Galvanizing refers to a rust-proof method of laying metallic zinc on the surface of iron or steel. Zinc is a metal with high corrosion resistance. It can insulate iron from oxygen and water, so that iron cannot undergo the chemical reactions required for rusting. Since zinc is more mobile than iron, even if the zinc plated appears damage, zinc can still prevent rust by electrochemical means of sacrificial protection.
Cold galvanizing
Cold galvanizing is also called electro-galvanizing. It uses electrolysis equipment to degrease, pickle, and then put the pipe fittings into a solution composed of zinc salts, and connects the negative electrode of the electrolysis equipment. Place a zinc plate opposite the pipe fittings and connect it to the electrolytic when the positive pole of the equipment is powered on, a layer of zinc will be deposited on the pipe fittings by using the directional movement of current from the positive pole to the negative pole. Cold-plated pipe fittings are processed first and then galvanized.
Mechanical galvanizing
In a rotating drum filled with plated parts, glass balls, zinc powder, water and accelerator, the glass balls as the impact medium rotate with the drum, friction and hammering with the surface of the plated parts to generate mechanical and physical energy. Under the action of the accelerator, the plated zinc powder is "cold welded" to the surface of the plated part to form a smooth, uniform and fine coating with a certain thickness.
Hot dip galvanizing
The production process of hot-dip galvanized sheets mainly includes: original sheet preparation, pre-plating treatment, hot-dip plating, post-plating treatment, finished product inspection, etc. According to custom, the hot-dip galvanizing process is divided into two categories: off-line annealing and in-line annealing based on different pre-plating treatment methods.
Hot-dip galvanizing reacts molten metal with an iron matrix to produce an alloy layer, thereby combining the matrix and the coating. Hot-dip galvanizing is to pickle the steel parts first. In order to remove the iron oxide on the surface of the steel parts, after pickling, they are cleaned in an aqueous solution of ammonium chloride or zinc chloride or a mixed aqueous solution of ammonium chloride and zinc chloride. , and then sent into the hot dip plating tank. Hot-dip galvanizing has the advantages of uniform coating, strong adhesion, and long service life.