US3578511A - Solid metal molding - Google Patents

Solid metal molding Download PDF

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Publication number
US3578511A
US3578511A US783675A US3578511DA US3578511A US 3578511 A US3578511 A US 3578511A US 783675 A US783675 A US 783675A US 3578511D A US3578511D A US 3578511DA US 3578511 A US3578511 A US 3578511A
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United States
Prior art keywords
temperature
die
forming
critical
superplastic
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Expired - Lifetime
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US783675A
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English (en)
Inventor
Daniel L Mehl
Delbert T Wilson
Richard J Young
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International Business Machines Corp
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International Business Machines Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D26/00—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces
    • B21D26/02—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure
    • B21D26/053—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure characterised by the material of the blanks
    • B21D26/055—Blanks having super-plastic properties
    • 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
    • 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
    • B21J5/02—Die forging; Trimming by making use of special dies ; Punching during forging

Definitions

  • the anomalous superplastic or low flow stress behavior in metal is usually encountered in association with a gross retransformation of a metallurgical structure from an artificially constrained and hence unstable or metastable condition. Most commonly, gross metallurgical structural transformations the induced by heat energy and occur at specific energy levels or temperatures.
  • a com mon example of a typical so-called superplastic material is the 78% zinc-22% aluminum eutectoid which is prepared for superplastic behavior by quenching from a uniform temperature of about 600 degrees F. At the time of forming, conditioning of the material is completed by raising its temperature to between about 520 F. and the eutectoid invariant or 532 F. for the forming process.
  • the temperature of the eutectoid invariant has been demonstrated as a critical upper limit for obtaining superplastic behavior. Properly prepared material will lose its ability to exhibit the anomolous superplastic behavior if it is heated above its critical limit. Historically, steps have been taken to insure that the material being formed not exceed the eutectoid invariant. These steps principally have involved the use of sophisticated temperature controls on the dies and metal handling equipment to maintain a temperature as close as practically possible to the eutectoid invariant but always to the lower side.
  • a further object of our invention has been to provide a molding process for superplasticity material wherein the superplastic behavior is substantially eliminated immediately following complete part formation to enhance the handle-ability of the formed part.
  • Another important object of our invention has been to provide a molding process for superplastic materials and particularly the zinc-aluminum eutectoid wherein the process of molding is combined with a heat treatment process for enhancement of room temperature properties whereby the overall molding and heat treatment cycle time is reduced.
  • a further important object of our invention has been to provide a process for molding superplastic metals wherein accurate control of metal temperature at the level of maximum formability is obtainable by reliance on the dynamics of a predictable heat transfer situation rather than on the accuracy of an elaborate temperature control mechanism.
  • An additional object of our invention has been to improve the dimensional stability of parts formed by our process by obtaining a more uniform structure of the part before it is removed from the shaping die.
  • a prepared body of potentially superplastic metal is provided of a composition known to have a wholly solid phase above its critical superplastic temperature.
  • a precision mold cavity or die is provided preferably of a material having a significantly loiwer coeflicient of heat conductivity than the selected superplastic metal.
  • the mold or die is heated to a temperature substantially in excess of the critical forming temperature for the selected superplastic metal taking into consideration such principles of heat transfer as relative surface area to mass of the various mold configurations, the severity of deformation, particularly in small parts, the existence of an actual melting limit and a desired final part temperature.
  • the body of superplastic metal is placed in the mold where it can be heated from the die if desired or immediately deformed.
  • the temperature of the body of material rises as the body receives heat from the mold. This temperature rise is arrested locally at the temperature of phase transformation due to the absorption of heat required to effect the transformation. Formation should be completed by the time that any full section of the superplastic material has been completely transformed.
  • the part thus formed is further heated by the die to a temperature definitely above the critical superplastic forming temperature to assu", complete transformation of the metallurgical structure and the resulting increased strength necessary to enable its immediate removal from the die.
  • the additional heating prepares the formed material for a slow cool equilibrium phase transformation and grain growth and creep characteristics at room temperature.
  • FIG. 1 is a partially broken away perspective view of a molding die suitable for performance of our process.
  • FIG. 2 is a front cross-sectional view of a portion of the die shown in FIG. 1 and including a part in place as molded therein.
  • FIG. 3 is a typical phase diagram describing a eutectoid phase phenomena of the type that exists in the zinc-aluminum eutectoid.
  • FIGS. 1 and 2 there is shown a mold, die or similar shaping member forming a cavity 11 that is complementary to the configuration of the part P desired to be formed.
  • An eject pin or button 12 is provided for assisting removal of the part P after it is formed.
  • Heating means such as commercially available electrical resistance heaters 13 are embedded in the body of die 10 and are separated from the cavity 11 by some thickness 14 of die material. If the die body 10 is made of steel, for example, and it is desired to mold the zinc-aluminum eutectoid, the thickness 14 will determine the rate at which heat can be transferred from the heaters 13 to the body P being molded.
  • the thickness 14 can effectively behave as a control on the rate of temperature rise of the outer surface of the body P.
  • Heaters 13 are connected to a suitable power source (not shown) through cable 15 and are maintained at a predetermined elevated temperature within relatively wide temperature limits.
  • a top plate or cover 16 is provided for enclosing the die cavity 11 and includes an inlet opening 17 through which a blank or body of prepared stock superplastic metal P can be inserted. While the cover plate 16 is not shown as being heated, it may be desirable to include heaters similar to 13 in the top plate, particularly where large parts are being formed. In addition, top plate 16 can be made to include an insulating material particularly where a long forming process is involved.
  • top plate 16 is clamped or otherwise forceably held to the die body 10 and the body of superplastic material P is placed in the die through inlet opening 17.
  • body P is preheated to a temperature close to the forming temperature.
  • the body P may be preheated to within approximately 2% of the forming temperature, eg (taken on an absolute scale) between 500 and 520 degrees F., to minimize the requirements for heat transfer in the die itself.
  • a plunger or piston 18 is then closed down upon the body P and deforms the body by compression into intimate contact with the cavity 11.
  • the forming time is ideally selected such that complete formation just precedes complete transformation of the last to be formed portions of the part P.
  • the part P is left in the die cavity 11 for a short period of time (in the case of the zinc-aluminum this period can be as short as five seconds for moderately small parts) to assure complete transformation throughout the body.
  • the top cover 16 is then removed from the die and the part P which is above the critical temperature can be ejected by force exerted upwardly against eject pin 12.
  • the part as ejected can be slow cooled directly either in the air or under controlled conditions in a heat treat furnace to increase grain size and to permit equilibrium phase transformation of the alloy.
  • FIG. 3 shows a typical equilibrium phase relationship known as a eutectoid.
  • This specific eutectoid has a critical phase transformation at the eutectoid invariant of 532 F. and has a wholly solid phase a up to temperatures as high as about 800 F.
  • the a phase has strength characteristics like those of conventional metals Whereas the 4 strength of this material just below the eutectoid invariant, when a properly preconditioned state, is anomalously low.
  • EXAMPLE A typical part, as shown in FIG. 6, was repeatedly formed in accordance with our invention.
  • the part shown in FIG. 6 has an overall diameter 31 of 2.520 in., a peripheral rim width 32 of .690 in., a hub depth 33 of 1% in., a tooth height 34 of .055 in. and an overall weight of 177 grms.
  • the blank of stock metal from which it was formed was a disk having a diameter of 2.36 in., a depth or thickness of .483 in. and a center bore of .343 in.
  • the blank is preconditioned by homogenization at 600 F. for one hour followed by a water quench with agitation. Low temperature recalescence is permitted.
  • the blank is preheated at the time of forming to 500 E, which requires a period of about 2 minutes.
  • a die mold of AISI Type H13 and A181 C10l8 steels weighing 350 lbs. is heated by heaters totalling 6000 watts capacity and separated from this die cavity by 1% in. at the closest point, to an initial temperature of between 610-630 F. These heaters supplement the 29,300 watts available in press platens employed to clamp the die components together.
  • the blank disk was placed in the die which closes in a period of 5 seconds. Forming occurs under a load that varies to a maximum of 60,000 lbs. during a period of 4 to 7 seconds.
  • the part thus formed is left in the die under pressure for an additional 10 seconds to assure a temperature throughout in excess of 532 F.
  • the cycle is completed by opening the die (approximately five seconds) and ejecting the part (three to five seconds). During this eight to ten seconds, approximately 50% of the part remains in intimate contact with the 610630 F. lower die section, thus subjecting the part to additional heat treatment.
  • the part is air cooled to complete the combined forming and heat treating process.
  • Our invention can also be applied to sheet forming techniques as illustrated in FIG. 7.
  • a die or shaping member 40 like that described in aforesaid US. Pat. 3,340,101 is heated to above the critical temperature of blank sheet metal B by heaters 41.
  • a vacuum is applied to plenum 42 to create a fluid pressure across the opposed principle surfaces B and B of sheet B thereby deforming it into conformity with the die 40. After forming, the resulting part can be removed from the die 40 with little danger of distortion.
  • conditionable metal comprises, by weight, essentially 78% Zinc and 22% aluminum.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Shaping Metal By Deep-Drawing, Or The Like (AREA)
  • Forging (AREA)
US783675A 1968-12-13 1968-12-13 Solid metal molding Expired - Lifetime US3578511A (en)

Applications Claiming Priority (1)

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US78367568A 1968-12-13 1968-12-13

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US3578511A true US3578511A (en) 1971-05-11

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US (1) US3578511A (fr)
DE (1) DE1962410A1 (fr)
FR (1) FR2026037A1 (fr)
GB (1) GB1222629A (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3997369A (en) * 1974-05-13 1976-12-14 The British Aluminium Company Limited Production of metallic articles
FR2327002A1 (fr) * 1975-10-09 1977-05-06 St Joe Minerals Corp Procede de forgeage de haute precision donnant des details fins
US4065302A (en) * 1975-12-29 1977-12-27 The International Nickel Company, Inc. Powdered metal consolidation method
US4137105A (en) * 1977-06-20 1979-01-30 Gulf & Western Industries, Inc. Method of forming tooling for superplastic metal sheet
US4299111A (en) * 1979-06-04 1981-11-10 Greene Plastics Corporation Molding of superplastic metals
CN117300627A (zh) * 2023-11-03 2023-12-29 陕西多伦科技发展有限公司 一种金属一体化加工装置、方法及设备

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1392830A (en) * 1972-08-16 1975-04-30 Isc Alloys Ltd Forming of superplastic alloy sheet
FR2435299A1 (fr) * 1978-09-11 1980-04-04 Rockwell International Corp Procede de fabrication d'elements metalliques par formage superplastique et forgeage
DE2839469A1 (de) * 1978-09-11 1980-03-20 Rockwell International Corp Verfahren zur herstellung eines metallgebildes
SU1164951A2 (ru) * 1983-01-10 1986-10-07 Казанский Ордена Трудового Красного Знамени И Ордена Дружбы Народов Авиационный Институт Им.А.Н.Туполева Устройство дл импульсной гидравлической штамповки

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3997369A (en) * 1974-05-13 1976-12-14 The British Aluminium Company Limited Production of metallic articles
FR2327002A1 (fr) * 1975-10-09 1977-05-06 St Joe Minerals Corp Procede de forgeage de haute precision donnant des details fins
US4065302A (en) * 1975-12-29 1977-12-27 The International Nickel Company, Inc. Powdered metal consolidation method
US4137105A (en) * 1977-06-20 1979-01-30 Gulf & Western Industries, Inc. Method of forming tooling for superplastic metal sheet
US4299111A (en) * 1979-06-04 1981-11-10 Greene Plastics Corporation Molding of superplastic metals
CN117300627A (zh) * 2023-11-03 2023-12-29 陕西多伦科技发展有限公司 一种金属一体化加工装置、方法及设备

Also Published As

Publication number Publication date
GB1222629A (en) 1971-02-17
FR2026037A1 (fr) 1970-09-11
DE1962410A1 (de) 1970-07-02

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