Optimization of Galvannealing Parameters through Numerical Modeling of Galvannealing Process

Abstract

In the galvannealing process, a galvanized sheet is subjected to an annealing treatment to transform the zinc-coated steel sheet to iron-zinc alloy-coated steel. In the present work, the galvannealing process has been treated as a binary multiphase diffusional phase transformation reaction, and a rigorous mathematical model has been developed to simulate the galvannealing process. The results obtained by the model have been compared with experimental as well as plant data, and the results have been found to be in good agreement. The model prediction shows that the excessive growth of undesirable C and C 1 phases takes place when the iron content in the coating exceeds around 11 pct during galvannealing. It has also been observed that decreasing the line speed to obtain the desired iron content in the coating leads to excessive growth of the undesirable C and C 1 phases. It has been concluded that the developed mathematical model can be used to optimize the galvannealing parameters.

Phase Composition of Electrodeposited Fe—Zn Alloys

“…Nevertheless, it should be noted that phase composition of alloys of Fe-Zn system, both electrodeposited [11][12][13] and obtained by annealing of hot-dip zinc coating on steel substrates [14][15][16], is quite thoroughly investigated in the range of high zinc concentrations as these alloys are employed as corrosion-resistant coatings. However, the other possible areas of application of electrodeposited Fe-Zn alloys mentioned above also require more thorough investigations of this system in the range of high iron concentrations.…”

Surface Oxidation of the High-Strength Steels Electrodeposited with Cu or Fe and the Resultant Defect Formation in Their Coating during the Following Galvanizing and Galvannealing Processes

“…In addition, effects of microstructure, texture, intermetallic phases, coating composition, and post-treatments on the mechanical and corrosion properties of the galvannealed automotive steels have been widely investigated. [1][2][3][4][5][6][7][8][9][10][11][12] However, undesirable Mn and Si oxides may be formed on the surface of DP and TRIP steels during the annealing process in a reducing atmosphere, due to their high contents of Mn and Si. [13][14][15][16] The Mn and Si oxides have low wettability with the zinc coating and induce the formation of surface defects, such as craters, on the final galvannealed steel product.…”