US3735458A - Method of manufacturing rotary anodes for use in x-ray tube and rotary anodes manufactured by said method - Google Patents

Method of manufacturing rotary anodes for use in x-ray tube and rotary anodes manufactured by said method Download PDF

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Publication number
US3735458A
US3735458A US00087097A US3735458DA US3735458A US 3735458 A US3735458 A US 3735458A US 00087097 A US00087097 A US 00087097A US 3735458D A US3735458D A US 3735458DA US 3735458 A US3735458 A US 3735458A
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anode
supporting portions
joined
supporting
portions
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US00087097A
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F Magendans
Rheenan B Van
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US Philips Corp
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US Philips Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/02—Details
    • H01J35/04—Electrodes ; Mutual position thereof; Constructional adaptations therefor
    • H01J35/08—Anodes; Anti cathodes
    • H01J35/10—Rotary anodes; Arrangements for rotating anodes; Cooling rotary anodes

Definitions

  • the invention relates to a method of manufacturing rotary anodes for use in X-ray tubes, in which a discshaped anode portion mainly consisting of tungsten and a disc-shaped support mainly consisting of molybdenum are joined at increased temperature by pressure to form a disc-shaped assembly and to a rotary anode manufactured by carrying out said method.
  • the height of the permissible temperature is limited, for example, by the required mechanical rigidity, which usually decreases with an increase in temperature, whilst the values of the permissible temperature gradients are determined by the mechanical stresses produced by discrepancies in thermal expansions and being likely to give rise to cracks, when exceeding said mechanical rigidity, particularly in the target area of the anode for the electron beam.
  • the rotary anode is then loaded repeatedly for a short time, it being required to obtain radiation pulses of very high intensity and an accurately defined, reproducible sense.
  • the inventor has found that the methods hitherto known are not suitable for obtaining rotary anodes, at least not in a simple and cheap manner, so as to meet all requirements imposed on rotary anodes by modern X-ray technology.
  • a further method of joining is proposed in German Utility Model No. 1,622,218, in which a ring punched from tungsten sheet is connected with a molybdenum supporting portion by annealing the two superimposed portions in an inert gas atmosphere, for example, hydrogen and, if required, by exerting pressure.
  • an inert gas atmosphere for example, hydrogen and, if required, by exerting pressure.
  • this method is characterized in that in a non-oxidizing, preferably reduced atmosphere the said two portions are heated and subsequently joined by pre-processed faces and subjected to a quick-forming impact process, the thickness of the portions, the temperature at which the portions are joined and the deformabilities determined by the nature and quality of the materials of the portions being chosen so that during the impact the diameters of the two portions increase and their thicknesses decrease, the portions being at the same time rigidly secured to each other, the resultant assembly of the portions being subsequently annealed to remove stress in a nonoxidizing, preferably reducing atmosphere, after which the assembly is subjected in known manner to shaping processes to obtain the final shape of the rotary anode.
  • the invention provides, more particularly, a method in which a rotary anode is obtained, at least the anode portion of which has a density of material of at least 98 percent, also in the case in which the starting material of the anode portion does not yet exhibit said density of 98 percent.
  • the oxidation of the portion faces to be joined which may be harmful in this method of adhesion of the portions, is avoided by joining the discs and arranging them in a fitting, thin-walled envelope of a material not melting during the impact process and being indifierent to the discs, in which envelope the portions are heated and subjected to the impact.
  • the method according to the invention provides furtherrnore the advantage of a great freedom in choosing the starting materials for the anode and supporting portions so that the requirements for the rotary anode can be more fully satisfied.
  • a rotary anode having a supporting portion of high mechanical strength can be obtained from materials commercially available, already having the desired high mechanical rigidity, which is not reduced by the method according to the invention.
  • FIG. I shows the two portions of the rotary anode in a perspective view, the portions being joined one on the other in a protective envelope.
  • FIG. 2 shows the assembly resulting from the impact process in a perspective view, one sector being omitted.
  • FIG. 3 shows the assembly after removal of a peripheral part.
  • FIG. 4 shows the assembly having a peripheral part bent over through a small angle, a hole being provided for a shaft, the final shape of the rotary anode being thus achieved.
  • EXAMPLE I Method of manufacturing a double-layer rotary anode from a tungsten anode portion and a supporting portion of a cast molybdenum alloy.
  • the staring material of the anode portion is a rod of sintered tungsten having a rectangular section of about 34 X 23 mms, the porosity corresponding to a material density of 60 to percent. From this material wafers are sawed, which wafer is flattened by repeated rolling to a solid sheet of a density of more than percent, the thickness being 5 to 7 mms. From this sheet a circular disc of a diameter of about 49 mms is cut, this disc being smoothed to the optimum at least on one side by grinding and/or polishing so that at the same time a clean surface free of an oxide skin is obtained.
  • the starting material of the supporting portion is normally available on the marked, that is to say a molybdenum alloy known under the tradename TZM containing 0.55 to 40 (0.5) percent of titanium, 0.12 to 0.06 (0.08) percent of zirconium and 0.03 to 0.02 (0.015) percent of carbon, having an adequate density of at least 98 percent and being satisfactorily workable by temperature and deformation treatments already carried out in the factory.
  • the adjuvants of titanium and zirconium in the molybdenum have lowered the melting point so that this material can be cast and the recrystallization temperature is raised to 1,800C.
  • the increase in mechanical strength achieve in this manufacture of the rotary anode is maintained even under very heavy operational conditions provided in the temperature of the supporting portion remains below 1,800 C.
  • a disc is formed having a thickness of, for example, 25 mms and a diameter of 49 mms, smoothed on at least one side by conventional cutting processes.
  • the anode and supporting discs are then joined by their smooth sides and heated in an oven at a temperature of about l,650 C.
  • a temperature of about l,650 C In order to prevent oxidation of the joined smooth surfaces from interfering with the quality of the adhesion during the subsequent impact process the increase in temperature to l,650 C is carried out in the oven in a non-oxidizing (e.g., nitrogen) or reducing (e.g., hydrogen) atmosphere.
  • a further protection against oxidation is obtained by arranging the discs in a box-shaped envelope of the kind shown in FIG. 1 of the drawing.
  • the supporting disc 1 is arranged on the bottom 2 of a cylindrical box 3 having a wall thickness of about 0.4 mm.
  • This box is made of a material, which does not melt during the process and which is inert relative to the anode and supporting materials, for example molybdenum shaped in the form shown by deep-drawing.
  • FIG. 1 shows the thinner anode disc 6.
  • the two discs 1 and 6 join each other in the plane 7 by their clean, smooth surfaces.
  • the narrow gaps between the discs and the inner wall of the box 4 and between the wall of the box 3 and the wall of the box 4 form a very narrow communication channel, which has a maximum length by arranging the thicker supporting disc 1 on the bottom of the box 4 between the ambient atmosphere and the interface 7 of the portions 1 and 6.
  • a stretched wire for example, of molybdenum (not shown in FIG. 1) around the outer surface of the box 3 for holding the filled box 3 and the box 4 together when displaced, may improve the seal against the ambience to 100 percent.
  • the joined portions After heating at a temperature of l,650 in an oven (not shown) the joined portions are conveyed as quickly as possible, in order to restrict any oxidation and to minimize cooling, to a quick-action impact forming device.
  • Such devices permit of deforming a work piece very rapidlyby a high-energy impact.
  • a device known under the name of USI High-Energy Rate Machine was used.
  • the machine comprises a hammer and an anvil (each weighing about 350 kgs), which are moved towards to each other with high speed by means of the expansion of a strongly compressed gas.
  • FIG. 2 illustrates the assembly resulting from the method according to the invention in this example after the quick-forming impact process by means of the above-mentioned press, when the discs 1 and 6 are arranged in the box shown in FIG. 1.
  • the overall height of the joined discs is reduced by the impact to about one fifth, that is to say to about 6 ms.
  • the diameter of the resultant assembly 9 has then increased to D2 of about 10.5 ms, whilst the edges exhibit slight rounding-ofi'.
  • the molybdenum envelope is also flattened and forms cover layers 10 and 11 on the top and bottom sides of slight thickness, which layers have to be removed afterwards by grinding or polishmg.
  • the high-quality adhesion may be due to the fact that the diameters of the two disc; increase so that in the contact face the available structure and any troublesome oxide layers are broken up so to fresh material not yet having been in contact with the ambience in the two layers forms an intimate bond at a very high pressure.
  • the method can also provide any desired density of 98 percent of the anode portion and, if desired, also of the supporting portion; this is achieved in this example by starting from anode and support material having already a high density prior to the impact, which den-' sity is increased by the density obtained by the impact to at least 98 percent.
  • the adhesion may be considered to have-been achieved by a cold-state operation, which will be explained more fully hereinafter, no expensive-ovens are required, which are required for an adhesion by a sintering or annealing process. It is thus possible to obtain a satisfactory adaptation of the deformabilities of the materials of the anode and supporting portions during the impact process. Further possibilities of choosing the nature and properties of anode and support materials will be dealt with hereinafter.
  • a further advantageous feature of the method according to the invention resides in thefact that the material, particularly that of the electron-beam target plate-formed by the surface of the anode portion, does not exhibit a texture. This is conducive to the radiation properties of the anode portion in operation for known special uses in which the direction of the resultant X-ray beam is important, for example, in X-raytomography as stated above.
  • FIG. 3 shows the assembly obtained by grinding the disc shown in FIG. 2 into a suitable portion 13 of a diameter 3 of about 80 mms, whilst any remaining parts of the envelope, if used, as shown in FIG. 11 are removed.
  • a disc 15 of this shape shown in FIG. 4 can be obtained by cold deformation of a peripheral part 16 at about 1,000 C.
  • a hole 17 is drilled in the disc 115 for fastening the resultant rotary anode to a rotary shaft.
  • the portions 1 and 6 are enlarged to unequal extends, for example, because of the fact that at the working temperature the tungsten anode layer is scarcely or not at all deformed as compared with the molybdenum alloy layer, so that particularly towards the edge of the resultant assembly the thickness of the tungsten layer is too small, or the adhesion is of a less high quality, this may be improved, for example, by adjusting the thickness ratio between the anode and supporting discs, but the inventor has found that this ratio is not critical within a range between at least 1 3 and l 6 in this case with the aforesaid choice of material.
  • the process is substantially similar to that of the above Example I, the difierence being as follows.
  • the anode portion is similar to that of Example I.
  • the starting material for the supporting portion is molybdenum containing potassium silicate of (10 to 50) 10* percent, which is obtained by sintering a mixture of powdery molybdenum and potassium silicate.
  • the resultant material is porous, its density being 50 to 60 percent, so that its deformability is higher than the TZM" material of the support of Example I.
  • the supporting portion For adapting the deformability to that of the solid tungsten anode disc the supporting portion must have a smaller thickness in order to avoid that the whole deformation energy gets into the supporting portion, since this might lead to an excessively thin, hence probably weak supporting layer for the final anode.
  • the starting material may be sintered and porous
  • the process according to the invention may take a very short time, for example, 10 sec, in contrast to the known method, in which the adhesion is achieved by sintering or annealing, which takes the considerable time of several hours, the short period during which the supporting material may heat up above the recrystallization temperature in the method according to the invention little affects the increase in strength obtained by the impact on the supporting portion. With the high energy supply during the transient deformation the temperature may rise markedly, but the duration is too short for causing significant recrystallization, because of which, as stated above, the adhesion may be considered to having been achieved by a cold-deformation process.
  • Molybdenum adjuvants reducing the recrystallization rate for example, potassium silicate, provide the desired maintenance of the strength of the supporting portion at least for a longer period of operation, when the anode is operating at a temperature of the supporting portion above the recrystallization temperature of its material, in this case, molybdenum.
  • the two preceding Examples relate to a method in which the anode portion is made of solid tungsten, which is obtained from porous, sintered tungsten by rolling or other flattening operations.
  • this solid anode portion has stuck to it a preferably solid supporting portion of flattened, sintered material, this does not involve that the porosity of the supporting material in itself is inadmissible for carrying out the method according to the invention.
  • the porous supporting material may, however, be too thin for obtaining a satisfactory adaptation of deformabilities.
  • matching may be achieved, as an alternative, by using for the anode portion porous, sintered tungsten, instead of starting with solid material.
  • the porosity of sintered materials may be slightly affected by the manner of sintering, so that the adhesion of two sintered layers, for example, for a sintered tungsten sheet for the anode portion and a sintered molybdenum sheet for the supporting portion, may be obtained by the method according to the invention.
  • the supporting portion may be stiflened by known expedients, for example, the incorporation of silicon carbide needles or of a tungsten wire grid.
  • a method of manufacturing rotary anodes for use in X-ray tubes wherein a sintered disc-shaped anode portion mainly of tungsten and having a material density of from about to percent is provided and a disc-shaped supporting portion mainly of molybdenum are joined into a disc-shaped assembly, characterized by machining at least one face of said anode and supporting portions, heating said anode and said supporting portions in a non-oxidizing atmosphere, joining the machined faces of said anode and supporting portions together and subjecting said joined anode and supporting portions to a quick-deforming impact process while in said atmosphere so that during the impact process step the diameters of said anode and supporting portions increase and the thicknesses decrease, while said joined anode and supporting portions are firmly secured to each other, and annealing the resultant assembly of said joined anode and supporting portions in a non-oxidizing, atmosphere, whereby said joined anode and supporting portions are joined intimately together and stress relieved.

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  • Pressure Welding/Diffusion-Bonding (AREA)
US00087097A 1969-11-08 1970-11-05 Method of manufacturing rotary anodes for use in x-ray tube and rotary anodes manufactured by said method Expired - Lifetime US3735458A (en)

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Application Number Priority Date Filing Date Title
NL6916885.A NL158648B (nl) 1969-11-08 1969-11-08 Werkwijze voor het vervaardigen van een draaianode voor een roentgenbuis, alsmede draaianode verkregen volgens deze werkwijze.

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US3735458A true US3735458A (en) 1973-05-29

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US (1) US3735458A (enExample)
JP (1) JPS5416196B1 (enExample)
AT (1) AT312749B (enExample)
BE (1) BE758645A (enExample)
CA (1) CA935505A (enExample)
CH (1) CH514231A (enExample)
DE (1) DE2054040C3 (enExample)
FR (1) FR2082957A5 (enExample)
GB (1) GB1308679A (enExample)
NL (1) NL158648B (enExample)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4641333A (en) * 1984-09-14 1987-02-03 U.S. Philips Corporation Method of manufacturing an X-ray tube rotary anode and an X-ray tube rotary anode manufactured according to this method
US4944448A (en) * 1986-05-09 1990-07-31 Imatron, Inc. Composite electron beam target for use in X-ray imaging system and method of making same
EP0913854A1 (de) * 1997-10-30 1999-05-06 PLANSEE Aktiengesellschaft Verfahren zur Herstellung einer Drehanoden-baueinheit
WO2011018750A1 (en) 2009-08-11 2011-02-17 Koninklijke Philips Electronics N.V. Rotary anode for a rotary anode x-ray tube and method for manufacturing a rotary anode
WO2012097393A1 (de) * 2011-01-19 2012-07-26 Plansee Se Röntgendrehanode

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL158967B (nl) 1972-12-07 1978-12-15 Philips Nv Werkwijze voor de vervaardiging van een gelaagde roentgendraaianode, alsmede aldus verkregen gelaagde roentgendraaianode.
DE3226858A1 (de) * 1982-07-17 1984-01-19 Philips Patentverwaltung Gmbh, 2000 Hamburg Drehanoden-roentgenroehre
NL8300251A (nl) * 1983-01-25 1984-08-16 Philips Nv Werkwijze voor het vervaardigen van een draaianode voor roentgenbuizen en zo verkregen anode.

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2371754A (en) * 1942-04-22 1945-03-20 North American Aviation Inc Stiffened material
US2387903A (en) * 1944-03-14 1945-10-30 Mallory & Co Inc P R Contacting element

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2371754A (en) * 1942-04-22 1945-03-20 North American Aviation Inc Stiffened material
US2387903A (en) * 1944-03-14 1945-10-30 Mallory & Co Inc P R Contacting element

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4641333A (en) * 1984-09-14 1987-02-03 U.S. Philips Corporation Method of manufacturing an X-ray tube rotary anode and an X-ray tube rotary anode manufactured according to this method
US4944448A (en) * 1986-05-09 1990-07-31 Imatron, Inc. Composite electron beam target for use in X-ray imaging system and method of making same
EP0913854A1 (de) * 1997-10-30 1999-05-06 PLANSEE Aktiengesellschaft Verfahren zur Herstellung einer Drehanoden-baueinheit
WO2011018750A1 (en) 2009-08-11 2011-02-17 Koninklijke Philips Electronics N.V. Rotary anode for a rotary anode x-ray tube and method for manufacturing a rotary anode
US9031202B2 (en) 2009-08-11 2015-05-12 Plansee Se Rotary anode for a rotary anode X-ray tube and method for manufacturing a rotary anode
WO2012097393A1 (de) * 2011-01-19 2012-07-26 Plansee Se Röntgendrehanode
CN103329239A (zh) * 2011-01-19 2013-09-25 普兰西欧洲股份公司 旋转式x射线阳极
US9368318B2 (en) 2011-01-19 2016-06-14 Plansee Se Rotary X-ray anode
CN103329239B (zh) * 2011-01-19 2016-10-12 普兰西欧洲股份公司 旋转式x射线阳极
EP3109889A1 (de) * 2011-01-19 2016-12-28 Plansee SE Röntgendrehanode
US9767983B2 (en) 2011-01-19 2017-09-19 Plansee Se Rotary X-ray anode and production method

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Publication number Publication date
NL6916885A (enExample) 1971-05-11
CH514231A (de) 1971-10-15
CA935505A (en) 1973-10-16
BE758645A (fr) 1971-05-06
DE2054040C3 (de) 1979-11-29
AT312749B (de) 1974-01-10
JPS5416196B1 (enExample) 1979-06-20
GB1308679A (en) 1973-02-21
DE2054040B2 (de) 1979-04-05
FR2082957A5 (enExample) 1971-12-10
DE2054040A1 (de) 1971-05-27
NL158648B (nl) 1978-11-15

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