Characterization of Galvannealed HSLA Steels

Abstract

Galvannealed coatings are obtained by heat treating galvanized steel strips and are widely used in the automotive industry due to their improved properties. The variables influencing coating formation on high strength low alloy steel (HSLA) were analyzed. The study was carried out on samples obtained from an industrial plant and on samples coated in a hot dip process simulator. The mechanical properties of the steel substrate were evaluated, and the morphology and Fe content in the various phases of the coating and its characteristics were analyzed and compared. It was found that the Fe-Zn phases can be controlled and performed varying the temperature and holding time during the annealing cycles, avoiding the formation of undesirable phases.

Dissimilar fiber laser welding between dual phase and high strength low alloy steels

“…The next stage is an annealing treatment at around 500°C to 570°C where diffusion of iron into the zinc occurs [35]. This creates different layers of intermetallics as the iron moves through the thickness of the zinc coating [36,37].…”

“…The annealing process for GA coated samples occurs between 500°C to 570°C, which leads to the reason for the difference in thickness between the GI and GA samples which is that if the GA coating was thicker, a longer annealing process would be needed in order to allow for adequate diffusion of iron into the zinc coating. Therefore, the coating thickness is kept to a minimum in the GA process to allow for the different Zn-Fe phases to form throughout the coating [36]. In the GA coating, cracks can be seen, whereas in the GI coating, there are none.…”