CN114985734A - Powder isostatic compaction method - Google Patents
Powder isostatic compaction method Download PDFInfo
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- CN114985734A CN114985734A CN202210746275.4A CN202210746275A CN114985734A CN 114985734 A CN114985734 A CN 114985734A CN 202210746275 A CN202210746275 A CN 202210746275A CN 114985734 A CN114985734 A CN 114985734A
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- mold
- metal mold
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- resin
- sheath
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- 238000000034 method Methods 0.000 title claims abstract description 38
- 239000000843 powder Substances 0.000 title claims abstract description 22
- 238000005056 compaction Methods 0.000 title claims abstract description 7
- 239000002184 metal Substances 0.000 claims abstract description 52
- 229920005989 resin Polymers 0.000 claims abstract description 32
- 239000011347 resin Substances 0.000 claims abstract description 32
- 238000000748 compression moulding Methods 0.000 claims abstract description 13
- 238000010438 heat treatment Methods 0.000 claims abstract description 13
- 239000000956 alloy Substances 0.000 claims abstract description 11
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 11
- 239000012188 paraffin wax Substances 0.000 claims abstract description 11
- 239000007788 liquid Substances 0.000 claims abstract description 9
- 239000011812 mixed powder Substances 0.000 claims abstract description 8
- 229910010293 ceramic material Inorganic materials 0.000 claims abstract description 5
- 238000005520 cutting process Methods 0.000 claims abstract description 5
- 238000003825 pressing Methods 0.000 claims description 16
- 239000000463 material Substances 0.000 claims description 13
- 238000005485 electric heating Methods 0.000 claims description 6
- 229920001971 elastomer Polymers 0.000 claims description 5
- 238000000462 isostatic pressing Methods 0.000 claims description 5
- 238000012856 packing Methods 0.000 claims description 2
- 238000011049 filling Methods 0.000 abstract description 2
- 230000008569 process Effects 0.000 description 14
- 239000000203 mixture Substances 0.000 description 9
- 238000000465 moulding Methods 0.000 description 7
- 239000002245 particle Substances 0.000 description 7
- 238000007723 die pressing method Methods 0.000 description 6
- 239000000919 ceramic Substances 0.000 description 5
- 238000009694 cold isostatic pressing Methods 0.000 description 5
- 229910009043 WC-Co Inorganic materials 0.000 description 3
- 238000000280 densification Methods 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000003208 petroleum Substances 0.000 description 3
- 238000004321 preservation Methods 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 230000008707 rearrangement Effects 0.000 description 2
- 150000003505 terpenes Chemical class 0.000 description 2
- 235000007586 terpenes Nutrition 0.000 description 2
- 238000001291 vacuum drying Methods 0.000 description 2
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000011195 cermet Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920001568 phenolic resin Polymers 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 238000004663 powder metallurgy Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
Images
Classifications
-
- 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
- B22F3/03—Press-moulding apparatus 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
- B22F3/02—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
- B22F3/02—Compacting only
- B22F2003/026—Mold wall lubrication or article surface lubrication
Abstract
A powder isostatic compaction method is characterized by comprising the following steps: step one, filling mixed powder or compression molding soft blanks into a sheath mold, wherein the mixed powder or the compression molding soft blanks are hard alloy or metal ceramic materials added with 1-4wt.% of paraffin; putting the sheath mold into a vacuum box, vacuumizing and heating at 40-60 deg.C for 20-60 min; on the other side, resin is filled into a metal mold, and the metal mold is heated until the resin is completely softened therein; secondly, placing the sheath mold into a metal mold, and immersing the sheath mold into resin in the metal mold; and thirdly, driving a punch of the metal mold by adopting a press, enabling the punch to enter a mold cavity of the metal mold to apply pressure of 20-100MPa to the resin molten liquid, maintaining the pressure for 0-30S, then releasing the pressure, taking out the sheathing mold, and cutting the sheathing mold to obtain a formed green compact.
Description
Technical Field
The invention relates to a method for forming a hard alloy/metal ceramic product, which is applied to manufacturing the hard alloy/metal ceramic product.
Background
Powder press molding is a method of molding powder into a desired shape by applying an external pressure, and is the most commonly used molding method, and is widely used in the production of products such as powder metallurgy and fine ceramics. However, in the process of press forming, pressure loss caused by internal and external friction between particles and a die wall causes uneven stress on each part of the pressed compact, so that the density distribution of the pressed compact is uneven, and finally, uneven size shrinkage and uneven performance of a product are caused. In order to solve this problem, pressing methods such as two-way pressing, floating pressing, and pull-down pressing have been developed, and these methods have improved density uniformity as compared with one-way pressing, but cannot fundamentally solve the problem of uneven powder pressing density because the reason for the density difference cannot be solved in principle of molding.
As shown in fig. 1, in normal temperature, rubber or plastic is generally used as a sheathing mold material, liquid is used as a pressure medium, the pressure is generally 100 to 630MPa, and the density of powder is molded or a compression molding soft blank is homogenized by omnidirectional pressurization. As a molding process, compared with the conventional molding technology, the isostatic pressing molded product has high density which is 5-l 5% higher than that of one-way and two-way compression molding, and the density of the pressed blank is uniform and consistent. In the press molding, the density distribution of the green compact becomes uneven in both of the one-way and two-way pressing. This density variation can often reach more than 10% when pressing complex shaped articles. Although the cold isostatic pressing technology is an omnidirectional pressing technology, the density uniformity of a formed blank is improved, but the method has the defects of large equipment investment (special equipment is required), low efficiency, easy pollution to a blank body and the like.
Disclosure of Invention
The invention develops a powder isostatic pressing method aiming at the problems that the density is easy to be uneven in powder press forming and the equipment investment is large, the efficiency is low and the blank body is easy to be polluted in cold isostatic pressing.
In order to achieve the purpose, the invention adopts the structural technical scheme that: a powder isostatic compaction method is characterized by comprising the following steps:
step one, filling mixed powder or compression molding soft blank into a sheath mold made of rubber, wherein the mixed powder is a hard alloy or a metal ceramic material added with 1-4wt.% of paraffin, and the compression molding soft blank is also a hard alloy or a metal ceramic material added with 1-4wt.% of paraffin; putting the packaged covering die into a vacuum box, vacuumizing and heating at 40-60 ℃, and keeping the temperature for 20-60 min; on the other side, resin with softening point less than 70 ℃ is filled into the metal mold, and the metal mold is heated until the resin in the metal mold is completely softened;
secondly, putting the sheath mould heated in the first step into a metal mould, and immersing the sheath mould into the resin;
and thirdly, driving a punch of the metal mold by adopting a press, enabling the punch to enter a mold cavity of the metal mold, applying pressure of 20-100MPa to the resin molten liquid, maintaining the pressure for 0-30S, then releasing the pressure, taking out the sheathing mold, and cutting the sheathing mold to obtain a formed green compact.
In the scheme, the outer ring of the metal mold is provided with the electric heating ring, and the electric heating ring is used for heating the metal mold. Other existing heating means may also be used in practice.
In the scheme, the metal mold consists of a female mold, an upper punch and a material bearing plate with holes, wherein the material bearing plate with holes is arranged at the lower part in the mold cavity of the metal mold; and the second step of placing the secondary packing sleeve die on the center position of the perforated material bearing plate.
In the scheme, the resin can adopt various resins with the softening point of less than 70 ℃ such as terpene resin, petroleum resin, phenolic resin and the like.
The densification mechanism of the method is basically the same as that of the cold isostatic pressing process, and the difference between the densification mechanism and the cold isostatic pressing process is that the powder particle rearrangement and plastic deformation are more fully performed by heating the mixture with the forming agent. Thus, the method of the present invention allows higher and more uniform green densities to be achieved at lower pressures. The contribution of the low temperature and low pressure densification of the present invention is mainly achieved by two approaches: firstly, the lubricating effect generated by paraffin softening at low temperature can effectively reduce the internal friction among particles, so that the rearrangement of the particles is easy to carry out, and a compact stacking structure is convenient to obtain; secondly, the paraffin lubricant can greatly reduce the friction between the powder particles and the die wall, and reduce the loss of applied external pressure. The reduction of the inner friction between the particles and the friction of the die wall in the low-temperature isostatic pressing process relatively improves the effective pressing pressure acting on the powder body, and is beneficial to the improvement of the compact density.
The method of the invention has the following advantages:
(1) the production cost is low: special equipment is not needed, and equipment investment is low.
(2) The green compact density is high: under the same pressing pressure, the density of the pressed compact pressed by the process is 0.10-0.30 g/cm higher than that of the pressed compact pressed by the traditional method 3 。
(3) The green compact has high strength: compared with the traditional die pressing process, the strength of the pressed blank manufactured by the process can be improved by 10-40%, and the surface smoothness is good.
(4) The pressing pressure is low: when parts with the same density are obtained, the pressing pressure of the invention is reduced by at least 40MPa, which is beneficial to prolonging the service life of equipment and preparing products with complex shapes and large areas.
(5) The compact has uniform density distribution and good sintering performance: the blank prepared by the process disclosed by the invention has the advantage of higher density uniformity than parts prepared by the traditional method. After sintering, the sintering shrinkage is small, and the strength and the toughness are higher than those of the traditional process.
Drawings
FIG. 1 is a schematic representation of a prior art cold isostatic pressing technique;
fig. 2 is a schematic view of a metal mold pressed state in the first and second embodiments of the present invention.
In the figure: 1. punching; 2. a female die; 3. a material bearing plate with holes; 4. covering a die; 5. a resin; 6. mixing powder or compression molding soft blank.
Detailed Description
The invention is further described with reference to the following figures and examples:
the first embodiment is as follows:
a powder isostatic compaction method, comprising the steps of:
in the first step, a mixed powder is filled into the sheath mold according to the designed weight, the mixed powder is a hard alloy or a cermet material added with 1-4wt.% paraffin, specifically, a WC-Co hard alloy mixture containing 2wt.% of No. 56 paraffin, namely, the No. 56 paraffin content is 2wt.%, and the WC-Co hard alloy mixture content is 98 wt.%. The specific mixture ratio of the WC-Co hard alloy mixture is that the WC granularity is 0.8 mu m, and the content is 90 wt.%; co particle size 0.8 μm, content 10 wt.%; after the mixture is vibrated evenly, the sheath mold filled with the mixture is placed into a vacuum drying oven for vacuum pumping and heating, the heating temperature is 40-60 ℃, the heat preservation time is 20-60min, the optimal heating temperature is 60 ℃, and the heat preservation time is 30 min.
On the other side, resin with softening point less than 70 deg.C is filled into a metal mold, wherein the resin is terpene resin, and the resin is filled in an amount ensuring that the molten liquid height of the melted resin is not less than the height of the covering mold, and the metal mold is heated until the resin therein is completely softened; specifically, as shown in fig. 2, an electric heating ring is installed on the outer ring of the metal mold, and the metal mold is heated by the electric heating ring.
The metal mold is composed of a female mold 2, an upper punch 1 and a material bearing plate with holes 3, wherein the material bearing plate with holes 3 is arranged at the lower part in a mold cavity of the metal mold, as shown in figure 2.
And secondly, placing the covering mold into a metal mold, wherein the covering mold is immersed into resin in the metal mold, and as shown in figure 2 in particular, the covering mold 4 is placed at the center of a material bearing plate 3 with holes in the metal mold, and the periphery of the covering mold 4 is provided with the resin 5.
And thirdly, driving the upper punch 1 of the metal mold by using a common four-column hydraulic press, enabling the upper punch 1 to enter a mold cavity of the metal mold to apply pressure of 20-100MPa to the resin molten liquid, maintaining the pressure for 0-30 seconds, then releasing the pressure, taking out the sheathing mold 4, and cutting off the sheathing mold 4 to obtain a formed green compact.
In the concrete operation, the metal mold in the first step can be firstly positioned and clamped on the workbench of the common 40-ton four-column hydraulic press, the subsequent heating of the metal mold and the placing of the rubber cavity covering mold are finished on the workbench of the press, and the force application pressing is directly carried out by the press in the third step, so that the operation is convenient.
The green compact density of the compression molded soft blank pressed by the method of the embodiment is 0.10g/cm higher than that of the conventional method 3 (ii) a Compared with the traditional die pressing process, the green compact strength can be improved by 30 percent; the size precision of the sintered hard blank is improved by 20 percent compared with the traditional die pressing process.
Example two:
a powder isostatic compaction method, comprising the steps of:
step one, a cylindrical metal ceramic compression molding soft blank which is formed by ordinary die pressing and contains No. 2.5 wt.% of 48 paraffin is wrapped by a sheath die, and the specific mixture ratio of the materials of the metal ceramic compression molding soft blank is as follows: 40-65% of Ti (C, N), 22-32% of Ni powder, 12-18% of Mo powder and 5-8% of WC powder; then, putting the mixture into a vacuum drying oven for vacuumizing and heating, wherein the heating temperature is 50 ℃, and the heat preservation time is 20 min;
meanwhile, a pair of cylindrical metal molds are placed on the other side of the common four-column hydraulic press workbench, an electric heating ring is arranged on the outer ring of each metal mold, a certain amount of petroleum resin (the softening point of the resin is less than 60 ℃) is added into the molds, the height of the molten resin is not less than that of the rubber soft molds after the resin is melted, and the molds are heated to 60 ℃ until the resin is completely softened.
Secondly, placing the sheath mold covering the compression molding soft blank in the first step into a mold cavity of a metal mold, and immersing the sheath mold covering the compression molding soft blank in a molten liquid of petroleum resin;
and thirdly, starting a press, slowly feeding the upper punch into the die cavity to apply pressure of 20-100MPa to the molten liquid, maintaining the pressure for 5 seconds, then releasing the pressure, resetting the upper punch, taking the sheath die out of the molten liquid, and cutting the sheath die to obtain a formed green compact.
The green compact pressed by the method of this example had a density 0.20g/cm higher than the conventional method 3 (ii) a Compared with the traditional die pressing process, the green compact strength can be improved by 40 percent; the size precision of the sintered hard blank is improved by 30 percent compared with the traditional die pressing process.
The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.
Claims (3)
1. A powder isostatic compaction method, comprising the steps of:
the method comprises the following steps that firstly, mixed powder or compression molding soft blank is filled into a sheath die made of rubber, wherein the mixed powder is hard alloy or metal ceramic material added with 1-4wt.% of paraffin, and the compression molding soft blank is also made of the hard alloy or metal ceramic material added with 1-4wt.% of paraffin; putting the packaged covering die into a vacuum box, vacuumizing and heating at 40-60 ℃, and keeping the temperature for 20-60 min; on the other side, resin with softening point less than 70 ℃ is filled into the metal mold, and the metal mold is heated until the resin in the metal mold is completely softened;
secondly, putting the sheath mould heated in the first step into a metal mould, and immersing the sheath mould into the resin;
and thirdly, driving a punch of the metal mold by adopting a press, enabling the punch to enter a mold cavity of the metal mold, applying pressure of 20-100MPa to the resin molten liquid, maintaining the pressure for 0-30S, then releasing the pressure, taking out the sheathing mold, and cutting the sheathing mold to obtain a formed green compact.
2. The powder isostatic pressing method as claimed in claim 1, wherein: and an electric heating ring is arranged on the outer ring of the metal mold and used for heating the metal mold.
3. The powder isostatic pressing method as claimed in claim 1, wherein: the metal mold consists of a female mold, an upper punch and a material bearing plate with a hole, wherein the material bearing plate with the hole is arranged at the lower part in the mold cavity of the metal mold; and the second step of placing the secondary packing sleeve die on the center position of the perforated material bearing plate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210746275.4A CN114985734A (en) | 2022-06-29 | 2022-06-29 | Powder isostatic compaction method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210746275.4A CN114985734A (en) | 2022-06-29 | 2022-06-29 | Powder isostatic compaction method |
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| Publication Number | Publication Date |
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| CN114985734A true CN114985734A (en) | 2022-09-02 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202210746275.4A Pending CN114985734A (en) | 2022-06-29 | 2022-06-29 | Powder isostatic compaction method |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000087108A (en) * | 1998-09-10 | 2000-03-28 | Ishizuka Kenkyusho:Kk | Manufacture of cemented carbide |
| JP2001294488A (en) * | 2000-04-07 | 2001-10-23 | Tokai Carbon Co Ltd | Method of producing formed body composed of c/c material |
| US20040175286A1 (en) * | 2001-08-14 | 2004-09-09 | Apex Advanced Technologies, Llc | Lubricant system for use in powdered metals |
| JP2009286643A (en) * | 2008-05-27 | 2009-12-10 | Panasonic Electric Works Co Ltd | Method for manufacturing zirconium oxide-based sintered compact and zirconium oxide-based sintered compact prepared thereby |
| WO2013154145A1 (en) * | 2012-04-12 | 2013-10-17 | アイダエンジニアリング株式会社 | High-density molding device and high-density molding method for mixed powder |
| CN109454411A (en) * | 2018-12-25 | 2019-03-12 | 苏州新锐合金工具股份有限公司 | Manufacturing method with external screw thread hart metal product |
| CN111318692A (en) * | 2020-04-16 | 2020-06-23 | 上海钨睿新材料科技有限公司 | Cold isostatic pressing process for efficiently producing hard alloy bars |
-
2022
- 2022-06-29 CN CN202210746275.4A patent/CN114985734A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000087108A (en) * | 1998-09-10 | 2000-03-28 | Ishizuka Kenkyusho:Kk | Manufacture of cemented carbide |
| JP2001294488A (en) * | 2000-04-07 | 2001-10-23 | Tokai Carbon Co Ltd | Method of producing formed body composed of c/c material |
| US20040175286A1 (en) * | 2001-08-14 | 2004-09-09 | Apex Advanced Technologies, Llc | Lubricant system for use in powdered metals |
| JP2009286643A (en) * | 2008-05-27 | 2009-12-10 | Panasonic Electric Works Co Ltd | Method for manufacturing zirconium oxide-based sintered compact and zirconium oxide-based sintered compact prepared thereby |
| WO2013154145A1 (en) * | 2012-04-12 | 2013-10-17 | アイダエンジニアリング株式会社 | High-density molding device and high-density molding method for mixed powder |
| CN109454411A (en) * | 2018-12-25 | 2019-03-12 | 苏州新锐合金工具股份有限公司 | Manufacturing method with external screw thread hart metal product |
| CN111318692A (en) * | 2020-04-16 | 2020-06-23 | 上海钨睿新材料科技有限公司 | Cold isostatic pressing process for efficiently producing hard alloy bars |
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