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 method for coating a metal substrate, such as a steel strip, is disclosed. The method comprises vapour 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.

Abstract: A steel strip having a coating of an aluminium-zinc-silicon alloy on at least one surface of the strip is disclosed. The strip is characterised in that the aluminium-zinc-silicon alloy contains less than 1.2 wt. % silicon and also contains magnesium. A method of forming a coating of an aluminium-zinc-silicon alloy on a steel strip is also disclosed. The method includes moving steel strip upwardly through a coating pot containing a bath of an aluminium-zinc-silicon alloy and having an opening in a bottom wall of the pot and forming a coating of the alloy on the strip. The method is characterized by minimizing residence time of steel strip in contact with the aluminium-zinc-silicon alloy bath in the pot.

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 treating an Al/Zn-based alloy coated product that includes an Al/Zn-based alloy coating on a substrate is disclosed. The method includes the steps of rapid intense heating of the alloy coating for a very short duration, and rapid cooling of the alloy coating, and forming a modified crystalline microstructure of the alloy coating.

Abstract: A steel strip having a metal coating on at least one surface of the strip is disclosed. The strip is characterised in that the coating includes aluminium-zinc-silicon alloy that contains magnesium and the coating has small size spangles.

Abstract: A method of forming a metal coated steel strip that has a brushed finish is disclosed. The method includes skin pass rolling a metal coated steel strip to suppress and/or obscure the spangles on the surface and thereafter brushing the skin passed rolled strip.

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.