US20070292301A1 - Making Sintered, Iron-Based Alloy Parts By Using Boron-Containing Master Alloys - Google Patents
Making Sintered, Iron-Based Alloy Parts By Using Boron-Containing Master Alloys Download PDFInfo
- Publication number
- US20070292301A1 US20070292301A1 US10/599,298 US59929805A US2007292301A1 US 20070292301 A1 US20070292301 A1 US 20070292301A1 US 59929805 A US59929805 A US 59929805A US 2007292301 A1 US2007292301 A1 US 2007292301A1
- Authority
- US
- United States
- Prior art keywords
- iron
- boron
- density
- master alloy
- sintering
- 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.)
- Abandoned
Links
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
- C22C33/0207—Using a mixture of prealloyed powders or a master alloy
-
- 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
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/02—Compacting only
- B22F2003/023—Lubricant mixed with the metal powder
-
- 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
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/12—Both compacting and sintering
- B22F3/14—Both compacting and sintering simultaneously
- B22F2003/145—Both compacting and sintering simultaneously by warm compacting, below debindering temperature
-
- 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
- B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Powder Metallurgy (AREA)
Abstract
Description
- This invention relates to a method of making high-density (>7.0 g/ml) sintered, iron-based alloy parts using boron-containing Master Alloys, and to parts produced by this method.
- Structural parts of complex shape have been produced for over 50 years by powder metallurgy (PM). The simplest form of this process involves mixing a fine (<150 microns) metal (normally iron) powder with a lubricant and also such alloying additions as graphite and copper, pressing a green compact in a die under axial loading, and sintering the resulting part in a reducing atmosphere, typically at around 1120° C. In 2000 this process in all its forms was used to produce about 500,000 tons of parts, the vast majority of which were used in the automobile industry.
- Growth of application of the process, which provides complex and precise parts at low cost, is limited by the porosity of the parts, which reduces their properties, especially their dynamic properties such as impact resistance and fatigue strength. For this reason, applications are limited to less heavily loaded parts. To be applied in such parts as transmission gears for cars, a higher density than the currently achievable 7.0-7.2 g/ml range is needed, together with suitable alloying to allow surface hardening and heat treatment.
- A number of methods have been proposed to achieve higher densities. In powder forging, the sintered part is heated and forged: This raises density to ˜100% of solid (˜7.8 g/ml) but at considerable cost and with some reduction of precision. It has found significant, but limited application as a result. It is also possible to take the sintered part and press it again to densify, followed by a second sintering operation. This again increases costs, and cannot achieve full density, being limited to the range 7.2-7.4 g/ml. The use of high temperature sintering, normally considered as temperatures above 1120° C., the practical limit for mesh-belt furnaces, has also been tried. Temperatures of 1200-1300° C. have been used, but costs have been high and the improvements in properties modest. Temperatures of 1180-1250° C. are now in common use, but have not, in themselves, enabled the achievement of high density, high dynamic performance parts.
- The concept of adding a master alloy (MA) powder as a “sintering aid” to densify the part is well known, and is widely used in the fabrication of tungsten heavy alloy, tungsten carbide etc. However attempts to apply it to iron powder parts have had limited success. The use of ferrophosphorous additions has been quite successful, but the resulting properties tend to be reduced by brittle networks of phosphide. Additionally, work with ferrophosphorous additions required sintering temperatures between 1290° C. and 1380° C. and ultrahigh carbon additions (0.8 to 2.0) to achieve near full density, as disclosed by U.S. Pat. No. 5,516,483. In the 1970s work in Germany on the use of MCM (metal carbide master alloys) showed great promise, but it was found that the additives, in the form of finely milled carbides of vanadium, chromium, molybdenum and manganese, were extremely abrasive and tool life was drastically degraded, making production uneconomic. In any case these works, aiming at obtaining high strength materials, used double press-double sinter (DPDS) or forging methods for consolidating the PM steels. Single press-single sinter (SPSS) did not lead to materials with higher densities than 7.2 g/cc. A recent report highlighting the use of several Master Alloys was also directed towards the use of powder forging without attempting to reach high densities by SPSS.
- A basic object of the invention is the provision of an improved method of making high-density (>7.0 g/ml) sintered, iron-based alloy parts, and to parts produced by this method.
- According to a first aspect of the invention, there is provided method of making high-density (>7.0 g/ml) sintered, iron-based alloy parts characterised by the steps of:
- (i) mixing an atomised boron-containing master alloy powder, or a plurality of master alloy powders at least one of which is boron-containing, with a conventional iron or iron alloy powder; and
- (ii) pressing and sintering the mix to an increased density to produce the part required.
- A second aspect of the invention is directed to high density, sintered, iron-based alloy parts produced by the above defined method.
- The invention provides a new concept where, instead of utilising milled powders as MA additives, an atomised, essentially spherical additive is used. This allows the use of less hard a brittle alloys, as the atomising process does not, like milling, demand a brittle alloy be processed. It also reduces the abrasive nature of the resulting powders, as they do not have the sharp edges characteristic of a milled or ground product.
- The alloying approach adopted has also been the subject of intensive research, and MA compositions including a significant level of boron have been developed. As a result it has been possible to reach sintered densities in the range 7.2-7.8 without resorting to forging, DPDS or to extremely high sintering temperatures.
- Before pressing and sintering, graphite is added to the mix in conventional amounts as used in powder metallurgy technology.
- Before pressing and sintering, a lubricant is added to the mix in conventional amounts as used in powder metallurgy technology.
- The lubricant is a solid.
- The lubricant is a liquid.
- The lubricant is a solid dissolved in a liquid.
- The master alloy powder(s) contains from 1-20% by wt boron.
- The master alloy powder(s) has a mean particle size from 1-30 microns, preferably under 20 microns.
- Sintering is effected at temperatures in the range 1050° C. to 1300° C., preferably below 1200° C.
- Sintering is effected in a reducing, inert or vacuum atmosphere.
- From <6% by weight of atomised master alloy powder(s) is mixed with the conventional iron or low alloy powder.
- The pressing is cold pressing.
- The pressing is warm pressing <300° C.
- The pressed density of the part is 6.6-7.4 g/ml.
- The parts have a boron content above 0.1% by wt.
- The parts have a density from 7.2-7.8, preferably 7.4-7.6 g/ml.
Claims (18)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GBGB0407539.6A GB0407539D0 (en) | 2004-04-02 | 2004-04-02 | Making sintered iron based alloy parts by using boron-containing master alloys |
GB0407539.6 | 2004-04-02 | ||
PCT/GB2005/000904 WO2005095661A2 (en) | 2004-04-02 | 2005-03-09 | Making sintered, iron-based alloy parts by using boron-containing master alloys |
Publications (1)
Publication Number | Publication Date |
---|---|
US20070292301A1 true US20070292301A1 (en) | 2007-12-20 |
Family
ID=32247768
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/599,298 Abandoned US20070292301A1 (en) | 2004-04-02 | 2005-03-09 | Making Sintered, Iron-Based Alloy Parts By Using Boron-Containing Master Alloys |
Country Status (4)
Country | Link |
---|---|
US (1) | US20070292301A1 (en) |
EP (1) | EP1735477A2 (en) |
GB (1) | GB0407539D0 (en) |
WO (1) | WO2005095661A2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2015010272A (en) * | 2013-07-02 | 2015-01-19 | Ntn株式会社 | Sintered machine part and production method thereof |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2022083806A1 (en) * | 2020-10-19 | 2022-04-28 | Institute Of Physics Of Materials | Method of consolidating powders by volumetric forming |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3999952A (en) * | 1975-02-28 | 1976-12-28 | Toyo Kohan Co., Ltd. | Sintered hard alloy of multiple boride containing iron |
US4612048A (en) * | 1985-07-15 | 1986-09-16 | E. I. Du Pont De Nemours And Company | Dimensionally stable powder metal compositions |
US4861373A (en) * | 1985-07-15 | 1989-08-29 | Scm Metal Products, Inc. | Infiltrated powder metal part having improved impact strength tensile strength and dimensional control and method for making same |
US5330792A (en) * | 1992-11-13 | 1994-07-19 | Hoeganaes Corporation | Method of making lubricated metallurgical powder composition |
US5872322A (en) * | 1997-02-03 | 1999-02-16 | Ford Global Technologies, Inc. | Liquid phase sintered powder metal articles |
US6485540B1 (en) * | 2000-08-09 | 2002-11-26 | Keystone Investment Corporation | Method for producing powder metal materials |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS61186454A (en) * | 1985-02-15 | 1986-08-20 | Mitsubishi Metal Corp | Fe-base sintered alloy having superior corrosion and wear resistances |
FR2596067B1 (en) * | 1986-03-19 | 1991-02-08 | Metafram Alliages Fritte | PROCESS FOR MANUFACTURING SINTERED RAPID STEEL PARTS |
-
2004
- 2004-04-02 GB GBGB0407539.6A patent/GB0407539D0/en not_active Ceased
-
2005
- 2005-03-09 WO PCT/GB2005/000904 patent/WO2005095661A2/en active Application Filing
- 2005-03-09 EP EP05717969A patent/EP1735477A2/en not_active Withdrawn
- 2005-03-09 US US10/599,298 patent/US20070292301A1/en not_active Abandoned
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3999952A (en) * | 1975-02-28 | 1976-12-28 | Toyo Kohan Co., Ltd. | Sintered hard alloy of multiple boride containing iron |
US4612048A (en) * | 1985-07-15 | 1986-09-16 | E. I. Du Pont De Nemours And Company | Dimensionally stable powder metal compositions |
US4861373A (en) * | 1985-07-15 | 1989-08-29 | Scm Metal Products, Inc. | Infiltrated powder metal part having improved impact strength tensile strength and dimensional control and method for making same |
US5330792A (en) * | 1992-11-13 | 1994-07-19 | Hoeganaes Corporation | Method of making lubricated metallurgical powder composition |
US5872322A (en) * | 1997-02-03 | 1999-02-16 | Ford Global Technologies, Inc. | Liquid phase sintered powder metal articles |
US6485540B1 (en) * | 2000-08-09 | 2002-11-26 | Keystone Investment Corporation | Method for producing powder metal materials |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2015010272A (en) * | 2013-07-02 | 2015-01-19 | Ntn株式会社 | Sintered machine part and production method thereof |
Also Published As
Publication number | Publication date |
---|---|
WO2005095661A2 (en) | 2005-10-13 |
GB0407539D0 (en) | 2004-05-05 |
WO2005095661A3 (en) | 2006-08-24 |
EP1735477A2 (en) | 2006-12-27 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: ATOMISING SYSTEMS LIMITED, UNITED KINGDOM Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FERNANDEZ, FRANCISCO CASTRO;INIGUEZ, MIREN SARASOLA;MITCHELL, STEPHEN CHARLES;REEL/FRAME:018511/0705 Effective date: 20061108 Owner name: AMES - ALEACIONES DE METALES SINTERIZADOS SA, SPAI Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FERNANDEZ, FRANCISCO CASTRO;INIGUEZ, MIREN SARASOLA;MITCHELL, STEPHEN CHARLES;REEL/FRAME:018511/0705 Effective date: 20061108 Owner name: SCHUNK SINTERMETALLTECHNIC GMBH, GERMANY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FERNANDEZ, FRANCISCO CASTRO;INIGUEZ, MIREN SARASOLA;MITCHELL, STEPHEN CHARLES;REEL/FRAME:018511/0705 Effective date: 20061108 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |