Innovation in the Processing Technology of Train Coupler Buffers: Multi-process Collaboration Ensures Railway Safety

Recently, a rail transit equipment enterprise has achieved a significant breakthrough in the processing of train coupler draft gears. By integrating forging, numerical control machining, and intelligent detection processes, it has realized the precise manufacturing of key components. This technology has increased the energy absorption efficiency of the draft gear by 35% and has been applied to high-speed railway freight trains. "The core of train coupler draft gear processing lies in the design of multi-physical field coupling," introduced the technical director. The traditional casting process is difficult to meet the requirements of high-load impacts. The new solution adopts a combined process of "closed-die forging + five-axis milling". First, the alloy steel billet is heated to 1150°C for precision forging, and then the three-dimensional milling of the inner cavity of the draft gear is carried out through a numerical control program to ensure that the tolerance of the key mating surface is controlled within ±0.05mm. To improve the fatigue life, the team has developed the "gradient heat treatment" technology. The flame nozzle is guided by an industrial robot to perform segmented quenching on different areas of the draft gear, forming a micro-structure with alternating hard and soft parts. "This is equivalent to installing an 'elastic armor' on the metal." The inspection report shows that after the new draft gear has undergone a 2-million-cycle loading test, the permanent deformation is less than 0.3mm. A railway operation and maintenance company has reported that in the collision test of a 30-ton train, the peak value of the impact load of the draft gear using the new process has been reduced by 40%. "Especially the performance stability in low-temperature environments has significantly reduced the risk of derailment," said the safety director. The equipment failure rate has dropped to the lowest level in history. The enterprise has established a digital twin system for the processing of train coupler draft gears, which can predict the processing deformation in real time. The technical team revealed that they are developing internal defect detection equipment based on the principle of acoustic emission, which will be able to achieve 100% non-destructive testing in the future. "This will promote the intelligent and unmanned upgrade of train coupler draft gear processing." With the industrial application of this technology, the self-sufficiency rate of core components of rail transit in China is expected to exceed 90%, providing reliable safety guarantees for the railway construction under the Belt and Road Initiative.