Hot-dip galvanizing is a process of coating steel with a thin zinc layer which used to halt the formation of rust. The surface treatment is done by passing the steel through molten zinc at high temperature.It provides long-term protection for steel products.
The Zinc coating has corrosion resistance and sacrificial corrosion function which delay the production of red rust. The zinc coating of the hot dip galvanized steel is higher than electro-galvanized steel sheet so has better corrosion resistance.
Surface structure | Code No. | Features | Application |
---|---|---|---|
Conventional spangle | Z | Spangles condensated on zinc coating under normal conditions after galvanizing. |
Commercial purposes |
Small spangle | X | Surface in spangles smaller than conventional ones and due to controlled condensation of zinc coating. |
Applications where conventional spangles cannot meet the surface appearance requirements. |
Skin passed spangle | G | Surface structure after special skin pass treatment. |
Applications of high surface quality requirements, such as color coating base plates. |
Skin passed small spangle | GX | - | - |
Zero spangle | N | No visible spangles on coating surface as a result of a special production process. |
- |
Zn-Fe alloy | R | No spangle, gray, normally matter | Applicable to further painting |
Item | Description |
---|---|
Chromate treatment (L) | Chromate treatment is a chemical treatment with an aim to prevent white rusts formed on product surfaces during transportation and storage. |
Oiling (Y) | Oiling is to prevent white rusts formed on product surfaces during transportation and storage. |
Chromate treatment+ Oiling (LY) | Chromate treatment+ Oiling (LY) This treatment with oiling after surface chromate treatment is to further avoid the forming of white rusts. |
Grade | Chemical Composition.% Max | |||
---|---|---|---|---|
C | Mn | P | S | |
SGHC | 0.15 | 0.8 | 0.05 | 0.05 |
SGHC400 | 0.25 | 1.7 | 0.2 | 0.05 |
SGHC440 | 0.25 | 2 | 0.2 | 0.05 |
SGHC490 | 0.3 | 2 | 0.2 | 0.05 |
SGHC540 | 0.3 | 2.5 | 0.2 | 0.05 |
SGCC | 0.15 | 0.8 | 0.05 | 0.05 |
SGCH | 0.18 | 1.2 | 0.08 | 0.05 |
SGCD1 | 0.12 | 0.6 | 0.04 | 0.04 |
SGCD2 | 0.1 | 0.45 | 0.03 | 0.03 |
SGCD3 | 0.08 | 0.45 | 0.03 | 0.03 |
SGCD4 | 0.06 | 0.45 | 0.03 | 0.03 |
SGC340 | 0.25 | 1.7 | 0.2 | 0.05 |
SGC400 | 0.25 | 1.7 | 0.2 | 0.05 |
SGC440 | 0.25 | 2 | 0.2 | 0.05 |
SGC490 | 0.3 | 2 | 0.2 | 0.05 |
SGC570 | 0.3 | 2.5 | 0.2 | 0.05 |
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