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Weldability
EN AW 7020 generally has good weldability. In particular, MIG and TIG welding are well suited, producing load-bearing welds without significant loss of mechanical properties. Apart from resistance welding, many other common methods are also applicable. This is because the absence of copper makes welding easier. Common filler materials are AlMg4,5Mn0,7, AlMg4,5MnZr or AlMg5Mn.
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Machinability
Compared with other high-strength 7000-series alloys, EN AW 7020 offers good machinability, especially in the T651 temper. However, the high strength also causes relatively high tool wear. To limit tool wear, carbide tools and reduced cutting speeds are recommended. Chips are typically short-breaking during machining.
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Forgeability
EN AW 7020 has good forgeability. Both closed-die forging and open-die forging are suitable. In the heated state this material shows very good hot formability. Post-forging heat treatments may be necessary.
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Magnetism
Aluminum is a non-magnetic element. With the magnesium addition the alloy remains non-magnetic.
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Corrosion resistance
This alloy has only moderate corrosion resistance. In industrial environments it is usually sufficient, but under high mechanical stresses there is a risk of stress-corrosion cracking. Use in marine environments is not recommended due to high salt levels that promote pitting and crevice corrosion. Therefore, EN AW 7020 often benefits from additional surface treatments, such as protective anodizing, to improve corrosion resistance.
