Knowledge for Hot Dip Galvalume Steel

1、Definition of the Hot Dip Galvalume Steel Sheet Coil/Sheet

The Hot Dip Galvalume Steel Coil/Sheet is a kind of coated steel coil/sheet. With the cold rolled steel of different strength and thickness as substrate, it is produced through applying Al-Zn coat on both faces by hot dip process. In its coating, Al accounts for about 55%, Si 1.6%, while the remaining is Zn. It enjoys both the physical protective feature and durability of Al and the electrochemical protective property of Zn. And its surface has bright silver color and regular embossed-like figure, which are highly decorative.

Sectional-Structure-of-Galvalume-Steel.jpg        Construction-Applied-Galvalume-Steel.jpg

2、Characteristics of the Hot Dip Galvalume Steel Coil/Sheet

ItemGlGF(Zn-5%Al)Galvalume(55%AI-45%Zn)AI
Service Life FairFairGoodGood
Electrochemical ProtectionGoodGoodGoodN/A
Welding PerformanceGoodFairPoorPoor
Application with Wet ConcreteGoodPoorVery PoorVery Poor
Thermal ResistancePoorPoorGoodExcellent


3、The Galvalume layer has a good electrochemical protection to the Hot Dip Galvalume Steel Coil/Sheet.

Electrochemical-Protective-Principal-of-Galvalume-Steel.jpg

(1) Resistance to Corrosion

Hot-Dip Galvalume Steel Coil/Sheet has better performance in corrosion resistance than hot dip galvanized coil/sheet of the same thickness and its service life is 1-5 times longer than general hot dip galvanized coil/sheet.

(2) Salt Spray Test

Salt-Spray-Test-of-Galvalume-Steel.jpg

(3) Exposure test

Tough-Marine-Climate-Exposure-Test-of-Galvalume-Steel.jpg            Moderate-Marine-Climate-Exposure-Test-of-Galvalume-Steel.jpg

                                                   Tough marine climate                                                                                                                                  Moderate marine climate

Industrial-Climate-Exposure-Test-of-Galvalume-Steel.jpg            Countryside-Climate-Exposure-Test-of-Galvalume-Steel.jpg

                                                              Industrial climate                                                                                                                                     Countryside climate


4、Comparison by atmospheric exposure test

EnvironmentGI Average CorrosionGL Average Corrosion
g/m2/yμm/yg/m2/yμm/y
Tough Marine Climate1409.8162.2
Moderate Marine Climate181.340.54
Industrial Climate201.44.20.57
Countryside Climate40.281.30.17


Machinability-of-Galvalume-Steel.jpgIt can satisfy the processing requirements of rolling, coiling and others processes alike.

Machinability  It can satisfy the processing requirements of rolling, coiling and others processes alike.  

Thermal-Resistance-of-Galvalume-Steel.jpgCommon HDG steel plate normally works under 230℃, and has its color changed at 250℃, however, Galvalume steel plate can sustain the environment at 315℃ for long time.

Thermal Resistance  Common hot dip galvanized coil/sheet normally works under 230℃, and has its color changed at 250℃, however, Hot Dip Galvalume Steel Coil/Sheet can sustain the environment at 315℃ for long time.

High-Reflectivity-of-Galvalume-Steel.jpgReflection ability of heat and light is twice as much as those of hot-dip zinc steel sheet, and its reflectivity is more than 0.75, exceeding 0.65 (required by the EPA Energy Star Standard), which is an ideal construction materials of saving energy.

Hot Dip Galvalume Steel Coil/Sheet reflection ability of heat and light is twice as much as those of hot dip galvanized steel coil/sheet, and its reflectivity is more than 0.75, exceeding 0.65 (required by the EPA Energy Star Standard), which is an ideal construction material of saving energy.

4、Precautions while using Hot Dip Galvalume Steel Coil/Sheet

(1)The Hot Dip Galvalume Steel Coil/Sheet should be kept away from the alkaline medium.

(2)The roof made out of the Hot Dip Galvalume Steel Coil/Sheet requires a slope to help drainage and to alleviate corrosion.

(3)The Hot-Dip Galvalume Steel Coil/Sheet should have no direct contact with foundation concrete, wet wood, steel, lead and graphite.

(4)Use trimmed plate rather than the plate to be cut plate at jobsite.

(5)While the Hot Dip Galvalume Steel Coil/Sheet is piled and processed, its finger-print proof film should be protected from getting black due to dampness and high temperature.

(6)If the Hot Dip Galvalume Coil/Steel is used for foaming and bonding application, then, small-lot test is needed for the initial use, in order to prevent the poor bonding.


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