Aluminum alloy having excellent characteristic after natural aging at room temperature

Patent metadata

Field	Value
Publication number	US-9932658-B2
Application number	US-201414765987-A
Country	US
Kind code	B2
Filing date	Feb 24, 2014
Priority date	Feb 26, 2013
Publication date	Apr 3, 2018
Grant date	Apr 3, 2018

Abstract

A 6000-series aluminum alloy plate, which is obtained by introducing a minor amount of Sn into a 6000-series aluminum alloy plate that has a specific Mg and Si composition, and controlling the tissue of the plate on the basis of the tissue thereof under a specific heat treatment, shows an improved hem bendability even after aging for a long period of time at room temperature, as a characteristic after the natural aging, and increases the bake hardenability (BH response) in baking finishing a molded automobile panel.

First claim

The invention claimed is:

1. An Al—Mg—Si series alloy plate, comprising
Mg: 0.3 to 0.6 mass %,
Si: 0.4 to 1.4 mass %,
Sn: 0.01 to 0.3 mass %,
wherein 8×(Mg content)−(Si content)≤3.0, and
Al, and unavoidable impurities,
wherein the alloy plate has a microstructure comprising a number density of precipitates of a size from 2.0 to 20 nm of 5.0×10 21 N/m 3 or more in average measured by subjecting the alloy plate to artificial aging at 170° C. for 20 minutes and within a range of 300 nm×300 nm×100 nm under a transmission electron microscope of 300,000 magnifications at a central portion of a cross section perpendicular to a rolling direction of the plate.

2. The alloy plate according to claim 1 , further comprising one or more of
Mn in an amount greater than 0 mass % up to not more than 1.0 mass %,
Cu in an amount of greater than 0 mass % up to not more than 1.0 mass %,
Fe in an amount of greater than 0 mass % up to not more than 1.0 mass %,
Cr in an amount of greater than 0 mass % up to not more than 0.3 mass %,
Zr in an amount of greater than 0 mass % up to not more than 0.3 mass %,
V in an amount of greater than 0 mass % up to not more than 0.3 mass %,
Ti in an amount of greater than 0 mass % up to not more than 0.1 mass %,
Zn in an amount of greater than 0 mass % up to not more than 1.0 mass %, and
Ag in an amount of greater than 0 mass % up to not more than 0.2%.

3. The alloy plate of claim 1 , comprising Mg in an amount of 0.32 to 0.52 mass %.

4. The alloy plate of claim 1 , comprising Si in an amount of 0.63 to 1.2 mass %.

5. The alloy plate of claim 1 , comprising Sn in an amount of 0.04 to 0.21 mass %.

6. The alloy plate of claim 1 , comprising Mg in an amount of 0.32 to 0.52 mass %, Si in an amount of 0.63 to 1.2 mass %, and Sn in an amount of 0.04 to 0.21 mass %.

7. The alloy plate of claim 1 , wherein the number density of precipitates of a size from 2.0 to 20 nm is of 5.0×10 21 N/m 3 to 33.8×10 21 N/m 3 in average.

8. The alloy plate of claim 1 , wherein the number density of precipitates of a size from 2.0 to 20 nm is of 5.0×10 21 N/m 3 to 36.5×10 21 N/m 3 in average.

9. The alloy plate of claim 6 , wherein the number density of precipitates of a size from 2.0 to 20 nm is of 5.0×10 21 N/m 3 to 31.7×10 21 N/m 3 in average.

Assignees

• Kobe Steel Ltd

Inventors

• Shishido Hisao
• Matsumoto Katsushi
• Aruga Yasuhiro

Classifications

• C22F1/05

  of alloys of the Al-Si-Mg type, i.e. containing silicon and magnesium in approximately equal proportions · CPC title

• C22C21/02

  with silicon as the next major constituent · CPC title

• C22C21/10

  with zinc as the next major constituent · CPC title

• C22C21/14

  with silicon · CPC title

• C22C21/16 Primary

  with magnesium · CPC title