Knowledge for Hot Dip Galvanized Steel

1、Brief Introduction for Hot Dip Galvanized Steel Coil/Sheet

(1) Hot Dip Galvanized Steel Coil/Sheet has gone through a chemical process to keep it from corroding. The steel gets coated in layers of zinc because rust won't attack this protective metal. For countless outdoor, marine, or industrial applications, Hot Dip Galvanized Steel Coil/Sheet is an essential fabrication component.

Application-of-Galvanized-Steel.jpg

(2) The principal method of making steel resist corrosion is by alloying it with another metal, zinc.  Therefore, the zinc isn't exactly a sealer, like paint, because it doesn't just coat the steel; it actually permanently becomes a part of it. The zinc goes through a reaction with the iron molecules within the steel to form Hot Dip Galvanized Steel Coil/Sheet. The most external layer is all zinc, but successive layers are a mixture of zinc and iron, with an interior of pure steel. These multiple layers are responsible for the amazing property of the metal to withstand corrosion-inducing circumstances, such as saltwater or moisture. Zinc also protects the steel by acting as a "sacrificial layer." If, for some reason, rust does take hold on the surface of Hot Dip Galvanized Steel Coil/Sheet, the zinc will get corroded first. This allows the zinc that is spread over the breach or scratch to prevent rust from reaching the steel. 

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

A reaction of electrochemical protection occurs at such where base metal is exposed:

·Anodic reaction: Zn-2e=Zn2+   (The alloy coating loses electron, sacrificing itself in dissolution.)
·Cathodic reaction: Fe2++2e=Fe   (Fe gains electron reaction, being protected)

(3) The degree of hot dip galvanizing is usually represented as the zinc's weight per surface area rather than the thickness of the zinc, because this gives a better representation of how much metal has been applied. Steel often gets hot dip galvanized after individual parts have been formed, such as braces, nails, screws, beams, or studs. However, raw Hot Dip Galvanized Steel Coil/Sheet will withstand some bending and forming without flaking. Hot Dip Galvanized Steel Coil/Sheet can be found almost everywhere. You might be living in a steel frame house. You are no doubt surrounded by steel parts in your car that allow it to emerge from rainstorms unscathed. Many people work in an office with metal roofing made of Hot Dip Galvanized Steel Coil/Sheet. Besides being inexpensive and effective, this metal is popular because it can be recycled and reused multiple times.

2、Hot Dip Galvanized Steel Coil/Sheet Production Process

Galvanized-Steel-Production-Process.jpg

3、Characteristics of Hot Dip Galvanized Steel Coil/Sheet

   Features of Hot Dip Galvanized Steel Coil/Sheet
ItemProperty
Type of CoatingZinc
Zn-Fe Alloy
Surface StructureRegular Spangle
Zero Spangle(lead-free coating)
Finishing Spangle
Small Sapngle
Finishing Small Spangle
Coating FormEqual Thickness Zinc    Coating 40/40~225/225g/m²
Unequal Thickness Zinc Coating 30~150(each side)g/m²
Equal Thickness Zn-Fe Alloy Coating 30/30~90/90g/m²
Size RangeCold Rolled    Substrate:Thickness=0.3-0.8mm Width=800-1830
Hot Rolled Substrate:Thickness=1.8-2.8mm Width=900-1500
Steel GradesFor Drawing:Common    Use, Drawing Use,Elongation, Super Elongation,Ultra Super Elongation
For Structure:220-550Mpa(Yield Strength)
High Strength Steel for Cold Forming Use:180-420Mpa(Yield Strength)


4、Fixed Value for Chemical Composition of Hot Dip Galvanized Steel Coil/Sheet

   Low Carbon Steel
SubstrateGradesChemical    Composition(Melting Analysis)%
C
Si
Mn
P
S
Alt
Ti
Nb
Cold Rolled
Substrate
DC51D+Z,DC51D+ZF,
(St01Z,St02Z,St03Z)
0.100.500.0350.035
DC52D+Z(St04Z)
DC52D+ZF
0.080.450.0300.030
DC53D+Z(St05Z)
DC53D+ZF
0.080.400.0300.030
DC54D+Z(St06Z)
DC54D+ZF
0.010.100.300.0250.0200.0150.100
DC56D+Z(St07Z)
DC56D+ZF
0.010.100.300.0250.0200.0150.1000.100
Hot Rolled
Substrate
DD51D+Z
(St01ZR,St02ZR)
0.100.500.0350.035
DD54D+Z(St06ZR)0.010.100.300.0250.0200.0150.100


   Structural Steel
GradesChemical Composition(Melting Analysis)%

Si
Mn
P
S
Alt
S220GD+Z,S220GD+ZF0.130.500.0350.0350.015
S250GD+Z,S250GD+ZF0.160.600.0350.0350.015
S280GD+Z(StE280-2Z),S280GD+ZF0.200.800.0350.0350.015
S320GD+Z,S320GD+ZF0.231.000.0350.0350.015
S350GD+Z(StE345-2Z),S350GD+ZF0.251.500.0350.0350.015
S550GD+Z,S550GD+ZF0.251.500.0350.035


   High Strength Cold Forming Steel
SubstrateGradesChemical    Composition(Melting Analysis)%
C
Si
Mn
P
S
Alt
Ti
Nb
Cold Rolled SubstrateH220PD+Z,H220PD+ZF0.080.050.700.0800.0250.015
H260PD+Z,H260PD+ZF0.150.050.700.1000.0250.010
H300LAD+Z,H300LAD+ZF0.100.051.000.0300.0250.0150.0150.090
H340LAD+Z(HSA340Z),H340LAD+ZF0.100.051.000.0300.0250.0150.0150.090
H380LAD+Z0.160.051.500.0300.0250.0150.0150.090
H420LAD+Z(HSA410Z)0.160.051.500.0300.0250.0150.0150.090
H180BD+Z,H180BD+ZF0.040.050.700.6000.0250.020
H220BD+Z,H220BD+ZF0.060.050.700.8000.0250.020
H260BD+Z,H260BD+ZF0.080.050.700.1000.0250.020
H180YD+Z,H180YD+ZF0.010.100.700.0600.0250.0200.12
H220YD+Z,H220YD+ZF0.010.100.900.0800.0250.0200.12
H260YD+Z,H260YD+ZF0.010.101.600.1000.0250.0200.12

Hot Rolled
Substrate

DD51D+Z(St01ZR,St02ZR)0.100.500.0350.035
DD54D+Z(St06ZR)0.010.100.300.0250.0200.0150.01
HR340LAD+Z(HSA340+ZR)0.100.201.000.0300.0250.09
HR420LAD+Z(HSA410+ZR)0.120.201.000.0300.0250.09
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