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Heat treatment process for hardness of collet of cnc lathe

2019-11-29 11:11

In addition to the structural design and machining process of the CNC lathe spring collet, heat treatment is a more critical factor. Depending on the material, the spring collet needs different heat treatment methods. The relative spring collet The hardness requirements for each part of the head are also different.


LONNZ has been committed to research, development, production and sales of high precision CNC lathe spring chucks of various models and specifications since 2005, with concentricity of 0.003MM and a life of 600,000 times. Below we will use spring clamps for decades The head production experience will share the hardness requirements of the chuck of the CNC lathe and the heat treatment process of the chuck.


  • One-stage (overall) hardness method. 65mn, 60si2mn and other steels are generally quenched or isothermally quenched, and the overall hardness is 50-55 HRC. This method of heat treatment is simple, and the performance of the elastic part is ideal, but the hardness of the head is relatively low, it is easy to wear, and the service life is not high.


  • Two-stage hardness method. 9sicr, gcr15 and other steels are achieved by overall quenching and local tempering, and the hardness of the head is 60 ~ 63 HRC, and the hardness of the neck and tail is 50-55HRC. This heat treatment method often causes early brittle fracture due to insufficient elasticity of the neck and tail.


  • The collet chuck can also be achieved by overall heating and segmented cooling and quenching. For example, the Tioa collet chuck is heated to 810 ° C in a salt bath furnace (or flowing particle furnace). After heating, the head is partially water-quenched for about 5s. Then, all the human oil is cooled to make the neck and tail meet the hardness requirements. After processing, the hardness of the head is 50-55 HRC, and the hardness of the neck and tail is 40-45 HRC.


  • Three-stage hardness method. Steels such as ccr15 and 9sicr are installed in the fixture for overall heating. After the heat preservation, the chuck and the neck are placed in a 260-280 ° C nitrate isothermal tank. The overall fire at -400 ℃, the hardness of the neck is 50-55 HRC, and the hardness of the tail is 30 -35 HRC. As the hardness of the collet is not reached, for this purpose, 2/3 of the central head is locally heated and quenched in a neutral salt bath at 860 ° C ± 10 ° C to reach a head hardness of 60-63 HRC, and then the spring collet is at 200- The whole tempering is performed in a 220 ° C bath furnace to make it reach the final requirements. This heat treatment method is complicated but achieves high accuracy, the chuck is more practical and wear-resistant, and the life is longer.


LONNZ CNC lathe chucks are made of spring steel with guaranteed accuracy. The precision of the cutting tool can be guaranteed within 0.01-0.015. The segmented heat treatment can extend the life of the chucks and has good wear resistance. Performance, has been widely used in various types of CNC equipment, instrument lathes, automatic lathes, milling machines, grinding machines and other equipment.


CNC40 extended tungsten steel collet