High-speed rail application
Rail grinding of high-speed railway is a new topic for our country. The wheel-rail power caused by track irregularity has a significant impact on driving safety, stability and ride comfort with the increase of vehicle speed. For high-speed railway, some rails are not smooth, not to say reduce the comfort of the train, and may even lead to the damage of the track and vehicle or even the occurrence of traffic accidents, so it must be strictly controlled.
Rail is the main component of rail transit, rail and train wheels contact directly, its quality directly affects the safety and stability of running. After the operation of rail transit, the rail is in a harsh environment for a long time. Due to the dynamic role of the train, the natural environment and the quality of the rail itself, the rail is often damaged, such as cracks, wear and other phenomena, resulting in the reduction of rail life, the increase in maintenance workload, the increase in maintenance costs, and even serious impact on traffic safety.
Therefore, it is necessary to eliminate or repair the rail damage immediately to avoid affecting the safety of rail transit operation. These repair measures such as rail oiling, rail grinding and so on, among which rail grinding because of its high efficiency by the world's railway widely used.
Rail grinding was first developed in order to extend the service life of rail on heavy-haul railways, and the form of rail grinding has also developed from the initial repair grinding to maintenance grinding to the current particularly popular "frequent, rapid, mild" preventive grinding. Similarly, high-speed railways also implement rail grinding for maintenance and repair. The first rail grinding implemented after the new rail laying of high-speed railway is new rail grinding, which belongs to another type of grinding, called "rail pre-grinding" that is, preparatory grinding, which is completely different from the preventive rail grinding in the operation process.
After years of application and development, rail grinding technology has been widely used in rail maintenance and repair of high-speed railway, heavy haul railway and urban rail transit, effectively extending the service life of rail. In the application process, you need to pay attention to the following points:
1) Rail grinding requirements (rail short-term life or rail long-term life)
2) Purpose of rail grinding (reduce noise or reduce wear and damage)
3) Strategies for rail grinding (grinding strategy, grinding frequency, grinding mode, etc.)
4) Different grinding purposes require different grinding strategies, and the effect of rail grinding needs to be observed for a long time.
Rail grinding is a relatively expensive means of operation, and its application must be linked to the expected economic benefits. The effect of rail grinding application is as follows:
1) Increase the service life of the rail by 50%-100%
2) Reduce the risk of rail failure
3) Reduce the deterioration rate of wheels, track components and track geometry
4) Allow trains to run at higher speeds
5) Reduce wheel and rail noise.
When the grinding wheel is used as a grinding tool, there is rigid contact between the grinding wheel and the rail, so the grinding control technology is required to be higher, and the grinding wheel maintains sharp cutting performance by self-sharpening when grinding the rail, so the grinding wheel formula and manufacturing process are required to be higher.
The elastic contact between the sand belt and the steel bar avoids the rigid contact between the grinding wheel and the rail, and the sand belt belongs to the coated abrasive tool, and the effective utilization rate of the abrasive material is improved during the grinding process of the rail. Sanding belt has good heat dissipation, low noise, and will not cause rail surface burn and grinding tool breakage when sanding rail.
Preventive grinding of the rails and switches can extend the service life of the rails by 3 to 5 years. It not only improves the quality of line equipment, reduces the transportation cost, but also greatly improves the stability of passenger train operation, making passengers more comfortable to ride the train.
Diamond, cubic boron nitride is the world's highest hardness of the two materials, high hardness, good wear resistance, using it as an abrasive processing hard, brittle and other difficult to process workpiece, consumption is very small, not only can ensure the processing accuracy of the workpiece, but also improve the processing aging, but also effectively solve the problem of environmental pollution. Therefore, the following development trend has emerged: diamond abrasives replace ordinary silicon carbide abrasives, and CBN abrasives replace ordinary corundum abrasives.
Diamond sand belt: used for grinding and polishing of stone, glass, ceramics, monocrystalline silicon, polysilicon, synthetic materials, cemented carbide, aluminum alloy and other hard and brittle materials.
CBN belt: all kinds of iron base alloy, titanium alloy, stainless steel, superalloy, (nickel base and cobalt base alloy) and other hard and difficult to process materials and complex surface grinding processing.
