Product Code: ICA11_904

Thermal Modification of Zinc-Aluminum Coated Steel Using Lasers
Authors:
Remya Mathew, CAST CRC, Swinburne University of Technology; Hawthorn,Victoria Australia
Paul Stoddart, Industrial Research Institute Swinburne, Swinburne University of Technology; Melbourne Australia
David Nolan, Bluescope Steel Limited; New South Wales Australia
Yvonne Durandet, CAST CRC, Swinburne University of Technology; Melbourne Australia
Presented at ICALEO 2011

In many markets, Zn-55%Al-1.6%Si coated steel products are an important alternative to traditional galvanized products in the building industry. They combine the barrier protection of aluminium with the sacrificial protection of zinc, giving the advantages of both metals. The resulting alloy coating enhances corrosion resistance, making it suitable for applications such as roofing and wall cladding. Surface melting using laser irradiation can improve the localised corrosion resistance by modifying the coating microstructure through rapid melting and solidification processes. This paper discusses the effects of variations in topography, surface microstructures and surface composition on the surface melting characteristics of the coated steel. An understanding of the influence of these factors is required to ensure efficient coupling of the laser source and optimum energy absorption. Techniques like scanning electron microscopy, electron dispersive X-ray spectroscopy and surface profilometry are used for the analysis.