Analysis on Ring Forming in Rolling Bearing Manufacturing

The raw materials for manufacturing ferrules are cylindrical rod or tube materials. Currently, rolling bearing ferrules generally have the following manufacturing processes according to different molding processes.

　　a. (Bar stock) blanking-forging-annealing (or normalizing-turning (cold rolling)-heat treatment quenching, tempering-grinding-part inspection-demagnetization, cleaning-submission for assembly

　　b. (bar, tube) blanking-cold rolling forming-heat treatment quenching, tempering-grinding-parts inspection-demagnetization, cleaning-submission for assembly

　　c. (Tube material) blanking-turning forming-heat treatment quenching, tempering-grinding-part inspection-demagnetization, cleaning-submission for assembly

　　d. (Bar stock) blanking-cold (warm) extrusion molding-turning-heat treatment quenching, tempering-grinding-part inspection-demagnetization, cleaning-submission for assembly

　　 Ferrule forming method: At present, in ferrule processing, there are mainly the following forming methods: forging forming, turning forming, cold rolling and expanding forming and cold (warm) extrusion forming. Among the above forming methods, forging forming is the most widely used, accounting for about 80% of the total production. For some small general-purpose products, rods (tubes) can be directly turned into forming. Since the 1980s, some small and medium-sized enterprises in my country have adopted cold rolling and expansion and cold (warm) extrusion molding processes in the production of small and medium-sized ferrules.

　　 One, forging

　　 Through the forging process, the inherent defects of the metal can be eliminated, the metal structure can be improved, the metal streamline distribution is reasonable, and the metal compactness is good. Forging forming processing technology is widely used in bearing forming processing, and can complete the processing of small products with an inner diameter of ~20mm to large products with an outer diameter of 5000mm. Common forging forming methods are: hot forging, cold forging, and warm forging. Hot forging is the main form in my country.

　　Hot forging processing is further divided into: free forging processing technology, press forging technology, flat forging machine forging technology and high-speed upsetting machine forging technology due to its different forming processing equipment.

　　 2. Cold rolling forming

　　The cold rolling process is an advanced process method that can increase the utilization rate of materials, improve the compactness of the metal structure, and maintain the linearity of the metal flow. It is a chipless processing method. In theory, cold-rolled products can be directly processed for heat treatment and grinding without turning. At present, the cold rolling process is mainly used in medium and small deep groove ball bearings. The main process is:

　　 Forging blank (ring)-turning (except for grooves)-rolling (groove and chamfering) to adjust the diameter-soft grinding of both ends

　　 When cold rolling and forging is used, the accuracy of the product is not only affected by the accuracy of the equipment, but also by the accuracy of the molding die.

　　 Three, turning forming

　　In the bearing industry, the traditional turning forming technology is to use a special lathe, and use a concentrated process method to complete the forming process. However, due to the difficulty in adjusting the equipment used in this method, the low precision of the machine tool, and the low utilization of materials, this process method is being eliminated.

　　 With the development of science and technology, CNC turning machine tools develop rapidly and become increasingly perfect. At present, some products with complex shapes and high precision requirements are increasingly adopting CNC turning forming technology.