FORMABLE SINTERED ALLOY WITH DISPERSED HARD PHASE
An iron-base alloy of the present invention comprises a 20 to 50% weight fraction of prealloy steel of composition A and a 48 to 78% weight fraction of prealloy steel of composition B to which additional alloying to which additional alloying elements (and lubricant) are added in preparation of a powdered metal blended mixture. The resulting mixture composition of the embodiment comprises in % by mass: 0.4 to 1.0% of C; 0.5 to 3.5% of Cr; 0.1 to 1.7% of Mo; to 3.0% of Cu; and the balance being primarily Fe and unavoidable impurities. Ni and/or Mn may also be included in the resulting mixture composition.
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This application claims the benefit of U.S. Provisional Application No. 61/015,024 filed Dec. 19, 2007, which is hereby incorporated by reference.
BACKGROUNDThis invention relates to a formable sintered alloy with dispersed hard phase.
SUMMARYAt least one advantage of the present invention is provided by an iron based sintered body having a composition comprising in % by mass: 0.4 to 1.0% of C; 0.5 to 3.5% of Cr; 0.1 to 1.7% of Mo; 0.3 to 3.0% of Cu; and the balance being primarily Fe and inevitable impurities.
At least one advantage of the present invention is provided by a gear formed of an iron-based alloy comprising in % by mass: 0.4 to 1.0% of C; 0.5 to 3.5% of Cr; 0.1 to 1.7% of Mo; 0.3 to 3.0% of Cu; and the balance being primarily Fe and inevitable impurities.
At least one advantage of the present invention is provided by an iron based sintered body having a composition comprising in % by mass: 0.4 to 1.0% of C; 0.5 to 3.5% of Cr; 0.1 to 1.7% of Mo; 0.3 to 3.0% of Cu; 0.1 to 6.0 of Ni; 0.1 to 0.5 of Mn; the balance being primarily Fe and inevitable impurities.
Embodiments of this invention will now be described in further detail with reference to the accompanying drawing, in which:
A microscopic view of an embodiment of the composition of the present invention is shown in
An embodiment of the iron-base alloy of the present invention comprises a 20 to 50% weight fraction of prealloy steel of composition A and a 48 to 78% weight fraction of prealloy steel of composition B to which additional alloying elements (and lubricant) are added in preparation of a powdered metal blended mixture. The resulting mixture composition of the embodiment comprises in % by mass: 0.4 to 1.0% of C; 0.5 to 3.5% of Cr; 0.1 to 1.7% of Mo; 0.3 to 3.0% of Cu; and the balance being primarily Fe and unavoidable impurities. (The lubricant will volatilize during sinter and as such is not reflected in the composition %). The mixture is placed in a mold possessing the approximate shape of the finished product and subjected to compaction pressures of between generally 35 and 65 tsi to produce a green body compact. The green body compact is subsequently sintered at a temperature of between 1120˜C and 1180˜C for about 25 minutes in an atmosphere comprised of 90% nitrogen and 10% hydrogen. The sintered article subsequently is cooled at a rate not exceeding 0.5˜C/sec producing a sinter-hardened composite wear resistant microstructure of approximately 20 to 50% dispersed martensite in a matrix of fine pearlite. The sintered article subsequently is subjected to cold treatment and tempering for thermal stabilization. Upon completion of thermal treatment, the sintered article is placed in a mold possessing the desired shape of the finished product and subsequently subjected to forming pressures generally between 50 and 75 tsi to achieve dimensional refinement enabling production of discretely toleranced net-shape features. The sintered and formed article demonstrates acceptable sliding wear properties for pumping elements employed with ultra low sulfur diesel fuels (Shell MJ04 U.S. Worst Case Diesel) while offering the costs advantages of lean composition and reduced process complexity in comparison to prior art.
In one embodiment, Nickel may be added such that the resulting mixture composition of the embodiment comprises in % by mass: 0.4 to 1.0% of C; 0.5 to 3.5% of Cr; 0.1 to 1.7% of Mo; 0.3 to 3.0% of Cu; 0.1 to 6.0% Ni; and the balance being primarily Fe and unavoidable impurities. In another embodiment, the resulting mixture composition of the embodiment comprises in % by mass: 0.4 to 1.0% of C; 0.5 to 3.5% of Cr; 0.1 to 1.7% of Mo; 0.3 to 3.0% of Cu; 0.1 to 0.5% Mn; and the balance being primarily Fe and unavoidable impurities. In still another embodiment, the resulting mixture composition of the embodiment comprises in % by mass: 0.4 to 1.0% of C; 0.5 to 3.5% of Cr; 0.1 to 1.7% of Mo; 0.3 to 3.0% of Cu; 0.1 to 6.0% Ni; 0.1 to 0.5% Mn; and the balance being primarily Fe and unavoidable impurities.
In one embodiment, the sintered and formed article may be a gear, such as a gear for a gerotor. Testing of a sintered and formed gear in accordance with the present invention was subjected to an accelerated pump durability test with the results of the prior art control gear shown in
Although the principles, embodiments and operation of the present invention have been described in detail herein, this is not to be construed as being limited to the particular illustrative forms disclosed. They will thus become apparent to those skilled in the art that various modifications of the embodiments herein can be made without departing from the spirit or scope of the invention. Accordingly, the scope and content of the present invention are to be defined only by the terms of the appended claims.
Claims
1. An iron based sintered body having a composition comprising in % by mass:
- 0.4 to 1.0% of C;
- 0.5 to 3.5% of Cr;
- 0.1 to 1.7% of Mo;
- 0.3 to 3.0% of Cu; and
- the balance being primarily Fe and inevitable impurities.
2. The composition of claim 1 further comprising in % by mass: 0.1 to 6.0 of Ni.
3. The composition of claim 1 further comprising in % by mass: 0.1 to 0.5 of Mn.
4. A gear formed from the iron-based alloy comprising in % by mass: 0.4 to 1.0% of C; 0.5 to 3.5% of Cr; 0.1 to 1.7% of Mo; 0.3 to 3.0% of Cu; and the balance being primarily Fe and inevitable impurities.
5. An iron based sintered body having a composition comprising in % by mass: the balance being primarily Fe and inevitable impurities.
- 0.4 to 1.0% of C;
- 0.5 to 3.5% of Cr;
- 0.1 to 1.7% of Mo;
- 0.3 to 3.0% of Cu;
- 0.1 to 6.0% of Ni;
- 0.1 to 0.5% of Mn; and
Type: Application
Filed: Dec 19, 2008
Publication Date: Jun 25, 2009
Applicant: PARKER HANNIFIN CORPORATION (Cleveland, OH)
Inventors: Richard Scott (Cumberland, ME), Stephanie Renaud (Lewiston, ME), John Fulmer (Old Orchard Beach, ME)
Application Number: 12/339,565
International Classification: C22C 38/42 (20060101); C22C 38/20 (20060101);