Bluescope Steel Limited

David James Nolan

Qiyang Liu

Wayne Andrew Renshaw

Joe Williams

Ross McDowall Smith

Aaron Kiffer Neufeld

Bryan Andrew Shedden

Ross Mcdowall Smith

Red rust staining of Al/Zn coated steel strip in 'acid rain' or “polluted” environments can be minimised by forming the coating as an Al—Zn—Si—Mg alloy coating with an OT:SDAS ratio greater than a value of 0.5:1, where OT is the overlay thickness on a surface of the strip and SDAS is the measure of the secondary dendrite arm spacing for the Al-rich alpha phase dendrites in the coating. Red rust staining in “acid rain” or “polluted” environments and corrosion at cut edges in marine environments can be minimised in Al—Zn—Si—Mg alloy coatings on steel strip by selection of the composition (principally Mg and Si) and solidification control (principally by cooling rate) and forming MgSi phase particles of a particular morphology in interdendritic channels.

Corrosion protection with Al/Zn-based coatings

Red rust staining of Al/Zn coated steel strip in 'acid rain' or 'polluted' environments can be minimised by forming the coating as an Al&#x2014;Zn&#x2014;Si&#x2014;Mg alloy coating with an OT:SDAS ratio greater than a value of 0.5:1, where OT is the overlay thickness on a surface of the strip and SDAS is the measure of the secondary dendrite arm spacing for the Al-rich alpha phase dendrites in the coating. Red rust staining in &#x201c;acid rain&#x201d; or &#x201c;polluted&#x201d; environments and corrosion at cut edges in marine environments can be minimised in Al&#x2014;Zn&#x2014;Si&#x2014;Mg alloy coatings on steel strip by selection of the composition (principally Mg and Si) and solidification control (principally by cooling rate) and forming MgSi phase particles of a particular morphology in interdendritic channels.

A method for coating a metal substrate, such as a steel strip, is disclosed. The method comprises vapor or electro-depositing an alloy control material, as described herein, onto the substrate and passing the substrate through a bath of molten coating material and forming a coating of the coating material onto the deposited alloy control material.

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Gerringong, Australia

David James Nolan