Effect of Annealing Temperature on the Selective Oxidation and Reactive Wetting of a 0.1C-6Mn-2Si Advanced High Strength Steel During Continuous Galvanizing Heat Treatments

Medium-Mn advanced high strength steels are amongst the most promising candidates being investigated for future vehicle Body In White (BIW) applications in the automotive industry due to their superior combination of high specific strength and ductility versus the first generation advanced high strength steels (AHSS).1–4) Adoption of these materials has the potential to allow manufacturers to move towards safe, lighter vehicle designs in line with legislated fuel efficiency guidelines.1,5) The corrosion protection of these steels is essential for ensuring the long-term structural integrity of the vehicle and to meet consumer durability expectations, for which the preferred production route is the continuous hot-dip galvanizing process. However, selective oxidation of the main alloying elements envisaged for use in these steels, namely Mn and Si, can cause problems with reactive wetting by the continuous galvanizing zinc alloy bath.6–9) The presence of these thermodynamically stable oxides can prevent the substrate from being reactively wetted by the molten zinc alloy, thus preventing the formation of the desired Fe2Al5ZnX interfacial Effect of Annealing Temperature on the Selective Oxidation and Reactive Wetting of a 0.1C-6Mn-2Si Advanced High Strength Steel During Continuous Galvanizing Heat Treatments