The post-processing link of spring coiling machine alloy spring steel is a crucial step, which is directly related to the final performance, service life and appearance quality of the spring.
Stress relief annealing
During the coiling process of alloy spring steel, due to the rearrangement of the internal structure of the metal and local plastic deformation, large internal stress will be generated. If these internal stresses are not eliminated in time, the spring will deform during use, affecting the use effect. Therefore, the first processing step after coiling is stress relief annealing. The main purpose of stress relief annealing is to relax the internal structure of the metal through heating and insulation, thereby eliminating or reducing internal stress. Annealing temperature, insulation time and cooling rate are key parameters, which need to be determined according to the material and coiling process of the specific alloy spring steel.
Surface cleaning
During the coiling process, impurities such as cutting fluid, oil stains, and metal chips may remain on the surface of the spring. These impurities not only affect the appearance quality of the spring, but may also have an adverse effect on the subsequent surface treatment steps. Therefore, surface cleaning is required after coiling. Cleaning methods include sandblasting, pickling, electrolytic polishing, etc. The specific method to be selected depends on the material, surface condition and subsequent processing requirements of the spring.
Surface treatment
Surface treatment is an important means to improve the performance and service life of alloy spring steel springs. Common surface treatment methods include galvanizing, chrome plating, phosphating, shot peening, etc.
Galvanizing: It can improve the corrosion resistance of the spring and prevent it from rusting in a humid or corrosive environment.
Chrome plating: In addition to improving corrosion resistance, it can also increase the surface hardness and wear resistance of the spring, making it more suitable for use in harsh environments.
Phosphating: A layer of phosphate protective film is formed on the surface of the spring through chemical reaction, which improves the corrosion resistance of the spring and the bonding force with the coating.
Shot peening: The high-speed shot impacts the surface of the spring to produce a residual compressive stress layer, thereby improving the fatigue strength and stress corrosion resistance of the spring.
