Heat treatment method for motor shaft parts

　　(1)quenching and tempering heat treatment

　　45Steel is a kind of medium carbon structural steel, which has good cold and hot processing performance, good mechanical properties, low price and wide source. Its biggest disadvantage is low hardenability, not suitable for cross-sectional size and high requirementsmotor shaftThe workpiece.

Because45The hardenability of steel is low, so it should be used.10%High cooling rate salt solution. After entering the water,motor shaftThe workpiece should be fully hardened, but not fully cooled. If the workpiece is thoroughly cooled in salt water, it may break the workpiece. This is because when the motor shaft workpiece is cooled to approximately180degree, austenite quickly transforms into martensite, resulting in excessive structural stress. Therefore, when the quenched workpiece is rapidly cooled to this temperature region, a slow cooling method should be adopted. Because the outlet water temperature is difficult to control, it must be operated by experience. When the shaking of the workpiece in the water stops, the water can be air-cooled, and the oil cooling effect is better. in addition,motor shaftThe workpiece should be moving rather than stationary when entering the water. It should move regularly according to the geometry of the workpiece. Static cooling medium and static workpiece lead to uneven hardness and uneven stress, resulting in large deformation and even cracking of the workpiece.

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　　(2)Surface quenching and low temperature tempering

Surface quenching is a heat treatment process in which only the surface layer of the workpiece is quenched to change the structure and properties of the surface layer. It is achieved by a combination of rapid heating and immediate quenching cooling, that is, by rapid heating.motor shaftThe surface of the workpiece is rapidly heated to the quenching temperature, and when the heat is not completely transferred to the core, the surface layer is rapidly cooled, so that the surface layer is martensitic and hardened, while the core is still in an unquenched state, that is, it has good plasticity and toughness The original annealed, normalized or quenched and tempered structure.

　　(3)low temperature artificial aging

Heat the part120-150Stress relief annealing, long-term insulation(5-12Hours)Remove and cool in air. The aim is to reducemotor shaftClass parts of micro-stress and residual stress to prevent deformation and cracking. Low temperature artificial aging is simple and low cost. Compared with natural aging, it saves time and eliminates residual stress more thoroughly.