Research On Key Manufacturing Processes And Quality Control Technology On Switch Rail Heel Of High-speed Turnout

The manufacturing level of high-speed turnout is directly related to its high-speed trafficability,comfort and safety.As an important component of turnout structure,the manufacturing level of switch directly affects the quality of the whole group of turnouts,and the manufacturing of switch heel occupies most of the manufacturing process of the whole switch rail,so the continuous optimization of manufacturing process level of switch heel can bring about the continuous improvement of the quality of high-speed turnouts.This paper analyzes the manufacturing technology and process of high-speed switch rail heel,and researches the quality problems that are easy to be caused by the current process.Based on theses the improvement measures and quality control points are put forward.The main research work of this paper is focused on as follows:(1)Based on the analysis of the temperature and forging force in each part of the rail during the die forging process of the heel end of the switch rail and the characteristics of the die forging of the movable block at the heel end of the switch rail,it is concluded that the main reason for the necking of the transition section is that the temperature of the transition section is too high and the transition metal tends to flow longitudinally due to no longitudinal constraint.On this basis,some measures are put forward,such as decreasing the heating temperature of the transition section,increasing the size of the transition section properly and setting the limit strip in the waist mould,to avoid the necking problem of the transition section rail head.(2)Based on the analysis of the previous heat treatment process of the whole length and heel end of the switch rail,the causes of the softening of the heat affected zone at the heel end of the switch rail are obtained.Combined with the existing heat treatment process,the heat treatment process,tooling and quality control points of the blow quenching at the heel end of the switch rail are analyzed,and the results are verified.(3)Based on the analysis of the disadvantages and hidden dangers of the existingrail heel skew mode,this paper puts forward a solution to obtain the rail bottom 1 / 40 skew directly during the die forging process of the rail heel and the corresponding milling process of the rail heel by improving the forging die of the rail heel.