WO2000038854A1 - Method of fabricating fins on heat exchanger tubes - Google Patents

Method of fabricating fins on heat exchanger tubes Download PDF

Info

Publication number
WO2000038854A1
WO2000038854A1 PCT/US1999/030599 US9930599W WO0038854A1 WO 2000038854 A1 WO2000038854 A1 WO 2000038854A1 US 9930599 W US9930599 W US 9930599W WO 0038854 A1 WO0038854 A1 WO 0038854A1
Authority
WO
WIPO (PCT)
Prior art keywords
aluminum
coating
fins
tubes
welding
Prior art date
Application number
PCT/US1999/030599
Other languages
French (fr)
Inventor
Thomas B. Gibbons
Bard C. Teigan
Michael P. Borden
Original Assignee
Abb Alstom Power Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Abb Alstom Power Inc. filed Critical Abb Alstom Power Inc.
Priority to AU22069/00A priority Critical patent/AU2206900A/en
Publication of WO2000038854A1 publication Critical patent/WO2000038854A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
    • B21C37/15—Making tubes of special shape; Making tube fittings
    • B21C37/22—Making finned or ribbed tubes by fixing strip or like material to tubes
    • B21C37/26—Making finned or ribbed tubes by fixing strip or like material to tubes helically-ribbed tubes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • 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
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/20—Bonding
    • B23K26/32—Bonding taking account of the properties of the material involved
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • 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
    • B23K2103/00—Materials to be soldered, welded or cut
    • B23K2103/02—Iron or ferrous alloys
    • B23K2103/04—Steel or steel alloys
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • 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
    • B23K2103/00—Materials to be soldered, welded or cut
    • B23K2103/18—Dissimilar materials
    • B23K2103/20—Ferrous alloys and aluminium or alloys thereof

Definitions

  • the present invention relates to a method of fabricating heat exchange tubes having high thermal conductivity aluminum extended heat transfer surface attached to high pressure tube materials having a lower thermal conductivity.
  • a number of methods are known for fabricating finned heat exchange tubes. It is often desirable to employ tubes which are formed from high strength alloys, usually steel, in order to contain the high pressure fluid in the tube and to employ extended heat transfer surface of a different material having a high thermal conductivity attached to the outside periphery of the tube.
  • This extended heat transfer surface is usually in the form of ribs or fins which may take a number of forms.
  • One of the preferred forms is spiral fins.
  • the problem in fabricating finned heat exchange tubes where the tube is steel or similar ferrous metal and where the fins are high thermal conductivity aluminum is how to attach the fins to the tubes in a manner that provides a secure joint and a joint with high thermal conductivity.
  • a number of techniques have been used in the past such as mechanical attachments where the fins are placed in grooves in the tube and the groove is then crimped onto the fin such as in U.S. Patents 2,872,730 and 3,855,682.
  • Conventional welding techniques have not been used because of the difficulty of welding aluminum to steel.
  • the present invention involves a method of fabricating extended heat transfer surface onto tubes where the fins are aluminum or aluminum alloy and the tubes are a ferrous material.
  • the aluminum extended heat transfer surface is preferably in the form of spiral fins.
  • the ferrous tubes usually steel, are coated with a layer of material compatible with aluminum welding and the aluminum fins are welded to the layer of material by laser welding.
  • Figure 1 is a longitudinal cross section of a portion of a heat exchange tube with fins applied according to the present invention.
  • Figure 2 is an illustration of a helical fin to a heat exchange tube by laser welding.
  • the heat exchanger tubes are high strength materials, usually high strength steel or other ferrous alloys, suitable for pressure containment of the heat transfer fluid.
  • a longitudinal cross section of a portion of such a tube 1 2 is shown in Figure 1 .
  • Attached to the tube 1 2 is the aluminum or aluminum alloy extended heat transfer surface having a high thermal conductivity.
  • the extended heat transfer surface will usually take the form of fins which are spirally wound around the tube.
  • the fins can be of any desired geometry such as circular fins or longitudinal fins.
  • the thickness of the fins is normally in the range of .0040 - 0.080 inches ( 1 00 - 2000 ⁇ /77).
  • Figure 1 illustrates a fin section 14 already attached and a fin section 1 6 in the process of being attached.
  • Figure 2 illustrates a spiral fin 1 8 being wound around a tube 1 2 and welded as discussed later.
  • the present invention relates to the manner in which the fins are attached to the tube.
  • the first step in the process is to form a surface layer or coating 20 on the ferrous alloy tube 1 2 with the coating material being compatible with an aluminum welding procedure.
  • the coating material is usually aluminum or an aluminum alloy.
  • the coating is applied by established coating methods known in the art such as hot- dipping.
  • the thickness of the coating 20 is sufficient to provide a bond with the fin and is usually in the range of .0040 - .040 inch (100 - l OOO ⁇ m).
  • the present invention involves the welding of aluminum (the aluminum fin to the aluminum coating), conventional welding procedures that might be used to weld a steel fin to a steel tube cannot be used.
  • the present invention involves welding the fin to the coating using laser welding. This is diagrammatically illustrated in both Figures 1 and 2 where the laser beam 22 is directed at the juncture between the fin and the coating 20.
  • the weld seam 24 shown in Figure 1 covers a small area and is not very deep due to the surface effect of the laser welding. In fact, the weld only extends into the aluminum coating 20 and not into the steel tube 12. Therefore, the welding is simplified because it only involves welding aluminum to aluminum or aluminum alloy.
  • U.S. Patent 4,841 ,617 For a general disclosure of a method for welding a fin to a tube, reference is made to U.S. Patent 4,841 ,617. This same general method may be employed in the present invention where the fin is aluminum, the tube is steel and the tube is coated with aluminum.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Mechanical Engineering (AREA)
  • Plasma & Fusion (AREA)
  • Laser Beam Processing (AREA)

Abstract

Aluminum or aluminum alloy extended heat transfer surface is fabricated on ferrous metal tubes (12). The tubes (12), usually steel, are first coated with a layer (20) of a material compatible with aluminum welding. The coating (20) is usually aluminum or aluminum alloy. The fins (14, 16) are usually spiral fins (14, 16) and they are welded to the coating (20) by laser welding.

Description

Method of Fabricating Fins on Heat Exchanger Tubes
Background of the Invention
The present invention relates to a method of fabricating heat exchange tubes having high thermal conductivity aluminum extended heat transfer surface attached to high pressure tube materials having a lower thermal conductivity.
A number of methods are known for fabricating finned heat exchange tubes. It is often desirable to employ tubes which are formed from high strength alloys, usually steel, in order to contain the high pressure fluid in the tube and to employ extended heat transfer surface of a different material having a high thermal conductivity attached to the outside periphery of the tube. This extended heat transfer surface is usually in the form of ribs or fins which may take a number of forms. One of the preferred forms is spiral fins.
The problem in fabricating finned heat exchange tubes where the tube is steel or similar ferrous metal and where the fins are high thermal conductivity aluminum is how to attach the fins to the tubes in a manner that provides a secure joint and a joint with high thermal conductivity. A number of techniques have been used in the past such as mechanical attachments where the fins are placed in grooves in the tube and the groove is then crimped onto the fin such as in U.S. Patents 2,872,730 and 3,855,682. Conventional welding techniques have not been used because of the difficulty of welding aluminum to steel.
Summary of the Invention
The present invention involves a method of fabricating extended heat transfer surface onto tubes where the fins are aluminum or aluminum alloy and the tubes are a ferrous material. The aluminum extended heat transfer surface is preferably in the form of spiral fins.
The ferrous tubes, usually steel, are coated with a layer of material compatible with aluminum welding and the aluminum fins are welded to the layer of material by laser welding.
Brief Description of the Drawings Figure 1 is a longitudinal cross section of a portion of a heat exchange tube with fins applied according to the present invention.
Figure 2 is an illustration of a helical fin to a heat exchange tube by laser welding.
Description of the Preferred Embodiment
In accordance with the present invention, the heat exchanger tubes are high strength materials, usually high strength steel or other ferrous alloys, suitable for pressure containment of the heat transfer fluid. A longitudinal cross section of a portion of such a tube 1 2 is shown in Figure 1 . Attached to the tube 1 2 is the aluminum or aluminum alloy extended heat transfer surface having a high thermal conductivity. The extended heat transfer surface will usually take the form of fins which are spirally wound around the tube. However, the fins can be of any desired geometry such as circular fins or longitudinal fins. The thickness of the fins is normally in the range of .0040 - 0.080 inches ( 1 00 - 2000μ/77). Figure 1 illustrates a fin section 14 already attached and a fin section 1 6 in the process of being attached. Figure 2 illustrates a spiral fin 1 8 being wound around a tube 1 2 and welded as discussed later. The present invention relates to the manner in which the fins are attached to the tube. The first step in the process is to form a surface layer or coating 20 on the ferrous alloy tube 1 2 with the coating material being compatible with an aluminum welding procedure. The coating material is usually aluminum or an aluminum alloy. The coating is applied by established coating methods known in the art such as hot- dipping. The thickness of the coating 20 is sufficient to provide a bond with the fin and is usually in the range of .0040 - .040 inch (100 - l OOOμm).
Because the present invention involves the welding of aluminum (the aluminum fin to the aluminum coating), conventional welding procedures that might be used to weld a steel fin to a steel tube cannot be used. The present invention involves welding the fin to the coating using laser welding. This is diagrammatically illustrated in both Figures 1 and 2 where the laser beam 22 is directed at the juncture between the fin and the coating 20. The weld seam 24 shown in Figure 1 covers a small area and is not very deep due to the surface effect of the laser welding. In fact, the weld only extends into the aluminum coating 20 and not into the steel tube 12. Therefore, the welding is simplified because it only involves welding aluminum to aluminum or aluminum alloy. For a general disclosure of a method for welding a fin to a tube, reference is made to U.S. Patent 4,841 ,617. This same general method may be employed in the present invention where the fin is aluminum, the tube is steel and the tube is coated with aluminum.

Claims

Claims:
1 . A method of producing finned heat exchanger tubes comprising steel tubes and aluminum or aluminum alloy fins comprising the steps of: a. coating said steel tubes with aluminum or aluminum alloy; b. placing at least one aluminum or aluminum alloy fin in contact with said coating; and c. welding said aluminum or aluminum alloy fin to said coating.
2. A method as recited in claim 1 wherein said step of welding comprises laser welding.
3. A method of producing finned heat exchange tubes comprising ferrous alloy tubes and aluminum or aluminum alloy fins comprising the steps of: a. coating said ferrous alloy tubes with a coating compatible with aluminum welding; b. placing at least one aluminum or aluminum alloy fin in a desired position proximate to said coating, and c. laser welding said aluminum or aluminum alloy fin to said coating.
PCT/US1999/030599 1998-12-28 1999-12-21 Method of fabricating fins on heat exchanger tubes WO2000038854A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU22069/00A AU2206900A (en) 1998-12-28 1999-12-21 Method of fabricating fins on heat exchanger tubes

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US22174398A 1998-12-28 1998-12-28
US09/221,743 1998-12-28

Publications (1)

Publication Number Publication Date
WO2000038854A1 true WO2000038854A1 (en) 2000-07-06

Family

ID=22829177

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1999/030599 WO2000038854A1 (en) 1998-12-28 1999-12-21 Method of fabricating fins on heat exchanger tubes

Country Status (2)

Country Link
AU (1) AU2206900A (en)
WO (1) WO2000038854A1 (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009075596A2 (en) * 2007-12-11 2009-06-18 Energoinstal S.A. Method of manufacture of finned tubes using laser welding process
DE102016008344A1 (en) * 2016-04-18 2017-10-19 Schmöle GmbH Method for producing a finned tube and finned tube
EP3366406A1 (en) * 2017-02-24 2018-08-29 Outokumpu Oyj Resistance welding of unweldable metals with thermal sprayed interlayers
CN110091431A (en) * 2019-04-30 2019-08-06 西安理工大学 A kind of steel tube concrete pile and manufacturing method
CN111283328A (en) * 2020-03-19 2020-06-16 昆山华恒焊接股份有限公司 Method for welding heat exchange tube and tube plate
US20210291298A1 (en) * 2018-07-19 2021-09-23 Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) Method for manufacturing joined structure of dissimilar materials, and joined structure of dissimilar materials
RU2776711C2 (en) * 2017-02-24 2022-07-25 Оутокумпу Оюй Contact welding of non-welded metals using intermediate layers applied by thermal spraying

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4841617A (en) * 1987-08-11 1989-06-27 R. & G. Schmole Metallwerke Gmbh & Co. Kg Method for producing heat exchanger tubes
US5031694A (en) * 1988-07-08 1991-07-16 H.E.T. Limited Heat exchange device and method of manufacture therefor
EP0822025A1 (en) * 1996-08-03 1998-02-04 Balcke-Dürr GmbH Method of manufacturing corrosion resistant heat exchangers

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4841617A (en) * 1987-08-11 1989-06-27 R. & G. Schmole Metallwerke Gmbh & Co. Kg Method for producing heat exchanger tubes
US5031694A (en) * 1988-07-08 1991-07-16 H.E.T. Limited Heat exchange device and method of manufacture therefor
EP0822025A1 (en) * 1996-08-03 1998-02-04 Balcke-Dürr GmbH Method of manufacturing corrosion resistant heat exchangers

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009075596A2 (en) * 2007-12-11 2009-06-18 Energoinstal S.A. Method of manufacture of finned tubes using laser welding process
WO2009075596A3 (en) * 2007-12-11 2009-08-13 Energoinstal S A Method of manufacture of finned tubes using laser welding process
DE102016008344A1 (en) * 2016-04-18 2017-10-19 Schmöle GmbH Method for producing a finned tube and finned tube
EP3243598A3 (en) * 2016-04-18 2018-01-17 Schmöle GmbH Method of producing a finned tube using a laser beam and corresponding finned tube
KR20190122219A (en) * 2017-02-24 2019-10-29 오또꿈뿌 오와이제이 Resistance welding of non-weldable metals with sprayed intermediate layers
TWI762588B (en) * 2017-02-24 2022-05-01 芬蘭商奧托昆布公司 Resistance welding of unweldable metals with thermal sprayed interlayers
EP3369516A1 (en) * 2017-02-24 2018-09-05 Outokumpu Oyj Multistage joining process with thermal sprayed layers
US11548087B2 (en) 2017-02-24 2023-01-10 Outokumpu Oyj Resistance welding of unweldable metals with thermal sprayed interlayers
WO2019149336A1 (en) * 2017-02-24 2019-08-08 Outokumpu Oyj Multistage joining process with thermal sprayed layers
CN110312589A (en) * 2017-02-24 2019-10-08 奥托库姆普联合股份公司 Not solderable metal is welded with thermal spraying interlayer resistance
EP3366406A1 (en) * 2017-02-24 2018-08-29 Outokumpu Oyj Resistance welding of unweldable metals with thermal sprayed interlayers
US11524351B2 (en) 2017-02-24 2022-12-13 Outokumpu Oyj Multistage joining process with thermal sprayed layers
CN111432971A (en) * 2017-02-24 2020-07-17 奥托库姆普联合股份公司 Multi-stage bonding process using thermal spray coating
TWI783095B (en) * 2017-02-24 2022-11-11 芬蘭商烏托昆普公司 Multistage joining process with thermal sprayed layers
WO2018153785A1 (en) * 2017-02-24 2018-08-30 Outokumpu Oyj Resistance welding of unweldable metals with thermal sprayed interlayers
RU2776711C2 (en) * 2017-02-24 2022-07-25 Оутокумпу Оюй Contact welding of non-welded metals using intermediate layers applied by thermal spraying
KR102436341B1 (en) * 2017-02-24 2022-08-25 오또꿈뿌 오와이제이 Resistance Welding of Non-Weldable Metals with Thermal Spray Interlayers
US20210291298A1 (en) * 2018-07-19 2021-09-23 Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) Method for manufacturing joined structure of dissimilar materials, and joined structure of dissimilar materials
CN110091431A (en) * 2019-04-30 2019-08-06 西安理工大学 A kind of steel tube concrete pile and manufacturing method
CN111283328A (en) * 2020-03-19 2020-06-16 昆山华恒焊接股份有限公司 Method for welding heat exchange tube and tube plate

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Publication number Publication date
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