METALLURGICAL BONDING AND FORMING PROCESSES AND APPARATUS

• US 3,823,299 A
• Filed: 02/18/1972
• Issued: 07/09/1974
• Est. Priority Date: 09/08/1969
• Status: Expired due to Term

• Current Assignee: Solar Turbines Incorporated (Caterpillar Incorporated)
• Original Assignee: Arthur G. Metcalfe, Fred K. Rose
• Inventors: Metcalfe, Arthur G., Rose, Fred K.
• Primary Examiner(s): Truhe, J. V.
• Assistant Examiner(s): Jaeger, Hugh D.
• Application Number:
  US05/227,683
• Time in Patent Office: 872 Days
• Field of Search: 219/83,110,117,118
• US Class Current: 219/83
• CPC Class Codes: B21B 2027/086 heating internally
• CPC Class Codes: B21B 45/004 Heating the product
• CPC Class Codes: B21D 19/04 shaped as rollers
• CPC Class Codes: B21D 5/08 making use of forming-rollers B21D5/12 takes precedence
• CPC Class Codes: B21H 1/06 rings of restricted axial length extending closed shapes of metal bands by simultaneous rolling at two or more zones B21B5/00
• CPC Class Codes: B21H 7/00 Making articles not provided for in the preceding groups, e.g. agricultural tools, dinner forks, knives, spoons nails, pins B21G3/30
• CPC Class Codes: B23K 11/06 using roller electrodes
• CPC Class Codes: B23K 11/061 for welding rectilinear seams
• CPC Class Codes: B23K 11/087 for rectilinear seams
• CPC Class Codes: B23K 20/00 Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating

Abstract

Methods of and apparatus for forming a continuous solid state diffusion bond between metallic members in which the members to be joined are locally and progressively subjected to heat and pressure. Heating is achieved by workpiece resistance to controlled electrical current, and pressure is applied by rotatable electrodes that: generate contact between the members being joined and produce the deformation necessary to achieve a specified joint configuration therebetween; supply the controlled electric current to heat the workpiece locally and progressively; and are maintained at a temperature which results in essentially isothermal local conditions in the workpiece. Preferably, controls capable of regulating the bonding temperature are provided to insure that a uniform joint is produced. Methods of and apparatus for forming metallic members with and without bond formation by the techniques just described.

Claims

1. Metallurgical bonding apparatus for joining two or more metallic members into a unitary structure, comprising:

a. a rotatable, pressure applying electrode;

b. means disposed in spaced relation to said electrode for supporting the members to be joined;

c. means supporting said electrode for movement toward and away from said supporting means;

d. means for effecting a continuous movement of said members relative to said electrode;

e. means continuously operable to so bias said electrode toward said member supporting means that it engages one of said members and exerts a force of predetermined magnitude on said members as they are moved relative to said electrode;

f. means for heating both those portions of said rotatable electrode and those portions of the members being joined which are contiguous to the contact area between said electrode and the member against which it is biased and for impeding the flow of heat away from said heated portion of said electrode comprised in that said rotatable electrode is fabricated of a refractory metal or a refractory alloy and by means for connecting the members being joined across an electrical power source through said electrode and said supporting means; and

g. means for so regulating the current density through said members and the force exerted thereon by the rotatable electrode as to maintain the maximum temperature of said members below the melting point of the metals of which said members are composed but sufficiently high to create a plastic condition only in a localized zone contiguous to the faying surface and opposite the pressure applying electrode and thereby produce essentially complete contact between said members along the faying surface therebetween and permit the diffusion of atoms of the materials of which said members are composed across the faying surface to produce a bond between said members.

2. The apparatus of claim 1, wherein the means for supporting the members to be joined comprises a further rotatable electrode disposed with its axis of rotation so oriented that the lines of contact between the electrodes and the members against which they are biased follows the line of the joint between said members, said last-mentioned electrode also being fabricated of a refractory metal or a refractory metal alloy.

3. The apparatus of claim 1, wherein there are a plurality of electrodes as aforesaid and wherein said members are connected across the power source through each of said electrodes and including means for independently regulating the power through and pressure exerted by each of electrodes to thereby optimize the quality of the bonds produced by each of said electrodes.

4. The metallurgical bonding apparatus of claim 1, wherein the means for controlling the flow of current through the members being joined comprises a power supply adapted to be connected across an a.c. power source;

means connecting said power supply across the members being joined through said electrode;

a power controller connectEd to said power supply for regulating the magnitude of the power supplied thereto; and

a closed loop type control system connected to said power controller, said control system including means for generating a continuous feedback signal indicative of the bonding conditions and means operable in response to variations in the feedback signal to cause the power controller to vary the power supplied to said power supply, whereby the bonding temperature may be maintained at a preselected level or levels as the members being bonded are moved relative to said electrode.

5. The apparatus of claim 4, wherein said control system comprises a temperature regulating process controller connected to said power controller and a power transducer for producing a continuous signal indicative of the power consumption on the output side of said power supply and for transmitting said signal to said process controller.

6. The apparatus of claim 4, wherein said control system comprises a temperature regulating process controller connected to said power controller and means for producing a continuous signal indicative of the voltage drop across the members being joined and transmitting said signal to said process controller.

7. The apparatus of claim 4, wherein said control system comprises a temperature regulating process controller connected to said power controller and means for producing a continuous signal indicative of the magnitude of the current flow through the members being joined and transmitting said signal to said process controller.

8. The apparatus of claim 4, wherein said control system comprises a temperature regulating process controller connected to said power controller and means for producing a continuous signal indicative of the thermoelectric potential between the electrode and the members being joined and for transmitting said signal to said process controller.

9. The apparatus of claim 4, wherein said control system comprises a temperature regulating process controller connected to said power controller and means including an optical pyrometer for producing the signal indicative of bonding conditions and for transmitting said signal to said process controller.

10. The apparatus of claim 4, wherein said control system comprises a temperature regulating process controller connected to said power controller and means for producing a continuous signal indicative of the degree of deformation of the members being joined as the bond between them is formed and for transmitting said signal to said process controller.

11. The apparatus of claim 4, wherein said control system comprises a temperature regulating process controller connected to said power controller and ultrasonic transducer means for producing the signal indicative of bonding conditions and for transmitting said signal to the process controller.

12. The apparatus of claim 4, wherein said control system comprises a temperature regulating process controller and programmer means operatively connected to said process controller for determining the level at which the bonding temperature is maintained by the process controller.

13. The apparatus of claim 1, together with means for confining the members to be joined in abutting relationship comprising rotatable members adapted to engage opposite sides of an assemblage of the members, means rotatably supporting one of said rotatable members at a fixed location, a slide rotatably supporting the other of said rotatable members, guide means confining said slide to rectilinear movement toward and away from the fixedly supported rotatable member, and motor means for exerting a force of specified magnitude on said slide, whereby said rotatable members cooperate to confine the members to be joined therebetween.

14. The apparatus of claim 1, wherein the means for supporting the members to be joined comprises a table, means for fixedly positioning an assemblage of the members to be joined on said table, and means supporting said table for movement in a path in whiCh said rotatable electrode continuously engages one of the members being joined as said members are moved relative to said electrode.

15. The apparatus of claim 14, wherein said table supporting means comprises a plurality of table supporting rollers fixed to said frame and guide means fixed to said frame and confining said table to rectilinear movement relative to said frame.

16. The apparatus of claim 14, wherein there are a plurality of electrodes as aforesaid and including an electrode support and means rotatably supporting said electrodes from said support, whereby said apparatus is capable of simultaneously producing a plurality of bonds as said table is moved relative to said frame.

17. The apparatus of claim 1, together with means mounting the means for supporting the members to be joined for rotation about an axis extending in the same direction in which the force is applied by the rotatable electrode.

18. The apparatus of claim 1, together with tooling means adapted to be disposed between the rotatable electrode and the supporting means and to engage opposite sides of an assemblage of the members to be joined for maintaining said members in a selected relationship while they are joined.

19. The apparatus of claim 18, wherein said tooling means is configured to provide at least one cavity into which the metal comprising at least one of the members to be joined can flow as said members are joined to thereby impart a selected configuration to the unitary structure into which the members are joined.

20. Apparatus for the solid state forming of a metallic workpiece into a component of selected configuration, comprising:

a. a rotatable, pressure applying electrode;

b. means disposed in spaced relation to said electrode for supporting the workpiece;

c. means supporting said electrode for movement toward and away from said workpiece supporting means;

d. means continuously operable to so bias said electrode toward said workpiece supporting means that it exerts a force of selected magnitude on said workpiece;

e. means for heating both said workpiece in that region thereof between the pressure applying electrode and the workpiece supporting means and that portion of the electrode contiguous to the workpiece and for impeding the flow of heat away from said heated portion of said electrode to keep said electrode from chilling said workpiece comprised in that said electrode is fabricated of a refractory metal alloy and by means for connecting the workpiece across an electrical power source through the pressure applying electrode and the workpiece supporting means;

f. means for so regulating the current density through the workpiece and the force exerted on it by the rotatable pressure applying electrode as to maintain the temperature of said workpiece below its melting point but sufficiently high to produce in the heated region between the pressure applying electrode and the workpiece supporting means a localized zone only in which the workpiece is in a plastic and flowable condition; and

g. means for effecting a continuous translation of the workpiece relative to the pressure applying electrode and the workpiece supporting means to thereby cause the zone in which the plastic condition exists to proceed in continuous fashion along the workpiece.

21. The apparatus of claim 20, wherein the means for controlling the flow of current through the workpiece comprises a power supply adapted to be connected across an a.c. power source;

means connecting said power supply across said workpiece through said electrode;

a power controller connected to said power supply for regulating the magnitude of the power supplied thereto; and

a closed loop type control system connected to said power controller, said control system including means for generating a continuous feedback signal indicative of the forming conditions and means operable in response to variations in the feedback signal to cause the power controller to vary the power supplied to said power supply, whereby the temperature may be maintained at a preselected level or levels as the workpiece move relative to the rotatable electrode.