Properties
Aluminium-coated steels for enamelling are coated with an alloy of 90% aluminium and 10% silicon. A special enamel suitable for this type of coating must be used.
After forming, these products can be enamelled using a simpler, more economical and more environmentally friendly process than the conventional method.
There are two grades: Alusi® BEC and Alusi® BEA.
Advantages
Surface preparation of these grades before enamelling consists of no more than very meticulous degreasing (no pickling). Only one coat of enamel, with a thickness ranging between 80 and 100 µm, is required on one side only, the other side being protected naturally by the aluminium coating (formation of an aluminium oxide layer during firing). It is fired at 560°C, preferably in a convection oven.
A wet or dry enamelling process may be used.
The corrosion resistance of the non-enamelled side of the enamelled part is excellent: it can withstand the salt spray test for over 600 hours, in accordance with ISO 7253.
Applications
Alusi® BEC grade is especially suitable for enamelled self-cleaning catalytic ovens. Use of this grade rather than conventional enamelled material has the advantage that it is not necessary to apply a ground-coat layer of enamel. There is direct adhesion between the catalytic self-cleaning enamel and the aluminium-coated substrate. Its performance during catalytic cleaning cycles is in compliance with ISO 8291.
Alusi® BEA grade is designed for the enamelling of visible parts and can be used in the following fields of application:
- Enamelled casing parts for domestic appliances (hobs, control panels, cavity walls etc)
- Indoor architectural applications
Recommendations for use
Forming
Alusi® BEC and Alusi® BEA grades can be easily formed by bending, profiling or deep drawing. The aluminium coating has the advantage of increasing the friction coefficient. However, great care should be taken to avoid scratching or damaging the surface of the part, since this would produce surface blemishes after enamelling. The use of hard, polished chromium-plated tools is recommended.
Joining
After suitable adaptation of the welding parameters for cold rolled steel, Alusi® BEC and Alusi® BEA grades can be welded without any difficulty, whatever the welding process may be (spot welding, TIG/MIG/MAG etc). Other joining processes (clinching, crimping) may also be used.
Enamelling
Surface preparation:
Surface preparation before enamelling is very important. It is crucial, especially with Alusi® BEA grade, to perform meticulous alkaline degreasing followed by hot and cold rinsing, using demineralised water for the final rinse, in order to obtain a good surface appearance after enamelling.
Application of the enamel and firing:
- With Alusi® BEC grade, the catalytic enamel coating can be applied by a wet or dry process. Firing is performed at a temperature of about 560°C
- Alusi® BEA grade can be enamelled with a mat or glossy enamel suitable for firing at a low temperature, applied by a wet or dry process. It is fired at 560°C. The use of a convection oven is recommended in order to guarantee a homogeneous colour after enamelling
Spot welding of Alusi® BEC and Alusi® BEA grades
| Thickness (mm) | 0.6 | 1.2 | 2.0 |
| Welding current (kA) | 9.9 to 12.7 | 10.6 to 12.1 | 10.9 to 12.4 |
| Welding latitude (kA) | 2.8 | 1.5 | |
| Positioning time (periods) | 10 | 12 | 24 |
| Welding time (periods) | |||
| Holding time (periods) | |||
| Electrode pressure (daN) | 330 | 550 | |
| Type of electrode | Flat - 6 mm | ||
Dimensions
| Thickness (mm) | Min width | Alusi® BEC, Alusi® BEA |
| Max width | ||
| 0.50 ≤ th < 0.60 | 750 | 1250 |
| 0.60 ≤ th < 2.00 | 1525 |
Mechanical properties
| Alusi® BEC | T | 0.5 - 0.7 | < 260 | < 380 | ≥ 28 | ≥ 1.3 | ≥ 0.180 |
| 0.7 - 3 | ≥ 30 | ||||||
| Alusi® BEA | T | 0.5 - 0.7 | < 240 | < 370 | ≥ 30 | ≥ 1.3 | ≥ 0.180 |
| 0.7 - 1 | < 230 | ≥ 31 | |||||
| 1 - 3 | < 365 | ≥ 32 | |||||
| Grades in italics: not included in the standard | |||||||
Chemical composition
| Alusi® BEC | ≤ 0.060 | ≤ 0.40 | ≤ 0.025 | ≤ 0.025 | ≤ 0.05 | - |
| Alusi® BEA | ≤ 0.020 | ≤ 0.40 | ≤ 0.020 | ≤ 0.020 | ≤ 0.03 | ≥ 0.050 |
| Grades in italics: not included in the standard | ||||||
For commercial information (quotations, deliveries, product availability):
- Europe: http://www.arcelormittal.com/industry/agencies
- Other countries: contact@arcelormittal.com
For technical questions about these products: fce.technical.assistance@arcelormittal.com
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All details provided in the ArcelorMittal Flat Carbon Europe S.A. catalogue are for information purposes only. ArcelorMittal Flat Carbon Europe S.A. reserves the right to change its product range at any time without prior notice.