Study On Welding Process Optimization And Service Behavior Finite Element Simulation Of High Manganese Steel Frog

The high manganese steel frog plays an important role in railway transportation,and realizes the train track change and turning.This paper takes the high manganese steel frog as the research object,and optimizes the welding process by simulating the flash welding process between the high manganese steel frog and the high carbon rail.The wear mechanism and stress variation of high manganese steel under different impact frequency were studied.The simulation of the process of the train passing through the frog with different speed and axle load provides the basis for reducing the stress level and optimizing the service environment.Finally,the following results are obtained:The flash welding process of high manganese steel frog and high carbon rail can be divided into four stages: preheating,upsetting,pressure maintaining and cooling.The simulation results show that when the length of welding material is 25 mm,if the holding time is 10 s,the maximum temperature on one side of rail steel is 732 ?,which is higher than the AC1 temperature point of rail steel,and it is easy to cause martensite in the cooling process on one side of rail steel;when the holding time is 3 s,the maximum temperature on one side of rail steel is 668 ?,which is close to the actual welding results,and the temperature rise of rail steel does not exceed AC1 Temperature point requirements.From the simulation results of changing the length of welding material,when the total length of welding material is more than 25 mm,the temperature rise of rail steel in the whole welding process will not exceed AC1 temperature point when the holding time is 3 s.Under the same impact energy,impact times and different impact frequencies,the higher or lower the impact frequency is,the worse the wear resistance of high manganese steel is.The higher the impact frequency,the stronger the hardening effect of surface processing,the surface hardness can reach 468 hv at 200 times / min.The impact frequency is low,but the opposite is.The impact hardening layer of the sample is slightly deeper than that of the sample with high impact frequency when the impact frequency is low.The main mechanism of high manganese steel hardening is the formation of twin belts with high density and blocking cutting.When the train passes through the frog in reverse direction,the point rail of the frog receives great impact.The maximum stress is 40 mm away from the actual tip of the point rail.Under the same speed,the greater the axle load,the greater the stress on the surface of the frog when the train passes through the frog.Under the same axle load,the stress on the surface of the frog increases with the increase of speed in the range of 100 km/h-200 km/h.From 200 km/h to 300 km/h,the stress will decrease with the increase of speed.In a word,the effect of multiple increase of axle load on frog stress is greater than that of speed.