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Publication numberUS3829295 A
Publication typeGrant
Publication date13 Aug 1974
Filing date13 Oct 1972
Priority date23 Oct 1971
Also published asDE2251909A1, DE2251909C2
Publication numberUS 3829295 A, US 3829295A, US-A-3829295, US3829295 A, US3829295A
InventorsCadle T, Farmer E
Original AssigneeBrico Eng
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Sintered iron based articles infiltrated with copper based metals
US 3829295 A
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Description  (OCR text may contain errors)

3,829,295 SINTERED IRON BASED ARTICLES INFILTRATED WITH COPPER BASED METALS Edwin Bruce Farmer and Terence Michael Cadle, Coventry, England, assignors to Brico Engineering Limited, Coventry, England No Drawing. Filed Oct. 13, 1972, Ser. No. 297,363 Claims priority, application Great Britain, Oct. 23, 1971, 49,345/71 Int. Cl. B22f 3/26 US. Cl. 29-1821 6 Claims ABSTRACT OF THE DISCLOSURE A sintered metal article including a sintered skeleton having the composition 1.5-2.0% Nickel, 0.30.7% Molybdenum, 1-2% Copper, 0.1-0.3% Carbon, not more than 2% of Manganese, Silicon, Sulphur, and Phosphorus together (percentages being by weight), the remainder (apart from impurities and trace elements) being Iron, the sintered skeleton being infiltrated with Copper or Copper-based alloy, and the article being case-hardened.

This invention relates to sintered metal articles and to processes for their manufacture.

According to this invention in one aspect, a sintered metal article includes a sintered skeleton having the composition 1.5-2.0% Nickel, 0.3-0.7% Molybdenum, 1-2% Copper, 0.10.3% Carbon, not more than 2% of Manganese, Silicon, Sulphur and Phosphorus together (percentages being by weight), the remainder (apart from impurities and trace elements) being Iron, the sintered skeleton being infiltrated with Copper, or Copper-based alloy, and the article being case hardened.

Preferably the skeleton has substantially 1.75% Nickel, 0.5% Molybdenum. 1.5% Copper, 0.25% Combined Carbon.

According to this invention in another aspect, a process for the manufacture of sintered metal articles includes the steps of producing a sintered skeleton having the composition l.5-2.0% Nickel, 0.30.7% Molybdenum, 12% Copper, 0.l0.3% Carbon, not more than 2% of Manganese, Silicon, Sulphur and Phosphorus together, the remainder (apart from impurities and trace elements) being Iron, infiltrating the skeleton with Copper or Copper-based alloy in an amount between 8% and 25% of the skeleton, and then case-hardening the infiltrated article.

Preferably the sintered skeleton is infiltrated with 14% Copper or Copper-based alloy.

A process for the manufacture of articles in accordance with the invention will now be described by way of example.

A pre-alloy or partial pre-alloy in the form of a powder of less than 100 13.8. mesh size and the following composition is selected:

Percent Ni 1.5-2 Mo 0.3-0.7 Cu 1.0-2.0 Mn, Si, S, P Fe Remainder 1 Not exceeding 2% in total. (all the percentages in the specification are by weight).

This pre-alloy or partial pre-alloy powder is mixed with 01-03% (of the weight of the pre-alloy powder) of Carbon, in the form of graphite, and preferably with a small percentage e.g. 1% of a suitable lubricant such as Zinc Stearate. The constituents are thoroughly mixed in a suitable mixer.

3,829,295 Patented Aug. 13, 1974 The mixture is then pressed at 30-45 tons/sq. in. in a suitable powder metallurgy press, and sintered in a protective atmosphere, for example, a reducing atmosphere of dried cracked Ammonia or a Carbonaceous atmosphere of Endothermic Gas at a temperature in the range 1090 C.-ll20 C. for between 20 and 30 minutes. The lubricant disappears in the sintering process.

The sintered article or skeleton is then infiltrated with Copper or Copper-based alloy in an amount equal to between 8 and 25 of the weight of the article, for example, by placing the article in a suitable mould having walls which extend above the article and placing Copper or Copper-based alloy powder on the article, between the walls. The article is then heated in an oven to a temperature significantly above the melting point of Copper or its alloy, so that all the molten Copper or Copper-based alloy infiltrates into the pores of the article; the time of heating is such as to allow the Copper or Copper-based alloy to infiltrate the article uniformly.

Suitable Copper-based alloys are Copper plus 3% Cobalt, or Copper plus 5% Iron and 5% Manganese.

After infiltration the article is then case-hardened either by Carburising, Carbo-Nitriding or any other known or convenient method of Carbon case-hardening.

In one particular example the pre-alloy powder contained 1.75% Nickel, 0.5% Molybdenum, 1.5% Copper, which was mixed with 0.25% Graphite and 1% Zinc Stearate. After sintering in the above manner the skeleton was impregnated with 14% Copper.

The ultimate tensile strength of the article is shown by the following table:

Condition UTS, tons/sq. in. As sintered 27 Sintered and case-hardened 46 Sintered, infiltrated and case-hardened 65 Condition UTS, tons/sq. in. As sintered 27 Sintered and case-hardened 41 Infiltrated and case hardened 40 Other physical properties of articles made in accordance with the invention have been measured as follows:

Density gm./cc 7.0-8.0 Transverse rupture modulus p.s.i. 270,000 Impact strength (unnotched Charpy) ft. lb 27 We claim:

1. A sintered metal article consisting of a sintered skeleton infiltrated with copper or copper-based alloy, the skeleton having the composition, in percentages by weight:

Percent Nickel l.5-2.0

Molybdenum 0.3-0.7

Copper 1-2 Carbon 0. l0.3 Manganese, Silicon, Sulphur and phosphorus together Not exceeding 2 Iron (with impurities and trace elements) 93.0-97.1

3 4 the skeleton being infiltrated with Copper or Copper-based References Cited alloy, and the article being case-hardened after infiltration. UNITED STATES PATENTS 2. A sintered metal article, according to Claim 1, in whi h th skeleton has substantially 1.75% Nickel, 0.5% 3414391 12/1968 Brab 29' 182'1 Mo1ybdenum,1 5% COpper0 25% Carbon 3,694,173 9/1972 Farmer et al. 29182.1

3. A sintered metal article, according to Claim 1, in FOREIGN PATENTS which the infiltrated Copper or Copper-based alloy 1,071,3 3 19 7 Great i i 29 1 2 1 amounts to 8-25% of the skeleton. 720,050 12/1954 Great Britain 29-182.1

4. A sintered metal article, according to Claim 3, infiltrated with 14% Copper or Copper-based alloy. 10 C L D- Q ARFORTH, Primary Examiner 5. A sintered metal article, according to Claim 1, which 13 HUNT Assistant Examiner is case-hardened by carburising.

6. A sintered metal article, according to Claim 1, which US. Cl. X.R. is case-hardened by carbo-nitriding. 15 29--182.5, 182.7

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3983615 *5 Feb 19745 Oct 1976Toyo Kogyo Co., Ltd.Sliding seal member for an internal combustion engine
US4271239 *19 Jul 19782 Jun 1981Brico Engineering LimitedSintered metal articles and process for their manufacture
US4327156 *12 May 198027 Apr 1982Minnesota Mining And Manufacturing CompanyInfiltrated powdered metal composite article
US5145504 *8 Jul 19918 Sep 1992The Dow Chemical CompanyBoron carbide-copper cermets and method for making same
US5507336 *17 Jan 199516 Apr 1996The Procter & Gamble CompanyMethod of constructing fully dense metal molds and parts
US5906781 *11 Dec 199625 May 1999The Procter & Gamble CompanyMethod of using thermally reversible material to form ceramic molds
US5918293 *23 May 199529 Jun 1999Hoganas AbIron based powder containing Mo, P and C
US5927373 *12 Feb 199727 Jul 1999The Procter & Gamble CompanyMethod of constructing fully dense metal molds and parts
US73410937 Feb 200611 Mar 2008Llc 2 Holdings Limited, LlcCopper-based alloys and their use for infiltration of powder metal parts
WO2010074627A1 *21 Dec 20091 Jul 2010Höganäs Ab (Publ)Machinability improving composition
Classifications
U.S. Classification428/568, 75/238, 75/246
International ClassificationC22C38/00, B22F3/24, C22C33/02, B22F3/26
Cooperative ClassificationC22C33/0242
European ClassificationC22C33/02C