Fishplate Material Classification and Compatibility Standards
What are the materials and applicable scenarios of ordinary fishplates?
Ordinary fishplates are mostly made of Q235 and Q345 steel, with an all-metal structure and no insulating layer. This type of fishplate has low cost, simple processing technology and easy installation, and is suitable for non-electrified railways or sections without track circuits. For example, ordinary freight branch lines, industrial and mining special lines and other lines that have no requirements for insulation performance and only need to meet the strength requirements of rail connection. Q235 material fishplates are suitable for light traffic lines with small loads, while Q345 material can be used for conventional speed lines with medium loads. During use, it is necessary to ensure that the fishplate matches the rail specification accurately to avoid loose connection.
What are the structural characteristics and core functions of insulated fishplates?
Insulated fishplates add insulating materials between the metal bodies, and the commonly used insulating material is high-temperature resistant and aging resistant fiberglass board. Its core function is to block the transmission of track current, prevent current leakage from interfering with the track signal system, and ensure the normal operation control of trains. This type of fishplate is mainly used in the track circuit sections of electrified railways, and is a key component to ensure stable signal transmission. The insulating material needs to meet the requirements of long-term outdoor use and resist the erosion of environmental factors such as wind, rain and temperature difference. During installation, attention should be paid to protecting the insulating layer to avoid insulation failure caused by collision or extrusion, which will affect the line signal.
How to determine the number and specification of bolts for fishplates according to the rail model?
The bolt configuration of fishplates needs to match the rail weight and load requirements. The fishplate matching 43kg/m rail is equipped with 4 bolts per end, and the specification is mostly M22. This type of rail is light in weight and has a small load, so 4 bolts can meet the load transmission demand. The fishplates for 50kg/m and 60kg/m rails are equipped with 6 bolts per end, with the specification of M24. As the rail weight increases and the load increases, increasing the number and specification of bolts can disperse stress and avoid stress concentration at the joint. The fishplate for 75kg/m heavy-haul rail is equipped with 8 bolts per end, with the specification of M27. The heavy-haul line has an axle load of ≥30t, and more large-sized bolts are needed to improve the connection strength and prevent bolt breakage or deformation. The determination is based on the design load, cross-sectional dimensions and mechanical properties of the rail to ensure that the connection strength matches the rail body.
What performance should be focused on when selecting fishplates for heavy-haul lines?
Heavy-haul lines have extremely high requirements on the strength, wear resistance and fatigue resistance of fishplates. First, it needs to have sufficient tensile strength and shear strength to withstand the huge impact force generated by heavy-haul trains; second, it should have excellent wear resistance to reduce the wear at the joint when the train passes; at the same time, it needs to have good fatigue resistance to avoid cracks caused by long-term repeated loads. Most heavy-haul lines use materials with strength grades of Q345 and above, and some special sections adopt alloy steel materials to further improve performance. The processing accuracy of the fishplate also needs to be strictly controlled to ensure close fit with the rail and reduce damage caused by vibration.
What are the common faults of fishplates after installation and their preventive measures?
Common faults of fishplates after installation include bolt loosening, insulation layer damage, excessive wear at joints and crack generation. To prevent bolt loosening, tighten according to the specified torque, conduct regular re-tightening inspections, and apply special protective grease to the bolt threads. To avoid insulation layer damage, handle with care during installation and transportation to avoid impact by hard objects; clean up debris at the joint in time after installation to prevent squeezing the insulation layer. To reduce joint wear, ensure that the fishplate fits well with the rail to avoid excessive gaps leading to increased vibration; regularly check the joint status and grind uneven parts in time. To prevent cracks, select fishplates of qualified materials, avoid overloading, and regularly detect hidden defects through flaw detection.