CA1324485C - High pressure bonding process - Google Patents
High pressure bonding processInfo
- Publication number
- CA1324485C CA1324485C CA 588165 CA588165A CA1324485C CA 1324485 C CA1324485 C CA 1324485C CA 588165 CA588165 CA 588165 CA 588165 A CA588165 A CA 588165A CA 1324485 C CA1324485 C CA 1324485C
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- Prior art keywords
- interface
- bodies
- bonding process
- accordance
- improved bonding
- Prior art date
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Abstract
ABSTRACT
An improved bonding process comprises the steps of forming a first interim interface surface in a first body, the interface surface being selectively surrounded by portions of said first body, and forming a second exterior interface surface, the exterior interface surface selectively surrounding portions of the second body. The first and second bodies are assembled such that the first and second interfacing surfaces selectively contact each other. The dimensions of the first and second interface surfaces are selected such that pressure contact is maintained between them. The first and second bodies are subjected to a bonding cycle to form a bond along the first and second interface surfaces.
An improved bonding process comprises the steps of forming a first interim interface surface in a first body, the interface surface being selectively surrounded by portions of said first body, and forming a second exterior interface surface, the exterior interface surface selectively surrounding portions of the second body. The first and second bodies are assembled such that the first and second interfacing surfaces selectively contact each other. The dimensions of the first and second interface surfaces are selected such that pressure contact is maintained between them. The first and second bodies are subjected to a bonding cycle to form a bond along the first and second interface surfaces.
Description
o~ ~ 1324485 03 SPECI~ICATION
04 TITLE: High Pressure Bonding Proces~
05 INVENTOR: Shane J. Findlan o~
09 Field of t~e Invention `
11 The ;nvention relates ~o metal working proces~Qs and more 12 particularly to improved HIP Bonding processes particularly 13 suited for bonding au~tenitic materials.
14 : "
15D~SCRIPTION OF THE PRIOR ART
17Sp~c~ ed Pres~ure Bonding techniquQ~ are wldely availnbl~
18in thQ prior art. ~or example, U.S. PatQnt Number 4,628,008 lg issued to Conolly discu~sQs the assembly of "sticks" to form a de~ect-immuni~ed ma~or component such as a turbine disc or rotor.
21 Prior art tQchniques are further illugtrated by U.S. Patent No~
22 4,603,801, issued to Wan which discloses an interference fit seal 2~ to prevent the pressure transmitting medium from entering the 24 interfaces of the HIP bonding ~oint. The pressure transmitting medium i8 further describQd as a thick, high-vlscosity material, a6 such as molten glass, which is thick enough not to penetrate the 27 interference fit sQal. Other prior art techniques are 28 illustratQd by U.S. Patent No. 4,485,961, issued to Ekbon, which 29 illustrates a method for creating a weld using the HIP bonding technique. The ~oint i8 covered by a powder of similar composition to thQ material being ~oined, whi~h is in turn 2~485 01 Icovered by variou~ glass~ e composition~ that act as a pre~sure 02 ¦ transmitting medium. ~t elevated temperatures, the glass 03 ¦composition melts and provides a sealing boundary. The powder 04 !covering the joints is fused during the ~IP Bonding proces~ to 05 ¦complete the weld .
07 ¦ A method for sheathing tubular nuclear fuel elements i~
08 ¦disclosed in u.S~ Patent No. 3,s59,274, isqued to Granata.
09 ¦Zir~alloy sheathing tube is shrink fitted in-~ide of a uranium lo ¦ pipe. After shrink fitting, the assembly is heated and the 11 ¦ outside is cooled so as to form a diffu~ion bond at the 12 ¦ interface. The fusion is due to the expansion of the sheath, 13 ¦ contraction of the tube, and the heat at the interface.
16 ¦ SUMMARY OF THE INVI~NTION
18 The ~nvention w~ich is the sub~ect matter of this patent 19 application comprises an improved Preggure Bonding process. ~he invention was reduced to practice as a result of and i8 21 described ~ith respect to its usQ to implant a fault o~ known 22 characteristic in a larger body of austenitic material. Howaver, 23 it will bQ appreciated by those skilled in the art that the 24 hereinafter described bonding process has many uses.
`
26 In demonstrating the invention, a fault having the de~ired 27 characteristics wa~ ~ormed in a surface of a first body of 28 austQnitic material and implanted in a larger body of austenitic 29 material by bonding the first body of austenitic material to a second similar body. The larger body of austQnitic material was machined to form a cylindrical structure (fault sampleJ
1324~85 01 iicontaining the fault with the fault positioned at a predetermlned 02 ~llocation therein. A cyl~ndr~cal cavity having a diameter lesq 03 l than the diameter of the cylindrical structure was machined in a 04 1 third body of austenitic material . The cylindrical structur~
05 1 and the ~hird body were respectively cryogenically cooled and 06 l heated to insert the cylindrical structure into the cavity.
07 1 After insertion of the cylindrical structure, the combined 08 Ijstructure was stabilized to a uniform temperature causing an 09 ¦1 interference fit creating sufficient pressure at the interface l formed by the interior of the cavity and the outer surface of the 11 l cylindrical structure to cause }ocalized cold working of the 12 linterface surfaces.
13 l 14 ~ A non-oxidizing atmosphere was establishQd around the combined structure and the interface gealed. A bond free of 16 detectable variations in grain strUCtUrQ wa~ formed along the 17 iinterface using a HIP bonding cy~le without slgniflcantly 18 ¦altering the original grain structure of portions of the 19 ~austenitic material which had not been sub~ected to cold working.
21 In demonstrating the invention conventional walding was us~d 22 to seal tha bonding interface. Additionally, it has also been 23 demonstrated that an interference fi~ can be utilised to achieve 24 high temperature bonding without i80~atic pre8surQ. Without thè
iso~tatic pressura during the bonding cycle, a detectable 26 discontinuity may develop along the bond line. Such 27 discontinuity may not be ob~ectionable in some applications.
29 ~ It is believed that the cold wor~ed surfaces as~oclated with ¦the disclosed process results in a small graln structure along the lntor~nce to be bonded. Th se ~maller gr~ln- rocombine to ., 132~48~
for~. larger grains extending across the interface producing a bond. Grain regrowth during the bonding cycle progresses to co~.pletion at a te~.perature sufficiently low to prevent grain alterations in the portions of the material not subjected to cold working. l~is permits HIP bonding to be accomplished at a lower temperature. A lo~er bonding temperature is an `
especially useful characteristic of the i~.proved bonding .
process when utilized to bond au.stenitlc metals. ``` `-.
DESCRIP'rION OF TNE DRAWIIIGS , ~
Fi~ure 1 iæ a dra~ing illustratlng two bodies of ` .
austenitic ~.aterial used to forD the fault ~ample.
~'` :`'',".~'' "
Figure 2 is a dra~ing illustrating t~o bodies of au~tenltic ~aterial assenbled for HIP bonding. ~ ```
Figure 3 i8 a drauing illu~.trating a fault l~.planted ~`
..
ln a body of au~tenltlc material~ ~.
~ : :`
Figure ~ is a dra~ing lllustratlng the fault sample ` ~ .
after flnal nachinlng. ::
Flgure 5 is a drawlng illustrating a thlrd body of ~... .
au~tenitic naterial lncluding a cyllndrical cavlty mac~ined ~; -~ ::;.. ... : . . . .
thereln.
`'`'''''"': ,'"` ;"
Flgure 6 i8 a drawing lllustrating the test structure afte.r final a~senbly.
';'.` .
::... . :
~, ,,.~ :.
.,.,; , ..
4 .. :.
;~.,,.,~, :: :.:... . . ...
~,.. . ,, , . . . " ~ , . .
132~85 01 Figure 7 is a drawing illustrating the test strUcturQ after 02 bonding and final machining.
0~
04 Figure 8 is a flow chart illustrating a process for 05 preparing the defect sàmple.
07 Figure g is a flow chart for the Bonding Process comprising 08 the inven~ion.
DETAI1~D DESCRIPTION
13 ~t was necQssary to carefully selQct the size and shape of 14 bodies of austanitic ma~erial to be ~oined togethor by prior art HIP bonding procQsses~ By contrast tho procQss whieh is the 1~ sub~oct of the invention described in this patent applieation can 17 be usod to ~oin bodie~ of any d~sirod ~ize as long as a suitable 18 interfaeQ betueen the two bodies i~ maintained. A ~uitable 19 interfaeo is maintained a~ long as the bodies to be bonded togQther aro proporly ~achined and assembled in accordance with 21 the process which is the sub~eet of the diselosed invention.
23 FigurQs 1 through 4 illustrates the fault sample at various 24 stagQs of assembly. In practicing the invention as applied to implanting a fault in a test strueture tFigure 6), the desired 26 fault is implanted into a fault sample which i8 in turn implanted 27 into a larger body to form a test structure.
29 Two sub~tantially identical first and second bodies, 20 and 22, of austenitie material are utilized to form the fault sample 34 (Figure 4). Two similar interfaces, 24 and 26, of the bodies 1~ 132448~
01 ¦~of materials, 20 and 22, are severely cold-worked u~lng any 02 suitable machining technique. A fault 28 having the desired 03 characteri~tics is formed in one surface, for example surfacQ 26 04 of body 22, using any suitable prior art techniques. The first 05 and second bodies of material~, 20 and 22, are po~itioned in 06 contacting end-to-end relationship to each other and sealed 07 around the periphery of the interface formed by the contacting o~ surfaces by welding in a protective atmosphere. The seal wald is 09 illustrated at reference numèral 30. A single unitary body 32 is formed by HIP bonding the bodies, 20 and 22, together. The body 11 32 is then machined to ~orm a cylindrical fault sample 34 12 containing the fault 28 therein.
14AlternativQly, the fault 28 may be ~ormed as eomplementary 15portion~ in the surfaceg, 24 and a6, of the bodies, 20 and 22.
1~ WhilQ eonventional HIP bonding proeessQs have been successfully 17 ¦ used to bond relatively small eomponent8, such a~ ~or formlng the 18 ¦ fault sampl~ 34, they have not proved successful in bonding 19 larger eomponents. These diffieultiQs with the prior art processQs arQ believed to bQ causQd by an inability of these 21 processQs to maintain a ouita~le interfaee between the eomponents 22 to be bonded as the si~e of thQ interfacing surfaces of the 23 components incrQases.
25In first dQmonstxating the invention disclosed herein, the 26 fault Qample 34 was implanted into a third larger body of 27 identical material at a predetermined loeation. Speeifieally, 28 thQ fault samplQ 34 was in~erted into a cylindrical cavity 40 in 29 a third body 42 of austenitic material. The diameter of the cavity 40 is smaller than the outer diameter of the fault sample 34 produeing an interference fit.
ol !~ 1324485 02 Insertion of the fault sample `34 lnto the cavity 40 was 03 facilitated by heating the third body 42 and cryogenically 04 cooling the fault sample 34. After insertion of the fault 05 sample 34 into the body of material 42 the resulting test 06 structure was stabilized to a uniform temperature re~ulting in 07 extreme pressure at the interface of the body of au~tenitic 08 material 42 and the fa~lt sample 34. Thi~ pressure cau~e~
os cold-working of the interf~cing surfaces. S~al welding in a lo protectivQ atmosphere was utilized along the upper and lower 11 surfaces of tha third ~ody of material 42 and the fault samplQ
12 34 to seal ~he inter~ace. This results in the assemblQd test 13 structure illustrated in Figure 6. The agsembled test structure 14 was subjected to a HIP bonding cycle to form a unitary body free of abnormal~ties at the interface of the third body of 16 austenitic ~ater~al 42 and ~he fault sample 34 without causing 17 undesirablQ ~etallurgical changes ln t~e other portions o~ the 18 structure. The bond forms as the grains comprising the 19 cold-wor~ed surfaces r~form into larger grain~ extending across thQ interface. As previously discussed, this grain regrowth 21 restores the original grain structure along thQ bond an~
22 progresses to completion ~ithout altering the grain struCturQ of 23 portions of the au~tenitic material which have not bean sub~ected 24 to cold working.
26 After bonding, the test component can be machined into any 27 desired configuration. In the development program, it W~8 28 machined into a rectangular body as illugtrated in Figure 7 which 29 was sub~ectQd to varlous tests to demon8trate that the improved bonding process performed as desired.
Il 132~85 ol ! Figure 8 .Ls a flow chart of the process utilized to form the 02 fault sample 34. The first step `is to cut the austenltic 03 material to form the two substantially identical bodies, 20 and 04 26, which are subsequently HIP bonded to form the fault sample 34 05 (Figure 4)~ This step is functionally illustrated at reference 06 numeral 60, Figure 8.
07 :
08 Cold worked surfaces, 24 and 26, are produced by machining os selected surfaces of the ~wo rectan~ular bodie~, ao and 22. A
fault 28 is fabricated using any desired process. These steps 11 are functionally illustra~ed at reference numerals, 62 and 64. :
13 The fault 28 is installed in at least one surface of the 14 bodies, 20 and 22. Prot~ction for the interface i8 provided by a seal weld as illustrated in Figure 2. Proces~ step~ producing 16 these results are illu~trated ~t referQnc~ numerals, 66 and 68.
1~ The fault ~ample is HIP Bonded and maohined into final form to 18 produce the fault sample 34 as illustrated at raf~rence numerals, 19 70 and 72. :
ao 21 Fabrication of the test structurs is functionall~
22 lllustratad in Figure 9. Nore specifically, the first step in 23 the proces~ i~ to machine the cavity 40 in the third body of 24 austenitlc material 42, as functionally illustrated at reference numeral 80. After the cavity 40 has been machined, the fault 26 samplQ 34 is in~tal~ed into the cavity by heatinq the third body 27 of austenitic material 42 and cooling the fault sample 34. This 28 process is functionally illustrated at reference numeral 82.
29 After installation of the fault sample 34, the interface .is welded to ses~ the ~unction and the combined structure H:tP
bonded, as functionally illustrated at Reference Numerals, 84 and 1~ 132~485 ol 86. After bonding the test structure i8 machined into the 02 desired configuration, as functionally illustrated at Reference 03 Numeral 88.
05 Process parameters such as pres~ure and temparature for 06 performing the above described bonds are determined by the 07 characteristics of the matarials . Selection of these paramQters 08 is within the capability o~ tho~e skilled in the art. Also, the og process can be used to bond materials other than the austen~.tic lo materials described above.
l7 ~9 ~
04 TITLE: High Pressure Bonding Proces~
05 INVENTOR: Shane J. Findlan o~
09 Field of t~e Invention `
11 The ;nvention relates ~o metal working proces~Qs and more 12 particularly to improved HIP Bonding processes particularly 13 suited for bonding au~tenitic materials.
14 : "
15D~SCRIPTION OF THE PRIOR ART
17Sp~c~ ed Pres~ure Bonding techniquQ~ are wldely availnbl~
18in thQ prior art. ~or example, U.S. PatQnt Number 4,628,008 lg issued to Conolly discu~sQs the assembly of "sticks" to form a de~ect-immuni~ed ma~or component such as a turbine disc or rotor.
21 Prior art tQchniques are further illugtrated by U.S. Patent No~
22 4,603,801, issued to Wan which discloses an interference fit seal 2~ to prevent the pressure transmitting medium from entering the 24 interfaces of the HIP bonding ~oint. The pressure transmitting medium i8 further describQd as a thick, high-vlscosity material, a6 such as molten glass, which is thick enough not to penetrate the 27 interference fit sQal. Other prior art techniques are 28 illustratQd by U.S. Patent No. 4,485,961, issued to Ekbon, which 29 illustrates a method for creating a weld using the HIP bonding technique. The ~oint i8 covered by a powder of similar composition to thQ material being ~oined, whi~h is in turn 2~485 01 Icovered by variou~ glass~ e composition~ that act as a pre~sure 02 ¦ transmitting medium. ~t elevated temperatures, the glass 03 ¦composition melts and provides a sealing boundary. The powder 04 !covering the joints is fused during the ~IP Bonding proces~ to 05 ¦complete the weld .
07 ¦ A method for sheathing tubular nuclear fuel elements i~
08 ¦disclosed in u.S~ Patent No. 3,s59,274, isqued to Granata.
09 ¦Zir~alloy sheathing tube is shrink fitted in-~ide of a uranium lo ¦ pipe. After shrink fitting, the assembly is heated and the 11 ¦ outside is cooled so as to form a diffu~ion bond at the 12 ¦ interface. The fusion is due to the expansion of the sheath, 13 ¦ contraction of the tube, and the heat at the interface.
16 ¦ SUMMARY OF THE INVI~NTION
18 The ~nvention w~ich is the sub~ect matter of this patent 19 application comprises an improved Preggure Bonding process. ~he invention was reduced to practice as a result of and i8 21 described ~ith respect to its usQ to implant a fault o~ known 22 characteristic in a larger body of austenitic material. Howaver, 23 it will bQ appreciated by those skilled in the art that the 24 hereinafter described bonding process has many uses.
`
26 In demonstrating the invention, a fault having the de~ired 27 characteristics wa~ ~ormed in a surface of a first body of 28 austQnitic material and implanted in a larger body of austenitic 29 material by bonding the first body of austenitic material to a second similar body. The larger body of austQnitic material was machined to form a cylindrical structure (fault sampleJ
1324~85 01 iicontaining the fault with the fault positioned at a predetermlned 02 ~llocation therein. A cyl~ndr~cal cavity having a diameter lesq 03 l than the diameter of the cylindrical structure was machined in a 04 1 third body of austenitic material . The cylindrical structur~
05 1 and the ~hird body were respectively cryogenically cooled and 06 l heated to insert the cylindrical structure into the cavity.
07 1 After insertion of the cylindrical structure, the combined 08 Ijstructure was stabilized to a uniform temperature causing an 09 ¦1 interference fit creating sufficient pressure at the interface l formed by the interior of the cavity and the outer surface of the 11 l cylindrical structure to cause }ocalized cold working of the 12 linterface surfaces.
13 l 14 ~ A non-oxidizing atmosphere was establishQd around the combined structure and the interface gealed. A bond free of 16 detectable variations in grain strUCtUrQ wa~ formed along the 17 iinterface using a HIP bonding cy~le without slgniflcantly 18 ¦altering the original grain structure of portions of the 19 ~austenitic material which had not been sub~ected to cold working.
21 In demonstrating the invention conventional walding was us~d 22 to seal tha bonding interface. Additionally, it has also been 23 demonstrated that an interference fi~ can be utilised to achieve 24 high temperature bonding without i80~atic pre8surQ. Without thè
iso~tatic pressura during the bonding cycle, a detectable 26 discontinuity may develop along the bond line. Such 27 discontinuity may not be ob~ectionable in some applications.
29 ~ It is believed that the cold wor~ed surfaces as~oclated with ¦the disclosed process results in a small graln structure along the lntor~nce to be bonded. Th se ~maller gr~ln- rocombine to ., 132~48~
for~. larger grains extending across the interface producing a bond. Grain regrowth during the bonding cycle progresses to co~.pletion at a te~.perature sufficiently low to prevent grain alterations in the portions of the material not subjected to cold working. l~is permits HIP bonding to be accomplished at a lower temperature. A lo~er bonding temperature is an `
especially useful characteristic of the i~.proved bonding .
process when utilized to bond au.stenitlc metals. ``` `-.
DESCRIP'rION OF TNE DRAWIIIGS , ~
Fi~ure 1 iæ a dra~ing illustratlng two bodies of ` .
austenitic ~.aterial used to forD the fault ~ample.
~'` :`'',".~'' "
Figure 2 is a dra~ing illustrating t~o bodies of au~tenltic ~aterial assenbled for HIP bonding. ~ ```
Figure 3 i8 a drauing illu~.trating a fault l~.planted ~`
..
ln a body of au~tenltlc material~ ~.
~ : :`
Figure ~ is a dra~ing lllustratlng the fault sample ` ~ .
after flnal nachinlng. ::
Flgure 5 is a drawlng illustrating a thlrd body of ~... .
au~tenitic naterial lncluding a cyllndrical cavlty mac~ined ~; -~ ::;.. ... : . . . .
thereln.
`'`'''''"': ,'"` ;"
Flgure 6 i8 a drawing lllustrating the test structure afte.r final a~senbly.
';'.` .
::... . :
~, ,,.~ :.
.,.,; , ..
4 .. :.
;~.,,.,~, :: :.:... . . ...
~,.. . ,, , . . . " ~ , . .
132~85 01 Figure 7 is a drawing illustrating the test strUcturQ after 02 bonding and final machining.
0~
04 Figure 8 is a flow chart illustrating a process for 05 preparing the defect sàmple.
07 Figure g is a flow chart for the Bonding Process comprising 08 the inven~ion.
DETAI1~D DESCRIPTION
13 ~t was necQssary to carefully selQct the size and shape of 14 bodies of austanitic ma~erial to be ~oined togethor by prior art HIP bonding procQsses~ By contrast tho procQss whieh is the 1~ sub~oct of the invention described in this patent applieation can 17 be usod to ~oin bodie~ of any d~sirod ~ize as long as a suitable 18 interfaeQ betueen the two bodies i~ maintained. A ~uitable 19 interfaeo is maintained a~ long as the bodies to be bonded togQther aro proporly ~achined and assembled in accordance with 21 the process which is the sub~eet of the diselosed invention.
23 FigurQs 1 through 4 illustrates the fault sample at various 24 stagQs of assembly. In practicing the invention as applied to implanting a fault in a test strueture tFigure 6), the desired 26 fault is implanted into a fault sample which i8 in turn implanted 27 into a larger body to form a test structure.
29 Two sub~tantially identical first and second bodies, 20 and 22, of austenitie material are utilized to form the fault sample 34 (Figure 4). Two similar interfaces, 24 and 26, of the bodies 1~ 132448~
01 ¦~of materials, 20 and 22, are severely cold-worked u~lng any 02 suitable machining technique. A fault 28 having the desired 03 characteri~tics is formed in one surface, for example surfacQ 26 04 of body 22, using any suitable prior art techniques. The first 05 and second bodies of material~, 20 and 22, are po~itioned in 06 contacting end-to-end relationship to each other and sealed 07 around the periphery of the interface formed by the contacting o~ surfaces by welding in a protective atmosphere. The seal wald is 09 illustrated at reference numèral 30. A single unitary body 32 is formed by HIP bonding the bodies, 20 and 22, together. The body 11 32 is then machined to ~orm a cylindrical fault sample 34 12 containing the fault 28 therein.
14AlternativQly, the fault 28 may be ~ormed as eomplementary 15portion~ in the surfaceg, 24 and a6, of the bodies, 20 and 22.
1~ WhilQ eonventional HIP bonding proeessQs have been successfully 17 ¦ used to bond relatively small eomponent8, such a~ ~or formlng the 18 ¦ fault sampl~ 34, they have not proved successful in bonding 19 larger eomponents. These diffieultiQs with the prior art processQs arQ believed to bQ causQd by an inability of these 21 processQs to maintain a ouita~le interfaee between the eomponents 22 to be bonded as the si~e of thQ interfacing surfaces of the 23 components incrQases.
25In first dQmonstxating the invention disclosed herein, the 26 fault Qample 34 was implanted into a third larger body of 27 identical material at a predetermined loeation. Speeifieally, 28 thQ fault samplQ 34 was in~erted into a cylindrical cavity 40 in 29 a third body 42 of austenitic material. The diameter of the cavity 40 is smaller than the outer diameter of the fault sample 34 produeing an interference fit.
ol !~ 1324485 02 Insertion of the fault sample `34 lnto the cavity 40 was 03 facilitated by heating the third body 42 and cryogenically 04 cooling the fault sample 34. After insertion of the fault 05 sample 34 into the body of material 42 the resulting test 06 structure was stabilized to a uniform temperature re~ulting in 07 extreme pressure at the interface of the body of au~tenitic 08 material 42 and the fa~lt sample 34. Thi~ pressure cau~e~
os cold-working of the interf~cing surfaces. S~al welding in a lo protectivQ atmosphere was utilized along the upper and lower 11 surfaces of tha third ~ody of material 42 and the fault samplQ
12 34 to seal ~he inter~ace. This results in the assemblQd test 13 structure illustrated in Figure 6. The agsembled test structure 14 was subjected to a HIP bonding cycle to form a unitary body free of abnormal~ties at the interface of the third body of 16 austenitic ~ater~al 42 and ~he fault sample 34 without causing 17 undesirablQ ~etallurgical changes ln t~e other portions o~ the 18 structure. The bond forms as the grains comprising the 19 cold-wor~ed surfaces r~form into larger grain~ extending across thQ interface. As previously discussed, this grain regrowth 21 restores the original grain structure along thQ bond an~
22 progresses to completion ~ithout altering the grain struCturQ of 23 portions of the au~tenitic material which have not bean sub~ected 24 to cold working.
26 After bonding, the test component can be machined into any 27 desired configuration. In the development program, it W~8 28 machined into a rectangular body as illugtrated in Figure 7 which 29 was sub~ectQd to varlous tests to demon8trate that the improved bonding process performed as desired.
Il 132~85 ol ! Figure 8 .Ls a flow chart of the process utilized to form the 02 fault sample 34. The first step `is to cut the austenltic 03 material to form the two substantially identical bodies, 20 and 04 26, which are subsequently HIP bonded to form the fault sample 34 05 (Figure 4)~ This step is functionally illustrated at reference 06 numeral 60, Figure 8.
07 :
08 Cold worked surfaces, 24 and 26, are produced by machining os selected surfaces of the ~wo rectan~ular bodie~, ao and 22. A
fault 28 is fabricated using any desired process. These steps 11 are functionally illustra~ed at reference numerals, 62 and 64. :
13 The fault 28 is installed in at least one surface of the 14 bodies, 20 and 22. Prot~ction for the interface i8 provided by a seal weld as illustrated in Figure 2. Proces~ step~ producing 16 these results are illu~trated ~t referQnc~ numerals, 66 and 68.
1~ The fault ~ample is HIP Bonded and maohined into final form to 18 produce the fault sample 34 as illustrated at raf~rence numerals, 19 70 and 72. :
ao 21 Fabrication of the test structurs is functionall~
22 lllustratad in Figure 9. Nore specifically, the first step in 23 the proces~ i~ to machine the cavity 40 in the third body of 24 austenitlc material 42, as functionally illustrated at reference numeral 80. After the cavity 40 has been machined, the fault 26 samplQ 34 is in~tal~ed into the cavity by heatinq the third body 27 of austenitic material 42 and cooling the fault sample 34. This 28 process is functionally illustrated at reference numeral 82.
29 After installation of the fault sample 34, the interface .is welded to ses~ the ~unction and the combined structure H:tP
bonded, as functionally illustrated at Reference Numerals, 84 and 1~ 132~485 ol 86. After bonding the test structure i8 machined into the 02 desired configuration, as functionally illustrated at Reference 03 Numeral 88.
05 Process parameters such as pres~ure and temparature for 06 performing the above described bonds are determined by the 07 characteristics of the matarials . Selection of these paramQters 08 is within the capability o~ tho~e skilled in the art. Also, the og process can be used to bond materials other than the austen~.tic lo materials described above.
l7 ~9 ~
Claims (10)
1) An improved bonding process comprising the steps of a) selecting first and second bodies to be bonded together;
b) forming a first interim interface surface in said first body, said interface surface being selectively surrounded by portions of said first body;
c) forming a second exterior interface surface, said exterior interface surface selectively surrounding portions of said second body;
d) assembling said first and second bodies such that said first and second interfacing surfaces selectively contact each other and with the dimensions of said first and second interface surfaces selected such that pressure contact is maintained between said first and second interface surfaces.
e) subjecting said first and second bodies to a bonding cycle to form a bond along said first and second interface surfaces.
b) forming a first interim interface surface in said first body, said interface surface being selectively surrounded by portions of said first body;
c) forming a second exterior interface surface, said exterior interface surface selectively surrounding portions of said second body;
d) assembling said first and second bodies such that said first and second interfacing surfaces selectively contact each other and with the dimensions of said first and second interface surfaces selected such that pressure contact is maintained between said first and second interface surfaces.
e) subjecting said first and second bodies to a bonding cycle to form a bond along said first and second interface surfaces.
2) An improved bonding process in accordance with claim 1 further including the step of selecting the dimensions of said first and second interface surfaces such that the pressure between said surfaces is sufficient to cause changes in the characteristic of said interface surfaces, said changes promoting the formation of said bond.
3) An improved bonding process in accordance with claim 2 further including the step of forming a seal enclosing said interface surfaces.
4) An improved bonding process in accordance with claim 3 further including the step of surrounding said interface surface with a protective atmosphere before said seal is formed.
5) An improved bonding process in accordance with claim 4 wherein said bonding cycle includes the further steps simultaneously applying a preselected pressure to the exterior of said first and second bodies and (2) increasing the temperature of said first and second bodies to a preselected value.
6) An improved bonding process in accordance with claim 5 further including the steps of simultaneously increasing the temperature of said first body and decreasing the temperature of said second body to selectively change the dimensions of said first and second surfaces to aid in assembling said first and second bodies with pressure along said interface increasing as the temperature difference between said first and second bodies decreases.
7) An improved bonding process in accordance with claim 6 further including the steps of machining said first interface surfaces as a cylindrical cavity.
8) An improved bonding process in accordance with claim 7 further including the step of machining said second body to form a solid cylinder having an exterior surface comprising said second interface surface.
9) An improved bonding process in accordance with claim 8 wherein said first and second bodies are an austenitic metal.
10) An improved bonding process in accordance with claim 9 further including the steps of controlling the dimensions of said interface surfaces and the parameters of the bonding cycle to produce a bond free of discontinuity.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US14453788A | 1988-01-14 | 1988-01-14 | |
| US144,537 | 1988-01-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1324485C true CA1324485C (en) | 1993-11-23 |
Family
ID=22509034
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 588165 Expired - Fee Related CA1324485C (en) | 1988-01-14 | 1989-01-13 | High pressure bonding process |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1324485C (en) |
-
1989
- 1989-01-13 CA CA 588165 patent/CA1324485C/en not_active Expired - Fee Related
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| Date | Code | Title | Description |
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| MKLA | Lapsed |