HOT-DIP GALVANISED SHEET
MANUFACTURING PROCESS
The raw material we use is cold-rolled unannealed sheet, but we can also use pickled sheet (for rougher thicknesses). The sheet is coated with a thin layer of zinc, where the material is first heated (annealed gas) and then passes through a pot filled with liquid zinc. Hot-dip galvanised sheet is produced in thicknesses of approx. 0.35 to 4.0 mm.
STEEL GRADES
Mild steel:
Used when forming and drawing properties are more important than
tensile ones. Available in grades ranging from DX51D to DX56D.
Structural steel:
Used in the construction industry. Suitable for roll forming as well as simpler
bending. Guaranteed minimum yield and tensile strength values.
High-strength steel:
Offers great opportunities for weight savings.
Micro-alloyed:
Combines high strength and good plasticity. It has uniform tensile
properties and is intended for simpler forms of drawing and forming.
Dual phase steel:
Designated as DP (Dual Phase) and characterised by very good
plasticity in combination with high strength. The material has good work and bake
hardenability, which means that its yield strength is given a major boost
in connection with drawing as well as varnishing, where the varnish burns.
Rephos steel:
This is a phosphorus alloy (P) high-strength steel grade with very good
deep drawing properties. The ultimate strength of the finished detail
is obtained by means of work hardening during drawing.
| MECHANICAL PROPERTIES — SOFT STEELS | |||||
| EN 10 346 | Yield strength Re (N/mm2) |
Tensile strength Rm (N/mm2) |
Elongation A80 min. (%)* |
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| DX 51 D | Min. 140 | 270-500 | 22 | ||
| DX 52 D | 140-300 | 270-420 | 26 | ||
| DX 53 D | 140-260 | 270-380 | 30 | ||
| DX 54 D | 120-220 | 260-350 | 36 | ||
| DX 56 D | 120-220 | 260-350 | 39 | ||
| Values are based on samples taken transversely to the direction of rolling. *) For t ≤ 0.70 mm, two units of a lower value apply. |
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| MECHANICAL PROPERTIES — STRUCTURAL STEELS | |||||
| EN 10 346 | Yield strength Re min.(N/mm2) |
Tensile strength Rm min.(N/mm2) |
Elongation A80 min. (%)* |
||
| S 220 GD | 220 | 300 | 20 | ||
| S 250 GD | 250 | 330 | 19 | ||
| S 280 GD | 280 | 360 | 18 | ||
| S 320 GD | 320 | 390 | 17 | ||
| S 350 GD | 350 | 420 | 16 | ||
| S 550 GD | 550 | 560 | – | ||
| Values are based on samples taken along the direction of rolling. *) For t ≤ 0.70 mm, two units of a lower value apply. |
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| MECHANICAL PROPERTIES — HIGH-STRENGTH MICRO-ALLOYED STEELS | |||||
| EN 10 346 | Yield strength Re min.(N/mm2) |
Tensile strength Rm min.(N/mm2) |
Elongation A80 min. (%)* |
||
| HX 260 LAD | 260-330 | 350-430 | 26 | ||
| HX 300 LAD | 300-380 | 380-480 | 23 | ||
| HX 340 LAD | 340-420 | 410-510 | 21 | ||
| HX 380 LAD | 380-480 | 440-560 | 19 | ||
| HX 430 LAD | 420-520 | 470-590 | 17 | ||
| Values are based on samples taken transversely to the direction of rolling. | |||||
ZINC COATING
The amount of zinc on the sheet is stated in weight grades, the most common one being Z 275. The figure of 275 refers to the total weight of the coating in g/m2 on both sides of the sheet, e.g., in connection with a so-called triple test. (A somewhat lower weight is permissible in connection with a so-called single test.)
| Weight class | Zinc layer, incl. both sides (g/m2) | Zinc layer thickness per side* (μm) |
|
| Triple spot test, min. | Single Spot Test min | ||
| Z 100 | 100 | 85 | 7 |
| Z 140 | 140 | 120 | 10 |
| Z 200 | 200 | 170 | 14 |
| Z 275 | 275 | 235 | 20 |
| Z 350 | 350 | 300 | 25 |
| *) Layer thickness is calculated based on min. triple spot test values (1 μm = 7.14 g/m2) | |||
SURFACE
Surface appearance: |
|
| N | Normal rose pattern (found rarely in recent times) |
| M | Reduced rose pattern (has become standard) |
Surface quality: |
|
| A (Normal surface) | Small pores, rose pattern variations, dark spots, stripe marks and light passivation stains are permissible. Stretch levelling breaks and zinc run-off marks may appear. |
| B (Improved surface) | Skin-passed material. Small defects such as stretch levelling breaks, skin passing marks, scratches, indentations, rose patterns, zinc run-off marks as well as light passivation marks may appear. The surface exhibits no pores. |
| C (Superior surface) | Skin-passed material. One of the sides must be free from defects that can affect the appearance of a first-class varnished surface. The other side must fulfil, as a minimum, the requirements for surface quality B. |
Surface treatment: |
|
| C | Chemical passivation |
| 0 | Oiling |
| C0 | Chemical passivation + oiling |
We offer by default surface M A C and fulfil the requirements in accordance with the RoHS Directive.
THICKNESS TOLERANCES, ACCORDING TO EN 10 143
For steel grades with a specified min. yield strength <260.
| THICKNESS TOLERANCES, ACCORDING TO 10 143 (for steel with a specified min. yield strength <260) | |||
| Nominal thickness (mm) | Thickness tolerances for nominal width (mm) | ||
| ≤ 1200 | > 1200 ≤ 1500 | > 1500 | |
| ≥ 0,35 ≤ 0,40 | ± 0,04 | ± 0,05 | – |
| > 0,40 ≤ 0,60 | ± 0,04 | ± 0,05 | ± 0,06 |
| > 0,60 ≤ 0,80 | ± 0,05 | ± 0,06 | ± 0,07 |
| > 0,80 ≤ 1,00 | ± 0,06 | ± 0,07 | ± 0,08 |
| > 1,00 ≤ 1,20 | ± 0,07 | ± 0,08 | ± 0,09 |
| > 1,20 ≤ 1,60 | ± 0,10 | ± 0,11 | ± 0,12 |
| > 1,60 ≤ 2,00 | ± 0,12 | ± 0,13 | ± 0,14 |
| > 2,00 ≤ 2,50 | ± 0,14 | ± 0,15 | ± 0,16 |
| > 2,50 ≤ 3,00 | ± 0,17 | ± 0,17 | ± 0,18 |
| For min. yield strength ≥ 260 < 360 N/mm², tolerances are raised by 15-20 %. For min. yield strength ≥ 360 ≤ 420 N/mm², tolerances are raised by 30-40 %. Narrower tolerances are available at extra charge. |
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