Abstract: An Al—Zn—Si—Mg alloy coated strip that has Mg2Si particles in the coating microstructure is disclosed. The distribution of Mg2Si particles is such that the surface of the coating has only a small proportion of Mg2Si particles or is at least substantially free of any Mg2Si particles.

Abstract: 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 Mg2Si phase particles of a particular morphology in interdendritic channels.

Abstract: An Al—Zn—Si—Mg alloy coated strip that has Mg2Si particles in the coating microstructure is disclosed. The distribution of Mg2Si particles is such that a surface region of the coating has only a small proportion of Mg2Si particles or is at least substantially free of any Mg2Si particles.

Abstract: An Al—Zn—Si—Mg alloy coated strip that has Mg2Si particles in the coating microstructure is disclosed. The distribution of Mg2Si particles is such that the surface of the coating has only a small proportion of Mg2Si particles or is at least substantially free of any Mg2Si particles.

Abstract: 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 Mg2Si phase particles of a particular morphology in interdendritic channels.

Abstract: 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 Mg2Si phase particles of a particular morphology in interdendritic channels.

Abstract: A steel strip having a coating of a metal alloy on at least one surface of the strip is disclosed. The metal alloy contains aluminium, zinc, silicon, and magnesium as the major elements. The metal alloy also contains strontium and/or calcium and unavoidable impurities and optionally other elements that are present as deliberate alloying elements. The concentration of magnesium is at least 1 wt. % and the concentration of (i) strontium or (ii) calcium or (iii) strontium and calcium is greater than 50 ppm.

Abstract: 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 Mg2Si phase particles of a particular morphology in interdendritic channels.

Abstract: An Al—Zn—Si—Mg alloy coated strip that has Mg2Si particles in the coating microstructure is disclosed. The distribution of Mg2Si particles is such that the surface of the coating has only a small proportion of Mg2Si particles or is at least substantially free of any Mg2Si particles.

Abstract: An Al—Zn—Si—Mg alloy coated strip that has Mg2Si particles in the coating microstructure is disclosed. The distribution of Mg2Si particles is such that the surface of the coating has only a small proportion of Mg2Si particles or is at least substantially free of any Mg2Si particles.

Abstract: 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 Mg2Si phase particles of a particular morphology in interdendritic channels.

Abstract: An Al—Zn—Si—Mg alloy coated strip that has Mg2Si particles in the coating microstructure is disclosed. The distribution of Mg2Si particles is such that a surface region of the coating has only a small proportion of Mg2Si particles or is at least substantially free of any Mg2Si particles.

Abstract: An Al—Zn—Si—Mg alloy coated strip that has Mg2Si particles in the coating microstructure is disclosed. The distribution of Mg2Si particles is such that the surface of the coating has only a small proportion of Mg2Si particles or is at least substantially free of any Mg2Si particles.

Abstract: A steel strip having a coating of a metal alloy on at least one surface of the strip is disclosed. The metal alloy contains aluminium, zinc, silicon, and magnesium as the major elements. The metal alloy also contains strontium and/or calcium and unavoidable impurities and optionally other elements that are present as deliberate alloying elements. The concentration of magnesium is at least 1 wt. % and the concentration of (i) strontium or (ii) calcium or (iii) strontium and calcium is greater than 50 ppm.

Abstract: A method of controlling “rough coating” and “pinhole-uncoated” surface defects on a steel strip coated with a aluminum-zinc-silicon alloy. The alloy has 50-60% wt Al, 37-46% wt Zn and 1.2-2.3% wt Si. The method includes heat treating the steel strip in a heat treatment furnace and thereafter hot-dip coating the strip in a molten bath and thereby forming a coating of the alloy on the steel strip. The method is characterized by controlling the concentration of (i) strontium or (ii) calcium or (iii) strontium and calcium in the molten bath to be at least 2 ppm.

Abstract: 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 Mg2 Si phase particles of a particular morphology in interdendritic channels.

Abstract: A method of controlling “rough coating” and “pinhole-uncoated” surface defects on a steel strip coated with a aluminum-zinc-silicon alloy. The alloy has 50-60% wt Al, 37-46% wt Zn and 1.2-2.3% wt Si. The method includes heat treating the steel strip in a heat treatment furnace and thereafter hot-dip coating the strip in a molten bath and thereby forming a coating of the alloy on the steel strip. The method is characterized by controlling the concentration of (i) strontium or (ii) calcium or (iii) strontium and calcium in the molten bath to be at least 2 ppm.

Abstract: An Al—Zn—Si—Mg alloy coated strip that has Mg2Si particles in the coating microstructure is disclosed. The distribution of Mg2Si particles is such that the surface of the coating has only a small proportion of Mg2Si particles or is at least substantially free of any Mg2Si particles.

Abstract: An Al—Zn—Si—Mg alloy coated strip that has Mg2Si particles in the coating microstructure is disclosed. The distribution of Mg2 Si particles is such that a surface region of the coating has only a small proportion of Mg2Si particles or is at least substantially free of any Mg2Si particles.

Abstract: A steel strip having a coating of a metal alloy on at least one surface of the strip is disclosed. The metal alloy contains aluminium, zinc, silicon, and magnesium as the major elements. The metal alloy also contains strontium and/or calcium and unavoidable impurities and optionally other elements that are present as deliberate alloying elements. The concentration of magnesium is at least 1 wt. % and the concentration of (i) strontium or (ii) calcium or (iii) strontium and calcium is greater than 50 ppm.