Study On Impact Wear Behaviors Of Coupler Buffer Materials Of ZG25MnCrNiMo Steel

Railway is a main part of the national economy, especially the railway transportation. But there are still some technical problems in this field which are needed to be improved and solved. Coupler buffer device is a basic and important component of railway vehicle completing the connection of cars as well as the transfer of forces. The problems of the coupler buffer device are gradually exposed with the increasing need of higher speed and load of railway transportation in recent years. So it’s important to explore its wear mechanism. Now, There are few reports on the studies of impact wear about ZG25MnCrNiMo steel which is usually used as the material of the coupler buffer device under a tilt angle.The impact wear experiment of ZG25MnCrNiMo steel had been performed by the self-invited tester on the basis of the microscopic analysis of the critical worn parts of the used coupler buffer device. And the factors affecting the property of impact wear were investigated. This study is of important practical engineering application value and theoretical significance.Experiments were conducted with the ZG25MnCrNiMo steel made testing samples for the investigation of its impact wear behaviors. And the influences of tilt angle (0°,20° and 40°), impact times (1×104～1×106 times) and load (10 N,20 N and 40 N) on the impact wear behaviors had been studied. The impact wear morphology and mechanism were measured and analyzed by means of optical microscopy (OM), scanning electron microscopy (SEM) and surface profiler. The results were compared with the coupler buffer device’s wear analysis, and the conclusions were as following:(1) The abrasive wear and delamination were the main wear mechanisms for the mating surfaces of traction tables. Materials were continuously removed under the action of plough, while spalling occurred under the condition of concentrating stress and impact load with parallel crack formation. Both the wear of couple pinhole and slave plate mainly presented the impact and abrasive wear with obvious plastic deformation characteristic on the surface.(2) There were phenomena of serious plastic deformation and spalling on the surface of material and raised material on the edge of wear scar when the sample is tilted. The area of the wear scar increased with the increasing tilt angle when the depth of the wear scar reached the maximum at 20°.(3) The increase of impact numbers aggravated the wear degree of material. The area and depth of wear scar increased quickly at first, then tended to become slowly as the contact stress decreased when point to point contact changed to face to face contact. Meanwhile, the main wear zone transferred from the edge to the center of wear scar.(4) The plastic deformation was the main damage action when the impact load was ION. With the increase of impact load, work-hardening occurred on the surface. Cracks initiated and grew under the repeating action of impact load, which caused material delamination ultimately. Meanwhile, the area and depth of wear scar increased correspondingly.(5) It’s helpful to explore the wear mechanisms of ZG25MnCrNiMo steel served in practice as there are the similar wear properties on the material both used in the laboratory and railway wagon.