Electrical galvanized steel is made by plating steel with zinc in an electrochemical manner. Plating uses pure zinc or zinc and nickel.
Since electrical galvanized steel has a lower coating weight and has no heat-affected zones during the manufacturing process compared to GI and GA, it has the material characteristics and workability comparable to those of the base metals, that is, cold rolled (CR) or hot rolled (HR) sheets.
Substrate steel can be protected by the sacrificial anode reactions caused by the galvanic actions of Zinc and, even if it is exposed to air, can still be protected from corrosion by a thin film formed on the surface. (Some post-coated steel sheets are used for automobiles for better anti-corrosion property.)
The steel’s flat and even surface provide good conditions for painting. Phosphate treatment improves its paint adhesion and anti-corrosion properties after painting.
Pure Zn galvanized steel has lower weldability than cold rolled steel due to a wide area of contact under pressure and inferior electrical conductivity. However, it allows for spot or seam welding if its surface condition permits and post-treatment is applied.
Properties During Repeated Welding
White Rust Testing
Red Rust Testing
This product has been developed in order to improve the anti-corrosion durability (and prevent the through-hole corrosion) against deicers (e.g., NaCl, CaCl2) for melting ice from the roads in winter. In addition, since the coated layer of the product is solid and has a higher melting point than those of other plated layers by adding some Ni, the layer does not easily soften or melt as a Pure Zn coated layer does. The steel also allows for welding at a lower current than pure Zn galvanized steel and has a superior corrosion resistance over a long period of time.
Comparison of Corrosion Resistance Between Pure Zn and Zn-Ni
Comparison of Weldability Between Pure Zn and Zn-Ni
Structure of Coated Film
Cr6+, Cr3+/CrO3, resins and others were coated in order to improve the anti-corrosion and paint adhesion properties after Zn & alloy plating.
Some other chemicals having properties similar to chrome are applied.An example can be an organic-inorganic polymeric composite (containing some additives).
|Category||Post-Treatment Code||Full Name||Quality Features|
|PM||Phosphate Metallic||Printability, corrosion resistance, workability|
|Anti-fingerprinting||AG||Antifinger General||Anti-fingerprinting, corrosion resistance, conductivity|
|AL||Antifinger Lubricant||Anti-fingerprinting, corrosion resistance, resistance to blackening-after-processing|
|AC||Antifinger Conductivity||Anti-fingerprinting, corrosion resistance, conductivity|
|AF||Antifinger Formability||Anti-fingerprinting, corrosion resistance, workability|
|Black resin||BT, BL||-||-|
|Fuel tanks||GX||-||Solvent resistance, weldability, paintability|
Quality Features by Product
|Category||Post-Treatment Code||Coating Layer Structure||Characteristics||Common Uses||Site of Manufacturing|
|Pure-Zn||EG non-treated steel||XX||
|Color steel sheets, home appliances/ furniture||Yangso|
|Phosphate treated steel||PL(PP)
||Coating adhesion||For the painting of separate parts,
|Fingerprint-resistant steel sheets||AG/AL
(for deep drawing
|Black resin steel sheet||BT
|Outer panels of video appliances||Pohang|
||Raw corrosion resistance,
|Home appliances and automobiles,
|Auto fuel tank,