Damage cause analysis of coating failure of pot roll for hot-dip aluminizing
It is a conceptual diagram illustrating the substrate dissolution due to penetration of molten Al through micro-channels and the creation of cracks and delamination of the layers due to external friction force, F. Microchannels of defects such as pores and inter-splat boundaries are inevitably inher...
Gespeichert in:
Veröffentlicht in: | Engineering failure analysis 2023-12, Vol.154, p.107692, Article 107692 |
---|---|
Hauptverfasser: | , , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | It is a conceptual diagram illustrating the substrate dissolution due to penetration of molten Al through micro-channels and the creation of cracks and delamination of the layers due to external friction force, F.
Microchannels of defects such as pores and inter-splat boundaries are inevitably inherent in the thermal spray process when manufacturing the coating.
The external molten Al can penetrate through the channels and dissolve the metal component of the substrate, eventually initiating substrate corrosion and forming a sizeable molten pool bottom of the coating.
The friction force on the coating over this molten pool causes cracks. The cracks propagate by repetitive force and eventually form a coarse crack by coalescence, resulting in partial or whole layer delamination of the coating.
[Display omitted]
•The causes of surface damage of stabilizer rolls used for continuous aluminum hot-dip lines were studied.•The cause of the defect was the penetration of molten Al through a three-dimensional connected micro-defect structure.•The infiltrated Al melted the metal coating and base metal, and part of the coating fell off due to the flow of this liquid.•Forming a dense coating and lengthening the molten metal's penetration path by applying a multi-layer is recommended.
Hot-dip aluminized steel is produced by immersing cold-rolled steel in a molten aluminum bath for a certain period. However, the pot rolls immersed in the aluminum bath suffer significant surface damage due to the reactions with the molten bath. This study identified the cause of surface damage of the stabilizer roll used for continuous hot-dip plating of aluminum at 660 °C. The damage was caused by molten Al infiltrating a defective structure with interconnected pores and splat boundaries. This molten Al dissolves the metal components of both the coating and substrate. As the lower part of the coating melts and liquefies, repetitive external frictional forces lead to the formation and growth of cracks in the upper coating. That eventually leads to the upper part of the coating partially or entirely detaching, resulting in surface defects in the form of pits. Possible ways to extend the lifetime of the port rolls to suppress such damage have been proposed. |
---|---|
ISSN: | 1350-6307 1873-1961 |
DOI: | 10.1016/j.engfailanal.2023.107692 |