US20040175284A1 - Method of cryogenic treatment of tungsten carbide containing cobalt - Google Patents
Method of cryogenic treatment of tungsten carbide containing cobalt Download PDFInfo
- Publication number
- US20040175284A1 US20040175284A1 US10/693,778 US69377803A US2004175284A1 US 20040175284 A1 US20040175284 A1 US 20040175284A1 US 69377803 A US69377803 A US 69377803A US 2004175284 A1 US2004175284 A1 US 2004175284A1
- Authority
- US
- United States
- Prior art keywords
- tungsten carbide
- microwave
- cryogenic
- containing cobalt
- cryogenic treatment
- 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
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 title claims abstract description 41
- 239000010941 cobalt Substances 0.000 title claims abstract description 14
- 229910017052 cobalt Inorganic materials 0.000 title claims abstract description 14
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 title claims abstract description 14
- 238000000034 method Methods 0.000 title claims abstract description 11
- 238000009768 microwave sintering Methods 0.000 claims abstract description 12
- 230000035515 penetration Effects 0.000 claims 1
- 230000007797 corrosion Effects 0.000 abstract description 2
- 238000005260 corrosion Methods 0.000 abstract description 2
- 230000003628 erosive effect Effects 0.000 abstract 1
- 230000009286 beneficial effect Effects 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 239000000463 material Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- -1 impact strength Chemical compound 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
- C22F1/18—High-melting or refractory metals or alloys based thereon
-
- 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
- B22F3/24—After-treatment of workpieces or articles
-
- 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
- C22C1/05—Mixtures of metal powder with non-metallic powder
- C22C1/051—Making hard metals based on borides, carbides, nitrides, oxides or silicides; Preparation of the powder mixture used as the starting material therefor
-
- 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
- B22F3/24—After-treatment of workpieces or articles
- B22F2003/248—Thermal after-treatment
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/04—Hardening by cooling below 0 degrees Celsius
Abstract
A method of cryogenic treatment of tungsten carbide containing cobalt. A first step involves pre-treating tungsten carbide with microwave sintering, thereby changing the properties of the tungsten carbide. A second step involves lowering the temperature of the microwave sintered tungsten carbide gradually to cryogenic levels. A third step involves raising the temperature of the microwave sintered tungsten carbide gradually back to ambient temperatures. The described combination of microwave sintering and cryogenic treatment produces significant improvement in impact resistance, erosion and corrosion resistance and wear rate.
Description
- The present invention relates to a method of cryogenic treatment of tungsten carbide containing cobalt
- In order to increase the wear resistance of components made from tungsten carbide containing cobalt, the tungsten carbide is often subjected to some form of sintering treatment. However, cryogenic treatment has been found to have a detrimental effect on the properties of such tungsten carbide, such as impact strength, and is generally avoided.
- The present invention relates to a method of cryogenic treatment of tungsten carbide containing cobalt that has been determined to provide beneficial effects.
- According to the present invention there is provided a method of cryogenic treatment of tungsten carbide containing cobalt. A first step involves pre-treating tungsten carbide with microwave sintering, thereby changing the properties of the tungsten carbide. A second step involves lowering the temperature of the microwave sintered tungsten carbide gradually to cryogenic levels. A third step involves raising the temperature of the microwave sintered tungsten carbide gradually back to ambient temperatures.
- The cryogenic treatment of the microwave sintered tungsten carbide, as described above, has been determined to provide significant beneficial effects, as will hereinafter be further described. Pre-treating the tungsten carbide with microwave sintering. Microwave sintering appears to change the properties of the tungsten carbide in a way which enables beneficial effects to be obtained through subsequent cryogenic treatment.
- These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to in any way limit the scope of the invention to the particular embodiment or embodiments shown, wherein:
- THE FIGURE is a flow diagram illustrating a preferred method of cryogenic treatment of tungsten carbide.
- The preferred method of cryogenic treatment of tungsten carbide containing cobalt will now be described with reference to THE FIGURE.
- A first step involves pre-treating tungsten carbide containing cobalt with microwave sintering. Microwaves generated from
microwave generator 10 are channelled throughmicrowave waveguide 12 intomicrowave applicator 14 and thereby affectingtungsten carbide 16 within. It is believed that microwave sintering changes such properties of the tungsten carbide to make it compatible with subsequent cryogenic treatment. It is believed that microwave sintering rounds the edges of the grains. Smaller grain size can be used. - A second step involves lowering the temperature of the microwave sintered
tungsten carbide 18 gradually over a period of hours to cryogenic levels incryogenic unit 20. The temperature is lowered between 2-4 degrees Fahrenheit per minute to reduce thermal shock. - The temperature reached at cryogenic levels will depend upon whether helium or nitrogen is used in the cryogenic process. Nitrogen is the least expensive of the two gases and provides a cryogenic temperature of minus 320 Fahrenheit. For best results, the temperature should be held at cryogenic levels for a period of time. This “dwell time” is intended to ensure that the cold reaches to the core of the material. A dwell time of approximately one hour for every inch of thickness of the material is recommended.
- A third step involves raising the temperature of the microwave sintered
tungsten carbide 18 gradually over a period of hours back to ambient temperatures incryogenic unit 20. The same guidelines of 2 to 4 degrees per minute is recommended. - Beneficial Results Obtained Through Treatment:
- The results obtained through the above described process vary depending upon the cobalt content of the tungsten carbide. The cobalt content generally varies between 6% and 16%. As a general rule the higher the cobalt content, the more beneficial the results obtained.
- When compared to tungsten carbide that had been treated with microwave sintering alone, the above described combination of microwave sintering and cryogenic treatment:
- increased impact resistance by between 20% and 30%
- increased corrosion resistance by between 200% and 300%
- increased wear rate by between 200% and 300%
- increased toughness and ductility
- reduced residual stresses
- These results are both dramatic and unexpected. It is believed that with the finer grain size and rounded edges evidenced after microwave sintering enables the cryogenic treatment to bring the tungsten carbide down to more theoretical densities, further reducing porosities, producing finer grain structures and stronger more uniform molecular bonding of the tungsten carbide/cobalt matrix with reduced stresses.
- In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.
- It will be apparent to one skilled in the art that modifications may be made to the illustrated embodiment without departing from the spirit and scope of the invention as hereinafter defined in the Claims.
Claims (2)
1. A method of cryogenic treatment of tungsten carbide containing cobalt, comprising the steps of:
pre-treating tungsten carbide containing cobalt with microwave sintering, thereby changing the properties of the tungsten carbide;
lowering the temperature of the microwave sintered tungsten carbide gradually to cryogenic levels; and
raising the temperature of the microwave sintered tungsten carbide gradually back to ambient temperatures.
2. The method as defined in claim 1 , in which the microwave sintered tungsten carbide is held at cryogenic levels to permit cryogenic penetration into the microwave sintered tungsten carbide, prior to the raising of the microwave sintered tungsten carbide back to ambient temperatures.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA002409433A CA2409433A1 (en) | 2002-10-23 | 2002-10-23 | Method of cryogenic treatment of tungsten carbide containing cobalt |
CA2,409,433 | 2002-10-23 |
Publications (1)
Publication Number | Publication Date |
---|---|
US20040175284A1 true US20040175284A1 (en) | 2004-09-09 |
Family
ID=32399779
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/693,778 Abandoned US20040175284A1 (en) | 2002-10-23 | 2003-10-23 | Method of cryogenic treatment of tungsten carbide containing cobalt |
Country Status (2)
Country | Link |
---|---|
US (1) | US20040175284A1 (en) |
CA (1) | CA2409433A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN100453217C (en) * | 2007-01-11 | 2009-01-21 | 武汉理工大学 | Sintering method of WC-Co cemented carbide |
CN104190942A (en) * | 2014-08-19 | 2014-12-10 | 天津市华辉超硬耐磨技术有限公司 | Microwave sintering method for hard alloy |
CN105349926A (en) * | 2015-11-02 | 2016-02-24 | 浙江百达精工股份有限公司 | Method for manufacturing unleaded brass easy to cut, method for manufacturing balance weight and cooling device |
CN110218926A (en) * | 2019-07-10 | 2019-09-10 | 河源正信硬质合金有限公司 | A kind of super coarse-grain WC-Co hard alloy preparation method |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4614544A (en) * | 1985-01-23 | 1986-09-30 | E. I. Du Pont De Nemours And Company | High strength powder metal parts |
US4739622A (en) * | 1987-07-27 | 1988-04-26 | Cryogenics International, Inc. | Apparatus and method for the deep cryogenic treatment of materials |
US5259200A (en) * | 1991-08-30 | 1993-11-09 | Nu-Bit, Inc. | Process for the cryogenic treatment of metal containing materials |
US6004505A (en) * | 1996-07-26 | 1999-12-21 | Dennis Tool Corporation | Process and apparatus for the preparation of particulate or solid parts |
US6066290A (en) * | 1996-07-26 | 2000-05-23 | The Pennsylvania State Research Foundation | Method and apparatus for transporting green work pieces through a microwave sintering system |
US6141974A (en) * | 1997-07-11 | 2000-11-07 | Waldmann; Christian Clark | Cryogenic and heat process for treating sintered carbide metals to increase service life |
US6293986B1 (en) * | 1997-03-10 | 2001-09-25 | Widia Gmbh | Hard metal or cermet sintered body and method for the production thereof |
US6374932B1 (en) * | 2000-04-06 | 2002-04-23 | William J. Brady | Heat management drilling system and method |
-
2002
- 2002-10-23 CA CA002409433A patent/CA2409433A1/en not_active Abandoned
-
2003
- 2003-10-23 US US10/693,778 patent/US20040175284A1/en not_active Abandoned
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4614544A (en) * | 1985-01-23 | 1986-09-30 | E. I. Du Pont De Nemours And Company | High strength powder metal parts |
US4739622A (en) * | 1987-07-27 | 1988-04-26 | Cryogenics International, Inc. | Apparatus and method for the deep cryogenic treatment of materials |
US5259200A (en) * | 1991-08-30 | 1993-11-09 | Nu-Bit, Inc. | Process for the cryogenic treatment of metal containing materials |
US6004505A (en) * | 1996-07-26 | 1999-12-21 | Dennis Tool Corporation | Process and apparatus for the preparation of particulate or solid parts |
US6066290A (en) * | 1996-07-26 | 2000-05-23 | The Pennsylvania State Research Foundation | Method and apparatus for transporting green work pieces through a microwave sintering system |
US6293986B1 (en) * | 1997-03-10 | 2001-09-25 | Widia Gmbh | Hard metal or cermet sintered body and method for the production thereof |
US6141974A (en) * | 1997-07-11 | 2000-11-07 | Waldmann; Christian Clark | Cryogenic and heat process for treating sintered carbide metals to increase service life |
US6374932B1 (en) * | 2000-04-06 | 2002-04-23 | William J. Brady | Heat management drilling system and method |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN100453217C (en) * | 2007-01-11 | 2009-01-21 | 武汉理工大学 | Sintering method of WC-Co cemented carbide |
CN104190942A (en) * | 2014-08-19 | 2014-12-10 | 天津市华辉超硬耐磨技术有限公司 | Microwave sintering method for hard alloy |
CN105349926A (en) * | 2015-11-02 | 2016-02-24 | 浙江百达精工股份有限公司 | Method for manufacturing unleaded brass easy to cut, method for manufacturing balance weight and cooling device |
CN110218926A (en) * | 2019-07-10 | 2019-09-10 | 河源正信硬质合金有限公司 | A kind of super coarse-grain WC-Co hard alloy preparation method |
Also Published As
Publication number | Publication date |
---|---|
CA2409433A1 (en) | 2004-04-23 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |