Aluminum alloy extruded product exhibiting excellent surface properties, method of manufacturing the same, heat exchanger multi-port tube, and method of manufacturing heat exchanger including the multi-port tube

• US 20070017605A1
• Filed: 07/20/2006
• Published: 01/25/2007
• Est. Priority Date: 07/22/2005
• Status: Abandoned Application

• Current Assignee: DENSO Corporation, Sumitomo Light Metal Industries Limited (UACJ Corporation)
• Original Assignee: DENSO Corporation, Sumitomo Light Metal Industries Limited (UACJ Corporation)
• Inventors: Nakamura, Tomohiko, Hasegawa, Yoshiharu, Kawakubo, Masaaki, Hikida, Tatsuya, Yamashita, Naoki
• Application Number:
  US11/489,941
• Publication Number:
  US 20070017605A1
• Time in Patent Office: Days
• US Class Current: 148/550
• CPC Class Codes: C22F 1/08 of copper or alloys based thereon
• CPC Class Codes: F28F 1/022 with multiple channels
• CPC Class Codes: F28F 21/084 from aluminium or aluminium alloys
• CPC Class Codes: F28F 2255/16 extruded

Abstract

An aluminum alloy extruded product exhibiting excellent surface properties, comprising 0.8 to 1.6% of Mn and 0.4 to 0.8% of Si at a ratio of Mn content to Si content (Mn %/Si %) of 0.7 to 2.4, with the balance being Al and inevitable impurities, the number of intermetallic compounds with a diameter (circle equivalent diameter) of 0.1 to 0.9 μm dispersed in a matrix being 2×10⁵ or more per square millimeter. The aluminum alloy extruded product allows extrusion of a thin multi-port tube at a high limiting extrusion rate, prevents deposits from adhering to the surface of the extruded tube, and may be suitably used as a constituent member for an aluminum alloy automotive heat exchanger.

Claims

1. An aluminum alloy extruded product exhibiting excellent surface properties, comprising 0.8 to 1.6% (mass %;

hereinafter the same) of Mn and 0.4 to 0.8% of Si at a ratio of Mn content to Si content (Mn %/Si %) of 0.7 to 2.4, with the balance being Al and inevitable impurities, the number of intermetallic compounds with a diameter (circle equivalent diameter;

hereinafter the same) of 0.1 to 0.9 μ

m dispersed in a matrix being 2×

10⁵ or more per square millimeter.

2. The aluminum alloy extruded product according to claim 1, further comprising 0.05% or less of Cu.

3. The aluminum alloy extruded product according to claim 1, further comprising 0.2% or less of Mg.

4. The aluminum alloy extruded product according to claim 1, further comprising 0.30% or less of Ti.

5. A heat exchanger multi-port tube comprising the aluminum alloy extruded product according to claim 1.

6. A method of manufacturing an aluminum alloy extruded product exhibiting excellent surface properties, the method comprising:

melting and casting an aluminum alloy having the composition according to claim 1 to obtain an ingot;

subjecting the ingot to homogenization which includes a first-stage heat treatment in which the ingot is maintained at 550 to 650°

C. for two hours or more and a second-stage heat treatment in which the ingot is cooled to 400 to 500°

C. at an average temperature decrease rate of 20 to 60°

C./h and maintained at that temperature for three hours or more;

heating the ingot at 480 to 560°

C.; and

extruding the ingot.

7. A method of manufacturing an aluminum alloy extruded product exhibiting excellent surface properties, the method comprising:

melting and casting an aluminum alloy having the composition according to claim 1 to obtain an ingot;

subjecting the ingot to homogenization which includes a first-stage heat treatment in which the ingot is maintained at 550 to 650°

C. for two hours or more and a second-stage heat treatment in which the ingot is cooled to room temperature, heated to 400 to 500°

C. at an average temperature increase rate of 20 to 60°

C./h, and maintained at that temperature for three hours or more;

heating the ingot at 480 to 560°

C.; and

extruding the ingot.

8. A method of manufacturing a heat exchanger comprising extruding a heat exchanger multi-port tube using the method according to claim 6, and joining the multi-port tube to a heat exchanger by brazing.