Aluminum alloy material exhibiting excellent bendability and method for producing the same

Patent metadata

Field	Value
Publication number	US-9834833-B2
Application number	US-201114118789-A
Country	US
Kind code	B2
Filing date	Oct 6, 2011
Priority date	May 20, 2011
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

An aluminum alloy material exhibiting excellent bendability can be produced without performing a straightening step, and can be bent without developing orange peel. The aluminum alloy material is a T4-tempered material formed of an Al—Cu—Mg—Si alloy including 1.0 to 2.5 mass % of Cu, 0.5 to 1.5 mass % of Mg, and 0.5 to 1.5 mass % of Si, with the balance being aluminum and unavoidable impurities, a matrix that forms an inner part of the aluminum alloy material having a microstructure formed by recrystallized grains having an average crystal grain size of 200 μm or less, and the aluminum alloy material having a ratio of tensile strength/yield strength determined by a tensile test of 1.5 or more.

First claim

What is claimed is:

1. An aluminum alloy pipe material exhibiting excellent bendability, the aluminum alloy pipe material being a T4-tempered material formed of an Al—Cu—Mg—Si alloy comprising 1.5 to 2.5 mass % of Cu, 0.8 to 1.5 mass % of Mg, and 0.5 to 1.5 mass % of Si, with the balance being aluminum and unavoidable impurities, the aluminum alloy pipe material being obtained by a process comprising step (a) of homogenizing a billet of the Al—Cu—Mg—Si alloy, step (b) of hot-extruding the billet, step (c) of softening the extruded material, step (d) of cold-working the softened extruded material, step (e) of subjecting the cold worked extruded material to a solution treatment, step (f) of quenching the solution treated material, and step (g) of performing natural aging at room temperature, the homogenizing being performed at a temperature of 520° C. to 560° C. for at least 2 hours, the hot-extruding being performed at a temperature of 300° C. to 500° C., the softening being performed at a temperature of 350° C. to 400° C. for at least 30 minutes, the cold-working being performed at a working ratio of at least 15%, the solution treatment being performed at a temperature of 530° C. to 560° C. and at a time of at least 10 minutes, the quenching being performed so that an average cooling rate from the solution treatment temperature to 100° C. is at least 10° C./sec, and the natural aging being performed for at least 7 days, a matrix that forms an inner part of the aluminum alloy pipe material having a microstructure formed by recrystallized grains having an average crystal grain size of no more than 200 μm, and the aluminum alloy pipe material having a tensile strength of from 308-409 MPa, a yield strength of from 194-245 MPa, and a ratio of tensile strength (MPa)/yield strength (MPa) of at least 1.5.

2. The aluminum alloy pipe material exhibiting excellent bendability according to claim 1 , wherein the average crystal grain size is 47 to 200 μm.

3. The aluminum alloy pipe material according to claim 1 , wherein the Al—Cu—Mg—Si alloy further comprises at least one of up to 0.35 mass % of Mn, up to 0.30 mass % of Cr, up to 0.15 mass % Zr, and up to 0.15 mass % of V, at least one of Mn, Cr, Zr and V being present in the aluminum alloy pipe material.

4. The aluminum alloy pipe material according to claim 1 , wherein the Al—Cu—Mg—Si alloy further comprises at least one of 0.15 mass % or less of Ti and 50 ppm or less of B.

5. The aluminum alloy pipe material according to claim 3 , wherein the Al—Cu—Mg—Si alloy further comprises at least one of 0.15 mass % or less of Ti and 50 ppm or less of B.

6. The aluminum alloy pipe material according to claim 1 , wherein the matrix that forms the inner part of the aluminum alloy material has a grain boundary coverage by precipitates of 30% or less.

7. The aluminum alloy pipe material according to claim 3 , wherein the matrix that forms the inner part of the aluminum alloy material has a grain boundary coverage by precipitates of 30% or less.

8. The aluminum alloy pipe material according to claim 4 , wherein the matrix that forms the inner part of the aluminum alloy material has a grain boundary coverage by precipitates of 30% or less.

Assignees

• Minoda Tadashi
• Nakai Yasuhiro
• Uacj Corp

Inventors

• Minoda Tadashi
• Nakai Yasuhiro

Classifications

• C22C21/14

  with silicon · CPC title

• C22F1/057 Primary

  of alloys with copper as the next major constituent · CPC title

• C22C21/16

  with magnesium · CPC title