EP0431019B1 - Systeme de disque a double alliage - Google Patents

Systeme de disque a double alliage Download PDF

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Publication number
EP0431019B1
EP0431019B1 EP89909656A EP89909656A EP0431019B1 EP 0431019 B1 EP0431019 B1 EP 0431019B1 EP 89909656 A EP89909656 A EP 89909656A EP 89909656 A EP89909656 A EP 89909656A EP 0431019 B1 EP0431019 B1 EP 0431019B1
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EP
European Patent Office
Prior art keywords
disk
vent
workpiece
die
bondline
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EP89909656A
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German (de)
English (en)
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EP0431019A1 (fr
EP0431019A4 (en
Inventor
John M. Hyzak
Thimoty E. Howson
Wilford H. Couts, Jr.
Steven H. Reichman
Hugo E. Delgado
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Wyman Gordon Co
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Wyman Gordon Co
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Priority claimed from US07/225,907 external-priority patent/US5106012A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
    • B21K1/00—Making machine elements
    • B21K1/28—Making machine elements wheels; discs
    • B21K1/32—Making machine elements wheels; discs discs, e.g. disc wheels
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
    • B21J5/00—Methods for forging, hammering, or pressing; Special equipment or accessories therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/02—Blade-carrying members, e.g. rotors

Definitions

  • the disks which support the blades rotate at a high speed in a relatively elevated temperature environment.
  • the temperatures encountered by the disk at its outer or rim portion may be in the region of 820°C (1500°F), whereas in the inner bore portion which surrounds the shaft upon which the disk is mounted, the temperature will typically be much lower, less than 520°C (1000°F).
  • a disk may be limited by the creep properties of the material in the high temperature rim area and by the tensile properties of the material in the lower temperature bore region.
  • Another object of the invention is to provide a method of making an axisymmetric gas turbine disk having optimum bore properties in its bore region and optimum rim properties in its rim region.
  • Another object of the invention is to provide a method by which defects in the bond between two alloys can be displaced to a zone which can be removed from the workpiece, the method also causing such strain at the bondline that undesirable effects of any remaining defects are minimized.
  • Another object of the invention is to provide a method by which defects in the bond between two alloy regions of a part can be displaced to a sacrificial zone which can be removed from the finished part, the displacement occurring in a highly efficient manner in which the minimum amount of alloy metal is displaced out of the part (into the sacrificial zone) while still causing removal of up to 99.9+% of the original bondline interface and associated defects, the method also causing such strain at the bondline that the undesirable effect of any remaining defects are minimized.
  • the present invention provides a method of forming a disk having a disk axis, a first disk face and a second disk face, and an annular outer edge which defines the outermost extent of the workpiece, the disk having a central portion formed of a first alloy and an annular peripheral portion formed of a second alloy, and the boundary between the central and peripheral portions being a surface of revolution about the disk axis and being defined by a generatrix having a first end and a second end, a line between the first end and the second end forming a bondline, the said surface having a first circular edge at the first face of the disk and generated by the first end of the generatrix, and a second circular edge at the second face of the disk and generated by the second end of the generatrix, and the disk also comprising material initially present at the boundary, comprising the steps of:
  • the said substantial amount may be at least 80%, preferably at least 90%, more preferably at least 95%, and most preferably at least 99% of the material initially present at the boundary.
  • the present invention can be used in two modes.
  • the first mode which shall be called forge boding, involves the application of the present forging method to pieces of metal which are simply in physical contact or have been bonded together in only a limited way such as tack welding, or encapsulation welding.
  • the forge bonding provides the primary means by which the two pieces of metal become bonded.
  • the second mode which shall be called forge enhanced bonding, the two pieces of metal are bonded by other means prior to the application of the forging technique of this invention.
  • the two pieces of metal are nickel-based superalloys formed from fine-grained powder metal, and, prior to forge enhanced bonding, have been diffusion-bonded together using the method of hot isostatic pressing.
  • the forging is accomplished under conditions which allow enhanced plastic flow or superplastic flow.
  • the invention also provides a gas turbine disk preform as set forth in claim 27 and a pair of forging dies as set forth in claim 28.
  • FIG. 1 shows a graphic representation of a forging workpiece which will be machined into a gas turbine disk.
  • the workpiece 10 is shown to still bear the sacrificial rib 11 which is positioned adjacent the bond between the bore or plug 13 and the rim 15.
  • FIG. 2 shows a cut-away view of a workpiece and, particularly, shows a section of the sacrificial ribs 11 and 17 which are adjacent the bondline 16.
  • the bondline 16 is, of course, in fact, a surface of revolution which represents the contact between the bore section 13 and the rim section 15.
  • FIG. 3 the disk is shown after the sacrificial rib 11 has been machined away from the disk.
  • That particularly appropriate geometry represents a method of forming a disk 150 having a disk axis 151, a first disk face 152, a second disk face 153, and an annular outer edge 171, which defines the outermost extent of the workpiece.
  • the disk also has a central portion 154 formed of a first alloy and an annular peripheral portion 155 formed of a second alloy.
  • the boundary 156 between the central and peripheral portions is a surface of revolution 157 about the disk axis 151 and is defined by a generatrix 158 having a first end 159 and a second end 160.
  • the surface 157 has a first circular edge 161 at the first face 152 of the disk 150 , generated by the first end 159 of the generatrix 158, and a second circular edge 162 at the second face 153 of the disk 150, generated by the second end 160 of the generatrix 158 .
  • the process comprises three steps.
  • the first step involves placing the disk 150 between a first die 163 having a first die face 164 and a second die 165 having a second die face 166.
  • Each die face has a concave impression 173 and 174 and the two impressions form a forging cavity 175.
  • At least one of said dies must have an annular vent 167 formed in its die face and on the surface of its impression, said vent 167 having two concentric vent edges 168 and 169 at the die face.
  • the second step involves causing the dies 163 and 165 to approach one another along a forging axis 170 which is parallel to the disk axis 151 so that the vent edges 168 and 169 straddle one of the edges of the surface, or, in some applications, straddle the location where the edge is desired.
  • This die movement causes forging action which is conducted in a manner to cause some of the first alloy and some of the second alloy, along with the material at the original bondline to flow into the vent along a line of movement substantially parallel to the forging axis to form a rib in the vent.
  • the third step involves removing the rib from the disk.
  • FIG. 4 shows a flow chart of a typical application of forge enhanced bonding (mode 2).
  • steps 21 and 22 respectively, the bore and rim sections would be formed, preferably by extrusion techniques, from fine-grained powdered metal into a billet.
  • steps 23 and 24 the bore and rim would be forged into preform shapes, preferably without causing grain growth.
  • steps 25 and 26 the parts are machined, and in particular, the mating surfaces are machined so that they are shape conforming to one another as the rim section fits peripherally about the bore section.
  • steps 27 and 28 the mating surfaces are cleaned, as, for example, by electro-polishing.
  • step 29 the bore and rim pieces are placed in contact and encapsulated in a vacuum environment.
  • This encapsulation can be accomplished by electron-beam welding simply at the outer edges of the bond surface, by electron-beam brazing in the same way, or by encapsulating the entire disk in a can.
  • the purpose is to keep the mating surfaces clean during the bond cycle (step 30).
  • step 30 the two pieces are diffusion bonded by exposing the workpiece to hot isostatic pressing.
  • step 31 the encapsulation is removed and in step 32, the bond is inspected.
  • Step 33 is where the workpiece is exposed to the forge enhanced bonding which will be discussed in detail subsequently.
  • step 34 the sacrificial rib is removed and inspected in step 35.
  • step 36 the bond within the workpiece itself is inspected.
  • the workpiece is machined to appropriate shape in step 37.
  • step 38 the workpiece is solution heat treated, either employing monotonic or differential heat treatment or a combination thereof.
  • step 39 the workpiece is aged (employing monotonic or differential heat treatment or a combination thereof), and in step 40 the workpiece is inspected.
  • FIG. 5 shows a flow sheet for the application of the present invention to forge bonding (mode 1). Essentially the preliminary activities are similar to those shown in FIG. 4 until step 59. In step 59, the bore and rim are placed in contact. At this point, the process may simply continue to the next step of forge bonding. This is particularly acceptable where the two pieces are force-fit together by designing the bondline with an appropriate draft angle or by using thermal expansion and contraction to form a very tight fit. However, it may be necessary, in appropriate circumstances, to tack weld the pieces together or to encapsulate the pieces in order to protect the clean surface from contamination.
  • FIGS. 6 through 11 demonstrate the steps of an application of the present invention in which vents 85 and 86 are simultaneously positioned at each end of the bondline during the forging process.
  • FIGS. 12 through 17 show a similar processing sequence in which the venting at one side is done in one strike and then the venting at the other side is done in the other strike. This will be called asymmetric venting as opposed to the symmetric venting of the process in FIGS. 6 through 11. This flexibility to adjust the vent shape and location allows the designer to control the metal flow into the vent and in so doing to control the displacement and straining of defects in the original bondline.
  • the disk which is shown in cross-section, is made up of a bore and a rim (which appears in two places).
  • the heavy dark line which appears at the bond lines represents potential defects which, as will be seen, are progressively moved out of the body of the workpiece and into the sacrificial ribs. Defects can be contaminates such as oxides, dirt, dust, voids, or inclusions in the metal. In addition, a defect can also be a grain, zone, or region of metal at or adjacent to the bondline which has a microstructure from the diffusion bond step not appropriate for service (depleted zone).
  • FIG. 6 shows the disk, or workpiece 70, in cross-section through its center, or axis.
  • the workpiece 70 is made up of a central bore or plug 71 and a rim 72, which appears in the drawing in two places.
  • the bore 71 and rim 72 are in contact at a bond surface 73 which is shown in the drawing as bondline 74 and bondline 75.
  • bondline 74 and bondline 75 can be bodies of defects shown as heavy dark lines 76 and 77.
  • the forging die 78 itself is made up of an upper die 79 and a lower die 81.
  • the impressions of both the upper die 79 and the lower die 81 include rib-forming vents 85 and 86 positioned at each of the ends of the bond lines. It should be understood that these vents are, in fact, circular grooves in the face of the die.
  • the forging dies of the present invention are normally shaped to closely conform to the initial shape of the workpiece or preform, except, of course, for the vents.
  • the forge bonding process causes little change in the shape of the workpiece and relatively small strains (metal flow) within the workpiece.
  • the exception is flow of the metal adjacent to the initial bondline. That metal flows toward the bondline and then flows parallel to and with the bondline outwardly from the ends of the bondline into the vents.
  • These large displacements and strains are concentrated almost entirely at and adjacent the bondline and at the region at the mouth of the vent.
  • the minimization of metal flow in the rest of the workpiece increases the predictability of the flow at the bondline and reduces flash as the dies close.
  • the process minimizes strain gradients in the workpiece and therefore minimizes microstructural changes that would result from strain gradients.
  • the dies are shaped so that they form a receptacle with the initial workpiece.
  • the receptacle local gap between the preform and the die surface
  • the receptacle is designed to passively accept metal flow during the process, and thereby to control the flow during the process.
  • This approach may be particularly useful in two situations. The first situation occurs when the volume of one alloy is much greater than that of the other. Applying the process to this situation can sometimes result in curving and radial displacement of the bondline. These results can he kept within acceptable limits by providing a receptacle to accept metal flow from the more plentiful alloy.
  • FIG. 6 shows the position of the workpiece and dies before the forging step.
  • the forging step has been carried out and it can be seen that material from the workpiece has flowed into the vents to form ribs on each side of the workpiece.
  • the defect material shown as dark lines, has been broken up, stretched out, and displaced outwardly from the bondline and into the area of the sacrificial ribs.
  • the dynamic movement of the metal during the forging operation causes effective displacement of defect material from the area of the bond lines and exposes any defect material left at the original bondline to very high levels of strain.
  • the straining and displacement of material at the bond lines is caused by general displacement induced in the bulk metal by the forging pressure. It is not merely the result of movement of the bore with respect to the rim as the dies close.
  • the forging operation is normally designed to be carried out at elevated temperature to lower the flow stress of the metal.
  • the forge process is designed to be carried out under isothermal conditions, that is, condition in which the workpiece and dies are at nominally the same temperature during forging and in which superplastic or enhanced plasticity deformation of the metal enhances metal flow to the bondline and into vent.
  • the process is designed so that the whole workpiece is heated to the same temperature during forging rather than the case of local heating of just the bondline region. This helps maintain microstructural uniformity throughout each alloy in the workpiece. It is also important to note that the die vents have been designed to effect a controlled and efficient displacement of the original bondline and associated defects.
  • the dies would be designed so that they closely fit the contour of the workpiece preform prior to forging. As a result, the large scale deformation is concentrated at the bondline.
  • Analytical simulations have shown that, via this general cavity design and loading situation (loading parallel to the metal movement into the vents), virgin metal is forced from both the bore and rim preforms to the bondline and the original bondline metal and defects are thereby forced out of the part geometry into the sacrificial ribs.
  • the vents are designed to remove the maximum amount of bondline metal for the least amount of total metal expelled into the sacrificial rib. It is also important to note that the forge bonding concept has shown excellent results in precise location of the final bondline. This ability to reproducibly predict the location of the bondline is imperative in turbine engine applications.
  • FIG. 8 shows the workpiece after the removal of the sacrificial ribs on each side of the workpiece. It can be noted that substantially all of the defect material (theoretically 99.9%+) has been displaced into the sacrificial ribs leaving little or no defect material within the remaining body of the workpiece once the sacrificial ribs have been removed. Because it has been noted that the exposure of defect materials to high strain within the workpiece significantly reduces the deleterious effect of the defect materials on the properties of workpieces, it is often appropriate to accept the very low level of defect material which remains in the workpiece at FIG. 8 and continue the processing of the workpiece in the conventional way.
  • FIGS. 9 through 11 show the sequence of the restrike. As can be seen by noting the location of the dark spots in the workpiece, they are displaced outward from the body of the workpiece into the sacrificial ribs where they are removed in FIG. 11.
  • FIGS. 12 through 17 show a process in which the ribs are formed in an asymmetric manner. This technique has been found to be very effective in various circumstances because there is no point along the bondline where the displacement reaches an essential equilibrium (zero displacement). As a result, the displacement which occurs at every point along the bondline, at one or the other of the two forging steps, effectively displaces the defects away from the body of the workpiece.
  • FIG. 12 shows the unprocessed workpiece 100 and the other elements which correspond roughly to those shown in FIG. 12. Note, however, that the lower die does not have the rim-forming vents.
  • the forging operation causes displacement of material from the area of the bondline upwardly into the vents of the upper die. This very effectively moves the material in this specific case from approximately the upper 90% of the bondline upward into the sacrificial rib area; the remaining 10% is highly strained and stretched over the thickness of the disk.
  • FIG. 14 the workpiece is shown after removal of the upper sacrificial rib.
  • this embodiment of the invention probably requires the further processing which is shown in FIG. 15. In that case, a new set of dies, in which there is no vent in the upper die, but there is a vent in the lower die, is used. It is also possible, in some applications, to design the workpiece so that, after the rib is removed from one side, the workpiece can be simply inverted and reforged, essentially reusing the original dies and vents.
  • FIG. 16 shows the second forging step in which displacement of the material at the bondline occurs downwardly into the vents in the lower die. This very effectively removes 90% of the remaining defects which were stretched across the bondline and essentially has removed 99% of the defects from the main body of the workpiece in two operations. The remaining defects have been stretched in two directions, thus significantly reducing their effect on properties.
  • FIG. 17 shows the removal of the lower sacrificial rib and shows that the defects have been effectively removed from the body of the workpiece. It should be kept in mind that any of the defects which remain in the body of the workpiece have been exposed to very significant strain, thereby, reducing their deleterious effects.
  • this process can shift 99+% of the original bondline and associated defects, out of the final shape or volume and into the sacrificial rib. This can be done in one or more forge operations depending on vent type (symmetric (in both dies), asymmetric (in one die)), vent offset from axis, vent profile shape, and vent volume or cross-sectional area.
  • vent type symmetric (in both dies), asymmetric (in one die)
  • vent offset from axis
  • vent profile shape vent profile shape
  • vent volume or cross-sectional area Typically one strike removes 80-90%, of the original bondline, and the second strike removes all but less than 1%. Since, normally, the defects, if present, are distributed along the original bondline, the amount of bondline removed correlates with the amount of defect removal. Furthermore, any remaining defects are deformed by 350% or more, thus substantially reducing their contribution to low cycle fatigue failure.
  • the amount of bondline which is displaced can be changed (increased) by modifying the vent geometry. For example, it is possible to remove 99% of the bondline in a single operation using an enlarged cavity.
  • the defects in question may include trapped dirt, oxides and voids, metallurgical defects and undesired interface alloys, and carbide precipitates, and gamma prime depleted zones. In essence, new metal from the body of the alloys is presented to the bondline.
  • the preferred embodiment of the present invention involves a series of process steps for forming a dual-alloy disk suitable to be formed into rotors, such as those used in gas turbine engines.
  • the technical approach is centered on technology best described as “forge bonding” or “forge enhanced bonding".
  • forge bonding is sometimes alternatively used generically to denominate the forging operation itself which is the focus of both modes. In experiments, the feasibility of this technology for producing a dual-alloy disk with a high integrity bond has been demonstrated.
  • the concept of forge bonding powdered metal superalloys includes four basic steps:
  • Step #3 the finish forge operation.
  • the purpose of this operation is to highly deform the original bondline and to displace the original bondline material with inherent defects outside of the finish machined part.
  • a schematic of a bonded preform in a set of dies is shown in FIG. 6. The dies are designed such that the deformation in the finish forge operation is concentrated at the bondline.
  • Figures 18 and 19 show the results of an analytical simulation of the forge enhanced bonding operation. The simulation was carried out using the ALPID (Analysis of Large Plastic Incremental Deformation) finite element, metal deformation computer program and appropriate metal property data.
  • ALPID Analysis of Large Plastic Incremental Deformation
  • Figure 18 shows one quarter section in profile of a workpiece in a die with symmetrically-cross-sectioned, equally-radially-spaced, forge enhanced bonding vents.
  • This case is for the symmetric (top and bottom cavities of the same size, same symmetric profile and same distance from the disk axis) die vents.
  • Only one quarter section needs to be modelled because of geometric symmetry.
  • the line pattern in Figure 18 on the workpiece represents a finite element grid or mesh. Each line intersection represents a point of metal and each closed figure represents a zone of metal.
  • Fig. 18-19 case is relatively simple, the result is relatively quantitatively accurate.
  • Figures 20 -27 involve more complex cases, and the finite element grids portray the grid distortion as a result of metal flow for the last 20% of the process cycle. Cumulative patterns are not available because a " remeshing " process is required in these complex cases. Thus, while these figures do not quantitatively portray the process, they do generally represent the qualitative metal flow pattern generated by the vent geometry.
  • Figure 19 shows the displacement of the grids after the forge enhanced bonding operation.
  • the displacement and strain are concentrated at the bondline, resulting in efficient removal of the original bondline and defects.
  • seven of the eight zones of metal adjacent to the bondline in figure 18 have been displaced into the vent (out of the part) in figure 19 as a result of one forging operation.
  • the fine spacing of the vertical lines at the bondline shows the movement of virgin metal from the body of the forging to the bondline to replace the original bondline material, which has been forced into the vent.
  • the strains and displacements are effective in removing defects from the original bondline. This has been demonstrated in forging of subscale, plane strain coupons. In the extreme, highly oxidized, unbonded interfaces have been dramatically improved by forge bonding. In one test of two Rene' 95 superalloy preforms, forge bonding caused 200% strain and 85% bondline displacement out of the part final shape. Cutting off the top and bottom "ribs" and reforging increased the bondline strain to 350% and the bondline displacement to 98% out of the final shape. The bondline which remained in the final shape was substantially defect free.
  • the forge bond approach to producing a dual alloy disk also gives exceptional control of the bondline position.
  • the original diffusion bond location can be controlled to machining tolerances ( ⁇ 0.05 mm (0.002")).
  • Subsequent forging in the finish dies is also a controllable process since the deformation is concentrated in the area of the bondline, and flow is from both sides of the bondline toward the center and then outward parallel to and along the bondline.
  • Metal flow is predictable using finite element modeling. This standard situation is shown in Figures 18 and 19. Because the flow of metal in the process has been found to be consistent and predictable, the process can be refined for specific special problems. For example, the vent shape can he used to normalize the effect of differing flow characteristics of the two alloys.
  • This aspect of this invention involves the shape of the cross-section of the vent and/or the position of the vent edges in relation to the edge of the bondline.
  • the cross-sectional shape of the vent would be symmetric on each side of the bondline.
  • the shape of the vent can be skewed to open up the side adjacent the alloy with the greater flow resistance in order to normalize the net flow of each alloy into the vent and, thereby, stabilize the bondline. Note that this vent profile is shown in Figure 24 although that figure also involves a different aspect of the invention (vent offset from axis).
  • the separate disk portions For assembly and bonding purposes, it is sometimes desirable to form the separate disk portions so that they mate with a draft angle. This allows the mating surface machining tolerance to be less critical (because conic sections are self-adjusting), and, if the surface of the inner element is slightly oversized, allows an enhanced degree of pressure to occur at the bondline at various points in the process. However, it is sometimes desirable to eliminate this draft angle during the forge bonding step so that the radial location of the bondline is uniform across the thickness of the disk.
  • the present invention provides an effective method for removing the draft angle.
  • the die vents can be so designed in shape and location (location of the top and bottom vents relative to each other) to accomplish this. It is, therefore, important to note that the forge enhanced bonding concept provides precise and predictable control of the finished forged bondline location and shape (especially draft angle).
  • the vents in the upper and lower dies should be set at different distances from the disk axis, i.e., with the edges of each vent straddling the locations where the edges of the surface are desired.
  • the non-equal radius (offset) vent arrangement will cause the draft angle to be formed where none previously existed.
  • Figures 26 (before) and 27 (after) show how an existing draft angle can be maintained.
  • the first factor is the cross-sectional area of the vent, especially in relation to the bondline length.
  • Other important factors are, second, the cross-sectional shape of the vents, third, the relationship between the height and the mouth width of the vents, and ,fourth, the relationship between the vent mouth widths and the disk thickness.
  • references to cross-sectional areas and to dimensions in the cross-sectional plane relate directly to and incorporate the three-dimensional geometry of the specific application or workpiece.
  • the cross-sectional area of a vent relates directly to the volume of the vent, although the relationship is not always simple.
  • the cross-sectional shape and cross-sectional area of the vents play an important role in optimizing this invention.
  • the cross-sectional area of the vent will determine how much metal is moved out of the workpiece by the vent.
  • the total metal moved from the workpiece by a particular application of this invention will be roughly equal to the total cross-sectional area of the vents used, with each reuse of a vent considered a separate use.
  • this invention requires a total movement of metal out of the workpiece equivalent to the initial thickness of the disk (the thickness dimension) at the initial bondline times one quarter (25%) that dimension.
  • this invention requires a movement of metal out of the workpiece equivalent to the initial thickness of the disk (the thickness dimension) at the bondline times one half (50%) the thickness dimension.
  • the invention requires a movement of metal out of the workpiece equivalent to the thickness dimension times 100% of the thickness dimension.
  • the optimization balances increasing defect removal against increasing waste of metal.
  • the metal removal may be accomplished in one or in more than one operation, depending on engineering considerations such as die strength, forge press capabilities, etc. In applications where freedom from bondline defects is not a critical requirement (e.g., where the presence of 20% of initial defects is tolerable) less metal removal than described may be appropriate.
  • the cross-sectional shape of the vents can take many forms.
  • the preferred shape would be roughly that of a triangle with a base side initially adjacent the workpiece and forming the mouth of the vent and a height line defining the distance between the base side and the farthest vent point from the base side. In practice, the inside and outside corners would be rounded.
  • the two vent profiles shown in figures 20 (a balanced or symmetric profile) and 24 (unbalanced or asymmetric profile) have been found to be particularly effective, not only in operation but also in analytical computer modeling. These vents might be described as bell-shaped.
  • the vents can be characterized by a height (H), a radius of curvature (RC) at the crown (closed end), a draft angle (A1 and A2) for each side, and entrance radii of curvature (ER1 and ER2).
  • the width (W) (mouth) of the vent is defined by the intersection of the vent wall (along the draft angle) with the continuation of the die impression (die face). The entrance radii are not involved in defining the vent width.
  • the relationship between the width of the vent mouth and the disk thickness or initial bondline length is significant.
  • a narrow mouth or width tends to concentrate flow at the bondline and therefore removes the maximum original bondline for the minimum total metal displaced into the vent. This represents the theoretically most efficient process with the least wasted metal.
  • a narrow width restricts metal flow due to frictional effects along the vent wall, and this restriction of flow is undesirable.
  • a wider mouth has the opposite effects.
  • the ratio between the vent width and initial bondline length should be two or less, preferably between 2.0 and 0.1, and optimally between 1.0 and 0.2. These values apply to the symmetric cross section. Appropriate adjustment must be made for asymmetrical profile cases.
  • the total cross-sectional vent area of both vents will be equal to or greater than the average width of the vents times the initial length of the bondline.
  • the cross-section of the vent will be substantially triangular with a base side against the workpiece, the width (W) of the vent being the length of the base side, and the height being the length of a height line which is a line representing the distance between the base side and the vent point farthest from base side.
  • the cross-section may be symmetric on both sides of the height line, or it may be asymmetric, i.e., the portion of the base side on one side of the height line is greater than the portion on the other side.
  • the width of the vent should be small compared to the height of the vent.
  • the height of a symmetric vent profile should be equal to or greater than one-half the width of the vent . It is preferred that the height of the vent is at least the width of the vent, and optimally at least twice the width of the vent.
  • the total cross-sectional area of the vents employed in the method equals approximately the average vent width of all of the vents employed in the method times the initial thickness of the disk. It should be understood that each edge of the vent will be curved, but that the vent width will be determined as if curves (entrance radii) were not present.
  • the method set out in this description is particularly useful when applied to superalloys and when applied under conditions that allow the metal flow to occur in an enhanced plasticity mode. More specifically, to achieve enhanced plasticity, certain alloys must have been previously processed to develop and maintain extremely fine grain size. Then, the process of the present invention is carried out at a temperature approaching the recrystallization temperature but below the grain-coarsening temperature of the alloys and employing low strain rates. This normally requires that both the dies and workpiece be heated to approximately the recrystallization temperature of the workpiece. The metal of the workpiece flows far more readily than would be observed at lower and significantly higher temperatures and faster strain rates, and this results in effective and predictable flow of metal from along the length of the bond line and outward into the vents. This allows the use of forge enhanced bonding vents with greater height-to-width ratios which increase the efficiency of the bondline removal. By employing the present method under conditions which allow enhanced plasticity, the process can be effectively employed on alloy pairs which would otherwise not be suitable choices.
  • enhanced plasticity shall be used to address the general regime in which the flow stress of a workpiece is lowered by isothermally forging at elevated temperature and low strain rate while maintaining fine grain structure.
  • Superplasticity refers to the portion of this regime in which strain rate sensitivity is 0.35 or greater.
  • Subsuperplasticity refers to the portion of the regime in which strain rate sensitivity is less than 0.35.
  • the forge bond concept does provide a unique non-destructive means of "testing" the quality of the bondline.
  • the material that is forged into the vents represents over 99% of the original bondline. That material can be removed from the forging as a destructible "test ring", and examined. It will provide a check on the quality of the original diffusion bond, especially on its cleanliness. It will also be a check on the forging of the bondline; the bondline should be present in the rib and in a predictable orientation.
  • Another potential application of the restrike capability would involve machining and sonic inspection of just the bondline region after forging. Again, if there was a defect present, the part could be reforged in the forge enhanced bonding die to remove that bondline defects and then reinspected.
  • the ability of the forge enhanced bonding concept to precisely control the location and orientation of the bondline after forging may be critical to the success of non-destructive inspection, especially sonic inspection.

Claims (28)

  1. Méthode pour façonner un disque (150) qui comporte un axe de disque (151), une première face de disque (152) et une deuxième face de disque (153), ainsi qu'un bord annulaire extérieur (171) qui définit l'extrémité la plus à l'extérieure de la pièce à travailler, ledit disque (150) possédant une partie centrale (154) formée d'un premier alliage et une partie annulaire périphérique (155) formée d'un deuxième alliage, la frontière (156) entre les parties centrale et périphérique (154, 155) constituant une surface de révolution (157) autour de l'axe du disque (151) et étant définie par une génératrice (158) ayant une première extrémité (159) et une deuxième extrémité (160), une ligne entre la première extrémité (159) et la deuxième extrémité (160) formant une ligne de liaison, ladite surface (157) comprenant un premier bord circulaire (161) situé sur la première face (152) du disque (150) et généré par la première extrémité (159) de la génératrice (158) ainsi qu'un deuxième bord circulaire (162) situé sur la deuxième face (153) du disque (150) et généré par la deuxième extrémité (160) de la génératrice (158), ledit disque (150) comportant également du matériau initialement présent dans la frontière (156), cette méthode comprenant les étapes suivantes:
    (a) placer le disque (150) entre une première matrice (163) avec une première face de matrice (164) et une deuxième matrice (165) avec une deuxième face de matrice (166), au moins une des matrices (163, 164) comportant d'un évent annulaire (167) façonné dans la face de matrice (164, 166) correspondante, l'évent (167) ayant deux bords concentriques d'évent (168, 169) dans la face de matrice (164, 166), le profil de la section transversale de l'évent (167) dans un plan radial par rapport à l'axe du disque (151) ayant une ligne de base qui relie les bords d'évent (168, 169) et une ligne de crête s'étendant sur la perpendiculaire partant de la ligne de base et allant au point du profil qui est le plus éloigné de la ligne de base;
    (b) faire que les matrices (163, 165) s'approchent l'une de l'autre le long de l'axe de forgeage (170) qui est parallèle à l'axe du disque (151), alors que l'on maintient le disque (150) et l'évent (167) substantiellement coaxiaux, de sorte que les bords d'évent (168, 169) chevauchent une ligne circulaire sur une surface du disque (150), ladite ligne circulaire correspondant à l'emplacement désiré de l'un des bords circulaires (161, 162) de la surface, et faire qu'ainsi quelque peu du premier alliage et quelque peu du deuxième alliage, ensemble avec une quantité substantielle du matériau qui était présent dans la frontière (156) coulent dans l'évent (167) le long d'une ligne de mouvement essentiellement parallèle à l'axe de forgeage (170) pour former une nervure (11) dans l'évent (167); et
    (c) enlever la nervure (11) du disque (150).
  2. Méthode telle que revendiquée dans la revendication 1, suivant laquelle un superalliage constitue l'un des alliages ou les deux alliages.
  3. Méthode telle que revendiquée dans la revendication 1 ou 2, suivant laquelle la génératrice (158) est une ligne droite.
  4. Méthode telle que revendiquée dans la revendication 3, suivant laquelle, avant sa mise en oeuvre, la génératrice (158) est parallèle à l'axe du disque (151), ou elle a un angle de dépouille par rapport à l'axe du disque (151) et, après l'exécution de la méthode, la génératrice (158) est parallèle à l'axe du disque (151).
  5. Méthode telle que revendiquée dans la revendication 3, suivant laquelle, avant la mise en oeuvre, la génératrice (158) est parallèle à l'axe du disque (151), ou elle a un angle de dépouille par rapport à l'axe du disque (151) et, après l'exécution de la méthode, la génératrice (158) possède un angle de dépouille par rapport à l'axe du disque (151).
  6. Méthode telle que revendiquée dans une quelconque des revendications 1 à 5, suivant laquelle la distance entre chaque point sur la surface de révolution (157) et l'axe du disque (151) est plus réduite que la distance entre le bord extérieur du disque (150) et l'axe du disque (151).
  7. Méthode telle que revendiquée dans une quelconque des revendications 1 à 6, suivant laquelle l'évent (167) est présent dans l'une seulement des faces (164, 166) de matrice.
  8. Méthode telle que revendiquée dans la revendication 7, suivant laquelle, après l'étape (c), ou bien la pièce à travailler (100) est retournée et les étapes de la méthode sont répétées, ou la pièce à travailler (100) est placée dans une deuxième paire de matrices de forgeage (163, 165) dans laquelle l'évent (167) est dans l'autre face (164, 166) de matrice et les étapes de la méthode sont répétées.
  9. Méthode telle que revendiquée dans une quelconque des revendications 1 à 6, suivant laquelle la première face de matrice (164) est pourvue d'un premier évent (85) et la deuxième face de matrice (166) est pourvue d'un deuxième évent (86), le premier évent (85) et le deuxième évent (86) étant équidistants ou non équidistants par rapport à l'axe (151) du disque au cours de l'exécution de la méthode, alors que le profil de la section transversale des évents (85, 86) est symétrique ou asymétrique autour de la ligne de crête.
  10. Méthode telle que revendiquée dans une quelconque des revendications 1 à 9, suivant laquelle la méthode est exécutée de telle façon que la pièce à travailler (10, 70, 100) se déforme avec une plasticité accrue.
  11. Méthode telle que revendiquée dans la revendication 10, suivant laquelle la pièce à travailler (10, 70, 100) se déforme de façon subsuperplastique ou de façon superplastique.
  12. Méthode telle que revendiquée dans une quelconque des revendications 1 à 11, suivant laquelle la méthode est exécutée avec l'intégralité de la pièce à travailler (10, 70, 100), et de préférence aussi avec les matrices (79, 81, 163, 165) à approximativement la même température élevée.
  13. Méthode telle que revendiquée dans une quelconque des revendications 1 à 11, suivant laquelle la méthode est exécutée avec les matrices (79, 81, 163, 165) et avec l'intégralité de la pièce à travailler (10, 70, 100) à approximativement la même température élevée et de telle manière que la croissance du grain de la pièce à travailler est supprimée.
  14. Méthode telle que revendiquée dans une quelconque des revendications 1 à 13, suivant laquelle substantiellement tout le matériau présent au départ dans la ligne de liaison est forcé à se déplacer dans l'évent ou dans les évents (85, 86, 167).
  15. Méthode telle que revendiquée dans une quelconque des revendications 1 à 14, suivant laquelle il se produit un écoulement suffisant dans l'évent ou dans les évents (85, 86, 167) pour causer un écoulement d'un volume massif à l'intérieur d'essentiellement l'intégralité de la pièce à travailler (10, 70, 100)
  16. Méthode telle que revendiquée dans une quelconque des revendications 1 à 15, suivant laquelle la surface du profil de l'évent est égale à ou plus grande que la longueur de la ligne de base multipliée par la longueur initiale de la ligne de liaison.
  17. Méthode telle que revendiquée dans une quelconque des revendications 1 à 16, suivant laquelle le profil de l'évent est substantiellement triangulaire.
  18. Méthode telle que revendiquée dans la revendication 17, suivant laquelle le profil est symétrique sur les deux côtés de la ligne de crête.
  19. Méthode telle que revendiquée dans la revendication 17, suivant laquelle la part du côté de la base sur un côté de la ligne de crête est plus grande que la part sur l'autre côté.
  20. Méthode telle que revendiquée dans une quelconque des revendications 1 à 19, suivant laquelle la hauteur du profil de l'évent est égale à ou plus grande que la longueur de la ligne de base, de préférence elle est au moins deux fois égale à ladite longueur.
  21. Méthode telle que revendiquée dans une quelconque des revendications 1 à 20, suivant laquelle la surface totale de la section transversale des évents (85, 86, 167) employée dans la méthode est égale approximativement à la largeur moyenne de l'embouchure de tous les évents employés dans la méthode multipliée par l'épaisseur initiale du disque (150).
  22. Méthode telle que revendiquée dans une quelconque des revendications 1 à 21, suivant laquelle aucune partie de la nervure ne s'étend plus loin que l'axe (151) du disque que ne le fait le bord extérieur (171).
  23. Méthode telle que revendiquée dans une quelconque des revendications 1 à 22, suivant laquelle, au cours de l'étape (b), les bords (168, 169) de l'évent (167) sont tous plus proches de l'axe (151) du disque que le bord extérieur (171) du disque (150).
  24. Méthode telle que revendiquée dans une quelconque des revendications 1 à 23, suivant laquelle chaque face de matrice (164, 166) est pourvue d'une empreinte de forge qui englobe un des évents (167), et, excepté pour ce qui est des évents (167), les formes des empreintes des matrices de forgeage (163, 165) définissent une cavité qui s'adapte intimement à la forme initiale de la pièce à travailler (10, 70, 100), l'écoulement vers les évents (167) durant le procédé de forgeage étant de préférence si substantiel qu'à l'exception des nervures (11) auprès des évents (167), il n'y a que peu de changement dans la forme de la pièce à travailler (10, 70, 100) au cours du procédé, et les déplacements et les déformations dans la pièce à travailler (10, 70, 100) sont concentrés le long de la frontière au cours de l'écoulement du métal près et au voisinage de ladite frontière vers les évents (167).
  25. Méthode telle que revendiquée dans une quelconque des revendications 1 à 24, suivant laquelle, à la suite de l'étape (c), le procédé est répété sur la ligne de liaison qui résulte de l'application précédente du procédé.
  26. Méthode telle que revendiquée dans une quelconque des revendications 1 à 25, suivant laquelle ladite quantité substantielle consiste dans essentiellement toute la matière initialement présente dans la frontière, ou elle s'élève à au moins 80%, de préférence à environ 90%, de la matière initialement présente dans la frontière.
  27. Une préforme appropriée pour façonner un disque de turbine à gaz, la préforme comportant:
    (a) un disque (10) qui est pourvu d'un axe de disque, d'une première face de disque et d'une deuxième face de disque, ainsi que d'un bord annulaire extérieur qui définit l'extrémité la plus à l'extérieure du disque (10), ledit disque (10) possédant une partie centrale (13) formée d'un premier alliage et une partie annulaire périphérique (15) formée d'un deuxième alliage, la frontière (16) entre les parties centrale et périphérique constituant une surface de révolution autour de l'axe du disque et étant définie par une génératrice ayant une première extrémité et une deuxième extrémité, ladite surface comportant un premier bord circulaire situé sur la première face du disque (10) et généré par la première extrémité de la génératrice, ainsi que d'un deuxième bord circulaire situé sur la deuxième face du disque (10) et généré par la deuxième extrémité de la génératrice, et
    (b) une nervure sacrificatoire (11) solidaire d'une face du disque (10) et adaptée pour en être enlevée, la nervure (11) étant située entièrement à l'intérieur du bord extérieur et ayant la frontière (16) qui passe à travers elle, de sorte qu'elle contient un peu de chaque alliage, ainsi que des défauts qui existent dans la frontière, essentiellement tous ces défauts existant dans cette part de la frontière qui est située à l'intérieur de la nervure (11), alors que le solde de ces défauts a été hautement déformé.
  28. Une paire de matrices de forgeage adaptées pour façonner un disque (150) qui est pourvu d'un axe de disque (151), d'une première face de disque (152) et d'une deuxième face de disque (153), ainsi que d'un premier bord annulaire extérieur (171) qui définit l'extrémité la plus à l'extérieure de la pièce à travailler, ledit disque (150) possédant une partie centrale (154) formée d'un premier alliage et une partie annulaire périphérique (155) formée d'un deuxième alliage, la frontière (156) entre les parties centrale et périphérique (154, 155) constituant une surface de révolution (157) autour de l'axe (151) du disque et étant définie par une génératrice (158) ayant une première extrémité (159) et une deuxième extrémité (160), ladite surface (157) comportant un premier bord circulaire (161) situé sur la première face (152) du disque (150) et généré par la première extrémité (159) de la génératrice (158), ainsi que d'un deuxième bord circulaire (162) situé sur la deuxième face (153) du disque (150) et généré par la deuxième extrémité (160) de la génératrice (158), cette paire de matrices de forgeage comportant:
    (a) une première matrice (163) avec une première face de matrice (164) et une première empreinte (173) formée dans sa face de matrice (164) et adaptée pour recevoir le disque (150), la première matrice (163) comportant un évent annulaire (167) façonné dans la face de matrice (164) et dans ladite empreinte, ledit évent (167) ayant deux bords concentriques d'évent (168, 169) dans la face de matrice (164), les deux étant entièrement à l'intérieur de l'empreinte (173) et positionnées pour chevaucher un bord circulaire désiré du disque (150), et
    (b) une deuxième matrice (165) ayant une deuxième face de matrice (166) et une deuxième empreinte (174) adaptée pour recevoir le disque (150).
EP89909656A 1988-07-29 1989-07-28 Systeme de disque a double alliage Expired - Lifetime EP0431019B1 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US225907 1981-01-19
US07/225,907 US5106012A (en) 1989-07-10 1988-07-29 Dual-alloy disk system
US37792589A 1989-07-10 1989-07-10
US377925 1989-07-10
PCT/US1989/003292 WO1990002479A2 (fr) 1988-07-29 1989-07-28 Systeme de disque a double alliage

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EP0431019A1 EP0431019A1 (fr) 1991-06-12
EP0431019A4 EP0431019A4 (en) 1991-07-31
EP0431019B1 true EP0431019B1 (fr) 1994-06-22

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JP (1) JP2721721B2 (fr)
AT (1) ATE107558T1 (fr)
AU (2) AU4180989A (fr)
DE (1) DE68916432T2 (fr)
GB (1) GB2239826B (fr)
WO (1) WO1990002479A2 (fr)

Cited By (2)

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KR101347034B1 (ko) 2012-11-20 2014-01-03 주식회사 노아닉스 스텐트 코팅장치
US8956700B2 (en) 2011-10-19 2015-02-17 General Electric Company Method for adhering a coating to a substrate structure

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5100050A (en) * 1989-10-04 1992-03-31 General Electric Company Method of manufacturing dual alloy turbine disks
US5161950A (en) * 1989-10-04 1992-11-10 General Electric Company Dual alloy turbine disk
FR2723868B1 (fr) * 1994-08-24 1996-09-20 Snecma Procede d'obtention d'une piece circulaire metallique a aubes
ATE218184T1 (de) * 1996-02-29 2002-06-15 Siemens Ag Turbinenwelle aus zwei legierungen
US8480368B2 (en) * 2010-02-05 2013-07-09 General Electric Company Welding process and component produced therefrom

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3046640A (en) * 1957-12-04 1962-07-31 Reynolds Metals Co Process and product of zinc and aluminum lamination
US3098022A (en) * 1960-08-11 1963-07-16 Anthony J Karnie Covering a core by extrusion
US3259969A (en) * 1963-01-22 1966-07-12 Central Cable Corp Method of making butt welded joints
US4094453A (en) * 1976-08-02 1978-06-13 Alforge Metals Corporation, Limited Method for pressure welding metal workpieces
US4529452A (en) * 1984-07-30 1985-07-16 United Technologies Corporation Process for fabricating multi-alloy components

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8956700B2 (en) 2011-10-19 2015-02-17 General Electric Company Method for adhering a coating to a substrate structure
KR101347034B1 (ko) 2012-11-20 2014-01-03 주식회사 노아닉스 스텐트 코팅장치

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DE68916432T2 (de) 1995-01-19
WO1990002479A3 (fr) 1990-05-31
ATE107558T1 (de) 1994-07-15
GB9001813D0 (en) 1990-09-05
JPH04500040A (ja) 1992-01-09
GB2239826A (en) 1991-07-17
EP0431019A1 (fr) 1991-06-12
JP2721721B2 (ja) 1998-03-04
EP0431019A4 (en) 1991-07-31
DE68916432D1 (de) 1994-07-28
AU4156593A (en) 1993-09-30
AU4180989A (en) 1990-04-02
WO1990002479A2 (fr) 1990-03-22
GB2239826B (en) 1992-10-21

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