Hardness Requirement and Heat Treatment Method of Spring Clamp

Spring chuck is a common tool in machine tools, which is irreplaceable at present. It has a wide range of applications, high efficiency but easy to damage, so the consumption is huge. Spring chuck according to the different materials, the need for heat treatment is also different, the relative parts of the spring chuck hardness requirements are also different.
Spring chuck
1. One-stage (whole) hardness method. The overall hardness of 65mn, 60Si2Mn and other steels is 50-55 HRC after whole process quenching or isothermal quenching. This heat treatment method is simple, the performance of elastic parts is ideal, but the head hardness is low, easy to wear, and the service life is not high.
2. Two-stage hardness method. 9sicr, GCr15 and other steels were obtained by whole quenching and partial tempering. Head hardness was 60-63 hrc, neck and tail hardness was 50-55 hrc. The early brittle fracture of the neck and tail is often caused by the insufficient elasticity of the heat treatment method.
It can also be achieved by integral heating and sectional cooling quenching, such as tioa spring chuck, which is heated to 810 C in salt bath furnace (or flowing particle furnace). After heating, the head is first quenched by local water for about 5 seconds, then all human oil is cooled to make the neck and tail meet the hardness requirements. After treatment, the head hardness is 50-55 hrc, the neck hardness and the tail hardness are 40-45 hrc.
3. Three-stage hardness method. CCr15, 9SiCr and other steels are heated integrally in fixture. After holding, the clamp head and neck are put into the nitrate isothermal tank at 260-280 C. The clamp tail is air-cooled, and when it is cooled to black, it also enters the nitrate isothermal. Then the clamp neck hardness is 50-55 HRC and the clamp tail hardness is 30-35 hrc. Because the hardness of the chuck is not reached, 2/3 of the central chuck is heated and quenched locally in a neutral salt bath at 860 +10. The hardness of the head is 60-63 hrc. Finally, the spring chuck is tempered entirely in a bath furnace at 200-220 to meet the final requirements. This heat treatment method is complicated.