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Bearings I believe that everyone has seen that the bicycles we often use also have bearings, and the cars we often ride also have bearings, but the size and style of the bearings are different. At present, the best bearings in the world are SKF bearings. So how is the steel ball in the SKF bearing made? Many people still don't know the manufacturing process of the bearing. The steel ball inside the bearing is very important. If the hardness is not good, then the whole bearing will not work. Below we will introduce the basic knowledge of hard grinding of the lower bearing steel ball.
Steel ball processing technology: The method of grinding the hard-rolled steel ball of the bearing steel ball after grinding in the grinding machine is called hard grinding. Its function is to eliminate the soft grinding (or light grinding) defects and remove the surface oxidation generated during the heat treatment. Decarburization, deformation and troostite defects further improve accuracy and surface quality. During or after the hard grinding of the steel ball, the surface defects should be visually inspected. After the cold pickling, the burns should be examined. The burns can be generally divided into secondary tempering burns and secondary quenching burns. The secondary tempering burns are black after cold pickling. After the secondary quenching burn, after cold pickling, the middle is gray martensite, surrounded by black troostite. Linear burns, spot burns, and bipolar burns (large ball burns).
Causes of bipolar burns:
1. Some dead angles on the machine tool, so that the individual balls can not get the normal grinding surface into a large ball, the big ball only revolves in the groove, and is not rotated by the two groove edges of the grinding wheel;
2. A certain groove is blocked by foreign objects such as grinding wheel block and material head, and is not detected and eliminated in time. After a long time, the groove will become shallow. When the ball re-enters the groove, a bipolar burn may occur.