Effect of Dew Point and Alloy Composition on Reactive Wetting of Hot Dip Galvanized Medium Manganese Lightweight Steel

Abstract

For its application development, the medium manganese lightweight steel with 3 wt.% and 10 wt.% Mn contents was galvanized in continuous hot dip galvanizing (HDG) simulator and the process parameters on the production line were adopted. Combined with the experimental analysis and thermodynamic calculation, the effect of dew point and alloy composition on the reactive wetting of the steel was investigated. It was shown that MnO existed as a stable oxide for the medium Mn steel with 5 wt.% Al as long as Mn content exceeded 5.1 wt.%. The galvanizability of the steel with 10 wt.% Mn was deteriorated resulting from the formation of a thick and continuous external MnO layer, which had adverse effects on the wettability. MnO particles in the form of unstable phase can be found at the surface of 3Mn steel galvanized at dew point +10 °C. It distributed sparsely and the reactive wettability can be obtained by “bridging connection”, which mitigated the damage of external oxidation. Moreover, the lower dew point, the less tendency to form external oxide. Although the decrease of dew point to −30 °C had a certain benefit for coating quality, the galvanizing quality of 10Mn steel could not be improved due to the formation of a thick MnO layer. Therefore, the Mn content played a stronger role than dew point on the reactive wetting of hot dip galvanized medium manganese lightweight steel.

Application of X-rays Diffraction for Identifying Thin Oxide Surface Layers on Zinc Coatings

“…This work presents the results of a detailed theoretical analysis of zinc coatings based on grazing incidence X-ray diffraction technique. The samples grown using the hot-dip galvanizing process [1][2][3][4]8,13,14,16,[18][19][20], chemical vapor deposition by pack cementation [5][6][7][8]13,14,16,[21][22][23][24][25] and wire flame thermal spray [9][10][11][12][13][14]16,[26][27][28] were examined using scanning electron microscopy (SEM), Bragg-Brentano and grazing incidence XRD, with specific interest in the composition of the thin zinc oxide layer formed on the surface. The X-rays theoretical penetration depth for all three types of sample was also calculated and compared to the experimental results.…”

Computational thermodynamic study of SiC chemical vapor deposition from MTS‐H2*

“…SSUB6 and its previous version have been widely used and assessed in various material systems. [57][58][59][60][61][62][63][64] Since SSUB6 enables us to also study modified SiC deposits, that is, (Si, X, Y)C, where X and Y are additives, we adopted this new, updated database for gas species in this study and for future work.…”

Effect of Hot-Dip Galvanizing Process on Selective Oxidation and Galvanizability of Medium Manganese Steel for Automotive Application

“…Based the on previous study [14], for aluminum-containing light steel, the oxygen partial pressure is the major factor that determines the type and morphology of oxides on the surface of the steel samples. In present work, according to Formulas (1) and (2) [17], the oxygen potential corresponding to annealing process can be obtained as shown in Table 2.…”

“…Yang et al [14] combined the experimental analysis and thermodynamic calculation to analyze the effect of oxygen partial pressure on the formation of surface oxides in medium manganese lightweight steel. It seems feasible to evaluate the galvanizability of experimental steel by calculating the variation of oxide under different oxygen partial pressures.…”