Hot-dip galvanized pipe “zinc flower” you understand?

Seamless steel pipe hot dip coating surface in the solidification of the coating metal crystallization pattern, this crystallization pattern of galvanized seamless pipe is particularly obvious, showing the appearance of beautiful zinc crystals, and thus become an important feature of the appearance of hot-dip galvanized seamless pipe, usually referred to as this crystallization pattern for the “zinc flower”. When the galvanizing solution contains other metal impurities, zinc flower is produced. Zinc flower size and shape depends on the type and amount of impurities contained in the galvanizing solution, common impurities are lead, aluminum, antimony, bismuth, tin and other metals.

According to the size of the diameter of the zinc flower, it can be divided into the following three kinds:

(a) large zinc flower

 With the naked eye can distinguish the diameter of zinc flowers greater than 3mm is called large zinc flowers, also known as normal zinc flowers or natural zinc flowers. The internationally recognized optimum size is 8~12mm.

(b) Small zinc flowers

 Zinc flower diameter of 1~2mm zinc flower is called small zinc flower. When the hot-dip galvanized seamless pipe from the galvanized pool out, to the zinc layer is not solidified when spraying water mist or zinc powder, then a water mist droplets, a zinc powder particles will form a crystallization center, so that the number of zinc flowers per unit area increases and becomes smaller, so the surface of the galvanized seamless pipe will be formed with the naked eye can be distinguished by the formation of small zinc flowers, the traditional production of this process is called a small zinc flower products. Because this process often causes uneven zinc flowers, uneven surface color, and high production costs, so this process is currently not much use.

(c) No Zinc Flowers

Tube can not be seen on the naked eye zinc flower, known as no zinc flower, also known as zero zinc flower, which is through the control of the chemical composition of the zinc solution to complete. Hot-dip galvanizing only to the zinc solution with a certain content of aluminum, do not add lead, antimony, tin, you can produce no zinc flower products. This process does not increase the equipment, does not increase the production cost, can obtain a uniform and consistent surface appearance, so this process has been widely promoted in the world.

In nature, lead and zinc are symbiotic deposits, using pyrometallurgical smelting, lead liquid density in the lower part of the zinc liquid density is small in the upper part, which can be separated. However, the saturation concentration of lead in the zinc liquid is 2%, so there is a large amount of lead in the crude zinc. Hot-dip galvanizing has a history of more than 150 years, when there is no modern refining technology, only the use of crude zinc for hot zinc plating production, because the zinc liquid mixed into the lead, so the hot galvanized pipe will certainly appear zinc flower. Therefore, for a long time on the formation of hot-dip galvanized seamless pipe must have zinc flower, no zinc flower is not hot-dip galvanized seamless pipe of the wrong view. In fact, from the long-term use, no zinc flowers of hot-dip galvanized seamless pipe performance will be better.