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The cause of the bearing steel ball cracking have? For example

by:Waxing     2020-11-12
Steel ball is total bearing load of ball bearing, roller is one of the important components of bearing, but we are in the process of using bearings, often find bearing steel ball cracking phenomena, such as: bearing steel ball wear trace, bearing steel ball has obvious extrusion, partial defects of bearing steel ball, steel ball bearings in cracks and steel ball surface spalling, etc. As shown in figure 1. Figure 1 that exactly what reason can cause cracking of bearing steel ball? In the following 崋 bearing network (for short ) According to the understanding of bearing steel ball knowledge, to share the relevant knowledge. 1, according to the bearing steel ball crack fracture were analyzed, and some parts are in linear distribution of the material, the edge light and uneven, there are obvious traces of extrusion and wear of the bearing steel ball fracture phenomenon. There may be three possible cause by the analysis of bearing steel ball craze: ( 1) After installation into the bearing steel ball is used in the process of cracking, cracking direction to the direction of rolling material. ( 2) Ball core is a clear loose stripe, banded carbide overweight and the surface contains oxygen, calcium, magnesium and other elements. In addition, the stripe size is about 0. 25 mm, which determine the existence of steel ball the core porosity, belongs to the metallurgical defects, which is lead to steel ball in the use of the main causes of crack occurring in the process. ( 3) Steel ball that overheating quenching tempering brittleness increases, reduced the compressive strength, make the ball more prone to cracking. When the small size of steel ball or fracture extrusion, and serious wear and tear, unable to determine material rolling direction, also hard to do regular fracture analysis, can by the metallographic method, by observing the relationship between morphology and microstructure defects found the main cause of cracking. Figure 22, as shown in chart 2, this kind of bearing steel ball overall brightness, no high temperature becomes angry, but there is a flaw in approximately 10 mm, exist near the crack of peeling phenomenon. Through the analysis, the causes of cracking of bearing steel ball is mainly due to quenching heating temperature is exorbitant, carbide dissolution in great quantities, make austenitic obviously increase the carbon content and cooling when mesh or half carbide network in the grain boundary. Observation and failure analysis and microstructure of steel ball, concluded that failure of steel ball overheating phenomenon appeared in the quenching process. At the same time, the steel ball organization exists in the banded carbide, make poor carbon area in the process of heat treatment overripe. So that the ball during quenching is easy to cause the quenching crack large deformation. That is to say, the quenching crack caused by quenching temperature is too high. Quenching crack refers to in the process of hardening or occurring in the process of room temperature placed after quenching crack, belong to the macro crack, caused by macro internal stress. After quenching cracking in the process of follow-up work, steel ball and the influence of the quenching crack defects cycle fluctuation under the action of contact stress contact fatigue spalling. Note: in the process of heat treatment of steel ball, should strictly control the heat treatment process parameters, to ensure the stability of heat treatment temperature and holding time. 3, some bearing steel ball to present local bump, or oval shaped, but after shelling of steel ball surface light, complete imagination. The cause of bearing steel ball this phenomenon may be caused by external factors such as operating conditions, but quite a number of factors is due to the steel ball itself. Defects such as raw materials or manufacturing defects, etc. , and the raw material factors and the existing macrostructure defect is mainly divided into surface defects, and the influence of the microstructure defects in three aspects. Another part of the invalidation of bearing steel ball may also be caused by fatigue.
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