Automotive Worldwide
Steels coated with galfan zinc-aluminium alloy
Extract from the product catalogue -European edition
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Steels coated with galfan zinc-aluminium alloy Zinc coatings and thin organic coatings
Applications The ductility and strong anti-corrosion properties of galfan make it a coating highly suited for deep-drawn parts and parts requiring a high level of corrosion protection. In certain applications, a 10 micron galfan coating can replace a 20 micron galvanized coating, providing better weldability, drawability, and corrosion resistance. Galfan can thus reduce costs, symplifying secondary processes and eliminating the need for post-treatment.. It can be used to replace thick galvanized coating and post-galvanizing treatments. Parts: Electric motor housings Filter, airbag cartridges Windscreen wipers and mechanism Door plates Window drive rails Oil sumps Electronics boxes
Technical characteristics Surface appearance Galfan has a cellular surface which appears mottled. Unpainted galfan acquires a patina over time, its initial metallic appearance dulls to a matte gray.
Cellular surface appearance -galfan
Hardness The coating, composed of 95% zinc and 5% aluminum, has a eutectic structure lending it excellent ductility and the thin intermetallic layer at the steel/coating interface guarantees excellent coating adhesion. These two properties enable galfan to be used for making components that are particularly difficult to form.
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These two properties enable galfan to be used for making components that are particularly difficult to form.
Micrographic cross-section and structure
Surface finish The three surface finishes defined in the EN 10327 standard are available to suit customer requirements. Coating thickness The standard galfan coating values and corresponding thicknesses are as follows:
EN 10327 standard ZA095 ZA130 ZA200 ZA255 ZA300
Minimum nominal g/m² double side (3 pts) 95 130 200 255 300
µm per side 7 10 15 20 23
Coating process Galfan is obtained by continuous hot dip coating in a bath of molten metal made up of approximately 95% zinc and 5% aluminium.
Recommendations for use and secondary processing Corrosion In general, galfan has a higher corrosion resistance compared to a standard galvanized product. Sacrificial protection provides effective corrosion resistance at the sites of mechanical damage (impact, scratches, gravel impingement) and also prevents corrosion of cut edges.
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Sacrificial protection provides effective corrosion resistance at the sites of mechanical damage (impact, scratches, gravel impingement) and also prevents corrosion of cut edges. Its superior corrosion resistance allows galfan to be an alternative to thicker galvanised coatings and post-galvanization treatments.
Full-side corrosion resistance during an automotive cyclical corrosion test
Example of resistance to salt spray: 5% NaCl
Drawing Due to its eutectic structure and the thin intermetallic layer, galfan is a ductile coating suitable for deep-drawing operations, without risk of cracking, delamination or contamination of the equipment by powdering. TM The use of pre-lubricating oils and of thin organic films (Extrafilm ) can further improve drawing properties.
Welding Galfan performs well in spot welding with: a welding range well suited to industrial requirements, longer electrode life compared to galvanised steel with the same corrosion resistance (coating twice as thin). This advantage arises mainly in the case of applications where the corrosion resistance specified would require very high zinc values when using hot-dipped galvanized.
Comparison of electrode life
© ArcelorMittal | Last update: 21-09-2015 4
