Four fatal flaw causes truck bearing sudden burning shaft, hot axle

Van most eagerly axis accident is caused by sudden burning shaft, the shaft to the sudden combustion hot axle, warming faster, short duration, often a large interval had cut the shaft run down. After the hot axle bearing parts most have crack damage, broken, have been beyond recognition. The main reason for the hot axle is broken of bearing parts. The following four fatal flaw as a direct result of bearing parts crack, crack damage, damage can directly lead to van sudden shaft, hot axle phenomenon. 1, bearing steel, raw material inside there are serious defects in railway locomotive vehicles bearing is the use of high carbon chromium bearing steel, two kinds of main steel GCr15 and GCr15SiMn. At present, the metallurgical industry in terms of process equipment, smelting technology and a certain distance with developed countries in the world, the product internal quality inspection means and technology remains to be further perfect, manufacturing of bearing steel internal unavoidably have some defects. Production of railway vehicle rolling bearing factory also not to test the steel internal defects of advanced instrument, bearing steel raw material internal defects most found no, but only as a good material to make the bearing. Although there are a rolling bearing in the process of production of bearing parts inspection checks ( Continuity and residual method) Process, but also can find bearing parts surface or near surface defects, the internal defects of bearing parts is not found in time, can only as a qualified spare parts factory. 。 2, low bearing heat treatment quality of bearing heat treatment quality is low, crack, broken lead to bearing parts. Such as metal material heat treatment when overheating, toughness, brittleness, brittle fracture in the operation of the rolling element bearing, and even broken. 3, maintains a crack damage according to the survey statistics, maintains a crack, damage is caused by van unexpected burning shaft of rolling bearing, the important reason for the hot axle. Since May 2007, completed on truck, it is forbidden to use the steel cage bearing, but according to statistics, there are nearly 100000 sets of steel cage bearing are still in use, is a major safety concerns. 197726 type bearing of production in our country, the number of roller more than foreign same type bearings, roller diameter and keep the window frame beam width and sectional area is smaller, the intensity is reduced. Cage is to use stamping processing, the processing technology and equipment is not very perfect, cage caused by uneven expansion deformation and crack. And the vast majority of crack in at the window, has a great deal of concealment, if once leak before assembly roller, mount after the roller is harder to find. 4, bearing parts inspection from time to tome leak phenomenon from the steel mills in bearing steel bearing manufacturing factory is must carry on the inspection and selection before processing, if can be eliminated by rotary cut surface is defective, the light can be eliminated by grinding. Bearing when processed into semi-finished products, Component forming grinding repaired,) , it is necessary to adopt magnetic suspension detection, artificial judgment. Due to the bearing factory production line production, inspection work a lot of work, unavoidably exists residual misjudgment phenomenon. In recent years, various, wheel factory and car depot in the sampling inspection before use, often find new bearing parts ( Especially the roller) Crack. Each unit using the new system and overhaul bearing adopt sampling inspection, sampling rate is only 2%, chance is quite big, there is a problem of bearing smoke less than and treated as qualified bearing loading situation is objective existence.