Galvannealed AHSS automotive steels

Galvannealed coated Docol® AHSS steels are made by running the steel coil through the continuous hot-dip zinc bath and then heat treating the steel inline to diffuse iron from the substrate into the zinc layer.

The iron content of the coating provides unbeatable resistance weldability, meaning longer electrode life together with low galling in forming. Galvannealed is designated by GA in the VDA 239-100 standard, ZF (for EN 10346:2015 standard) and A (for ASTM standards) and is informally known as a zinc-iron or hot-dip galvannealed (HDGA) coating.

Formability GA-coated AHSS

Galvannealed coatings have a higher hardness than traditional zinc (GI) coatings, providing increased scratch protection during forming. GA coatings can lead to powdering, which can be minimized or eliminated by the proper forming set-up and by specifying thin Galvannealed coatings — which most automotive OEMs want anyway. GA coatings have good laser-cutting properties, which can reduce your laser cutting costs.

Weldability of GA-coated AHSS

In general, Galvannealed-coated steels are considered optimal for the resistance welding of corrosion-resistance AHSS steels. Compared to traditional zinc (GI) coatings, galvannealed coatings allow a much larger range in welding currents. With lower welding currents, GA coatings allow for longer electrode service life. With the correct welding parameters, GA welded joints are comparable to those on uncoated AHSS.

Adhesive and mechanical joining of GA-coated AHSS

Galvannealed AHSS can be joined using a variety of appropriate adhesives. As with all adhesive processes, protective oils and chemical treatments may need to be removed prior to bonding. Mechanical joining can be accomplished via bolts, rivet tabs, and non-tabs.

Galvannealed: GA/ZF/A/HDGA/zinc-iron coatings

Available on select:

  • Docol Complex Phase
  • Docol Dual Phase & Dual Phase Tubes
  • Docol HSLA & HSLA Tubes

Download the full range of Docol corrosion-resistant AHSS steels

Download the full listing of our 50+ commercially available metal-coated automotive steels, as well as the 20 coated AHSS steels we’re offering for customer trial testing.

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Docol® Product program for the automotive industry

Is galvannealed AHSS right for your automotive application?

Our corrosion resistance experts at the SSAB Knowledge Service Center are ready to help. Just contact your local Docol Representative.

Need to see SSAB’s full offering of AHSS automotive steels? Go to our steels overview page.

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