Hot dipped galvalume steel coil/sheet, put based steel sheet in melting zinc, then it will be the sheet sticking of a layer of zinc.At present mainly adopts continuous galvanizing process, namely put the continuous roll of steel coil in the melt zinc plating tank,then alloying the galvanized steel.This kind of steel plate is made by hot dipped method, but after the leaving the zn tank, immediately heated to a temperature of about 500 ℃, it form a zinc and iron alloy membrane.This kind of galvanized coils has good coating of the adherence and weldability.
Galvalume products ( GL) use cold rolled steel sheets with various strengths and thicknesses as the raw materials and are coated with aluminum (Al 55%), zinc (Zn 43.5%) and silicon (Si 1.5%) alloy. It possesses excellent anti-corrosion properties. Product Features: Derived from hot-dip aluminum galvanization and hot-dip zinc galvanization technology, Galvalume products possess excellent properties of both products, i.e. the exceptional anti-corrosion and anti-oxidation properties of hot-dip aluminum galvanization, and superior electric-chemical properties of hot-dip zinc galvanization, which make Galvalume sheets less prone to rust and corrosion at the edge and on the scratched surface. The major properties of Galvalume steel sheets include the following:
(1) Smooth surface and superior anti-corrosion property. They can resist corrosion up to 2 to 6 times longer than hot-dip zinc galvanized steel sheets;
(2) Excellent heat resistance and anti-oxidation properties. They will not tarnish under 300℃ and can be used normally under 500℃ for a long time. They can resist corrosion caused by water and mud. Its ability to resist corrosion caused by water is better than that of hot dip aluminum galvanization, and its ability to resist corrosion caused by mud is better than that of hot-dip zinc galvanization. They are the ideal materials for auto mufflers, exhaust pipes, food dryers, water heaters, etc. In addition, its heat reflection ratio exceeds 75% and is twice as high as zinc galvanized steel sheets;
(3) Excellent properties for being coated and processed. They are highly adhesive to organic color coatings. Its processed and welded properties are similar to those of zinc galvanized steel sheets. They can be bent and pressed while maintaining exceptionally beautiful appearance. Since aluminum is lighter than zinc (the density of aluminum and zinc galvanization is 3.7kg/dm3 as compared with 7.1kg/dm3 for zinc galvanization), for galvanization of the same thickness, aluminum and zinc galvanization reduces the amount of metal used and hence results in cost savings.