The effect of selective oxidation on galvanizing and galvannealing reactions of dual-phase Steels
Journal
ECS Transactions
Journal Volume
53
Journal Issue
33
Pages
61-69
Date Issued
2013
Author(s)
Abstract
Dual Phase Steels (DP steels), which have high strength with an excellent formability, offer potential for weight savings in the automotive industry because of their high strength and excellent formability. Alloying elements, such as Mn, Mo, Si, and Cr, are commonly added in DP steels. The alloy elements not only enhance the mechanical properties of the steel substrate, but also play an important role in the following GI and GA process. In this work, two kinds of DP steels were used, labeled HDA and HDB, in which HDB had more Mn, Si, Cr than HDA. Further GA treatments resulted in more Fe-Zn IMCs for HDA than HDB samples. This retardation in the Fe-Zn alloy reaction in HDB can be attributed to the selective oxidation at the steel surface during the annealing process prior to hot dipping. Those external selective oxides were too small to be observed by the SEM, but can be confirmed by TEM observations and OCP tests. Moreover, GDOES analyses clearly revealed that those IMCs were formed by the transformation from the Fe-Al inhibition layer.
SDGs
Type
conference paper