Why are shaped springs to be galvanized?
1. Generally, the galvanized layer is passivated after being plated, and the passivation can improve the maintenance function of the plating layer and the added surface is beautiful.
2. The thickness of the zinc and cadmium coating determines the level of maintenance. The thickness of the thickness should generally be selected according to the working environment at the time of use. The thickness of the galvanized layer is recommended to be selected within the range of 6 to 24/μm; the thickness of the cadmium plating layer is recommended to be selected within the range of 6 to 12/μm.
3. The galvanizing and cadmium plating of the spring is carried out in a cyanide electrolyte. In the electroplating process, in addition to zinc or cadmium plating, a part of the reduced hydrogen enters the crystal lattice of the plating layer and the base metal. Internal stress is formed to make the coating and spring on the spring brittle, also called hydrogen embrittlement.
4. Because the strength of the spring material is very high, coupled with the large deformation of the spring when forming, it is particularly sensitive to hydrogen embrittlement. If hydrogen is not removed in time, the cracking of the spring is often formed, in order to eliminate some of the electroplating process. Disadvantages, improve the physical and chemical functions of the spring, extend the service life of the spring, improve the corrosion resistance of the coating, must be post-plating treatment, that is, dehydrogenation treatment.
5. The dehydrogenation treatment is carried out immediately after electroplating, perhaps within a few hours. The intention of removing hydrogen is obtained by heating the plated spring at a temperature of 200 to 215 ° C for 1 to 2 hours (or 2 hours or more).
What is the effect of the plating protection of various springs?
1. There are many kinds of metal maintenance layers. As far as springs are concerned, it is generally used to obtain a metal maintenance layer by electroplating. The electroplated maintenance layer not only maintains corrosion, but also improves the appearance of the spring. Some electroplated metals also improve the working function of the spring, such as improving surface hardness, adding wear resistance, improving thermal stability, and preventing ray corrosion. However, if it is purely for the corrosion of the spring, the electroplated zinc layer and the cadmium plating layer should generally be used.
2. Zinc is relatively stable in boring air, hardly changes, and is not easy to change color. A white film of zinc oxide or zinc carbonate is formed in the moist air. This dense film prevents continued corrosion. Therefore, the galvanized layer is used for the anti-corrosion maintenance layer of the spring under normal atmospheric conditions.