For micro motors, Q235A round steel is a commonly used material, 45 carbon round steel is a commonly used material for small and medium-sized motors, while for large motors, as well as high-speed, high-torque motors, special requirements are placed on the material of the shaft, and quenched and tempered shafts and forged shafts are used more often.
Simply put, quenching and tempering refers to a dual heat treatment method of dipping and high-temperature tempering. Through quenching and tempering, the performance and material of the rotating shaft can be greatly improved, and the strength, plasticity and toughness are good, and good comprehensive mechanical properties can be obtained. Forging is a processing method that uses forging machinery to apply pressure to metal billets to cause plastic deformation to obtain forgings with certain mechanical properties, certain shapes and sizes. Through forging, the cast looseness and hole defects of the metal can be eliminated. In large special-purpose motors and generators, forged shafts are often used under working conditions with high loads, severe working conditions, and inconvenient maintenance and replacement.
●Related knowledge of common shaft forgings●
Shaft forgings are one of the typical forgings often encountered in equipment, including motor products. It is mainly used to support transmission parts, transmit torque and bear loads. Shaft forgings are rotating body forgings, and their main feature is that the length dimension is greater than the diameter dimension. They are generally composed of the outer cylindrical surface, conical surface, inner hole and thread of the concentric shaft and the corresponding end surface. According to the different structural shapes, shaft forgings can be divided into smooth shafts, stepped shafts, hollow shafts and crankshafts. According to the matching characteristics of the equipment, the appropriate raw materials and forging processes can be selected by comprehensively considering factors such as applicability, economy and reliability.
Shaft forgings can be made of bar stock, forgings and other blanks according to the use requirements, production type, equipment conditions and structure. For shafts with similar outer diameters, bar stock is generally used; for stepped shafts or important shafts with large outer diameter differences, forgings are often used, which not only saves materials but also reduces the workload of mechanical processing and improves mechanical properties. ●45 steel is one of the most commonly used materials for shaft parts and is also a common material for shaft forgings. This material is cheap and can obtain better cutting performance, higher strength and toughness and other comprehensive mechanical properties after quenching and tempering. The surface hardness can reach 45~52HRC after quenching.
●40Cr alloy structural steel is suitable for small and medium-sized motor shafts with relatively high requirements, and is also suitable for shaft forgings with medium precision and high speed. After tempering and quenching, this type of material has good comprehensive mechanical properties. ●Bearing steel GCr15 and spring steel 65Mn can reach a surface hardness of 50~58HRC after tempering and surface high-frequency quenching, and have high fatigue resistance and good wear resistance, and can manufacture high-precision shafts. ●38CrMoAIA nitrided steel can be used for the spindle of precision machine tools. After tempering and surface nitriding, this steel can not only obtain a high surface hardness, but also maintain a softer core and good impact toughness. Compared with carburized and quenched steel, it has the characteristics of small heat treatment deformation and higher hardness.
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