As well as corrosion protection, coatings can also offer properties which improve the finished state of the steel. ArcelorMittal’s range of metallic coatings include products which are designed for specific steels or parts of the vehicle.
ArcelorMittal’s metallic coatings can be comprised of a pure metal (usually zinc) or an alloy of different elements. Most combine two or three of the following elements:
Jetgal® has been specifically developed by ArcelorMittal for cold rolled advanced high strength steel (AHSS) used in automotive applications such as Fortiform®. This pure zinc coating is applied using a hydrogen-free coating process known as Jet Vapor Deposition (JVD).
JVD applies a fine coating of zinc to a moving strip of steel in a vacuum. Developed by ArcelorMittal's Global R&D divsion and the CRM Group, the technology is significantly more environtally friendly than any other coating process. It is also future-proof to ensure it can be applied to any future AHSS steel ArcelorMittal may develop. A Jetgal® coating provides a very homogenous coating (up to 10 µm thick) and avoids AHSS becoming more brittle under the influence of hydrogen. The homogeneity of the coating improves corrosion protection significantly and provides an excellent aspect after cold stamping and painting.
For the exposed parts of vehicles, ArcelorMittal recommends Ultragal® which has been designed for premium painted finishes. Ultragal® reduces the waviness of the steel’s surface, an effect which is introduced during stamping operations.
Another pure zinc coating, Ultragal® is applied using a hot dip galvanization process. Parameters are optimized at every stage of the process to control the level of waviness after deformation. The result is a perfectly smooth surface which can be seen with the naked eye.
Zagnelis® Protect is ArcelorMittal’s leading metallic coating for the non-visible parts of vehicles. An alloy of aluminum and magnesium, Zagnelis® Protect offers increased drawability compared to pure zinc coatings.
The coating is recommended for deep drawn parts such as airbag cartridges, oil sumps, and electronic boxes. Zagnelis® Protect is also highly effective on parts which require a high level of corrosion protection such as windscreen wipers and mechanisms, filters, and window drive rails. It can be applied to both cold and hot rolled substrates.
ArcelorMittal also offers Zagnelis® Surface for parts which require a lower level of protection. Zagnelis® Surface offers improved corrosion protection and drawability compared to traditional coatings such as electroplating and galvannealing.
For parts which require a lower level of protection, ArcelorMittal offers Extragal®
Extragal® is a pure zinc coating which is available with exposed and unexposed surface qualities. Coating thickness can be up to 25 µm.
For parts which require thermal insulation, ArcelorMittal recommends Alusi. An alloy of aluminum and silicon, Alusi can be applied up to 35 µm thick. This ensures the steel can resist:
• High temperature oxidation
Alusi is ideal for applications such as heat shields, exhaust systems, and underbody parts. Alusi is also advised for hot stamped parts.
By contrast, Galfan is recommended for deep drawn parts and parts which require a high level of corrosion protection. This includes electric motor housings, filters, and electronic boxes.
Summary of ArcelorMittal's metallic coatings for automotive - click to enlarge the image
ArcelorMittal recently unveiled Jetgal®. This revolutionary new coating has been specifically developed by ArcelorMittal for cold rolled advanced high strength steel (AHSS) used in automotive applications such as Fortiform®.
This pure zinc coating is applied using a hydrogen-free coating process known as Jet Vapor Deposition (JVD). It allows vehicle makers to achieve the most uniform corrosion protection available on the market today.