Development of a Dross Build-Up Growth Process Model for Hot-Dip Galvanizing Considering Surface Reaction Kinetics

Georg Reiss, Werner Eßl, Raluca Andreea Trasca, Claudia Mugrauer, Mihaela Stefan-Kharicha, Abdellah Kharicha, Eva Gerold, Frank Goodwin

Research output: Contribution to journalArticleResearchpeer-review


The minimization of unwanted dross build-up formation on the sink rolls in continuous hot-dip
galvanizing lines is a key goal of the industry. In this study, the CFD multi-physics modeling of
the surface reaction kinetics for dross build-up growth and the coupling to the mass transfer is
the basis for the evaluation of relevant process parameters. The results of a virtual Design of
Experiments were processed by neural network approaches, as well as linear regression
modeling to build a surrogate process model. It was found that the bath Al concentration has
the highest effect (> 80 pct) on the dross build-up rate on the sink rolls. Operating the zinc bath
at higher Al concentrations decreases the dross build-up reaction rate. Furthermore, it was
found by the CFD multi-physics model that the local dross build-up rate increases toward the
edges of the roll grooves which might lead to the occurrence of strip surface defects.
Original languageEnglish
Pages (from-to)53-63
Number of pages11
JournalMetallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science
Issue numberFebruary
Early online date10 Nov 2023
Publication statusPublished - Feb 2024

Bibliographical note

Publisher Copyright: © 2023, The Minerals, Metals & Materials Society and ASM International.


  • Dross Build-Up
  • Grwoth Process Model
  • Hot-Dip Galvanizing

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