After the bearing is installed, the reasons that cause the bearing to rotate difficultly After the bearing is installed, when the outer ring or shaft of the bearing is rotated by hand, the rotation is not flexible. The main reasons are as follows: 1) The oxide scale, dust and other dirt enter the bearing. Cushion pressure and grinding are produced; 2) Corrosive media such as moisture, acid, alkali enter the bearing, causing the bearing to rust; 3) The bearing clearance is too small, or the inner ring is expanded due to temperature rise when the bearing is working 4), insufficient, excessive or dry lubricant; 5), the manufacturing accuracy of the journal, shoulder, and bearing seat is too low or deformed in use; 6), the installation and sealing are not correct, such as the sealing is too tight or There is friction between the seal and related parts; 7), the cage is deformed; 8), the axial preload is too large for the preloaded bearing. Bearings must be overheated during operation or in a high-intensity operation environment. Therefore, in order to prevent the damage of the bearing caused by the heat phenomenon, we must not take corresponding measures. (1) Strictly control the forging heating temperature and heating holding time of the lcrl8Ni9]ri stainless steel box and flange parts to prevent the workpiece from overheating and causing the workpiece to produce coarse grain defects. (2) The heat treatment and solution treatment temperature of the bearing workpiece should not be too high, the holding time should not be too long, the heating temperature should not be higher than 1150 °C, and the holding time should be calculated as 1-l_5min/mm. (3) In the forging production of the workpiece, if the forging ratio is too small and the final forging temperature is too high, coarse-grained structure defects are also prone to occur. The forging ratio of the workpiece should be appropriate and sufficient, and the final forging temperature should be moderate. (4) For the coarse workpiece with overheated structure, the method of forging to refine the grain can be used to eliminate defects, prevent the orange peel surface defects of the workpiece during cold deformation, and improve the surface quality of the workpiece.