US3708283A - Process for preparing cemented ferrochrome - Google Patents
Process for preparing cemented ferrochrome Download PDFInfo
- Publication number
- US3708283A US3708283A US00107804A US3708283DA US3708283A US 3708283 A US3708283 A US 3708283A US 00107804 A US00107804 A US 00107804A US 3708283D A US3708283D A US 3708283DA US 3708283 A US3708283 A US 3708283A
- Authority
- US
- United States
- Prior art keywords
- ferrochrome
- percent
- weight
- binder
- particles
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/02—Making ferrous alloys by powder metallurgy
- C22C33/0235—Starting from compounds, e.g. oxides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/09—Mixtures of metallic powders
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/04—Making non-ferrous alloys by powder metallurgy
-
- 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
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12014—All metal or with adjacent metals having metal particles
- Y10T428/1216—Continuous interengaged phases of plural metals, or oriented fiber containing
Definitions
- a cemented ferrochrome material including from 15 to 99 percent of ferrochrome and from 1 to 85 percent of a metallic binder.
- the material is made by mixing or milling together particles of ferrochrome and the binder metal until the particle size of the mixture is substantially less than 325 mesh, compacting and heating to a temperature within the range of l850 2400F.
- the product has excellent corrosion resistance, high hardness, good strength and is highly impermeable to liquids. It may be used in any applications in which such properties are desirable, such as a ball pen balls, wear pads and mounts adapted to be adhered to materials having compatible coefiicients of thermal expansion.
- the present invention relates to a cemented ferrochrome material having particularly advantageous properties and to a powder metallurgy process for preparing the same.
- Another object of the invention is to provide a cemented ferrochrome material of low porosity with a resulting high impermeability.
- a further object of the invention is to provide a cemented ferrochrome material having a low coefficient of thermal expansion.
- Another and further object of the invention is to provide a cemented ferrochrome material which is of low cost as compared to other powder metal products with similar corrosion resistant properties.
- a still further object of the invention is to provide a novel process for preparing a cemented ferrochrome material having the advantageous properties set forth above.
- FIG. 1 is a photomicrograph of a product according to the invention taken at a magnification of 250 times;
- FIG. 2 is a photomicrograph of this same product taken at a magnification of 1250 times.
- the product of the invention comprises a composite mass of finely divided ferrochrome particles cemented together by a binder metal or alloy having a melting point lower than that of the ferrochrome.
- the product may contain from to 99 percent by weight of ferrochrome and from 1 to 85 percent by weight of binder, but it is preferred that the ferrochrome be present in an amount between 25 and 95 percent by weight and the metallic binder in an amount between about 5 and 75 percent by weight.
- the percentage of ferrochrome is decreased, the hardness decreases, but the strength and toughness are increased. Accordingly, a balance will be struck in accordance with the particular use to which a given product is to be put.
- temperatures are employed in the making of the product which are above the melting point of the binder and at the sintering temperatures of the ferrochrome. Accordingly, particles of ferrochrome will be sintered at their points of contact. There will be very little contact between particles of ferrochrome in products which are high in binder and proportionately more in products which are high in ferrochrome.
- the metallic binder substantially completely fills all of the spaces between particles of ferrochrome.
- the product can be made to have an extremely low porosity and thus is to all practical purposes impermeable to liquids of every description. It is to be stressed that the ferrochrome to a large extent maintains its separate identity so that the product is a composite one, although some alloying may take place and the smaller ferrochrome particles may dissolve, at least partially, in the liquid binder.
- the size of the ferrochrome particles is quite important. They should have a distribution ranging from less than 1 micron to 50 microns. Particularly good products are those in which the ferrochrome particles prior to being subjected to sintering temperature during fabrication were of a size such that percent by weight would pass through a 325 mesh screen. A very satisfactory product is one in which 99 percent by weight of the ferrochrome particles are of a size less than 20 microns.
- the ferrochrome of the material according to the invention should contain from about 60 to 75 percent by weight of chromium, from about 25 to 40 percent by weight of iron and from about 0.1 to 7 percent carbon.
- chromium from about 25 to 40 percent by weight of iron
- iron from about 0.1 to 7 percent carbon.
- any of the ferrochromes commercially available as an alloying ingredient these ferrochromes being sold in particulate form, although not in the finely divided form desired in the present products.
- Both high carbon and low carbon ferrochromes, as well as one containing silicon, may be used in making the present products, but a high carbon ferrochrome is preferred.
- a particularly preferred high carbon ferrochrome is one containing about 70 percent by weight of chromium, 25 percent by weight of iron and 5 percent by weight of carbon.
- the following is a typical screen analysis in weight percent of a commercial ferrochrome of this description:
- a particularly suitable binder for preparing the materials of the invention is a mixture of iron and cast iron.
- the iron is the most economical of the binder materials and the cast iron, because of its low melting point, promotes the liquid phase sintering which occurs in the process of manufacture which will be described in detail hereinafter.
- Substantially pure iron powders such as ANCOR MH-l sponge iron powder, manufactured by the Hoeganaes Sponge lron Corporation of Riverton, N. J., and cast iron powders are commercially available. Typical screen analyses of available iron and cast iron powder in weight percent are set forth as follows:
- the iron or cast iron powder can be used separately, superior properties are obtained from mixtures of the two; the preferable range of the iron powder being 50 to 90 percent by weight. It is to be understood, of course, that in the final cemented ferrochrome product, the iron and cast iron will have combined to form a steel. Alternatively, a steel powder can be used directly in place of a mixture of iron and cast iron powders.
- the products of the invention are made by a novel powder metallurgy technique which ensures the obtaining of a material having the advantageous properties set forth above.
- the as-received ferrochrome and metallic binder powders are milled together to provide an intimate mixture of finely divided ferrochrome and binder particles. This can suitably be done in a ball mill and milling should preferably be continued until the particle size of the resulting mixture is such that 90 percent will pass through a 325 mesh screen. Milling may be continued until 99 percent of the particles are less than 20 microns in size. Milling will ordinarily be carried out for a period of from 24 to 100 hours depending on equipment used.
- the resulting intimate mixture of finely divided powders is then compacted in a mechanical or hydraulic press approximately to the shape of the desired final article under a pressure of to 40 tons/sq. in.
- This may be accomplished with the aid of a conventional lubricant or organic resin binder, a suitable lubricant comprising about 2 weight percent of paraffin wax, the powders being coated with the lubricant or binder prior to compacting. If a lubricant or binder is used, it is preferably removed before subjecting the compact to the heating step next to be described.
- the compact is heated to a temperature within the range of l850 2400 F in an inert or reducing environment achieved by the establishment of vacuum conditions or by provision of a blanket of an inert gas, such as helium, or by use of a reducing gas, such as dissociated ammonia.
- the binder particles are converted to a totally liquid phase which substantially completely fills all of the voids or spaces between the particles of ferrochrome. As stated above, there may be sintering of ferrochrome particles, but this is not necessary.
- the sintering stage of the process can ordinarily be completed by heating at the stated temperature for from 15 to minutes.
- EXAMPLE 1 The following powders were ball milled in a small steel mill with steel balls for 1 12 hours:
- the parts showed very little wear and no corrosion when used in the pen nib flexing apparatus as replacement for chromium plated tool steel wear pads'which had chipped and corroded.
- FIG. 1 of the drawings is a photomicrograph of the product of this example at a magnification of,250X and FIG. 2 is a photomicrograph of the same product at a magnification of 1250X.
- the continuous skeletal phase is ferrochromium and the binder phase between the particles is steel.
- Example 11 The procedure of Example 11 was used to prepare sintered discs composed of 85 percent by weight of ferrochrome and 15 percent by weight of steel binder. The following amounts of powder were used:
- the milled powder from each batch was mixed with 2 percent by weight of paraffin wax and standard tensile test specimens (Metal Powder Association Standard 8-50) compacted at 15 tons/in
- the green specimens were pack e d in 30 mesh alumina an d the wax was removed by heating slowly to 800 F in dissociated ammonia.
- Final sintering was carried out in a vacuum furnace by heating at 2250 F for 30 minutes at 0.2 0.5 torr. pressure. Properties of the various cemented ferrochromes are given in the following table:
- the milled powder was waxed, compacted into transverse rupture test specimens (Metal Powder Association Standard 13-62), and the specimens sintered in either dissociated ammonia or vacuum. Properties of the various compositions were as follows:
- test results show the novel materials of the present invention have properties that are comparable to many commercially available P/M products and that by varying the percentages of the constituents of the compositions it is possible to vary their characteristics over relatively wide limits thereby making them useful for various industrial applications.
- ferrochrome Monel (70% by weight of nickel and 30% by weight of copper)
- the mixture of milled powders with a composition of 80 percent by weight of ferrochrome and percent by weight binder alloy was processed into balls as described in Example 1.
- the balls had a microhardness of DPH 603 and gave satisfactory writing performance in ball pen points.
- EXAMPLE X An experiment was conducted using silver as the binder metal for ferrochrome.
- the powdered metals in ratios to give 10 percent, 20 percent and 30 percent by weight silver composites were mixed together in a mortar, compacted in a 0.25 inch diameter cylindrical steel die at 20 tons/in and sintered in a vacuum furnace at 1850 F for 30 minutes at l torr. pressure of helium. There was little or no shrinkage of the compact but metallographic examination indicates good wetting of the ferrochrome particles by the silver.
- Example X1 The experiment of Example X was repeated except that palladium powder was added to prepare a composition of 80 percent by weight of ferrochrome, 16 percent by weight of silver and 4 percent by weight of palladium. Sintering at 2200 F resulted in a compact with a good strength but little shrinkage.
- Example XII The experiment of Example X was repeated except that a prealloyed powder of percent by weight of silver, 20 percent by weight of palladium and 10 percent by weight of manganese was used as the binder metal to prepare a composition of 70 percent by weight of ferrochrome and 30 percent by weight of the silverpalladium-manganese alloy. Sintering at 2350 F for 15 minutes at 200 torr. helium pressure resulted in shrinkage from 0.250 inches to 0.240 inches in diameter. The part had good strength and a hardness value of 30N-75.
- cemented ferrochrome materials which are hard, dense, highly impermeable, corrosion resistant and of good strength.
- the materials have a low coefficient of thermal expansion, generally of the order of 5 microinch/inch/F.
- the materials of the invention can be used, in general, for any of the applications for which stainless steel parts formed by powder metallurgy techniques from stainless steel powders have been used.
- the present materials are particularly suited for the manufacture of ball point pen balls.
- a process for preparing a cemented ferrochrome material comprising:
Abstract
Description
Claims (3)
- 2. A process as claimed in claim 1 in which the mixture of ferrochrome particles and said particles of metal or alloy are milled until 99 percent of all particles are of a size less than 20 microns.
- 3. A process as claimed in claim 1 in which said mixture of particles contains from about 25 to 95 percent by weight of said ferrochrome and from about 5 to 75 percent by weight of said metal or alloy.
- 4. A process as claimed in claim 1 in which said binder metal is a mixture of iron and cast iron.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10780471A | 1971-01-19 | 1971-01-19 |
Publications (1)
Publication Number | Publication Date |
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US3708283A true US3708283A (en) | 1973-01-02 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US00107804A Expired - Lifetime US3708283A (en) | 1971-01-19 | 1971-01-19 | Process for preparing cemented ferrochrome |
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Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3773474A (en) * | 1971-04-26 | 1973-11-20 | W Horn | Multi-phase strip from particle and powder mixtures |
US4011051A (en) * | 1974-05-02 | 1977-03-08 | Caterpillar Tractor Co. | Composite wear-resistant alloy, and tools from same |
EP0795367A1 (en) * | 1996-02-27 | 1997-09-17 | Degussa Aktiengesellschaft | Silver-iron material for electrical switch contacts and process for its preparation |
US20050132843A1 (en) * | 2003-12-22 | 2005-06-23 | Xiangyang Jiang | Chrome composite materials |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2370396A (en) * | 1943-07-16 | 1945-02-27 | Hardy Metallurg Company | Powder metallurgy |
-
1971
- 1971-01-19 US US00107804A patent/US3708283A/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2370396A (en) * | 1943-07-16 | 1945-02-27 | Hardy Metallurg Company | Powder metallurgy |
Non-Patent Citations (3)
Title |
---|
ASM Metals Handbook, 1948 Ed., pp. 338 339, TA 472, A3, 1948. * |
Eisenkolb, Powder Metallurgy, 1961, pp. 75 95, TN 695.P54. * |
Eisenkolb, Stahl und Eisen, Vol. 78, No. 3, Feb. 6, 1958, pp. 141 148, T5 300.S7. * |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3773474A (en) * | 1971-04-26 | 1973-11-20 | W Horn | Multi-phase strip from particle and powder mixtures |
US4011051A (en) * | 1974-05-02 | 1977-03-08 | Caterpillar Tractor Co. | Composite wear-resistant alloy, and tools from same |
EP0795367A1 (en) * | 1996-02-27 | 1997-09-17 | Degussa Aktiengesellschaft | Silver-iron material for electrical switch contacts and process for its preparation |
US5985440A (en) * | 1996-02-27 | 1999-11-16 | Degussa Aktiengesellschaft | Sintered silver-iron material for electrical contacts and process for producing it |
US20050132843A1 (en) * | 2003-12-22 | 2005-06-23 | Xiangyang Jiang | Chrome composite materials |
WO2005068673A1 (en) * | 2003-12-22 | 2005-07-28 | Caterpillar, Inc. | Chrome composite materials |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: PARKER PEN (BENELUX) N.V., TAKKEBIJSTERS 1, (4811 Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:PARKER PEN COMPANY THE A CORP. OF DE.;REEL/FRAME:004562/0893 Effective date: 19860131 Owner name: BANKERS TRUST COMPANY Free format text: SECURITY INTEREST;ASSIGNOR:PARKER PEN (BENELUX) N.V.;REEL/FRAME:004547/0644 Effective date: 19860131 |
|
AS | Assignment |
Owner name: PARKER PEN (BENELUX) N.V.,NETHERLANDS Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:BANKERS TRUST COMPANY;REEL/FRAME:004823/0983 Effective date: 19871029 Owner name: PARKER PEN (BENELUX) N.V., TAKKEBIJSTERS 1, (4811 Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:BANKERS TRUST COMPANY;REEL/FRAME:004823/0983 Effective date: 19871029 |
|
AS | Assignment |
Owner name: PARKER PEN (BENELUX) B.V. Free format text: RE-RECORD OF INSTRUMENT RECORDED MARCH 5, 1986, AT REEL 4562 FRAMES 0893-898 TO CORRECT NAME OF ASSIGNEE IN A PREVIOUSLY RECORDED ASSIGNEE.;ASSIGNOR:PARKER PEN COMPANY, THE, A DE CORP.;REEL/FRAME:004880/0123 Effective date: 19880316 Owner name: BANKERS TRUST COMPANY Free format text: RE-RECORD OF INSTRUMENT RECORDED MARCH 5, 1986 AT REEL 4547 FRAMES -0644-0648 TO CORRECT NAME OF ASSIGNOR IN A PREVIOUSLY RECORDED ASSIGNMENT.;ASSIGNOR:PARKER PEN (BENELUX) B.V.;REEL/FRAME:004880/0131 Effective date: 19880316 |
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AS | Assignment |
Owner name: PARKER PEN (BENELUX) B.V. Free format text: RE-RECORD OF AN INSTRUMENT RECORDED JAN. 14, 1988, AT REEL 4823, FRAME 983-987 TO CORRECT THE NAME OF THE ASSIGNEE;ASSIGNOR:BANKERS TRUST COMPANY, A DE. CORP.;REEL/FRAME:005093/0539 Effective date: 19871029 |