Dongguan spiral duct market is generally divided into three categories according to material: galvanized spiral duct, stainless steel spiral duct and composite spiral duct. Among them, the stainless steel duct is of the best quality and strong applicability, but the price is high. The most widely used spiral air duct on the market is galvanized sheet. Galvanized sheet spiral duct basically has the characteristics of stainless steel spiral duct, but the price is relatively two-thirds or even lower than stainless steel duct. Composite spiral air ducts are generally used in places where the external environment is relatively ordinary and the requirements on the air ducts are not too high.
As the iron sheet is prone to chemical reactions in various environments, it causes corrosion and rust. And zinc hardly changes in dry air. In humid air, a dense zinc zinc carbonate film is formed on the zinc surface. Dongguan spiral duct is mainly coated with a layer of zinc on the duct iron sheet to protect the sheet. After the zinc coating is passivated, dyed or coated with a light protectant, it can significantly improve its protection and decoration.
The production process of straight seam steel pipe is simple, the production efficiency is high, the cost is low, and the development is fast. The strength of spiral steel pipes is generally higher than that of straight seam welded pipes. Welded pipes with larger diameters can be produced from narrower billets. Welded pipes with different diameters can also be produced from billets of the same width. However, compared with straight seam pipes of the same length, the weld seam length is increased by 30 to 100%, and the production speed is lower. Therefore, most of the smaller-diameter welded pipes use straight seam welding, and large-diameter welded pipes mostly use spiral welded pipes.