Hot-dip galvanizing, it is at high temperatures the zinc ingots melt, being placed in the auxiliary material, then the metal structure is immersed in a zinc plating bath, so that the metal member attached to a layer on the zinc layer. The hot galvanized advantage depend on its preservative ability, the better the adhesion and hardness of the galvanized layer.
Cold galvanizing is a zinc salt solution by electrolysis, to the plating on the coating, in general, which do not have heating, the amount of zinc rarely encountered humid environment is very easy to fall off. The cold galvanizing physical treatment, just in the surface brush a layer of zinc, zinc coating so easy to fall off the use of hot-dip galvanized construction.
Process of hot-dip galvanizing and cold galvanizing
Hot dip galvanized is immersed in liquid zinc dissolved workpiece degreasing, pickling, dipping, drying a certain period of time and put forward.
Cold galvanizing, also called electro-galvanized, is the use of electrolysis device to the workpiece into the composition of the zinc salt solution, after degreasing, pickling, and connecting the negative electrode of the electrolytic device; zinc plate placed at the opposite side of the workpiece is connected in the electrolytic device the positive electrode, the power is turned on, a current from the positive electrode to the negative directional movement, it will be deposited on the workpiece with a layer of zinc.
Appearance of hot-dip galvanizing and cold galvanizing
Cold galvanizing looks more smooth, bright, color passivation process plating layer is yellow-green in color, was colorful. Plating layer was bluish-white or white with white passivation process was green, white coating passivation process and the sun was significant Colorful angle. The complex workpiece angular edges parts prone to “electrical burning” from gloomy, the parts of the zinc layer thick. Yin corner site is easy to form a current dead undercurrent gray area and the area zinc layer is thinner. The workpiece overall zinc tumor, caking phenomenon.
Hot dip galvanized look a little rough compared to the electro-galvanized, silvery white, look prone process waterlines and a few drops of tumor is more obvious, especially in the one end of the workpiece. Hot dip galvanized zinc layer than a few times of the electro-galvanized thick corrosion protection is several times that of the electro-galvanized.
Post time: Sep-19-2019