Galvanized seamless tube process

Zinc is soluble in acid, can also be dissolved in alkali, so called amphoteric metals. Zinc hardly changed in the dry air. In humid air, the zinc surface will generate basic zinc carbonate film. Containing sulfur dioxide, hydrogen sulfide and marine atmosphere, zinc corrosion resistance is poor, especially in the hot and humid atmosphere containing organic acid, the zinc coating can easily be corroded. On steel substrate, the zinc coating are anodic coating, it is mainly used to prevent corrosion of iron and steel, the merits of its relationship with the protective properties of the coating thickness is very big. After passivation of zinc coating, dyeing or coating protective agent, can significantly improve its protective and decorative. In recent years, with the development of galvanizing process, using high-performance zinc brightener, galvanized from mere protection purposes ingress protection - decorative applications.

Zinc coating process:
1, dehydroepiandrosterone
2, passivation
3, coloring

Galvanized seamless tube process include: original board ready → plated hot dip after treatment → finished product inspection before plating process. Accordance with the customary pre-plating treatment is often based on different methods of the hot dip galvanizing process is divided into the line and the line outside the annealing annealing two categories.

Outside the line annealing: Before hot-rolled or cold-rolled steel sheet is hot-dip galvanizing operations into the line, the first pumping hearth or hood-type annealing furnace annealing furnace recrystallization annealing, so that the line does not exist galvanized the annealing process. Before the hot-dip galvanized steel must maintain a presence of dirt, oxide and other active surface clean pure iron. This method is for the method of pickling annealed to remove surface scale, and then coated with a layer protected by a zinc chloride or zinc chloride, and a mixed solvent consisting of the composition, thereby preventing re-oxidation of the steel sheet .

In-line annealing: is provided directly by the cold-or hot-rolled coil plant as raw hot galvanized plate, protecting the gas line in the hot dip galvanizing operations recrystallization annealing.