CA1079040A - Soldered tube end - Google Patents
Soldered tube endInfo
- Publication number
- CA1079040A CA1079040A CA300,125A CA300125A CA1079040A CA 1079040 A CA1079040 A CA 1079040A CA 300125 A CA300125 A CA 300125A CA 1079040 A CA1079040 A CA 1079040A
- Authority
- CA
- Canada
- Prior art keywords
- sleeve
- solder
- cylindrical
- swaging
- pipe ends
- Prior art date
- Legal status (The legal status 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 status listed.)
- Expired
Links
Landscapes
- Non-Disconnectible Joints And Screw-Threaded Joints (AREA)
Abstract
SOLDERED TUBE END
ABSTRACT OF THE DISCLOSURE
An initially loose fitting aluminium sleeve is pre-tinned with fluxless solder and, while the solder is molten, is swaged down and rotated to form a tight soldered joint connecting two aluminium tube ends, or an aluminium tube end to a copper tube end.
ABSTRACT OF THE DISCLOSURE
An initially loose fitting aluminium sleeve is pre-tinned with fluxless solder and, while the solder is molten, is swaged down and rotated to form a tight soldered joint connecting two aluminium tube ends, or an aluminium tube end to a copper tube end.
Description
In the art of joining the ends of metal tubes together~
particularly if one or both of the tubesare of an aluminum base alloy, it has been known to provide a solid coating of fluxless solder on a surface of at least one of two tubular elements to be joined together and, after heating the solder to its melting point, to slide the tubular elements against each otherto disturb the oxide coating normally present on aluminum and thereby facilitate the bonding of the solder to metallic aluminum beneath the oxide layer. However, the necessary sliding fit complicates the operation and requires the expense of manufacturing to close tolerances.
It has also been known to connect tube ends by enlarging one to fit over the other, or by soldering each to a connecting sleeve fitting over both.
In accordance with the present invention, a method of forming a tight soldered joint between a first hollow, cylindrical member and a second cylindrical member, the first cylindrical member having an inner cylindrical surface loosely overlapping and coaxial with an outer cylindrical surface of the second cylindrical member, comprising the steps of precoating at least one of the said surfaces with solder, heating the soldered surface to the melting temperature of the solder, and, while maintaining the melting temperature, swaging down the first cylindrical member to reduce the diameter thereof and bring its inner surface into an interference fit with the outer surface of the second cylindrical member, and while performing the swaging operation, simultaneously also moving one of the cylindrical members relative to the other to cause the said surface to slide against each other, thereby tending to penetrate the surfaces to expose bare metal to the molten solder.
The invention also provides a method of connecting two aluminum pipe ends comprising the steps of precoating .
solder on the interior surface of a sleeve memberr at least adjacent its two opposite ends~ or on the exterior surfaces of the pipe ends, the sleeye being a loose fit over the pipe ends, maintaining the temperature of the sleeve and pipe ends high enough to melt the solder~ and while the solder is melted~
swaging down at least the opposite ends of the sleeve until the sleeve ends grip the pipe ends in an interference fit, and during the swaging operation simultaneously moving the sleeve relative to the pipe ends~ thereby tending to rub through the naturally occurring oxide on the aluminum surfaces adjacent the solder to expose bare metal to the molten solder, ~-The accompanying drawings show, for purpose of illustration only, present preferred embodiments of the invention, in which:
Fig. 1 is a diagrammatic cross-sectional view taken along the axis of a pair of tube ends with a sleeve positioned over the gap between them, the sleeve being precoated with solder in accordance with the invention;
Fig. 2 shows a diagrammatic cross-sectional view corresponding to Fig. 1, except that a pair of swage blocks of the invention are also shown after swaging down and soldering the sleeve to the tube ends in accordance with the invention;
Fig. 3 shows diagrammatically the swaging tool of which the swage blocks are shown in Fig. 2, viewed endwise relative to Fig. 2 but omitting the tube ends and sleeve assembly and -showing the swage blocks spaced slightly apart; and Fig. 4 corresponds in larger scale to Fig. 3 but shows details of a present preferred tool of the invention.
DESCRIPTION
Referring now more particularly to the drawing, and initially to Fig. 1, there is illustrated a pair of tubes 10 and 12 in aligned end-to-end relation, with their respective ends 14 and 16 facing each other. Although the _ 3 _ ends 14 and 16 are illustrated as belng spaced, they could be abutting.
A sleeve 18 extends loosely around the ends 14 and 16 and across the ~oint between them~ to ~oin the two tubes 10 and 12. At least the outer ends 22 and 24 of the inner surface of sleeve 18 are precoated with solder 20, suitable for rluxless soldering of aluminum-base alloys. When ~oin-lng parts of aluminum-base alloys or copper-base alloy.s, whether aluminum to aluminum or aluminum to copper, the present preferred solder is 95% zinc and 5% aluminum. Another solder example is a zinc base solder comprising about 2 to 5 percent aluminum, up to about 5 percent copper, and up to about 1 percent magnesium by wei~ht, such as the solder sold ~nder the trade name of Ney 380 manufactured by Ney Metals, Inc., of Brooklyn, New York, comprising 90% zinc, 5% aluminum, 4.~% copper and 0.1% magnesium, balance aluminum.
~he sleeve 18 is placed over one Or the tubes 10 or 12 before the tubes are moved to the position shown in the drawing, and then the sleeve 18 is moved lengthwise until its ends 22 and 24 overlap both of the tube ends 14 and 16.
The sleeYe is preferably made to fit loosely over the tube ehds 14 and 16, thus facilitat^ng the operation and avoiding the cost of producing the sleeve and tube ends to fine ~olerances.
When the parts are thus assembled 9 at least the ends 22 and 24 of sleeve 18 are swaged down to reduce their diameter. Heat is applied to the sleeve ends so that the ~older coating 20 is molten during swaging. The tube ends 14 and 16 are preferably preheated to assist in melting the .
.
.
107gO40 ' solder. Such meltin~ temperature is maintalned as the swaging action brings the inner solder-bearing surfaces of the sleeve ends 22 and 24 against the outside of ~he ~ubular ends 14 and 16, and simultaneously sleeve 18 ls 5. moved relative to the tube ends 14 and 16, preferably rotationally, but possibly longitudinally, to disturb ~he.naturally-occurring oxide coating around the outside o~ the tube ends 14 and 16. This ensures that the solder will bond to the metalIic aluminum beneath th~ oxide coating. The result is a tight soldered ~oint bet~een the tube ends 14 and 16.
The above-described swagin~ action is preferably accomplished by means of the swaging tool 26 illustrated in Figs. 2 and 3. Tool 26 comprises a pair of blocks 28 and 30 respectively mounted on the ends o~ a pair of elongated elements pivoted on a pin 36 operated by handles 38 and 40 in the manncr of a pair of p~iers. Although this simple form of actuation is illustrated for conven-ience, it is preferable to use an adjustable toggle to 20 give better leverage for gripping, such as exemplified in the well-known form.of lockin~ pliers sold under the (~ig. ~) trademark "Vise Grip" / Opposed semi-cylindrical die faces 42 and 44 respectively formed in the blocks 28 and 30 are . pressed toward each other when the handles 38 and 40 are pressed toward each other. The die faces 42 and 44 are cham~ered at their side edges, as sho~n at 46 in Fig. 3, and respectively have longitudinal grooves 48 and 50 .
midway around each die ~ace, in order to provide small ' , .
, ., . , - , .
~079040 spaces ror flo~l o~ metal from the outside Or sleeve 18 when the blocks 28 and 30 are pressed together. The metal Or sleeve 18 ln these spaces helps to prevent rotary slippage Or the blocks 28 and 30 relative to sleeve 18, especially if the outside as well as the inside Or sleeve 18 is precoated with solder. The die ~aces 42 and 44 could extend straight across between the opposite ends Or blocks 28 and 30, which would result in ~waging down the whole length Or sleeve 18, as might be pre~erred when ~oining abutting tube ends. However, swaging ef~ort is reduced by relieving the middle por-tions 52 and 54 Or the respective die races 42 and 44 when ~oining spaced tube ends, so that only the ends 22 and 24 of the sleeve 18 are swaged down, as sho~n in the drawing. Electrical heater elements (not shown) can be mounted in the blocks 28 and 30 ~or internally heating the blocks 28 and 30 and thus also the sleeve ends 22 and 24.
The blocks 28 and 30 are prererably bored out to ~orm the die ~aces 42 and 44 while they are clamped against each other, to provide a bore having a diameter ælightly smaller than the sum Or the outside diameter o~
~he tube ends 14 and 16 plus twice the thickness Or the respective tube ends, and to make contact between the blocks act as a limit to control the degree of swaging action. Thus, when the blocks 28 and 30 are pressed ~ogether by the handles 38 ~nd 40, a slight inter~erence ~it will be created between the inside o~ the sleeve ends 22 and 24 with the tube ends 14 and 16. The _6-.
iO790~0 thickness o~ solder precoatlng 20 (includlng any solderwhich may be precoated around the outside Or the sleeve 18) is considered ne~ligible for determining the dimen-sions necessary to achieve the said lnterference fit, slnce the solder when molten is squeezed out until it has very little thickness between the parts being swaged down.
In a specific example of the practice of the invèn-tion, a coaxial cable was connected by first silver soldering together the two abutting copper tube ends constituting the inside element of the coaxial cable.
The outside element of the cable to be ~oined ~ere a pair Or aluminum-base alloy tubes concentrically surround-ing and radially spaced from the copper inner tube. In order to provide access to the abutting inside copper ends for such solderin~, the outside tube ends had to be posit~oned about an inch (2.5 cm) apart. The outside ~ubes had an outside diameter Or .410 inch (1.69 cm) and a wall thickness Or .022 inch (.559 mm) and were not precoated with solder or flux. An aluminum-base alloy æleeve was earlier precoated with 95% zinc - 5% aluminum ~older by complete submersion in a bath of molten solder whlle sub~ected to ultrasinic vibration to improve the bond. The sleeve precoated wlth solid solder was ini-tially positioned around one o~ the outer tube ends awayrrom the ~oint between them. After silver soldering the copper inner tube ends, a gas torch was used to preheat the spaced outer tube ends, the sleeve was slid over the --7~
.
~oint between the aluminum cnds to a pOSitiOIl li~e that shown ln ~ig. 1, an~ ~he ~as torch was applied to preheat the sleeve to the melting temperature Or the solder. The swaging tool blocks, which had a die face bore of .423 inch (1.075 cm), were in the meanwhile preheated by the gas torch, and were clamped around the sleeve and pressure was exerted until the blocks came against the sleeve long enough to heat the tube - ends to solder melting temperature and hard enough to tighten the sleeve around the tube ends. The swaging t~ol was then ~0 rotated several times back and ~orth through an arc of about 30, carrying the sleeve with it, while the tube ends remained ~tationary. Then the blocks were pressed together until abut-~ing each other, as shown diagran~atically in Fig. 2, thereby ~waging down the sleeve until it had an interference fit with the spaced aluminum ~ube ends. The grip of the blocks was then released and the ~oint was ready for use. The swaging operation take~ about ~ half a minute or less for tubes of this size.
Another example Or the practice of the invention con-sists of ~oining two tube ends for use in a refrigeration 8ystem, one being of an aluminum base alloy and the other being of rerrigerant g-ade copFer, while in abutting rela-- tlonship. The aluminum tube erd had an outside diameter of .500 inch (1.27 cm), and a wall thickness of .037 inch (.855 mm), while the copper tube had the same outside diameter and a wall thickness of .030 inch (.693 mm). The tube ends were not precoated with solder or flux. The 81eeve to form the ~oint was of aluminum base alloy and was about 7/8 inch long (2.22 cm), with a wall thickness Or .050 inch (.127 mm) and a die face bore of .525 inch (1.335 cm).
~ -8-.
iO79040 The .sleeve was entirely precoated with solder as ln the previous example. The s~ragin~ and soldeIing operations were as described above, except that the joint di~fered rrom that diagra~atically illustrated in Fig. 2 in `that the tube ends were abutting and the swaging blocks were not relieved in the middle, so that the sleeve was uniformally swaged down from one end to the other.
The swage blocks used in the above-stated examples were of mild steel. However, stainless steel or other material less subject to reaction with the solder, ~rould be pre~erable.
The temperatures o~ the blocks and joint assembly were determined by observing melting of the solder. When the solder is molten it is slippery between the sleeve and tube ends, and this is ~elt when the blocks and slee`ve are rotated relative to the tube ends. In general, the temperature range Or the region to be Joined is pre-~erably between the m~lting point o~ the solder (about 720F) up to about 800F).
Aluminum base alloys suitable ~or the purpose o~ the lnventlon are electrical grade, 1200, 3003, and 6061, to name just a few examples. In general, any fluxless æolderable aluminum base alloy can be ~oined in accordance with the invention. While th~ invention is not advantage-ous ~or ~oining copper tubes to copper tubes, because copper can more readily be soldered by other methods, it is advantageous ~or ~oining aluminum tubes to copper tubes, as ln the above-stated example. Attentlon is also drawn ..9 _ to the fact that the invention is applicàble to Joining s~lid wires or bars, instead Or tubes, While present preferred embodiments of the inven-tion and method of practicing the same have been illus-trated and described, it will be understood that the ~.nvention is not l~mited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.
~io~
.
. . .
particularly if one or both of the tubesare of an aluminum base alloy, it has been known to provide a solid coating of fluxless solder on a surface of at least one of two tubular elements to be joined together and, after heating the solder to its melting point, to slide the tubular elements against each otherto disturb the oxide coating normally present on aluminum and thereby facilitate the bonding of the solder to metallic aluminum beneath the oxide layer. However, the necessary sliding fit complicates the operation and requires the expense of manufacturing to close tolerances.
It has also been known to connect tube ends by enlarging one to fit over the other, or by soldering each to a connecting sleeve fitting over both.
In accordance with the present invention, a method of forming a tight soldered joint between a first hollow, cylindrical member and a second cylindrical member, the first cylindrical member having an inner cylindrical surface loosely overlapping and coaxial with an outer cylindrical surface of the second cylindrical member, comprising the steps of precoating at least one of the said surfaces with solder, heating the soldered surface to the melting temperature of the solder, and, while maintaining the melting temperature, swaging down the first cylindrical member to reduce the diameter thereof and bring its inner surface into an interference fit with the outer surface of the second cylindrical member, and while performing the swaging operation, simultaneously also moving one of the cylindrical members relative to the other to cause the said surface to slide against each other, thereby tending to penetrate the surfaces to expose bare metal to the molten solder.
The invention also provides a method of connecting two aluminum pipe ends comprising the steps of precoating .
solder on the interior surface of a sleeve memberr at least adjacent its two opposite ends~ or on the exterior surfaces of the pipe ends, the sleeye being a loose fit over the pipe ends, maintaining the temperature of the sleeve and pipe ends high enough to melt the solder~ and while the solder is melted~
swaging down at least the opposite ends of the sleeve until the sleeve ends grip the pipe ends in an interference fit, and during the swaging operation simultaneously moving the sleeve relative to the pipe ends~ thereby tending to rub through the naturally occurring oxide on the aluminum surfaces adjacent the solder to expose bare metal to the molten solder, ~-The accompanying drawings show, for purpose of illustration only, present preferred embodiments of the invention, in which:
Fig. 1 is a diagrammatic cross-sectional view taken along the axis of a pair of tube ends with a sleeve positioned over the gap between them, the sleeve being precoated with solder in accordance with the invention;
Fig. 2 shows a diagrammatic cross-sectional view corresponding to Fig. 1, except that a pair of swage blocks of the invention are also shown after swaging down and soldering the sleeve to the tube ends in accordance with the invention;
Fig. 3 shows diagrammatically the swaging tool of which the swage blocks are shown in Fig. 2, viewed endwise relative to Fig. 2 but omitting the tube ends and sleeve assembly and -showing the swage blocks spaced slightly apart; and Fig. 4 corresponds in larger scale to Fig. 3 but shows details of a present preferred tool of the invention.
DESCRIPTION
Referring now more particularly to the drawing, and initially to Fig. 1, there is illustrated a pair of tubes 10 and 12 in aligned end-to-end relation, with their respective ends 14 and 16 facing each other. Although the _ 3 _ ends 14 and 16 are illustrated as belng spaced, they could be abutting.
A sleeve 18 extends loosely around the ends 14 and 16 and across the ~oint between them~ to ~oin the two tubes 10 and 12. At least the outer ends 22 and 24 of the inner surface of sleeve 18 are precoated with solder 20, suitable for rluxless soldering of aluminum-base alloys. When ~oin-lng parts of aluminum-base alloys or copper-base alloy.s, whether aluminum to aluminum or aluminum to copper, the present preferred solder is 95% zinc and 5% aluminum. Another solder example is a zinc base solder comprising about 2 to 5 percent aluminum, up to about 5 percent copper, and up to about 1 percent magnesium by wei~ht, such as the solder sold ~nder the trade name of Ney 380 manufactured by Ney Metals, Inc., of Brooklyn, New York, comprising 90% zinc, 5% aluminum, 4.~% copper and 0.1% magnesium, balance aluminum.
~he sleeve 18 is placed over one Or the tubes 10 or 12 before the tubes are moved to the position shown in the drawing, and then the sleeve 18 is moved lengthwise until its ends 22 and 24 overlap both of the tube ends 14 and 16.
The sleeYe is preferably made to fit loosely over the tube ehds 14 and 16, thus facilitat^ng the operation and avoiding the cost of producing the sleeve and tube ends to fine ~olerances.
When the parts are thus assembled 9 at least the ends 22 and 24 of sleeve 18 are swaged down to reduce their diameter. Heat is applied to the sleeve ends so that the ~older coating 20 is molten during swaging. The tube ends 14 and 16 are preferably preheated to assist in melting the .
.
.
107gO40 ' solder. Such meltin~ temperature is maintalned as the swaging action brings the inner solder-bearing surfaces of the sleeve ends 22 and 24 against the outside of ~he ~ubular ends 14 and 16, and simultaneously sleeve 18 ls 5. moved relative to the tube ends 14 and 16, preferably rotationally, but possibly longitudinally, to disturb ~he.naturally-occurring oxide coating around the outside o~ the tube ends 14 and 16. This ensures that the solder will bond to the metalIic aluminum beneath th~ oxide coating. The result is a tight soldered ~oint bet~een the tube ends 14 and 16.
The above-described swagin~ action is preferably accomplished by means of the swaging tool 26 illustrated in Figs. 2 and 3. Tool 26 comprises a pair of blocks 28 and 30 respectively mounted on the ends o~ a pair of elongated elements pivoted on a pin 36 operated by handles 38 and 40 in the manncr of a pair of p~iers. Although this simple form of actuation is illustrated for conven-ience, it is preferable to use an adjustable toggle to 20 give better leverage for gripping, such as exemplified in the well-known form.of lockin~ pliers sold under the (~ig. ~) trademark "Vise Grip" / Opposed semi-cylindrical die faces 42 and 44 respectively formed in the blocks 28 and 30 are . pressed toward each other when the handles 38 and 40 are pressed toward each other. The die faces 42 and 44 are cham~ered at their side edges, as sho~n at 46 in Fig. 3, and respectively have longitudinal grooves 48 and 50 .
midway around each die ~ace, in order to provide small ' , .
, ., . , - , .
~079040 spaces ror flo~l o~ metal from the outside Or sleeve 18 when the blocks 28 and 30 are pressed together. The metal Or sleeve 18 ln these spaces helps to prevent rotary slippage Or the blocks 28 and 30 relative to sleeve 18, especially if the outside as well as the inside Or sleeve 18 is precoated with solder. The die ~aces 42 and 44 could extend straight across between the opposite ends Or blocks 28 and 30, which would result in ~waging down the whole length Or sleeve 18, as might be pre~erred when ~oining abutting tube ends. However, swaging ef~ort is reduced by relieving the middle por-tions 52 and 54 Or the respective die races 42 and 44 when ~oining spaced tube ends, so that only the ends 22 and 24 of the sleeve 18 are swaged down, as sho~n in the drawing. Electrical heater elements (not shown) can be mounted in the blocks 28 and 30 ~or internally heating the blocks 28 and 30 and thus also the sleeve ends 22 and 24.
The blocks 28 and 30 are prererably bored out to ~orm the die ~aces 42 and 44 while they are clamped against each other, to provide a bore having a diameter ælightly smaller than the sum Or the outside diameter o~
~he tube ends 14 and 16 plus twice the thickness Or the respective tube ends, and to make contact between the blocks act as a limit to control the degree of swaging action. Thus, when the blocks 28 and 30 are pressed ~ogether by the handles 38 ~nd 40, a slight inter~erence ~it will be created between the inside o~ the sleeve ends 22 and 24 with the tube ends 14 and 16. The _6-.
iO790~0 thickness o~ solder precoatlng 20 (includlng any solderwhich may be precoated around the outside Or the sleeve 18) is considered ne~ligible for determining the dimen-sions necessary to achieve the said lnterference fit, slnce the solder when molten is squeezed out until it has very little thickness between the parts being swaged down.
In a specific example of the practice of the invèn-tion, a coaxial cable was connected by first silver soldering together the two abutting copper tube ends constituting the inside element of the coaxial cable.
The outside element of the cable to be ~oined ~ere a pair Or aluminum-base alloy tubes concentrically surround-ing and radially spaced from the copper inner tube. In order to provide access to the abutting inside copper ends for such solderin~, the outside tube ends had to be posit~oned about an inch (2.5 cm) apart. The outside ~ubes had an outside diameter Or .410 inch (1.69 cm) and a wall thickness Or .022 inch (.559 mm) and were not precoated with solder or flux. An aluminum-base alloy æleeve was earlier precoated with 95% zinc - 5% aluminum ~older by complete submersion in a bath of molten solder whlle sub~ected to ultrasinic vibration to improve the bond. The sleeve precoated wlth solid solder was ini-tially positioned around one o~ the outer tube ends awayrrom the ~oint between them. After silver soldering the copper inner tube ends, a gas torch was used to preheat the spaced outer tube ends, the sleeve was slid over the --7~
.
~oint between the aluminum cnds to a pOSitiOIl li~e that shown ln ~ig. 1, an~ ~he ~as torch was applied to preheat the sleeve to the melting temperature Or the solder. The swaging tool blocks, which had a die face bore of .423 inch (1.075 cm), were in the meanwhile preheated by the gas torch, and were clamped around the sleeve and pressure was exerted until the blocks came against the sleeve long enough to heat the tube - ends to solder melting temperature and hard enough to tighten the sleeve around the tube ends. The swaging t~ol was then ~0 rotated several times back and ~orth through an arc of about 30, carrying the sleeve with it, while the tube ends remained ~tationary. Then the blocks were pressed together until abut-~ing each other, as shown diagran~atically in Fig. 2, thereby ~waging down the sleeve until it had an interference fit with the spaced aluminum ~ube ends. The grip of the blocks was then released and the ~oint was ready for use. The swaging operation take~ about ~ half a minute or less for tubes of this size.
Another example Or the practice of the invention con-sists of ~oining two tube ends for use in a refrigeration 8ystem, one being of an aluminum base alloy and the other being of rerrigerant g-ade copFer, while in abutting rela-- tlonship. The aluminum tube erd had an outside diameter of .500 inch (1.27 cm), and a wall thickness of .037 inch (.855 mm), while the copper tube had the same outside diameter and a wall thickness of .030 inch (.693 mm). The tube ends were not precoated with solder or flux. The 81eeve to form the ~oint was of aluminum base alloy and was about 7/8 inch long (2.22 cm), with a wall thickness Or .050 inch (.127 mm) and a die face bore of .525 inch (1.335 cm).
~ -8-.
iO79040 The .sleeve was entirely precoated with solder as ln the previous example. The s~ragin~ and soldeIing operations were as described above, except that the joint di~fered rrom that diagra~atically illustrated in Fig. 2 in `that the tube ends were abutting and the swaging blocks were not relieved in the middle, so that the sleeve was uniformally swaged down from one end to the other.
The swage blocks used in the above-stated examples were of mild steel. However, stainless steel or other material less subject to reaction with the solder, ~rould be pre~erable.
The temperatures o~ the blocks and joint assembly were determined by observing melting of the solder. When the solder is molten it is slippery between the sleeve and tube ends, and this is ~elt when the blocks and slee`ve are rotated relative to the tube ends. In general, the temperature range Or the region to be Joined is pre-~erably between the m~lting point o~ the solder (about 720F) up to about 800F).
Aluminum base alloys suitable ~or the purpose o~ the lnventlon are electrical grade, 1200, 3003, and 6061, to name just a few examples. In general, any fluxless æolderable aluminum base alloy can be ~oined in accordance with the invention. While th~ invention is not advantage-ous ~or ~oining copper tubes to copper tubes, because copper can more readily be soldered by other methods, it is advantageous ~or ~oining aluminum tubes to copper tubes, as ln the above-stated example. Attentlon is also drawn ..9 _ to the fact that the invention is applicàble to Joining s~lid wires or bars, instead Or tubes, While present preferred embodiments of the inven-tion and method of practicing the same have been illus-trated and described, it will be understood that the ~.nvention is not l~mited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.
~io~
.
. . .
Claims (9)
1. A method of forming a tight soldered joint between a first hollow, cylindrical member and a second cylindrical member, the first cylindrical member having an inner cylindrical surface loosely overlapping and coaxial with an outer cylindrical surface of the second cylindrical member, comprising the steps of pre-coating at least one of the said surfaces with solder, heating the soldered surface to the melting temperature of the solder, and, while maintaining the melting temperature, swaging down the first cylindrical member to reduce the diameter thereof and bring its inner surface into an interference fit with the outer surface of the second cylindrical member, and while performing the swaging operation, simultaneously also moving one of the cylindrical members relative to the other to cause the said surface to slide against each other, thereby tending to penetrate the surfaces to expose bare metal to the molten solder.
2. A method according to claim 1,in which at least one of the metal members has its portion which forms its said cylindrical surface composed of an aluminium base alloy.
3. A method according to claim 1, in which at least one of the metal members has its portion which forms its said cylindrical surface composed of a copper base alloy.
4. A method according to claim 1, in which the method is used to join two second metal members consisting of the ends of two tubes and a surrounding sleeve forming the first metal member, whereby the tube ends are joined to each other through the sleeve.
5. A method according to claim 4, in which the surfaces of the sleeve which are to overlap the surfaces of the tube ends are precoated with solder.
6. A method according to any preceding claim, wherein the step of moving one of members relative to the other during swaging is performed rotationally.
7. A method of connecting two aluminium pipe ends comprising the steps of precoating solder on the ineterior surface of a sleeve member, at least adjacent its two opposite ends, or on the exterior surfaces of the pipe ends, the sleeve being a loose fit over the pipe ends, maintaining the temperature of the sleeve and pipe ends high enough to melt the solder, and while the solder is melted, swaging down at least the opposite ends of the sleeve until the sleeve ends grip the pipe ends in an interference fit, and during the swaging operation simultaneously moving the sleeve relative to the pipe ends, thereby tending to rub through the naturally occurring oxide on the aluminium surfaces adjacent the solder to expose bare metal to the molten solder.
8. A method according to claim 7, wherein the precoating of solder is on the interior surface of the sleeve member.
9. A method according to claim 7 or 8, wherein the movement of the sleeve relative to the pipe ends is rotational movement.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA300,125A CA1079040A (en) | 1978-03-30 | 1978-03-30 | Soldered tube end |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA300,125A CA1079040A (en) | 1978-03-30 | 1978-03-30 | Soldered tube end |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1079040A true CA1079040A (en) | 1980-06-10 |
Family
ID=4111119
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA300,125A Expired CA1079040A (en) | 1978-03-30 | 1978-03-30 | Soldered tube end |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1079040A (en) |
-
1978
- 1978-03-30 CA CA300,125A patent/CA1079040A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |