Hot-dip galvanizing of products from various steels
To protect ferrous metals from corrosion, they can be subjected to hot-dip galvanizing. You can digitize cast iron, including malleable, cast steel, hot and cold rolling steel. This process can be subjected to alloy and stainless steel.
Of course, the quality of zinc treatment depends on the chemical composition of the base material. However, if the purpose of galvanizing is corrosion protection, in this case, the dependence on the composition of the metal is practically absent.
Unevenness of the coating that occurs when galvanizing objects with variable chemical composition, in no way affects the main purpose of galvanizing – corrosion protection.
In the process of processing zinc sometimes changes color and texture. However, under normal conditions, the color and texture are evenly restored, but the design is already protected from corrosion.
The change in the surface of the steel depends on the size of the zinc layer. But galvanizing is also influenced by the way the object is made. It depends on what parameters of etching and galvanizing will be selected. This is necessary in the processing of zinc, such as:
- Rusted surfaces;
- Specially treated surfaces;
- Forged steel;
- Hot rolling steel;
- Cold rolling steel;
- Sand castings;
- Acid treated surfaces;
- Steel with a high level of alloying additives.
It often happens that the chemical cleaning of steel paint residues, varnish, various lubricants can not be removed completely. But for the galvanizing process, it is critical to clean the surface intended for processing completely. Therefore, before the process it is necessary to subject the soiled surface to mechanical cleaning.
If the object for galvanizing consists of parts made of different types of steel:
- Different steels should be galvanized separately, and only after processing it will be possible to assemble them again;
- Do not combine a combination of old and new steels or castings and rolled products;
- Do not use very rusty parts with new ones. If this combination can not be avoided, then clean the surface sandblasting.
If the stainless steel does not contain Nickel, which is necessary in the process of galvanizing, it will not be possible to digitize.
There may also be problems with galvanizing alloy steel containing an increased amount of silicon. The coating, which is formed by zinc treatment, will create anti-corrosion protection, but will be thick and easy to break off.