​In recent years, the surface finishing (finishing) treatment of springs has also been recognized by spring designers.

The finishing (finishing) process is to put the spring directly into the inclined centrifugal, spiral vibrating, vortex and other series of finishing machines, and add an appropriate amount of abrasives, abrasives and water for finishing. Normally, it takes about 20~30min. The specific time depends on the shape of the spring and the amount of the device. After finishing, take out the spring and rinse it with tap water, then immerse it in the SM series water film replacement anti-rust oil for several minutes and then take it out. At this time, a 5μm anti-rust oil film is attached to the spring surface, which protects the spring from rust. This treatment method greatly supports the traditional complicated procedures, such as degreasing, cleaning, pickling, and dehydrogenation.

At present, the springs using the finishing process include: plunger springs for oil pump nozzles and pressure regulating springs for fuel injectors; support springs for refrigerator compressors. The comparison of the performance (life) and corrosion resistance between the light-finished (finished) and conventional oxidized or plated springs does not wait for further tests and practices to draw more reliable conclusions.

Removal method of unqualified paint layer:

At present, some factories use oil to burn the paint layer, and then use shot blasting to clean the surface, but the operation process causes considerable pollution, and fire is prone to occur during manual operation.

The paint layer is carbonized with concentrated sulfuric acid, but strong acid itself can cause hydrogen embrittlement, so spring is not suitable.

The use of KRT paint remover, the swelling method, peels off the paint layer, does not damage the spring substrate, simple operation, is a relatively advanced method, but the use of commercial paint remover may lead to increased costs, but if the scrap rate is reduced, the overall The cost will not rise.

Metal protective layer of spring

There are many types of metal protective layers. As far as springs are concerned, gold plating is generally used to obtain the metal protective layer. The electroplated protective layer can not only protect from corrosion, but also improve the appearance of the spring. Some electroplated metals can also improve the working performance of springs, such as improving surface hardness, increasing wear resistance, improving thermal stability, and preventing radiation corrosion. But if it is purely for the corrosion of the spring, the electro-galvanized layer and the electro-cadmium layer should generally be used.

How to finish the spring surface?
Zinc is relatively stable in dry air, hardly changes, and is not easy to change color. A white film of zinc oxide or carbon zinc carbonate is formed in humid air. This dense film prevents further corrosion. Therefore, the galvanized layer is used as the anti-corrosion protection layer of the spring under normal atmospheric conditions. Zinc coating is not suitable for springs that are in contact with solutions such as sulfuric acid, hydrochloric acid, caustic soda, and working in humid air such as sulfur trioxide.

Generally, passivation treatment is carried out after the galvanized layer, which can improve the protective performance of the coating and increase the appearance of the surface.