Title: Parametric study of surface melting in zinc-aluminium coated steels

Authors: Remya Mathew; Paul R. Stoddart; David Nolan; Yvonne Durandet

Addresses: Swinburne University of Technology, Hawthorn, VIC, 3122, Australia ' Swinburne University of Technology, Hawthorn, VIC, 3122, Australia ' BlueScope Steel Limited, Port Kembla, NSW, 2505, Australia ' Swinburne University of Technology, Hawthorn, VIC, 3122, Australia

Abstract: The corrosion resistance of Al-Zn-Si coated steel sheets is superior to traditional galvanised products because they combine the barrier protection of aluminium with the sacrificial protection of zinc. The corrosion resistance can be further improved by using laser surface re-melting and rapid solidification to refine the coating microstructure. To achieve the desired microstructural changes by surface melting, the surface temperature and treated-depth of the components must be precisely controlled and this depends on the laser parameters such as power, spot size and processing speed. This paper presents the results of a parametric study of laser surface melting of zinc-aluminium coatings. A model was used to determine the processing conditions required to achieve an optimal surface microstructure. The model results were consistent with the observed microstructure of both the coating and the steel substrate. This analysis provides a better understanding of the effect of the processing parameters on the coating microstructures.

Keywords: parametric study; zinc-aluminium coatings; laser surface melting; LSM; steel coating; zinc; aluminium; corrosion resistance; rapid solidification; coating microstructure; laser parameters; laser power; spot size; laser processing speed; modelling.

DOI: 10.1504/IJSURFSE.2014.060481

International Journal of Surface Science and Engineering, 2014 Vol.8 No.2/3, pp.124 - 137

Received: 01 Feb 2013
Accepted: 20 Jun 2013
Published online: 17 May 2014 *

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