Research On Coupler Operation And Its Performance Improvement For Railway Heavy Load Freight Cars

With development of heavy load freight cars on Datong-Qinhuangdao railway lines, single freight car payload, numbers of freight cars in train consist and running speed are increased. Especially in operation of heavy haul train of 20,000 gross payloads, 16 and 17 types of couplers of heavy load freight cars are under unprecedented great pressure, which consequently result in more failures. Based on the research on operation and maintenance of 16 and 17 types of couplers, the paper presents that cracks on coupler tail pin hole pulling curve surface, knuckle pulling S surface and yoke rear corner are main failures of couplers of heavy load freight cars. By analysis on chemical composition, mechanical performance and metallurgical structure of sample of failed coupler and on change of operation conditions, the reasons for the above cracks are found. Therefore respective improvement proposal in structure and manufacturing process is put forward, combined with American F coupler technology. The paper demonstrates and proves that the improvement proposal is feasible based on FEA, fatigue life estimation and test proof on the proposal.At present, both the improvement proposal and measures have been reviewed and approved by MOR and successfully applied and popularized in Chinese railways.