The Failure of Tamping Tools Manifested By Wear And Fatigue fracture
The failure of tamping tools is mainly manifested by wear and fatigue fracture.The most severe damage is at the front end of the palm and the side rounded corners, followed by the front end of the tools palm.The fracture generally occurs at the junction of the cylindrical surface and the tapered surface.
Whether it is worn or broken, the internal tamping tools are more serious than the external side.
When tamping, the tamping tools first hits the ballast at a certain speed and then inserts it into the track bed.The ballast horns slide on the tamping tools palms, with the vibration and grip of the cymbal, ballast with sharp edges and corners cuts the palm to form microscopic chips.A more sleek ballast causes plastic deformation or scratches on the surface of the tools palm.
Metal is deformed by multiple times.Producing cracks by deforming beyond the allowable extension limit of the material.It will continue to interact with the ballast, and the crack will expand.Wear increases as the mileage increases.
Therefore, the wear of the tamping tools is the impact of the sliding abrasive wear,The wear rate in the height direction of the tools palm is much greater than the wear speed in the thickness direction.Because the abrasive is a variety of rocks, the hardness is different, and the track bed conditions are also different.
For loose ballast track beds, the tamping tools is less affected and less worn.For the dense bed of granite ballast, tamping tools wear is serious.
In addition, for wet track beds, the corrosive action of water also reduces the wear resistance of the tamping tools.
Due to the different positions of the tamping tools during the track bed operation, the resistance is greatly different.
The outer of the tamping tools on both sides are inserted into the sleeper ballast. It is easier to clean the ballast and the resistance is less.
The middle inner ridges of tamping tools are inserted into the sleeper ballast in pairs, and the ballast is tightly packed, which is difficult to discharge, and the tamping tools are subjected to large resistance.Therefore, the inner palm of tamping tools wears faster than the outer.However, the wear of the outer tamping tools is different.
From the forward direction, the front outer tamping tools is inserted into the unworked sleeper railway bed.Then the posterior tamping tools are generally inserted into the sleeper track bed after the previous tamping operation, and the track bed is loose.Therefore, the front tools is wear faster than the posterior one.
The reason for the serious wear on the side of the inner tamping tools is that the gap between the adjacent inner tools is larger during operation, and the ballast is easier to squeeze into between the two tamping tools;
The gap between adjacent tamping tools is small, and the ballast is not easy to squeeze in.Therefore, the wear of the tamping tools is not only related to the material and force , but also related to the hardness, grain size, shape, orbital bed condition and environment of the ballast.