Characterizing Reactive Wetting Kinetics of High-Mn Dual-Phase Steels in Hot-Dip Galvanizing Baths

摘要

High-Mn (> 2.5 wt percent) steels have seen limited use in automotive applications due to the limitations imposed by continuous hot-dip galvanizing. Tenacious oxides which form during annealing have been seen as hindering the reactive wetting process, resulting in low quality coatings. Characterization of the reactive wetting process has usually been limited to qualitative observations of the coating after processing and is quite subjective. A method of determining the reactive wetting kinetics, and subsequently the wettability of the substrate, by directly measuring the wetting force as a function of time is introduced. Following the aforementioned methodology, this contribution aims to investigate the effect of annealing parameters and bath composition on the reactive wetting of two commercial steels (IF and 1.4Mn) along with three experimental high-Mn dual-phase steels in an effort to determine the dynamic wetting characteristics of these alloys. The results can be useful in alloy design to determine the levels of Mn which can be tolerated such that improvements in hardenability can be balanced with galvanizability.