Galvanising

When metal coatings are precipitated from aqueous solutions, there is a possibility that hydrogen will diffuse into the surface of the spring. This is particularly the case with the high-strength spring steels used for disc springs.

A hydrogen-induced, delayed brittle-fracture (hydrogen embrittlement) may occur. The risk of hydrogen embrittlement can be reduced by a suitable heat treatment process after galvanising (effusion annealing), but not completely eliminated. Where possible, coatings applied by electrolytic galvanisingshould be avoided because of the risk of hydrogen embrittlement.

Electro-galvanizing

Zinc is chemically more basic than steel. Zinc protects itself by reacting with the atmosphere to form passive protective coatings andif the zinc coating is damaged, it protects steel cathodically. The level of protection against corrosion is roughly proportional to the thickness of the zinc coating. Additional protection can be provided adding a chromate finish. Chromate coatings are available in variouscolours. A subsequent thermal treatment is required to expel the hydrogen. Galvanic coatings are applied mostly for decorative purposes and are used for both indoor and outdoor purposes.

The properties of the materials used by Mubea are listed in the following tables, and can be downloaded here:

» Download material properties tables as a .pdf document

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