US3157540A - High pressure process for improving the mechanical properties of metals - Google Patents

High pressure process for improving the mechanical properties of metals Download PDF

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Publication number
US3157540A
US3157540A US32888A US3288860A US3157540A US 3157540 A US3157540 A US 3157540A US 32888 A US32888 A US 32888A US 3288860 A US3288860 A US 3288860A US 3157540 A US3157540 A US 3157540A
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United States
Prior art keywords
pressure
materials
metals
treated
hardness
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Expired - Lifetime
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US32888A
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English (en)
Inventor
Alfred R Bobrowsky
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BASF Catalysts LLC
Engelhard Industries Inc
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Engelhard Industries Inc
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Priority to US32888A priority Critical patent/US3157540A/en
Priority to SE5526/61A priority patent/SE302311B/xx
Priority to DEE21140A priority patent/DE1235865B/de
Priority to GB19572/61A priority patent/GB971712A/en
Priority to DE1962E0022383 priority patent/DE1288568B/de
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Publication of US3157540A publication Critical patent/US3157540A/en
Anticipated expiration legal-status Critical
Assigned to ENGELHARD CORPORATION reassignment ENGELHARD CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: PHIBRO CORPORATION, A CORP. OF DE
Expired - Lifetime legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D10/00—Modifying the physical properties by methods other than heat treatment or deformation
    • 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
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
    • B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
    • B23P15/16—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass plates with holes of very small diameter, e.g. for spinning or burner nozzles
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F3/00—Changing the physical structure of non-ferrous metals or alloys by special physical methods, e.g. treatment with neutrons
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S72/00—Metal deforming
    • Y10S72/70—Deforming specified alloys or uncommon metal or bimetallic work
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/4998—Combined manufacture including applying or shaping of fluent material
    • Y10T29/49982—Coating

Definitions

  • one object of the invention is to increase the pressure which may be obtained with conventional hydrostatic pressure apparatus.
  • a supplemental layer of material over the inner sample material to be compressed, where the supplemental layer is of a solid, non-elastomeric material having the property that it is reduced in volume with increasing pressure more rapidly than the sample which is to be pressurized.
  • the reduction in volume of the outer layer is accompanied by an abrupt densification, which is particularly helpful in the intensification of the pressure on the inner sample.
  • the pressure on an article can be intensified by encasing the article in material which decreases in volume more rapidly than the article, with increasing pressure, and then subjecting the encased article to elevated pressure.
  • the outer casing may be of a material, such as bismuth or bismuth containing alloys, which is sub in theproperties of these substances.
  • the effect of the high pressure is to increase the number, location and arrangement of dislocations in the crystalline structure of the iron Dislocations are defects in crystalline material and are described in detail in a book entitled Dislocations and Plastic Flow in Crystals by A. H. Cottrell, Oxford, Clarendon Press, 1953. According to theory, the number and form of dislocations aifects some properties of materials such as hardness, creep resistance, and electrical conductivity, but does not .a'ifect certain other properties, such as the modulus of elasticity, for example, to any great extent. Following the high pressure treatment as described above, the samples were found to have permanently improved hardness and creep resistance. Other observable factors also indicated that the number and location of dislocations in the material have been greatly altered.
  • crystalline 'material is subjected to high pressure to produce alteration in the number and location of dislocations in the material and significantly change a group of properties of the materials which are dependent on dislocations, and force is thereafter applied to the material to utilize the properties which have been changed.
  • the pressure-treated element may be used as a Wear-resistant surface, as a structural element, or as a magnetic or electrical component, in systems where the properties provided by alterations of dislocations are desirable.
  • this phase of the present invention does not involve deformation of the materials as by macroscopic stresses other than hydrostatic, nor does it involve'changes in the gross crystal structure of materials such as the transformation of graphite or other forms of carbon to diamonds. Instead, it encompasses only permanent changes other than those specified above in solid crystalline materials produced by hydrostatic forces.
  • the threshold at which significant permanent changes in the properties of the pressure-treated material occur will be designated the dislocation alteration threshold.
  • This threshold is characterized by the increase in creep resistance by more than ten percent, or by an increase in indentation hardness number of about three points or more, as these criteria are defined hereinafter.
  • the present invention contemplates subjecting a solid crystalline material to a high pressure beyond the dislocation alteration threshold, and assembling the material into a device in which the permanently altered properties of the material improve the operation of the device. It is also to be noted that the components are preferably fabricated to the proper shape prior to pressure treatment.
  • the wearing surfaces of an apparatus may be provided with hydrostatically.pressure-hardened components.
  • hydrostatically.pressure-hardened components One example of the use of such components is in the Wearing surfaces of the nozzles in synthetic fiber-extruding devices such as spinnerettes
  • Hydrostatically pressure-hardened conducting material may also be employed as electrical contact elements.
  • - Semiconductors and magnetic cores may also be treated to change their electrical properties.
  • FIG. 2 is a cross-sectional view of a sphere of one material encased in a shell of a diiferent material
  • FIG. 4 is a chart showing comparative creep test results for untreated and pressure-treated specimens
  • FIG. 5 shows a simple electrical circuit diagram employing a pressure-treated magnetic core, in accordance with the invention
  • FIG. 6 represents a circuit including a vacuum tube having a semiconductor source of electrons which has been pressure-treated, in accordance with the invention
  • FIG. 7 shows a switch in which the contacts have been pressure treated, in accordance with the invention.
  • FIG. 8 represents a spinnerette in which the spinning nozzles have been hardened pursuant to the principles of this invention.
  • the circle 12 represents a homogeneous sphere of crystalline material.
  • the word crystalline is defined as having atoms arranged in a fairly regular pattern or lattice.”
  • Polymeric materials are included as crystalline because of a type of regularity of molecular structure possessed by them.
  • the radius of the sphere 12 at atmospheric pressure is indicated by r
  • a high pressure in the order of thousands of atmospheres, is applied to the sphere 12, the radius r, is reduced to another radius indicated in FIG, 1 by the radius r
  • Another radius r within the sphere 12 is similarly reduced toasmaller radius r,,. V r
  • FIG. 2 is a cross-sectional view of another sphere in which the outer shell 14 is of the same material as that shown in FIG. 1, and wherein the central coremember 16 has a smaller compressibility, or is less compressible than the outer shell 14.
  • the radius r of the outer shell 14 is reduced to the radius r upon the application of high hydrostatic pressure. .
  • The' change from radius r to radius r,, will be less than the shift from'radius r to radius r in the case of the isotropic sphere of FIG. 1.
  • the radius r 'however which is approximately equal to r under atmospheric pressure conditions, it. is
  • radius r3 isjgreater th'an'the'radius '1-
  • the pressure throughout the sphere is generally accepted to be equal to the pressure applied to the outer surface of the sphere.
  • "m FIG. '2 if the inner sphere 16 were not present, the; inner radius r of the shell 14 would be reduced to the'jradius a; as indicated in FIG. l.'
  • an increase in pressure may be obtained by encasing a specimen having a given compressibility in a jacket of larger compressibility. Under these conditions, the outer, more compressible material will exert additional force on the inner core member, thus subjecting it to higher pressures than are applied to the entire core and jacket assembly.
  • materials which undergo an abrupt densification or reduction in volume under pressure may be employed. Such a property may be found in combination with a material having a higher compressibility than the encased material. Many materials are known which have such abrupt reductions in volume, and in some cases they are a result of a poly:
  • specimens were formedfrom vacuum melted and simultaneously vacuum-cast iron.
  • the jacket 20 on each of the four samples was composed of an eutectic alloy which'melts at 203 F., just be" low the temperature of boiling water. *The'alloy included 16 percent tun 32 percent lead; and 52 percent'bismuth by weight. Of the four specimens, 'twowere subjected to a high hydrostatic pressure ofabout 28,000 to 35,000 atmospheres in a pressure apparatus of a known type. The 'alloy jacket is more easily compressible than the iron by a factor of about five, At pressures of above 25,000:at-" mospheres, the alloy jacket abruptly densifies, enhancing pressure on the specimen in the manner described above...
  • samples C and D- were the pressure-treated samples, and samples A and B were the untreated samples.
  • yield strain or extension at elevated temperature was decreased, the amount of transient and the rate of the steady-state creep was greatly decreased, and that rupture-life was increased.
  • the mechanical strength at elevated temperatures is increased significantly.
  • the mechanical strength of certain untreated materials is greatly reduced even at the boiling point of water (100 C.; 212 F.)
  • the pressure-treated materials show high mechanical strength at these lower temperatures and even beyond the 800 F. level at which the creep tests were conducted.
  • the process in accordance with the present invention enhances mechanical properties of metals such as creep resistance. In addition, it alters the physical properties of solid crystalline material. Another advantage is that no dies are required to maintain shape.
  • components may be fabricated in a relatively soft condition, and may subsequently be pressure hardened without alteration of size or shape. Furthermore, a
  • the prolonged application of hydrostatic pressure beyond the dislocation alteration threshold produces permanent defect structure changes in crystalline materials.
  • the pressure applied to the two iron samples C and D was well beyond this threshold.
  • thedislocation alteration threshold requires an increase in the creep resistance by about 10 percent or an increase in hardness number of about three points, as noted below.
  • One criterion of creep resistance is the minimum slope of a plot of longitudinal strain versus time as indicated in FIG. 4.
  • the pressure-treated specimens C and D had minimum creep rates of 3 hundred thousandths and 2 hundred thousandths of an inch per inch, per hour, respectively.
  • the untreated specimens had creep rates of and 93 hundred thousandths of an inch, per hour,re spectively.
  • the pressure-treated specimens were from 10 to 50 times more creep resistant than the untreated specimens.
  • the dislocation alteration threshold is defined as the level at which the creep resistance increases by more than ten percent and the hardness increases by at least three points in either the DPH or Brinell hardness systems. At this level and beyond, significant improvement in the dislocation dependent properties of crystalline materials may be observed.
  • FIGS. 5 through 8 represent applications for crystalline materials which have been subjected to pressure treatment as described above.
  • the magnetic core 22 of a transformer is made of pressure treated magnetic material.
  • alternating current signals from the source 24 are coupled to the load 26 by the windings 28, 30, and 32 on the core 22.
  • the increase in dislocations in the core 22 serves to decrease the conductivity of the core material. Accordingly, the loss in the core material as a result of stray induced currents is reduced.
  • signals from the source 34 are amplified by the tube 36 and applied to the load 38.
  • the tube 36 may include a plate electrode 40, a grid 42, and a semiconductor body 44 for providing electrons.
  • the semiconductor body 44 may include a p-type portion 46 and an n-type layer 48 forming a p-n junction.
  • a direct current biasing source 50 and an adjustable resistor 52 apply a low biasing voltage across the p-n junction in the semiconductor body 44.
  • a semiconductor body may have its electron emission properties improved by the introduction of dislocations which pass through the p-n junction near the surface of the semiconductive body. Pressure treatment beyond the dislocation alteration threshold serves to introduce such dislocations through the p-n junction, and therefore.
  • the arrangement ofFI G. 7 includes a contact mounting 'arm58, insulating support members 60 and 62, a source of current 64, and a load 66.
  • the arrow 68 indicates the application of force, through any suitable mechanical linkage to the contact mounting arm 58.
  • pressure-treated components make them suitable for wearing elements.
  • they are useful in spinnerettes-in which filaments are formed by extrusion at high pressure.
  • a spinnerette assembly is shown which'ineludes the spinning nozzles 70 and. 72, the plate 74 in which the nozzles are'mounted, and the holder 76 in which the spinnerette plate 74 is mounted.
  • the spinning nozzles may be made of platinum or other, know spinnerette materials. Following formation of the individual spinning nozzles 70, 72 into the. proper shape as shown in FIG. 8, they are subjected to pressure treatment beyond the dislocation alteration threshold. They are then 'assembled into the complete spinnerette as shown in FIG. 8.
  • the spinning nozzles are machinedor otherwise formed prior to pressure treatment when the metal is soft, and, after hardening by pressure treatment,
  • the nozzles are assembled into the completed spinnerette.
  • specimens of FIG. 3 were of substantially pure iron.
  • other specific materials which'may beused include other comomnly used'magnetic materials; silicon and germanium as well'as the other known semi'conduc: tive materials; silver, copper and other good conductors;
  • a process for improving'the mechanical properties of metal specimens without substantial dimensional change thereof which comprises the steps of encasing the specimen in a solid non-elastomeric jacket, said jacket having compressibility greater than that of the encased specimen, and subjecting'the encased'specimen to high hydrostatic pressure between 1,000 and 50,000 atmospheres:
  • the specimen treated is of a metal selected from the group consisting of iron, germanium, silver, copper and metals of the platinum group. 1 i 5. The process of claim 1 wherein the specimen treated is magnetic.
  • jacket is of a material selected from the group consisting of cerium, bismuth, barium, antimony andalloys thereof.
  • jacket is an alloy of bismuth, tin and lead

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Powder Metallurgy (AREA)
US32888A 1960-05-31 1960-05-31 High pressure process for improving the mechanical properties of metals Expired - Lifetime US3157540A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US32888A US3157540A (en) 1960-05-31 1960-05-31 High pressure process for improving the mechanical properties of metals
SE5526/61A SE302311B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1960-05-31 1961-05-26
DEE21140A DE1235865B (de) 1960-05-31 1961-05-26 Verfahren zur Verbesserung der mechanischen Eigenschaften von festen kristallinen Koerpern durch Druckeinwirkung
GB19572/61A GB971712A (en) 1960-05-31 1961-05-30 High pressure processes and pressure treated products
DE1962E0022383 DE1288568B (de) 1960-05-31 1962-02-09 Verfahren zur Verbesserung der mechanischen Eigenschaften von festen, kristallinen Koerpern

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US32888A US3157540A (en) 1960-05-31 1960-05-31 High pressure process for improving the mechanical properties of metals

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DE (1) DE1235865B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
GB (1) GB971712A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
SE (1) SE302311B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3329535A (en) * 1965-05-11 1967-07-04 Curtiss Wright Corp Pressure treatment of superalloys and method of making turbine blade therefrom
US3496624A (en) * 1966-10-25 1970-02-24 Aluminum Co Of America Castings

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4523748A (en) * 1983-09-02 1985-06-18 R & D Associates Very high pressure apparatus for quenching

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1891234A (en) * 1929-11-06 1932-12-20 Us Pipe & Foundry Company Method of modifying internal strains in metal objects
US2107943A (en) * 1936-06-05 1938-02-08 Kellogg M W Co Method of manufacturing composite seamless tubes
US2268617A (en) * 1938-11-01 1942-01-06 Nat Standard Co Method of making copper clad wire
US2588583A (en) * 1948-12-18 1952-03-11 Celanese Corp Process for spinning
US2588584A (en) * 1949-11-12 1952-03-11 Celanese Corp Spinning artificial filamentary materials
US2615411A (en) * 1951-03-16 1952-10-28 Walton S Clevenger Method and apparatus for hydraulic work hardening
US2689398A (en) * 1948-03-24 1954-09-21 Plessey Co Ltd Method of making magnetizable compacts
US2871558A (en) * 1946-07-02 1959-02-03 Colbeck Eric Winearls Sheathing uranium
US2878140A (en) * 1957-05-01 1959-03-17 Vitro Corp Of America Densification of coating by use of isostatic hydraulic pressure
US2945285A (en) * 1957-06-03 1960-07-19 Sperry Rand Corp Bonding of semiconductor contact electrodes
US2952896A (en) * 1958-04-11 1960-09-20 Texas Instruments Inc Fabrication techniques for transistors
US2958789A (en) * 1957-04-23 1960-11-01 Bell Telephone Labor Inc Transistor circuit
US2962605A (en) * 1957-01-18 1960-11-29 Csf Junction transistor devices having zones of different resistivities

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1891234A (en) * 1929-11-06 1932-12-20 Us Pipe & Foundry Company Method of modifying internal strains in metal objects
US2107943A (en) * 1936-06-05 1938-02-08 Kellogg M W Co Method of manufacturing composite seamless tubes
US2268617A (en) * 1938-11-01 1942-01-06 Nat Standard Co Method of making copper clad wire
US2871558A (en) * 1946-07-02 1959-02-03 Colbeck Eric Winearls Sheathing uranium
US2689398A (en) * 1948-03-24 1954-09-21 Plessey Co Ltd Method of making magnetizable compacts
US2588583A (en) * 1948-12-18 1952-03-11 Celanese Corp Process for spinning
US2588584A (en) * 1949-11-12 1952-03-11 Celanese Corp Spinning artificial filamentary materials
US2615411A (en) * 1951-03-16 1952-10-28 Walton S Clevenger Method and apparatus for hydraulic work hardening
US2962605A (en) * 1957-01-18 1960-11-29 Csf Junction transistor devices having zones of different resistivities
US2958789A (en) * 1957-04-23 1960-11-01 Bell Telephone Labor Inc Transistor circuit
US2878140A (en) * 1957-05-01 1959-03-17 Vitro Corp Of America Densification of coating by use of isostatic hydraulic pressure
US2945285A (en) * 1957-06-03 1960-07-19 Sperry Rand Corp Bonding of semiconductor contact electrodes
US2952896A (en) * 1958-04-11 1960-09-20 Texas Instruments Inc Fabrication techniques for transistors

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3329535A (en) * 1965-05-11 1967-07-04 Curtiss Wright Corp Pressure treatment of superalloys and method of making turbine blade therefrom
US3496624A (en) * 1966-10-25 1970-02-24 Aluminum Co Of America Castings

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Publication number Publication date
SE302311B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1968-07-15
DE1235865B (de) 1967-03-09
GB971712A (en) 1964-10-07

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Owner name: ENGELHARD CORPORATION 70 WOOD AVENUE SOUTH, METRO

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:PHIBRO CORPORATION, A CORP. OF DE;REEL/FRAME:003968/0801

Effective date: 19810518