Specification and Properties
Product Characteristic
| Product | Coating Layer Structure | Characteristics |
|---|---|---|
| GA (Galvannealed Steel) |
 |
By a thermal diffusion process, steel sheet and zinc react to produce an alloy. The weld ability and the paint ability are superior to galvanized steel sheet. |
| GI (Galvanized Steel) |
 |
While molten zinc solidifies on the strip suface, normal zinc crystallization suppessed creating fine crystals. The surface will be flatted and has a fined appearance after painting. Paint ability and corrosion resistance is superior to regular products. |
Coating weight
Coating weight minimum (Both –sided coating)
| Coating weight code | Average value of Double-sided, Triple Spots Method | Average value of Double-sided, Single Spots Method | JS G 3302 | POSCO |
|---|---|---|---|---|
| 60 | 60 | 51 | (Z06), F06 | K060, S060 |
| 80 | 80 | 68 | Z10, F10 | K080, S080 |
| 100 | 100 | 85 | Z12, F12 | K100, S100 |
| 120 | 120 | 102 | Z12, F12 | K120, S120 |
| 180 | 180 | 153 | Z18 | K180 |
| 220 | 220 | 187 | Z22 | K220 |
| 275 | 275 | 234 | Z27 | K275 |
Remark
1. For non-alloy products, “Z” is added in front of JS, “K” in front of POSCO products. For alloy products, “F” is added in front of JS, and “S” in front of POSCO products.
2. For both-side, triple spots coating weight, the average value of the measurement of 3 test pieces is applied.
3. For one-side, single spot coating weight, the minimum value of the measurement of 3 pieces is applied.
Chemical Treatment
| NC | Cr-free |
|---|---|
| SP | Slidable Pre-phosphate |
| XX | Non post treatment |
Chromate free (NC) performance
Cr-free treatment for a post-treatment is effective in preventing any white rust from surface of galvanized and galvannealed steel. POSCO-TCS Cr-Free steel sheet is POSCO’s environment friendly that does not include chromium 6+ or any other compound of chromium, known as a harmful element to the human body.
Compared property between the Cr-free treated and Cr treated product, POSCO products are treated by Cr-free. These property show that Cr-free treated product has the lubrication property better than the Cr treated product. Other properties have a nearly result.
Chromate Treatment
Chromate free treatment
Slidable phosphate (SP) performance
POSCO provides Galvannealed steel with inorganic lubricant coating to improve press formability for automotive parts. The lubricant effect is obtained by and the other properties (weldability, corrosion resistance and paintability) are also improved by lubricant coating on Galvannealed steel.
Side outer panel with high formability