US3120436A - Powdered metal article and method of making - Google Patents

Powdered metal article and method of making Download PDF

Info

Publication number
US3120436A
US3120436A US9782661A US3120436A US 3120436 A US3120436 A US 3120436A US 9782661 A US9782661 A US 9782661A US 3120436 A US3120436 A US 3120436A
Authority
US
Grant status
Grant
Patent type
Prior art keywords
article
iron
copper
furnace
powder
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
Application number
Inventor
Harold T Harrison
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.)
Presmet Corp
Original Assignee
Presmet Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Grant date

Links

Images

Classifications

    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C33/00Making ferrous alloys
    • C22C33/02Making ferrous alloys by powder metallurgy
    • C22C33/0242Making ferrous alloys by powder metallurgy using the impregnating technique
    • YGENERAL 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
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/12All metal or with adjacent metals
    • Y10T428/12014All metal or with adjacent metals having metal particles
    • Y10T428/1216Continuous interengaged phases of plural metals, or oriented fiber containing

Description

Feb. 4, 1964 H. 'r. HARRISON 3,120,436

POWDERED METAL ARTICLE AND METHOD OF MAKING Filed March 25, 1961 NIX WHITE CAST IRON POWDER AND PURE IRON POWDER PRESS AT 15-50 TONS/SQJN.

PLACE IN PROXIMITY T0 COPPER ALLOY PASS THROUGH FURNACE PREHEAT AT 500-12 00? FlRs'r ZONE AT I650E (8 MINUTES) szcorvo 20m:

AT zooon (8 MINUTES) INVENTOR. Harold T. Harrison United States Patent Ofiice 3,120,43fi Patented Feb. 4, 1%64 3,120,436 PGWDERED METAL ARTICLE AND METHOD OF MAKING Harold T. Harrison, Worcester, Mass, assignor to The Presmet Corporation, Worcester, Mass, a corporation of Massachusetts Filed Mar. 23, 1961, Ser. No. 97,826 2 Claims. (Cl. 75-200) This invention relates to a powdered metal article and a method of making the same and more particularly to a sintered iron-carbon article which has been infiltrated with copper, or a copper base alloy.

In powder metallurgy it is well known that articles made with powdered pure iron, after compacting and sintering, have a strength in the order of 15,000 p.s.i. When such a pure iron article is infiltrated with copper the strength goes to the neighborhood of 60,000 p.s.i. When a powdered metal article is made with about 1% of carbon (Where the carbon is in combined form), the article has a strength of around 26,000 p.s.i. and, when such an iron-carbon article is infiltrated with copper, the strength goes to the neighborhood of 90,000 p.s.i. The last-named alloy, therefore, is a very desirable product. Alloys produced by powder metallurgy infiltration techniques are described in ASTM specification B-30358T and they account for a large tonnage of structural parts produced by the industry. Class B and C alloys containing definite percentages of carbon exhibit mechanical properties that are as good as those produced by any of the other powder metallurgy techniques, even as good as those techniques using double pressing and double sintering.

In many cases the economics of the process for producing iron-carbon parts that have been copper-alloy infiltrated precludes its use. One factor that contributes considerably to the expense of the processing is the need for a double furnace operation. The common method of manufacture is to mix the appropriate amount of graphite powder with pure iron powder. This mixture is compacted and then sintered to diffuse the graphite and iron. The resulting iron and iron-carbide skeleton is then infiltrated with the copper-base alloy in a second furnace operation. Infiltration is impossible until all or substantially all of the free graphite has been transformed to the iron-carbide phase by the initial sintering operation; the poor wettability of graphite by molten copper or its alloys is responsible for this condition. These and other difiiculties experienced with the prior art articles and methods have been obviated in a novel manner by the present invention.

It is, therefore, an outstanding object of the invention to provide a powdered metal article and a method of making it, wherein the article has a very high strength and is economical to manufacture.

Another object of this invention is the provision of an iron-carbon powdered metal article which is infiltrated with copper and which makes use of inexpensive materials.

A further object of the present invention is the provision of an iron-carbon powdered metal article, copper infiltrated, which is produced by a single-pass furnace treatment, thus omitting a handling operation, making the first piece emerging from the furnace immediately available for inspection, and saving fuel in the operation.

It is another object of the instant invention to provide a method of producing an iron-carbide powdered metal article with copper infiltration by a process which is less likely to decarburize in a furnace having a marginal atmosphere.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, the mode of its operation and the manner of its organization may be better understood by referring to the following description taken in connect-ion with the accompanying drawing forming a part thereof, in which:

The single figure is a flow chart illustrating the method of producing a powdered metal article using the principles of the present invention.

In a general way, the present invention accomplishes the sintering and infiltration operation in one furnace pass. This is accomplished by the use of a cast iron powder containing 4% carbon in the form of iron carbide, rather than using a graphite powder for the carbon addition as was the practice in the past. This cast iron (4% carbon) powder is diluted with commercially pure iron powder in the proper amount to obtain a mix that will result in the total carbon content desired in the finished product. Articles pressed from this mix can be infiltrated and sintered in one furnace operation inasmuch as there is no free graphite to reduce wettability of the molten copper phase. Diffusion of carbon is quite rapid and the end product is entirely homogeneous with respect to the iron carbide phase.

An example of the use of the method of the invention involved mixing a powder of white cast iron powder (having 4% carbon in combined form and no free carbon) with a powder of commercially pure iron to give an overall carbon content of 1% which resulted in around 0.8% carbon in the finished article. This powder was formed and pressed at 30 tons per square inch to form a compact article. Then, the article was passed through a furnace. The furnace is provided with a pre-heating zone in which the temperature gradually increased to 1200 F. This had the effect of expelling the zinc stearate which was used as a die lubricant in the initial mix. The article was then passed into a first zone of the furnace in which the temperature was at 1650 F., which temperature was below the melting point of the copper alloy. It should be pointed out that before passing the article through the furnace it was placed in intimate contact with a copper alloy piece of sufiicient volume to substantially infiltrate the powdered metal article, so that the molten copper or alloy would substantially fill the interstices of the iron skeleton. In any case, this first zone pre-sintered the iron part of the compact to provide a strong skeleton. Ilhis served to resist the forces of disintegration which normally takes place when liquid copper soaks into an unsintered skeleton. This effect of attempting to infiltrate an unsintered iron skeleton with copper is similar to the effect that one has when a fairly substantial cake of mud is dropped into a pail of water; the water causes the cake to disintegrate. The article is next passed into and through a second zone of the furnace at 2,000 F., which temperature is above the melting point of the copper alloy. The molten copper is drawn into the article and infiltrates it by capillary action. The finished article was then removed from the furnace. In the example, the article remained in the first zone for eight minutes and in the second zone for eight minutes. The ultimate tensile strength was 83,400 p.s.i.

'It should be pointed out that experience has shown that the white cast iron powder may contain from 3 /2% to 4%% carbon in combined form. Furthermore, the pressing operation may take place from 15 to 50 tons per square inch, although it is usually in the range of from 25 to 30 tons per square inch. The first zone of the furnace in which the pre-sintering operation takes place may have a temperature from l600 to 1850 F.; of course, the temperature of this Zone depends on the melting point of the particular copper alloy. If pure copper is used, it would be higher than an alloy of, say, zinc or tin. The

e,120,ase

temperature in the second zone may lie in the range of from 1750 to 2050 F.; in any case, it is above the melting point of the copper or its alloy.

The advantages of the process of the invention are many. First of all, the white cast iron powder is less expensive than commercially pure iron powder, so that the initial material used in producing the article are less expensive. The use of a single pass furnace treatment has several advantages. First of all, the handling operation used in a two-pass furnace operation adds considerably to the cost in the form of labor expense; with a two-pass operation it is necessary to cool the articles and then to carry them back to be passed through the furnace for the second time. Of course, the furnace temperatures and everything have to be changed between the two passes. Another advantage is that, if the operation is not going properly, this fact becomes evident as soon as the first piece comes through the furnace. With the old methods it was necessary to completely process all of the articles in a first furnace pass and then to start them passing through the second furnace pass; only then was the article completely finished and available for inspection. With the present method changes can be made in the operation on the batch before the batch has completely passed through the furnace. Another advantage is that it has been noted that an article made according to the present method is less likely to de-carburize in a furnace atmosphere which is marginal with respect to carbon potential. Since it is expensive to regulate the furnace very carefully to avoid a marginal atmosphere, the fact that the present article is less susceptible to decarburization in such an atmosphere is a decided advantage in operating commercially.

While certain novel features of the invention have been shown and described and pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes in the forms and details of the invention illustrated and in the operation of the method may be made by those skilled in the art without departing from the spirit of the invention.

The invention having been thus described, what is claimed as new and desired to secure by Letters Patent is:

l. A method of forming a powdered metal article, comprising the step of mixing white cast iron powder with pure iron powder, pressing the resulting powder mixture to obtain a formed article, placing the formed article in contact with a quantity of copper in the solid state, and passing the article and copper through a furnace having a first zone at a temperature below the melting point of the copper and a second zone at a temperature above the melting point of the copper.

2. A method of forming a powdered metal article, comprising the steps of mixing an iron powder having 4% by weight of carbon in combined form with pure iron powder in an amount sufiicient to give between 0.2% to 1.25% by weight of carbon in the article, pressing the mixture of powders at a pressure in the range of from 15 to 50 tons per square inch to obtain a formed article, placing the formed article in physical contact with a quantity of copper in the solid state, and passing the formed article and the copper in contact therewith through a furnace having a first Zone at a temperature in the range from 1600 to 1850 F., to produce at least partial sintering of the formed article, and a second zone at a temperature in the range from 1750 to 2050 F., to cause infiltration of the copper into the formed article.

References Cited in the file of this patent UNITED STATES PATENTS 2,198,254 Loering Apr. 23, 1940 2,422,439 Schwarzkopf June 17, 1947 2,706,694 Haller Apr. 19, 1955 2,759,846 Vosler Aug. 21, 1956 2,778,742 Shipe Jan. 22, 1957 2,851,354 Scanlan et al. Sept. 9, 1958 FOREIGN PATENTS 308,819 Great Britain Feb. 20, 1930 720,050 Great Britain Dec. 15, 1954

Claims (1)

1. A METHOD OF FORMING A POWDERED METAL ARTICLE, COMPRISING THE STEPS, OF MIXING WHITE CAST IRON POWDER WITH PURE IRON POWDER, PRESSING THE RESULTING POWDER MIXTURE TO OBTAIN A FORMED ARTICLE, PLACING THE FORMED ARTICLE IN CONTACT WITH A QUANTITY OF COPPER IN THE SOLID STATE, AND PASSING THE ARTICLE AND COPPER THROUGH A FURNACE HAVING A FIRST ZONE AT A TEMPERATURE BELOW THE MELTING POINT OF THE COPPER AND AT A SECOND ZONE AT A TEMPERATURE ABOVE THE MELTING POINT OF THE COPPER.
US3120436A 1961-03-23 1961-03-23 Powdered metal article and method of making Expired - Lifetime US3120436A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US3120436A US3120436A (en) 1961-03-23 1961-03-23 Powdered metal article and method of making

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US3120436A US3120436A (en) 1961-03-23 1961-03-23 Powdered metal article and method of making

Publications (1)

Publication Number Publication Date
US3120436A true US3120436A (en) 1964-02-04

Family

ID=22265319

Family Applications (1)

Application Number Title Priority Date Filing Date
US3120436A Expired - Lifetime US3120436A (en) 1961-03-23 1961-03-23 Powdered metal article and method of making

Country Status (1)

Country Link
US (1) US3120436A (en)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3334408A (en) * 1964-10-08 1967-08-08 Metal Innovations Inc Production of powder, strip and other metal products from refined molten metal
US3343927A (en) * 1963-12-18 1967-09-26 Motor Wheel Corp Sintered metal brake drum
US3359623A (en) * 1965-05-13 1967-12-26 Talon Inc Method for making refractory metal contacts having integral welding surfaces thereon
US3414391A (en) * 1963-12-13 1968-12-03 Porter Prec Products Inc Ferrous die element formed of powdered metal impregnated with copper
US3459547A (en) * 1967-06-28 1969-08-05 Burgess Norton Mfg Co Method of making a structural alloy steel containing copper and other alloy elements
US3929476A (en) * 1972-05-05 1975-12-30 Minnesota Mining & Mfg Precision molded refractory articles and method of making
JPS5133706A (en) * 1974-09-17 1976-03-23 Mitsubishi Heavy Ind Ltd Komitsudoshoketsuko no seizohoho
JPS5147507A (en) * 1974-10-22 1976-04-23 Mitsubishi Heavy Ind Ltd Komitsudoshoketsukono seizohoho
JPS51123715A (en) * 1975-04-21 1976-10-28 Brother Ind Ltd A process for producing sintered moldings
JPS51151208A (en) * 1975-06-20 1976-12-25 Komatsu Ltd A vibrationproof sintered alloy
US4158719A (en) * 1977-06-09 1979-06-19 Carpenter Technology Corporation Low expansion low resistivity composite powder metallurgy member and method of making the same
JPS54100907A (en) * 1978-01-26 1979-08-09 Takaoka Kogyo Kk Production of sintered ironncarbon material
US5217683A (en) * 1991-05-03 1993-06-08 Hoeganaes Corporation Steel powder composition
WO1996005014A1 (en) * 1994-08-17 1996-02-22 WELLER, Emily, I. Soldering iron tip made from a copper/iron alloy composite

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB308819A (en) * 1928-03-31 1930-02-20 Gen Electric Improvements in and relating to multiple metals and methods of manufacturing the same
US2198254A (en) * 1936-08-07 1940-04-23 Gen Motors Corp Method of making composite metal structures
US2422439A (en) * 1943-01-29 1947-06-17 American Electro Metal Corp Method of manufacturing composite structural materials
GB720050A (en) * 1951-06-13 1954-12-08 American Electro Metal Corp Corrosion-resistant coatings on copper infiltrated ferrous skeleton bodies
US2706694A (en) * 1952-03-15 1955-04-19 Allied Prod Corp Process of externally infiltrating powdered metal articles
US2759846A (en) * 1952-09-05 1956-08-21 Gen Motors Corp Method of impregnating porous metal parts with a lower melting point metal
US2778742A (en) * 1953-05-25 1957-01-22 Gen Motors Corp Method of impregnating a porous ferrous part with copper
US2851354A (en) * 1954-01-13 1958-09-09 Schwarzkopf Dev Co Process of forming sintered sheets having copper infiltrated portions

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB308819A (en) * 1928-03-31 1930-02-20 Gen Electric Improvements in and relating to multiple metals and methods of manufacturing the same
US2198254A (en) * 1936-08-07 1940-04-23 Gen Motors Corp Method of making composite metal structures
US2422439A (en) * 1943-01-29 1947-06-17 American Electro Metal Corp Method of manufacturing composite structural materials
GB720050A (en) * 1951-06-13 1954-12-08 American Electro Metal Corp Corrosion-resistant coatings on copper infiltrated ferrous skeleton bodies
US2706694A (en) * 1952-03-15 1955-04-19 Allied Prod Corp Process of externally infiltrating powdered metal articles
US2759846A (en) * 1952-09-05 1956-08-21 Gen Motors Corp Method of impregnating porous metal parts with a lower melting point metal
US2778742A (en) * 1953-05-25 1957-01-22 Gen Motors Corp Method of impregnating a porous ferrous part with copper
US2851354A (en) * 1954-01-13 1958-09-09 Schwarzkopf Dev Co Process of forming sintered sheets having copper infiltrated portions

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3414391A (en) * 1963-12-13 1968-12-03 Porter Prec Products Inc Ferrous die element formed of powdered metal impregnated with copper
US3343927A (en) * 1963-12-18 1967-09-26 Motor Wheel Corp Sintered metal brake drum
US3334408A (en) * 1964-10-08 1967-08-08 Metal Innovations Inc Production of powder, strip and other metal products from refined molten metal
US3359623A (en) * 1965-05-13 1967-12-26 Talon Inc Method for making refractory metal contacts having integral welding surfaces thereon
US3459547A (en) * 1967-06-28 1969-08-05 Burgess Norton Mfg Co Method of making a structural alloy steel containing copper and other alloy elements
US3929476A (en) * 1972-05-05 1975-12-30 Minnesota Mining & Mfg Precision molded refractory articles and method of making
JPS5133706A (en) * 1974-09-17 1976-03-23 Mitsubishi Heavy Ind Ltd Komitsudoshoketsuko no seizohoho
JPS5819722B2 (en) * 1974-09-17 1983-04-19 Mitsubishi Heavy Ind Ltd
JPS5147507A (en) * 1974-10-22 1976-04-23 Mitsubishi Heavy Ind Ltd Komitsudoshoketsukono seizohoho
JPS5819738B2 (en) * 1974-10-22 1983-04-19 Mitsubishi Heavy Ind Ltd
JPS51123715A (en) * 1975-04-21 1976-10-28 Brother Ind Ltd A process for producing sintered moldings
JPS5810459B2 (en) * 1975-04-21 1983-02-25 Burazaa Kogyo Kk
JPS51151208A (en) * 1975-06-20 1976-12-25 Komatsu Ltd A vibrationproof sintered alloy
JPS5536259B2 (en) * 1975-06-20 1980-09-19
US4158719A (en) * 1977-06-09 1979-06-19 Carpenter Technology Corporation Low expansion low resistivity composite powder metallurgy member and method of making the same
JPS54100907A (en) * 1978-01-26 1979-08-09 Takaoka Kogyo Kk Production of sintered ironncarbon material
US5217683A (en) * 1991-05-03 1993-06-08 Hoeganaes Corporation Steel powder composition
WO1996005014A1 (en) * 1994-08-17 1996-02-22 WELLER, Emily, I. Soldering iron tip made from a copper/iron alloy composite
US5553767A (en) * 1994-08-17 1996-09-10 Donald Fegley Soldering iron tip made from a copper/iron alloy composite
US5579533A (en) * 1994-08-17 1996-11-26 Donald Fegley Method of making a soldering iron tip from a copper/iron alloy composite

Similar Documents

Publication Publication Date Title
US3372021A (en) Tungsten addition agent
US3348967A (en) Process of making an article having a hard carbide, boride or silicide outer region
US3382066A (en) Method of making tungsten-copper composites
US5328657A (en) Method of molding metal particles
US4915605A (en) Method of consolidation of powder aluminum and aluminum alloys
US4765950A (en) Process for fabricating parts from particulate material
US2893102A (en) Article fabrication from powders
US2386604A (en) Method of molding under pressure metallic powders
US4341557A (en) Method of hot consolidating powder with a recyclable container material
US4604259A (en) Process for making copper-rich metal shapes by powder metallurgy
US4612162A (en) Method for producing a high density metal article
US2456779A (en) Composite material and shaped bodies therefrom
US3915699A (en) Method for producing metal dies or molds containing cooling channels by sintering powdered metals
US3700435A (en) Method for making powder metallurgy shapes
US3702243A (en) Method of preparing deoxidized steel
US2123416A (en) graham
US2244608A (en) Process of making alloys of aluminum beryllium
US2888738A (en) Sintered metal bodies containing boron nitride
US3357818A (en) Metallurgical powder mixtures and mixing methods therefor
US4029476A (en) Brazing alloy compositions
US3749571A (en) Cold-pressed compositions
US2331909A (en) Gear and the like
US4483820A (en) Method of making sintered powder metallurgical bodies
US5269830A (en) Process for synthesizing compounds from elemental powders and product
US4888054A (en) Metal composites with fly ash incorporated therein and a process for producing the same