Steel sheet coated with aluminum-magnesium
View Patent ↗The present invention relates to an aluminum-magnesium coated steel plate using vacuum coating, wherein an aluminum-magnesium coating layer is constituted by 1 to 45 wt % of magnesium, a balance of aluminum, and other inevitable impurities, and an Al 3 Mg 2 alloy phase is formed in the aluminum-magnesium coating layer by performing heat treatment of the steel plate.
1. A steel plate having an aluminum-magnesium alloy layer, comprising:
a steel plate;
an aluminum-iron alloy layer formed on an upper portion of the steel plate; and
the aluminum-magnesium alloy layer formed on an upper portion of the aluminum-iron alloy layer,
wherein the aluminum-magnesium alloy layer includes 1 to 45 wt. % of magnesium based on a total weight of the aluminum-magnesium alloy layer,
the aluminum-magnesium alloy layer is formed in a crystal grain form,
crystal grains of the aluminum-magnesium alloy layer are formed by an α phase and a β phase (Al 3 Mg 2 ), and
an average grain diameter of the crystal grains is 0.1 to 2 μm.
2. The steel plate of claim 1 , wherein, in the aluminum-magnesium alloy layer, an α phase and a β phase (Al 3 Mg 2 ) are mixed.
3. The steel plate of claim 2 , wherein the aluminum-iron alloy layer is formed in a thickness that is 1 to 50% of a thickness of an alloy layer including the aluminum-iron alloy layer and the aluminum-magnesium alloy layer in a direction normal to the surface of the aluminum-magnesium alloy layer.
4. The steel plate of claim 3 , wherein, in the aluminum-iron alloy layer, an iron component of the steel plate is diffused into a coating layer to form an Al x Fe y layer, and the Al x Fe y layer satisfies the following conditions:
in the Al x Fe y layer, x is 1 to 3 and y is 0.5 to 1.5.
5. The steel plate of claim 4 , wherein a thickness of the aluminum-iron alloy layer is 0.2 to 1 μm.
6. The steel plate of claim 1 , wherein a thickness of the aluminum-magnesium alloy layer is 0.5 to 30 μm.
7. The steel plate of claim 1 , wherein, in the aluminum-magnesium alloy layer, an area ratio of the β phase/α phase of the crystal grain is 10 to 70% in a horizontal cross-sectional plane of the aluminum-magnesium alloy layer.
8. The steel plate of claim 7 , wherein an XRD intensity ratio Iβ (880)/Iα (111) of the α phase and the β phase of the aluminum-magnesium alloy layer is 0.01 to 1.5.