Product & Services

Specification and Properties

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.
GL
(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

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Products & Services
Specification and Properties