Aluminum alloy extruded product for heat exchangers and method of manufacturing the same

• US 20050189047A1
• Filed: 02/09/2005
• Published: 09/01/2005
• Est. Priority Date: 02/13/2004
• Status: Active Grant

• Current Assignee: DENSO Corporation, UACJ Corporation, UACJ Extrusion Corporation (UACJ Corporation)
• Original Assignee: DENSO Corporation, Sumitomo Light Metal Industries Limited (UACJ Corporation)
• Inventors: Kawakubo, Masaaki, Nakamura, Tomohiko, Hasegawa, Yoshiharu, Hikida, Tatsuya, Yamashita, Naoki, Itoh, Yasunaga
• Granted Patent: US 7,767,042 B2
• Time in Patent Office: Days
• US Class Current: 148/689
• CPC Class Codes: C22C 21/00 Alloys based on aluminium
• CPC Class Codes: C22F 1/04 of aluminium or alloys based thereon
• CPC Class Codes: F28F 21/084 from aluminium or aluminium alloys
• CPC Class Codes: F28F 2255/16 extruded

Abstract

A high-strength aluminum alloy extruded product for heat exchangers which excels in extrudability, allows a thin flat multi-cavity tube to be extruded at a high critical extrusion rate, and excel in intergranular corrosion resistance at a high temperature, and a method of manufacturing the same. The aluminum alloy extruded product includes an aluminum alloy including 0.2 to 1.8% of Mn and 0.1 to 1.2% of Si, having a ratio of Mn content to Si content (Mn %/Si %) of 0.7 to 2.5, and having a content of Cu as an impurity of 0.05% or less, with the balance being Al and impurities, the aluminum alloy extruded product having an electric conductivity of 50% IACS or more and an average particle size of intermetallic compounds precipitating in a matrix of 1 μm or less.

Claims

1. An aluminum alloy extruded product for heat exchangers, which comprises an aluminum alloy comprising 0.2 to 1.8% (mass %;

hereinafter the same) of Mn and 0.1 to 1.2% of Si, having a ratio of Mn content to Si content (Mn %/Si %) of 0.7 to 2.5, and having a content of Cu as an impurity of 0.05% or less, with the balance being Al and impurities, the aluminum alloy extruded product having an electric conductivity of 50% IACS or more and an average particle size of intermetallic compounds precipitating in a matrix of 1 μ

m or less.

2. The aluminum alloy extruded product for heat exchangers according to claim 1, wherein the aluminum alloy further comprises 0.4% or less (excluding 0%;

hereinafter the same) of Mg.

3. The aluminum alloy extruded product for heat exchangers according to claim 1, wherein the aluminum alloy further comprises 1.2% or less of Fe.

4. The aluminum alloy extruded product for heat exchangers according to claim 1, wherein the aluminum alloy further comprises 0.06 to 0.30% of Ti.

5. The aluminum alloy extruded product for heat exchangers according to claim 1, wherein the aluminum alloy has an Si content of 0.4 to 1.2% and a total content of Mn and Si of 1.2% or more.

6. The aluminum alloy extruded product for heat exchangers according to claim 1, the aluminum alloy extruded product having a tensile strength of 110 MPa or more after being subjected to heating at a temperature of 600°

C. for three minutes and cooling at an average cooling rate of 150°

C./min.

7. A method of manufacturing the aluminum alloy extruded product according to claim 1, the method comprising:

subjecting an ingot of an aluminum alloy having the above composition to a first-stage homogenization treatment which includes heating the ingot at a temperature of 550 to 650°

C. for two hours or more and a second-stage homogenization treatment which includes heating the ingot at a temperature of 400 to 500°

C. for three hours or more to adjust the electric conductivity of the ingot to 50% IACS or more and the average particle size of the intermetallic compounds precipitating in the matrix to 1 μ

m or less; and

hot-extruding the resulting ingot.