The best equipment for spindle heat treatment-medium frequency induction heating power supply

As an important part of the machine tool, the spindle is required to have high strength and wear resistance. In order to improve its performance and service life, the spindle needs to be subjected to some heat treatment. Nowadays, the most commonly used equipment for heat treatment of spindles is medium frequency induction heating power supply. Today, Zhengzhou Gou's will tell you the process specifications for heat treatment of half shafts using this equipment.

The working conditions of the spindle require that the center of the spindle be tempered to (250±15) HBW; the hardness should be ≥59HRC. The processing process includes forging, annealing, rough machining, quenching and tempering, fine machining, induction heating surface quenching, low temperature tempering, fine grinding, and low temperature aging.

Heat treatment process specifications for spindle:

1. Annealing treatment. The purpose of annealing the half shaft is to eliminate structural defects caused by the forging process, uniformize the structure, refine the grains, and improve cutting performance. Generally, the heating temperature is 800°C, the holding time is 3 hours, and then the furnace is cooled to 550°C and air-cooled.

2. Conditioning and tempering treatment. In order to give the spindle as a whole good comprehensive mechanical properties, the workpiece needs to be modulated. The heating temperature is required to be 810°C and the holding time is 2.5 hours. The quenching and cooling method in the quenching and tempering treatment adopts the double-liquid quenching (water quenching and oil cooling) method, that is, first quenching in salt water with a concentration of 5% to 10% for 20 seconds. Then, immediately transfer to oil and cool to room temperature. Then perform high temperature tempering at 600℃×4h.

3. Medium frequency induction heating surface quenching. The frequency of induction heating is determined based on the required depth of the hardened layer. Due to the large size of the spindle and the required depth of the hardened layer ≥ 2mm, medium frequency induction heating surface quenching is selected. Medium frequency induction heating surface fire can give the spindle surface high hardness, high wear resistance and high fatigue strength. We generally use GS-ZP-200 medium frequency induction heating power supply for surface quenching. When quenching shaft parts, we generally use top positioning, but the force should be appropriate. Otherwise, the thin shaft is prone to bending deformation. For workpieces that cannot be positioned with the center, positioning sleeves or axial positioning ferrules can be used. If it is a stepped shaft, the small diameter part should be quenched first, and then the large diameter part should be quenched. During quenching, the hardness should be maintained in the range of ≥59HRC, and we should pay attention to the following points:

a. Two adjacent hardened areas on a shaft should be kept at a sufficient distance to avoid cracks in the transition area.

b. For flanged shafts and journals, the hardening zone should preferably start from the R rounded corner of the flange root. If the root does not need to be hardened, the distance between the hardened area and the fillet root should not be less than 5 to 8 mm.

c. When the shaft is quenched, an unhardened area of 2 to 8 mm can be reserved at the end of the shaft to avoid quenching cracks at the end of the shaft.

4 Low temperature tempering treatment. In order to ensure the high hardness, high wear resistance and high fatigue strength of the spindle surface, reduce internal stress and reduce brittleness, the spindle needs to be tempered. The tempering temperature is 160°C, and the holding time is 4 hours and then air cooled.

The heat treatment of machine tool spindles generally uses medium frequency induction heating machines for quenching, tempering, etc. This equipment can not only be used to quench and heat treat spindles, but also axle shafts, gears, hardware accessories, etc., and is widely used in auto parts, Machinery manufacturing and other fields. If you have any questions about the heat treatment and equipment of your medium frequency induction annealing machine, you can call us for consultation.