails and fishplates, and affect the overall stability of the track. The flatness is generally required not to exceed 0.5mm/m to ensure a good fitting effect.
- How to detect the machining accuracy of fishplates?
Use tools such as vernier calipers and micrometers to measure the thickness of the fishplate and check whether the thickness tolerance meets the standard. For the position of bolt holes, a coordinate measuring machine or a special template is used for detection to accurately measure the hole center distance and relative position deviation. Flatness detection can place the fishplate on a precision platform, measure the gap between it and the platform with a feeler gauge, or use a flatness detector for automatic detection to obtain the flatness error value. Through these detection methods, the machining accuracy of the fishplate is comprehensively evaluated.
- What process measures are there to improve the machining accuracy of fishplates?
Using high - precision processing equipment, such as CNC milling machines and grinders, can effectively ensure the accuracy and consistency of processing dimensions. Optimize the processing process, such as aging treatment after rough machining to eliminate internal stress, and then finish machining to reduce the impact of deformation on accuracy. Strengthen quality control in the processing process, calibrate equipment regularly, maintain and replace tools to ensure stable processing accuracy. At the same time, conduct strict inspection after processing, reject unqualified products, and ensure the machining accuracy of the delivered fishplates.