# US 10,307,813 B2 · Aluminum alloy heat exchanger and method of producing refrigerant tube used for the heat exchanger

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- Number: US 10,307,813 B2
- Document ID: US10307813B2
- Status: Granted
- Kind: B2
- Application number: 15/223,859
- Filed: 2016-07-29
- Published: 2016-11-17
- Granted: 2019-06-04
- Earliest claimed: 2009-06-24
- Assignees: Sumitomo Light Metal Industries, Ltd.
- Applicants: Sumitomo Light Metal Industries, Ltd.
- Inventors: Naoki Yamashita; Yasunaga Itoh; Yuji Hisatomi
- Web page: https://patentgrep.com/patent/US10307813B2

## CPC

- B21D 53/06: of metal tubes
- B23K 35/282: {Zn as the principal constituent}
- B23K 35/3607: {Silica or silicates}
- B23K 35/362: Selection of compositions of fluxes (B23K35/365, B23K35/368 take precedence)
- C22C 21/00: Alloys based on aluminium
- C22C 21/02: with silicon as the next major constituent
- C22C 21/10: with zinc as the next major constituent
- C22C 21/14: with silicon
- F28F 1/00: Tubular elements; Assemblies of tubular elements (specially adapted for movement F28F5/00)
- F28F 19/02: by using coatings, e.g. vitreous or enamel coatings
- F28F 19/06: of metal
- F28F 21/084: {from aluminium or aluminium alloys}
- B23K 2101/14: Heat exchangers
- F28D 2021/0084: {Condensers}
- F28D 2021/0085: {Evaporators}
- F28F 2275/04: by brazing
- B21D: WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL (working or processing of wire B21F)
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16)
- F28D: HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT (fluid heaters having heat generating means and heat transferring means F24H; furnaces F27; details of heat-exchange apparatus of general)

## Abstract

An aluminum alloy heat exchanger is produced by applying a coating material that is prepared by adding a binder to a mixture of an Si powder and a Zn-containing compound flux powder to a surface of an aluminum alloy refrigerant tube, assembling a bare fin that is formed of an Al—Mn—Zn alloy with the refrigerant tube, and brazing the refrigerant tube and the bare fin by heating in an atmosphere-controlled furnace, the refrigerant tube being an extruded product of an aluminum alloy that comprises 0.5 to 1.7% (mass %, hereinafter the same) of Mn, less than 0.10% of Cu, and less than 0.10% of Si, with the balance being Al and unavoidable impurities.

## Claims

### Claim 1

A method of producing an aluminum alloy refrigerant tube that is used in the manufacture of an aluminum alloy heat exchanger, comprising the steps of:
providing an ingot of an aluminum alloy comprising 0.5-1.7 mass % of Mn, less than 0.10% of Cu and less than 0.10% of Si, with the balance being Al and unavoidable impurities;
subjecting the ingot of the aluminum alloy to a homogenization heat treatment that holds the ingot at a temperature of from 400-650° C. for 4 hours or more; and
hot-extruding the ingot to produce the aluminum alloy refrigerant tube.

### Claim 2 (depends on 1)

The method of claim 1, wherein the homogenization heat treatment includes a first-stage heat treatment that holds the ingot at 570-650° C. for 2 hours or more, followed by cooling the ingot to 200° C. or less, and a second-stage heat treatment that holds the ingot at 400-550° C. for 3 hours or more.

### Claim 3 (depends on 1)

The method of claim 1, wherein the homogenization heat treatment includes a first-stage heat treatment that holds the ingot at 570-650° C. for 2 hours or more and a second-stage heat treatment that holds the ingot at 400-550° C. for 3 hours or more.

### Claim 4 (depends on 3)

The method of claim 3, wherein the aluminum alloy refrigerant tube has an aluminum alloy bare fin made of an Al—Mn—Zn alloy brazed thereto, the Al—Mn—Zn alloy further comprising at least one of 0.001 to 0.10 mass % of In and 0.001 to 0.10 mass % of Sn.

### Claim 5 (depends on 4)

The method of claim 4, wherein the homogenization heat treatment includes the first-stage heat treatment, followed by cooling the ingot to 200° C. or less, and the second-stage heat treatment.