Study On Optimal Post Heat Treatment Technology About High-speed Rail Welding Joint Of The Factory

Rapidly development has occurred on the high-speed and heavy freight of China railway.In the view of the Improvement on the mechanical properties of welded joints,the research on the optimization of the heat treatment shall be carried out.This article,based on the problems of grain size,elongation and the width of the heat affected zone of welded joints,studied the variation regularity of the performance of welding joints processed by the different heating device and process parameters,discussed the connection between the equipment parameters and process parameters.Tests have been conducted on the factors which influencing the elongation,the measures of reducing the normalizing temperature and cancelling the rail bottom spray wind device were taken to improve the elongation indicators.On the perspectives of the welding process,the size of the heating tools,low-frequency power,spray air pressure and normalizing temperature,experiements have been tested.The technical method was proposed which can improve the weld grain size grade of the welding joints and applied to the welding joints of different grades of rails.In the purpose of solving the problem of the oversize heat affected width,this article,based on the weld depth of each part of heat treatment,tested the different width,low-frequency power,high-frequency power,heat treatment temperature of the equipment.According to the trend of the graph of the normalized curve,explored the change rule of each parameter and determined the proper normalizing parameters.Based on the analysis of the above research,select the appropriate heating tool,heat treatment temperature,powerand spary air pressure,coordinate with the analyzing of the heat treatment curve,the appropriate normalizing parameters which can improve the mechanical properties of welded joints can be determined;The quality control measures of heat treatment were proposed in this article as well.