Numerical Simulation of Flow, Temperature and Composition Variations in a Galvanizing Bath

Abstract

-The modern hot dip galvanizing operation is a complex process subject to a number of configurational, physical, chemical and kinetic parameters. Small decreases in temperature can precipitate intermetallic dross particles, which can be entrained in the flow towards the strip leading to surface imperfections. The numerical simulations carried out in this study clearly define the spatial distribution of velocity, temperature and compositional variation in the bath. The modeling of the transient effects during ingot melting and non-melting periods have also identified the critical periods and zones within the bath where dross formation can occur within an operating cycle.Résumé -L'opération moderne de galvanisation à chaud est un procédé complexe exposé à plusieurs paramètres configurationnels, physiques, chimiques et cinétiques. De petites diminutions de température peuvent précipiter des particules intermétalliques de scories, lesquelles peuvent être entraînées dans l'écoulement vers la bande, conduisant à des imperfections de surface. Les simulations numériques effectuées dans cette étude définissent clairement la distribution spatiale de la vitesse, de température et de la variation de composition dans le bain. La modélisation des effets transitoires lors des périodes de fonte et d'absence de fonte du lingot a également identifié les périodes critiques ainsi que les zones dans le bain où la formation de scorie peut se produire à l'intérieur d'un cycle d'opération.

Review of Modeling and Simulation of Galvanizing Operations

“…Schematic of the top and side view of a galvanizing bath with ingot charging. Reproduced with permission . Copyright 2006, Association for Iron & Steel Technology (AIST).…”

“…A complete numerical analysis is described, based on transient state momentum and continuity equations taking into account the density variations of the melt due to temperature and composition variations in the range of compositions that are normally used. This approach resulted in a comprehensive analysis of the velocity vectors at any stage of the operation with periodic additions of ingots to the bath.…”

Effect of Fe 2 B orientation on erosion–corrosion behavior of Fe–3.5 wt.% B steel in flowing zinc

“…As such, many investigations on the corrosion behavior of metal in static liquid zinc have been conducted in the galvanizing industry [3][4][5]. In a continuous galvanizing line (CGL), the immersed bath equipment (e.g., sink, stabilizer rolls, and supporting bearing) is subjected to rigorous erosion-corrosion attack from the molten zinc; this attack results from the relative flow velocity of the surface of the immersed parts and molten zinc, which accelerates the deterioration of the parts [6][7][8]. Moreover, the accelerated deterioration leads to significant economic losses incurred from maintenance and replacement of the eroded parts.…”

Flow Field and Dross Behaviour in a Hot-Dip Round Coreless Galvanizing Bath

“…As evidence, Al-Zn liquid flows inside an induction channel as well as flow inside a HDG bath were illustrated by using the commercial computational fluid dynamics software using a model of mass and momentum with the k-ε turbulence model. [13][14][15][16] However, most studies focus more on channel-type HDG process in rectangle bath while less on a coreless HDG process, which differs from that of the channel-type rectangle one. The round coreless bath for hot dip aluminum zinc alloy is advantage to the coating of aluminum zinc liquid with high aluminum content compared to rectangular bath for hop dip zinc coating.…”

“…During the process, steel strip speed, width and bath configuration can influence the flow field of the Al-Zn liquid and alloy component, as well as the dross formation, distribution and coating quality of the steel strip. 3) Several previous investigations [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] have attempted to understand the flow characteristics in the process of hotdip rectangle galvanizing bath by performing numerical simulation and cold modeling experiment. Cold modeling experiment at a reduced scale is usually carried out to investigate the flow pattern of Al-Zn liquid in the HDG bath.…”