3 types of surface quality are available for hot dip galvanized steels that are suitable for cold forming.
A : The surface in the form it is coated
B: Improved surface (temper rolling applied)
C: Visible surface
Surface feature is described with a letter following quality.
DX51D+Z100 A: denotes a 100 gr/m2 coated surface while DX51D+Z denotes group A quality surface.
Surface Roughness:
This steel family is classifed according to Ra roughness values:
In the form it is coated |
: |
0,40 < Ra ≤ 1,30 μm |
Semi matt |
: |
Ra ≤ 0,90 μm |
Normal |
: |
0,60 < Ra ≤ 1,90 μm |
Rough |
: |
Ra > 1,60 μm |
Coating Amount:
Coating amounts are specified in the table.
Two Surfaces Total Coating Thickness |
Two Surfaces Min. Coating Thickness Weight (g/m2) |
(g / m2 ) |
Triple Spot Test |
Single Spot Test |
Z100 |
100 |
85 |
Z140 |
140 |
120 |
Z200 |
200 |
170 |
Z225 |
225 |
195 |
Z275 |
275 |
235 |
Surface Protection
Hot dip galvanized steels suitable for cold forming are produced by applying lubrication or passivation or both.
Lubrication reduces the risk of corrosion.
Chemical passivation protects galvanized steel surface against moisture and prevents formation of white rust.
Surface Smoothness
Surface smoothness can be given in two classes as normal and special in EN 10143 standard.
Tolerance Class |
Nominal Width |
Nominal Thickness |
<0,70 |
≥0,70<1,20 |
≥1,20 |
Normal |
≥600<1200 |
12 |
10 |
8 |
≥1200<1500 |
15 |
12 |
10 |
≥1500 |
19 |
17 |
15 |
Special |
≥600<1200 |
5 |
4 |
3 |
≥1200<1500 |
6 |
5 |
4 |
≥1500 |
8 |
7 |
6 |
All dimensional tolerances are given in mm.