The manufacturing process of compression springs mainly includes the following steps:
1, Roll forming
1. Cold rolling method and hot rolling method:
When the diameter of the spring steel wire is less than or equal to 8mm, the cold rolling method is commonly used, which requires heat treatment
before rolling and low-temperature tempering after rolling.
When the diameter is greater than 8mm, the hot rolling method is used, and the hot rolling temperature is usually between 800 ℃ and 1000 ℃. After hot
rolling, quenching and medium temperature tempering treatment are required.
2. Equipment selection:
Use a universal automatic spring winding machine for mass production.
Single piece and small batch production can be done on a regular lathe or by hand.
2, Heat treatment
1. Recrystallization annealing:
The spring formed by rolling needs to undergo recrystallization annealing treatment to stabilize its geometric dimensions and reduce quenching
deformation.
The annealing temperature is 550-650 ℃, and after holding for 1-1.5 hours, it is air-cooled.
2. Quenching and tempering:
Quenching: Heat to 850 ℃± 10 ℃ and hold for 10-15 minutes, then remove from the furnace and quench with oil to cool through.
Tempering: It is divided into corrective tempering and final tempering, which are carried out at around 20 ℃ and 420 ℃± 10 ℃ below the final tempering
temperature, respectively, to improve elasticity and eliminate internal stress.
3. High pressure treatment and shot blasting treatment:
● Strong pressure treatment: to generate residual stress in the spring to improve its load-bearing capacity and service life.
Shot peening treatment: Using pellets with a diameter of 0.3-0.5mm, sprayed by compressed air or centrifuge, significantly improves the strength and
service life of the spring.
3, End face treatment
Ensure the verticality of the compression spring and reduce deflection.
Usually, automatic grinding is used to process both end faces.
4, Surface treatment
Electrophoretic paint, spray coating, electroplating, etc.
The purpose is to improve the corrosion resistance and aesthetics of the spring.
5, Precision machining and inspection
● Precision machining process: Especially for ring springs, it is carried out on a CNC lathe to ensure the cone half angle of the ring.
● Characteristic testing: including mechanical performance testing and geometric dimension inspection of various parts.
special note
Special process of annular spring:
Raw material manufacturing usually uses forging or rolling methods.
After heat treatment, precision machining is required to ensure accuracy.
○ Must undergo strong pressure treatment to improve performance.
