Surface treatment is mostly required during and after heat treatment in order to remove oxidized skin and various contaminants from the metal surface, to reduce the activity of the bare surface of the metal, as well as before and during the application of protective and functional coatings to the surface of titanium and its alloys, which are intended to improve the properties of the metal surface, e.g. to prevent corrosion, oxidation, wear, etc. The conditions of pickling of titanium bars and their alloys are determined by the type of oxidized and existing reaction layers (characteristics), which in turn are influenced by the high temperature heating process and the processing.
The conditions of pickling of titanium rods and their alloys are determined by the type (characteristics) of the oxidized and existing reactive layers, which in turn are influenced by the high-temperature heating process and the increase in processing temperatures (e.g., forging, casting, welding, etc.). At low processing temperatures or high heating temperatures below 600X: only a thin oxide layer is generated, and at high temperatures an oxygen-rich diffusion zone is formed in the vicinity of a certain oxide layer, which must also be removed by pickling. Different methods of oxide removal can be used: mechanical methods for removing thick oxide layers and hard surface layers, oxide removal in molten salt baths and pickling in acid solutions to remove the oxide layer.
In many cases it is possible to use a combination of several methods, e.g. a combination of mechanical removal of the oxide layer followed by pickling, or a combination of salt bath followed by pickling, but in the case of oxidized and diffused layers formed at higher temperatures a special method is used, but oxidized layers formed at high temperatures of up to 600X: can be removed in most cases by a general pickling. However, most of the oxide layer formed at high temperature up to 600X: can be dissolved by general pickling.
