CN116145002A - Cemented carbide material for compression molding of precision glass lens and preparation method thereof - Google Patents
Cemented carbide material for compression molding of precision glass lens and preparation method thereof Download PDFInfo
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- 239000000463 material Substances 0.000 title claims abstract description 67
- 239000011521 glass Substances 0.000 title claims abstract description 33
- 238000000748 compression moulding Methods 0.000 title claims abstract description 23
- 238000002360 preparation method Methods 0.000 title claims abstract description 16
- 239000000843 powder Substances 0.000 claims abstract description 84
- 239000000956 alloy Substances 0.000 claims abstract description 53
- 238000002490 spark plasma sintering Methods 0.000 claims abstract description 15
- 239000000203 mixture Substances 0.000 claims abstract description 7
- 238000000465 moulding Methods 0.000 claims abstract description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 62
- 229910002804 graphite Inorganic materials 0.000 claims description 62
- 239000010439 graphite Substances 0.000 claims description 62
- 238000005245 sintering Methods 0.000 claims description 40
- 238000000498 ball milling Methods 0.000 claims description 39
- 229910045601 alloy Inorganic materials 0.000 claims description 38
- 239000011812 mixed powder Substances 0.000 claims description 31
- 238000001816 cooling Methods 0.000 claims description 24
- 238000002156 mixing Methods 0.000 claims description 11
- 238000011049 filling Methods 0.000 claims description 10
- 238000005070 sampling Methods 0.000 claims description 9
- 238000005488 sandblasting Methods 0.000 claims description 9
- 238000001291 vacuum drying Methods 0.000 claims description 9
- 238000003825 pressing Methods 0.000 claims description 8
- 238000010438 heat treatment Methods 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 238000009413 insulation Methods 0.000 claims description 2
- 238000012545 processing Methods 0.000 abstract description 4
- 238000001035 drying Methods 0.000 description 21
- 239000013590 bulk material Substances 0.000 description 16
- INZDTEICWPZYJM-UHFFFAOYSA-N 1-(chloromethyl)-4-[4-(chloromethyl)phenyl]benzene Chemical group C1=CC(CCl)=CC=C1C1=CC=C(CCl)C=C1 INZDTEICWPZYJM-UHFFFAOYSA-N 0.000 description 14
- 239000011651 chromium Substances 0.000 description 13
- 238000000034 method Methods 0.000 description 13
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- 230000000052 comparative effect Effects 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
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- 235000012431 wafers Nutrition 0.000 description 2
- 235000010724 Wisteria floribunda Nutrition 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- UFGZSIPAQKLCGR-UHFFFAOYSA-N chromium carbide Chemical compound [Cr]#C[Cr]C#[Cr] UFGZSIPAQKLCGR-UHFFFAOYSA-N 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
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- 238000007656 fracture toughness test Methods 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000005304 optical glass Substances 0.000 description 1
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- 229910003470 tongbaite Inorganic materials 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
- 238000007514 turning Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C29/00—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides
- C22C29/02—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides
- C22C29/06—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides based on carbides, but not containing other metal compounds
- C22C29/08—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides based on carbides, but not containing other metal compounds based on tungsten carbide
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- 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
- B22F3/10—Sintering only
- B22F3/105—Sintering only by using electric current other than for infrared radiant energy, laser radiation or plasma ; by ultrasonic bonding
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B11/00—Pressing molten glass or performed glass reheated to equivalent low viscosity without blowing
- C03B11/06—Construction of plunger or mould
- C03B11/08—Construction of plunger or mould for making solid articles, e.g. lenses
- C03B11/084—Construction of plunger or mould for making solid articles, e.g. lenses material composition or material properties of press dies therefor
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- 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
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C29/00—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides
- C22C29/02—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides
- C22C29/06—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides based on carbides, but not containing other metal compounds
- C22C29/067—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides based on carbides, but not containing other metal compounds comprising a particular metallic binder
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- 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
- B22F3/10—Sintering only
- B22F3/105—Sintering only by using electric current other than for infrared radiant energy, laser radiation or plasma ; by ultrasonic bonding
- B22F2003/1051—Sintering only by using electric current other than for infrared radiant energy, laser radiation or plasma ; by ultrasonic bonding by electric discharge
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
- Y02P40/57—Improving the yield, e-g- reduction of reject rates
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Abstract
The invention provides a hard alloy material for compression molding of a precision glass lens, a preparation method thereof and a precision glass lens molding die prepared from the hard alloy material. The hard alloy material is prepared by spark plasma sintering of a WC+A+B powder mixture, the total content of A+B powder is 0.3-3.0 wt%, the content of WC powder is 97.0-99.7 wt%, and A is Cr, based on the total weight of 100wt.% of the powder mixture 3 C 2 B is VC. The hard alloy material prepared according to the invention has high density, high hardness, fine grains and low thermal expansionThe coefficient, the processing performance and the surface flatness are good, and the mold material is very suitable for the mold material for the compression molding of the high-end glass lens.
Description
Technical Field
The invention belongs to the field of powder metallurgy, relates to a preparation method of a hard alloy material and application thereof, and more particularly relates to a preparation method of a hard alloy material for compression molding of a precision glass lens and a molding die prepared by the preparation method.
Background
Glass lenses, including spherical and aspherical lenses, have found wide application in optical, electro-optical and opto-mechanical systems. The aspheric lens can provide better optical performance and image quality than the traditional spherical lens by eliminating spherical aberration, increasing light transmittance and reducing the size and weight of an optical component, so that the aspheric lens is widely applied to optical devices such as military fields, thermal imaging devices, infrared devices, microscope telescopes, digital camera lenses and the like.
The traditional method of producing aspherical lenses is a material removal process such as turning, grinding and polishing techniques. However, they are uneconomical and impractical for mass production of aspherical lenses required for home products such as digital cameras, CD/DVD players, recorders and mobile phones. Thus, in recent years, a precision glass lens compression molding technique has been proposed. Currently, most optical glass lens lenses are produced by ultra-precise mold forming using cemented tungsten carbide (WC). WC has many excellent chemical and mechanical properties such as excellent chemical inertness, excellent abrasion resistance, high oxidation temperature, low thermal expansion coefficient, extremely high hardness, good red hardness, etc., which makes it an excellent glass lens precision molding mold material.
However, the shape accuracy of molded lenses varies significantly with the variation of mold quality. Although the traditional WC hard alloy material has high hardness, the brittleness is high, the processing is difficult, the surface forming quality of the prepared mold material is poor, and the defects of collapse, breakage, peeling of surface micro-area materials and the like are very easy to occur in the processing process. Meanwhile, due to periodic thermal shock and pressure circulation in the molding process, the mold is broken and is invalid, and the service life is extremely short. The application of WC materials in the field of precision glass lens forming is severely restricted by the conditions. At present, the materials for high-end glass lens forming molds in China still depend on import, mainly materials of Japanese NJS (brand M78) and Japanese Fuji (brand JF03 and brand J05), and the performances of the materials are shown in the following table. The imported high-end mold material can meet the production requirements of part of glass lenses in China to a certain extent at present, but still has the problems of low density, low fracture toughness, high purchase cost, long period, multiple unstable factors of goods sources and the like. Therefore, the development of the hard alloy material for compression molding of the high-performance precise glass lens and the preparation process thereof have important significance.
Table 1: inlet high-end die material performance summary table in China
Disclosure of Invention
The invention aims to remedy the defects of the prior art, and provides a hard alloy material for compression molding of a precision glass lens and a preparation method thereof, wherein the hard alloy material has high compactness, high hardness, fine grains, low thermal expansion coefficient, good processability, high surface flatness and high smoothness, and is very suitable for a mold material for compression molding of a high-end glass lens.
According to a first aspect of the present invention, there is provided a cemented carbide material for precision glass lens forming molds, the cemented carbide material being prepared by SPS sintering of a wc+a+b powder mixture comprising, based on 100wt.% of the total weight of the powder mixture: 97.0wt.% to 99.7wt.%, preferably 98.0wt.% to 99.6wt.%, more preferably 98.2wt.% to 99.6wt.% WC powder; 0.3 to 3.0wt.%, preferably 0.4 to 2.0wt.%, more preferably 0.4 to 1.8wt.% of a+b powder, a being Cr 3 C 2 B is VC.
Preferably, the powder mixture consists of the above-mentioned ranges of powder a, powder B and WC powder.
Preferably, the content of a powder is 0.0wt.% to 3.0wt.%, more preferably 0.0wt.% to 2.0wt.%.
Preferably, the content of B powder is 0.05wt.% to 3.0wt.%, more preferably 0.1wt.% to 2.0wt.%.
Here, the a+b powder means a mixture of one or two selected from the group consisting of a powder and B powder.
Preferably, the cemented carbide material has a relative density of not less than 99.8%.
Preferably, the cemented carbide material contains no other impurity phases other than the main phase.
Preferably, the hardness of the cemented carbide material is 2400HV 30 ～2700HV 30 Preferably 2500HV 30 ～2700HV 30 More preferably 2550HV 30 ～2700HV 30 。
Preferably, the grain size of the cemented carbide material is not more than 0.2 μm.
Preferably, the fracture toughness of the cemented carbide material is 6.5 MPa-m 1/2 ～8.5MPa·m 1/2 More preferably 7.0 MPa.m 1/2 ～8.0MPa·m 1/2 。
According to a second aspect of the present invention, there is provided a method of preparing a cemented carbide material according to the present invention, comprising the steps of:
1) Powder mixing: respectively placing WC powder, A powder and B powder into a hard alloy ball milling tank for ball milling and powder mixing, and carrying out vacuum drying on the obtained mixed powder; wherein the WC powder is present in an amount of 97.0wt.% to 99.7wt.%, preferably 98.0wt.% to 99.6wt.%, based on 100wt.% of the mixed powder; the total content of a+b powder is 0.3wt.% to 3.0wt.%, preferably 0.4wt.% to 2.0wt.%, a being Cr 3 C 2 B is VC;
2) And (5) die filling: placing the mixed powder obtained in the step 1) into a graphite female die, prepressing by adopting a hydraulic press, wherein the axial prepressing pressure is 10-20 MPa, and the pressure maintaining time is 5-15 min;
3) Sintering: placing the assembled graphite mold in a spark plasma sintering system, setting the axial pressure to be 10-50 MPa, vacuumizing to be less than 10Pa, and starting to electrify and sinter; the heating rate is set to 20-100 ℃/min, the sintering temperature is 1700-1950 ℃, and the preferred temperature is 1750-1900 ℃; preserving heat for 1-10 min, and cooling along with the furnace.
4) Sampling: and taking out the sample by using a hydraulic press, and adopting sand blasting to treat graphite on the surface of the sample to obtain the hard alloy material.
Preferably, the purity of the WC powder is 99.9% or more, and the powder particle size is 0.1 to 1.0 μm. The WC powder may be commercially pure WC powder.
Preferably, the Cr 3 C 2 The purity of the powder is more than 99.9%, and the granularity of the powder is 0.1-1.0 mu m. The Cr 3 C 2 May be commercially pure phase powder.
Preferably, the purity of the VC powder is more than 99.9%, and the granularity of the powder is 0.1-1.0 mu m. The VC powder is a commercially pure phase powder.
Preferably, the graphite die and the graphite pressure head are separated from the powder by graphite paper or graphite lining/gasket; and wrapping the thermal insulation graphite felt around the assembled graphite mold.
Preferably, the mixed powder is placed in the center of the graphite female die, and the upper graphite pressing head and the lower graphite pressing head are pressed into the graphite female die to the same depth.
Further preferably, in step 3), the axial pressure is 10 to 20MPa at a sintering temperature of less than 1400 ℃; pressurizing to 20-50 MPa, preferably 30-50 MPa, at a sintering temperature of more than 1400 ℃ and less than or equal to 1500 ℃; constant pressure sintering is carried out at the target pressure until the sintering is completed.
Preferably, in step 3), the temperature rising rate is set to 20-80 ℃/min; cooling at 20-80 deg.c/min, preferably 40-80 deg.c/min; the temperature is kept at 1600 ℃ and 1500 ℃, 1400 ℃, 1300 ℃ and 1200 ℃ for 1-3 min, preferably 1600 ℃ and 1400 ℃ for 1-2 min respectively; cooling to 1000-1200 deg.c, eliminating axial pressure, closing sintering current and cooling with furnace.
Preferably, the relative density of the hard alloy block material obtained by the method is not lower than 99.8%, and the object phase contains no other impurity phase except the main phase.
Preferably, the hardness of the cemented carbide bulk material obtained by the method according to the invention is 2400HV 30 ～2700HV 30 More preferably 2500HV 30 ～2700HV 30 Further more preferably 2550HV 30 ～2700HV 30 。
Preferably, the fracture toughness of the hard alloy block material obtained by the method is 6.5MPa m 1/2 ～8.5MPa·m 1/2 More preferably 7.0 MPa.m 1/2 ～8.0MPa·m 1/2 。
According to a third aspect of the present invention, there is provided a mold for press molding a precision glass lens, which is prepared from the cemented carbide material according to the present invention.
The invention has the following beneficial effects:
the preparation method of the hard alloy material for the compression molding of the precise glass lens comprises the steps of using commercial WC powder and Cr 3 C 2 The powder and VC powder are used as raw materials to prepare mixed powder, and SPS technology is adopted to prepare the powder. The preparation method is simple and quick, environment-friendly, wide in raw material source and good in process stability, and the prepared hard alloy material has high compactness, high hardness, fine grains, low thermal expansion coefficient, good processability and high surface flatness and smoothness, and is very suitable for a die for compression molding of high-end glass lenses.
Drawings
FIG. 1 is a surface Scanning Electron Microscope (SEM) photograph of a cemented carbide bulk material prepared according to example 1;
FIG. 2 is an Electron Back Scattering Diffraction (EBSD) grain and its orientation diagram of the cemented carbide bulk material prepared according to example 1;
fig. 3 is a thermal expansion coefficient test result of the cemented carbide bulk material prepared according to example 1.
Detailed Description
The present invention is further illustrated by the following examples, but embodiments of the present invention are not limited thereto.
In the following embodiments, firstly, cutting graphite paper according to the size of a graphite female die, placing the graphite paper on the inner wall of the female die or adopting a customized graphite inner bushing, and enabling the graphite paper to be perfectly attached to the inner wall; then the lower pressing head is placed into a graphite female die, and two layers of graphite paper or graphite wafers with the diameters consistent with the diameters of the pressing heads are placed into the graphite female die, so that the graphite female die is attached to the pressing heads; then filling the mixed powder in proportion into a graphite female die; finally, sequentially placing two layers of graphite paper or graphite wafers, and applying pre-pressing force and pressure maintaining by using a hydraulic press; and after the work is finished, wrapping the die by using a high-temperature graphite felt. The graphite mold and ram dimensions are determined by the sample size to be prepared.
The spark plasma sintering systems used in the examples described below were from Japanese SINTER LAND company under the model numbers LABOX-350 and LABOX-6020. It should be noted that the preparation of the hard alloy material block for the compression molding of the precision glass lens by using the method related to the invention and adopting equipment of other manufacturers and models is also within the scope of the invention.
The spark plasma sintering comprises pulse energization pressurized sintering, electric field assisted sintering, pulse current rapid sintering and the like.
The density results in the following examples were measured using an archimedes drainage method; hardness test was obtained using a vickers hardness tester under a load of 30kgf and a holding time of 15 s; fracture toughness test the total length of four cracks at the tip of an indentation was measured and calculated in accordance with international standard ISO 28079-2009, hardmetals-Palmqvist Toughness Test, and fracture toughness K was calculated in combination with the vickers hardness value of the sample under the indentation IC 。
Grain size is a measurement statistic by EBSD.
Tungsten carbide (WC) powder was commercially available in 99.9% purity.
Chromium carbide (Cr) 3 C 2 ) The powder was commercially available in 99.9% purity.
Vanadium Carbide (VC) powder was commercially available in 99.9% purity.
Example 1
Is prepared according to the following steps
Hard alloy block material for compression molding of precision glass lens, wherein the weight ratio is WC to Cr 3 C 2 ∶VC＝99.2∶0.5∶0.3。
1) Powder mixing: the powder weighed according to the weight ratio is put into a hard alloy ball milling tank for ball milling, wherein the total weight of the powder is 6500 g. Wherein, the grinding balls are hard alloy balls, the ball-material ratio is 3.5:1, the ball milling rotating speed is 100r/min, and the ball milling time is 48h. And carrying out high-temperature vacuum drying on the powder after ball milling, wherein the drying temperature is 70 ℃ and the drying time is 7 hours.
2) And (5) die filling: and (3) weighing the mixed powder obtained after the drying in the step (1) according to the requirement, putting the mixed powder into a graphite female die, prepressing the mixed powder by adopting a hydraulic press, wherein the prepressing pressure is 10MPa, and maintaining the pressure for 15min.
3) Sintering: placing the assembled graphite mold in a spark plasma sintering system, setting the axial initial pressure to be 20MPa, vacuumizing to be less than 10Pa, and starting to electrify and sinter; the temperature rising rate is set to be 20 ℃/min, when the temperature reaches 1400 ℃, the pressure is increased to 30MPa, then the temperature is continuously increased, and the sintering temperature is 1760 ℃; after heat preservation for 5min, cooling at 80 ℃/min, and heat preservation for 1min at 1400 ℃; cooling to 1000 ℃, removing the axial pressure, closing the sintering current, and cooling along with the furnace;
4) Sampling, taking out the sample by using a hydraulic press, removing graphite on the surface of the sample by adopting sand blasting treatment, and obtaining the hard alloy block material, wherein the surface of the hard alloy block material is smooth after finish machining treatment, and the defects of no collapse and the like are overcome, and the specific performance parameters are shown in the table 2.
Table 2: results of Performance test of cemented carbide bulk Material prepared in example 1
Fig. 1 is an SEM photograph of the cemented carbide bulk material prepared according to example 1. From the results, the hard alloy block material prepared in the embodiment has no defects of holes, collapse and the like on the surface, has excellent surface forming quality and high relative density, and mutually proves with the performance test results of the table 2.
Fig. 2 is an EBSD grain orientation diagram of the cemented carbide bulk material prepared according to example 1, from which it can be seen that the grain size of the cemented carbide bulk material prepared in this example is fine and uniform, without any abnormal grown grains, and the average grain size is not higher than 0.2 μm. The grains have no preferential orientation, and the material is proved to be isotropic.
Fig. 3 is a thermal expansion coefficient test result of the cemented carbide bulk material prepared according to example 1. Analysis of fig. 3 shows that the cemented carbide bulk material prepared in this example has a low coefficient of thermal expansion. Therefore, the mold prepared by using the hard alloy block material prepared in this example has excellent high-temperature dimensional accuracy.
In summary, the hard alloy block material prepared according to the invention has high compactness, high hardness, fine grains, low thermal expansion coefficient, good processing performance, high surface flatness and high smoothness, and is very suitable for die materials for compression molding of high-end glass lenses.
Example 2
Is prepared according to the following steps
Cemented carbide block material for compression molding of precision glass lens of (1), wherein the weight ratio of WC to Cr 3 C 2 ∶VC＝98.5∶1.4∶0.1。
1) Powder mixing: and putting 2000g of powder weighed according to the weight ratio into a hard alloy ball milling tank for ball milling. Wherein, the grinding balls are hard alloy balls, the ball-material ratio is 3.5:1, the ball milling rotating speed is 100r/min, and the ball milling time is 48h. And carrying out high-temperature vacuum drying on the powder after ball milling, wherein the drying temperature is 70 ℃ and the drying time is 4 hours.
2) And (5) die filling: and (3) weighing the mixed powder obtained after the drying in the step (1) according to the requirement, putting the mixed powder into a graphite female die, prepressing the mixed powder by adopting a hydraulic press, wherein the prepressing pressure is 10MPa, and maintaining the pressure for 10min.
3) Sintering: placing the assembled graphite mold in a spark plasma sintering system, setting the axial initial pressure to be 20MPa, vacuumizing to be less than 10Pa, and starting to electrify and sinter; the temperature rising rate is set to be 50 ℃/min, when the temperature reaches 1450 ℃, the pressure is increased to 50MPa, and then the temperature continues to rise, wherein the sintering temperature is 1880 ℃; after 5min of heat preservation, cooling at 50 ℃/min, and preserving heat at 1600 ℃ and 1400 ℃ for 2min; cooling to 1000 ℃, removing the axial pressure, closing the sintering current, and cooling along with the furnace;
4) Sampling, taking out the sample by using a hydraulic press, removing graphite on the surface of the sample by adopting sand blasting treatment, and obtaining the hard alloy block material, wherein the surface of the hard alloy block material is smooth after finish machining treatment, and the defects of no collapse and the like are overcome, and the specific performance parameters are shown in the table 3.
Table 3: results of Performance test of cemented carbide bulk Material prepared in example 2
Example 3
Is prepared according to the following steps
Cemented carbide block material for compression molding of precision glass lens of (1), wherein the weight ratio of WC to Cr 3 C 2 ∶VC＝99.5∶0.0∶0.5。
1) Powder mixing: the powder weighed according to the weight ratio is put into a hard alloy ball milling tank for ball milling, wherein the total weight of the powder is 4500 g. Wherein, the grinding balls are hard alloy balls, the ball-material ratio is 3.5:1, the ball milling rotating speed is 100r/min, and the ball milling time is 48h. And carrying out high-temperature vacuum drying on the powder after ball milling, wherein the drying temperature is 70 ℃ and the drying time is 6 hours.
2) And (5) die filling: and (3) weighing the mixed powder obtained after the drying in the step (1) according to the requirement, putting the mixed powder into a graphite female die, prepressing the mixed powder by adopting a hydraulic press, wherein the prepressing pressure is 10MPa, and maintaining the pressure for 15min.
3) Sintering: placing the assembled graphite mold in a spark plasma sintering system, setting the axial initial pressure to be 10MPa, vacuumizing to be less than 10Pa, and starting to electrify and sinter; the temperature rising rate is set to 25 ℃/min, when the temperature reaches 1400 ℃, the pressure is increased to 40MPa, then the temperature continues to rise, and the sintering temperature is 1760 ℃; after heat preservation for 1min, 80 ℃/min is cooled, and heat preservation is carried out for 1min at 1400 ℃; cooling to 1000 ℃, removing the axial pressure, closing the sintering current, and cooling along with the furnace;
4) Sampling, taking out the sample by using a hydraulic press, removing graphite on the surface of the sample by adopting sand blasting treatment, and obtaining the hard alloy block material, wherein the surface of the hard alloy block material is smooth after finish machining treatment, and the defects of no collapse and the like are overcome, and the specific performance parameters are shown in the table 4.
Table 4: results of Performance test of cemented carbide bulk Material prepared in example 3
Example 4
Is prepared according to the following steps
Hard alloy block material for compression molding of precision glass lens, wherein the weight ratio is WC to Cr 3 C 2 ∶VC＝99.0∶0.5∶0.5。
1) Powder mixing: and putting 1000g of powder weighed according to the weight ratio into a hard alloy ball milling tank for ball milling. Wherein, the grinding balls are hard alloy balls, the ball-material ratio is 3.5:1, the ball milling rotating speed is 100r/min, and the ball milling time is 48h. And carrying out high-temperature vacuum drying on the powder after ball milling, wherein the drying temperature is 70 ℃ and the drying time is 3 hours.
2) And (5) die filling: and (3) weighing the mixed powder obtained after the drying in the step (1) according to the requirement, putting the mixed powder into a graphite female die, prepressing the mixed powder by adopting a hydraulic press, wherein the prepressing pressure is 10MPa, and maintaining the pressure for 10min.
3) Sintering: placing the assembled graphite mold in a spark plasma sintering system, setting the axial initial pressure to be 20MPa, vacuumizing to be less than 10Pa, and starting to electrify and sinter; the temperature rising rate is set to be 60 ℃/min, when the temperature reaches 1400 ℃, the pressure is increased to 40MPa, then the temperature continues to rise, and the sintering temperature is 1750 ℃; after heat preservation for 1min, 80 ℃/min is cooled, and heat preservation is carried out for 1min at 1400 ℃; cooling to 1000 ℃, removing the axial pressure, closing the sintering current, and cooling along with the furnace;
4) Sampling, taking out the sample by using a hydraulic press, removing graphite on the surface of the sample by adopting sand blasting treatment, and obtaining the hard alloy block material, wherein the surface of the hard alloy block material is smooth after finish machining treatment, and the defects of no collapse and the like are overcome, and the specific performance parameters are shown in the table 5.
Table 5: results of Performance test of cemented carbide bulk Material prepared in example 4
Example 5
Is prepared according to the following steps
Hard alloy block material for compression molding of precision glass lens, wherein the weight ratio is WC to Cr 3 C 2 ∶VC＝99.0∶0.9∶0.1。
1) Powder mixing: putting 500g of powder weighed according to the weight ratio into a hard alloy ball milling tank for ball milling. Wherein, the grinding balls are hard alloy balls, the ball-material ratio is 3.5:1, the ball milling rotating speed is 100r/min, and the ball milling time is 48h. And carrying out high-temperature vacuum drying on the powder after ball milling, wherein the drying temperature is 70 ℃ and the drying time is 3 hours.
2) And (5) die filling: and (3) weighing the mixed powder obtained after the drying in the step (1) according to the requirement, putting the mixed powder into a graphite female die, prepressing the mixed powder by adopting a hydraulic press, wherein the prepressing pressure is 10MPa, and maintaining the pressure for 5min.
3) Sintering: placing the assembled graphite mold in a spark plasma sintering system, setting the axial initial pressure to be 20MPa, vacuumizing to be less than 10Pa, and starting to electrify and sinter; the temperature rising rate is set to be 50 ℃/min, when the temperature reaches 1450 ℃, the pressure is increased to 50MPa, and then the temperature continues to rise, wherein the sintering temperature is 1770 ℃; after 3min of heat preservation, cooling at 40 ℃/min, and preserving heat at 1600 ℃ and 1400 ℃ for 2min; cooling to 1000 ℃, removing the axial pressure, closing the sintering current, and cooling along with the furnace;
4) Sampling, taking out the sample by using a hydraulic press, removing graphite on the surface of the sample by adopting sand blasting treatment, and obtaining the hard alloy block material, wherein the surface of the hard alloy block material is smooth after finish machining treatment, and the defects of no collapse and the like are overcome, and the specific performance parameters are shown in the table 6.
Table 6: results of Performance test of cemented carbide bulk Material prepared in example 5
Comparative example 1
Is prepared according to the following steps
Hard alloy block material for compression molding of precision glass lens, wherein the weight ratio is WC to Cr 3 C 2 ∶VC＝100.0∶0.0∶0.0。
1) Powder mixing: putting 500g of powder weighed according to the weight ratio into a hard alloy ball milling tank for ball milling. Wherein, the grinding balls are hard alloy balls, the ball-material ratio is 3.5:1, the ball milling rotating speed is 100r/min, and the ball milling time is 48h. And carrying out high-temperature vacuum drying on the powder after ball milling, wherein the drying temperature is 70 ℃ and the drying time is 3 hours.
2) And (5) die filling: and (3) weighing the mixed powder obtained after the drying in the step (1) according to the requirement, putting the mixed powder into a graphite female die, prepressing the mixed powder by adopting a hydraulic press, wherein the prepressing pressure is 10MPa, and maintaining the pressure for 10min.
3) Sintering: placing the assembled graphite mold in a spark plasma sintering system, setting the axial initial pressure to be 20MPa, vacuumizing to be less than 10Pa, and starting to electrify and sinter; the temperature rising rate is set to be 60 ℃/min, when the temperature reaches 1400 ℃, the pressure is increased to 40MPa, then the temperature continues to rise, and the sintering temperature is 1700 ℃; maintaining the temperature for 3min, and reducing the temperature at 60 ℃/min; cooling to 1000 ℃, removing the axial pressure, closing the sintering current, and cooling along with the furnace;
4) Sampling, taking out the sample by using a hydraulic press, removing graphite on the surface of the sample by adopting sand blasting treatment, and obtaining the hard alloy block material, wherein the surface after finishing treatment has defects such as collapse, and the specific performance parameters are shown in the table 7.
Table 7: results of performance test of cemented carbide bulk Material prepared in comparative example 1
Comparative example 2
Is prepared according to the following steps
Hard alloy block material for compression molding of precision glass lens, wherein the weight ratio is WC to Cr 3 C 2 ∶VC＝95.0∶0.0∶5.0。
1) Powder mixing: putting 500g of powder weighed according to the weight ratio into a hard alloy ball milling tank for ball milling. Wherein, the grinding balls are hard alloy balls, the ball-material ratio is 3.5:1, the ball milling rotating speed is 100r/min, and the ball milling time is 48h. And carrying out high-temperature vacuum drying on the powder after ball milling, wherein the drying temperature is 70 ℃ and the drying time is 3 hours.
2) And (5) die filling: and (3) weighing the mixed powder obtained after the drying in the step (1) according to the requirement, putting the mixed powder into a graphite female die, prepressing the mixed powder by adopting a hydraulic press, wherein the prepressing pressure is 10MPa, and maintaining the pressure for 5min.
3) Sintering: placing the assembled graphite mold in a spark plasma sintering system, setting the axial initial pressure to be 20MPa, vacuumizing to be less than 10Pa, and starting to electrify and sinter; the temperature rising rate is set to be 70 ℃/min, when the temperature reaches 1400 ℃, the pressure is increased to 40MPa, then the temperature continues to rise, and the sintering temperature is 1820 ℃; directly closing sintering current without heat preservation, cooling to 1000 ℃ along with the furnace, and removing axial pressure;
4) Sampling, taking out the sample by using a hydraulic press, removing graphite on the surface of the sample by adopting sand blasting treatment, and obtaining the hard alloy block material, wherein the surface after finishing treatment has defects of collapse and the like, and the specific performance parameters are shown in the table 8.
Table 8: results of performance test of cemented carbide bulk Material prepared in comparative example 2
Claims (10)
1. Cemented carbide material for precision glass lens compression molding, wherein the cemented carbide material is prepared from a powder mixture of wc+a+b by SPS sintering, the content of WC powder being 97.0wt.% to 99.7wt.%, preferably 9, based on 100wt.% of the total weight of the powder mixture8.0wt.% to 99.6wt.%; the total content of a+b powder is 0.3wt.% to 3.0wt.%, preferably 0.4wt.% to 2.0wt.%; a is Cr 3 C 2 B is VC.
2. The cemented carbide material for precision glass lens compression molding as claimed in claim 1, wherein the cemented carbide material has a relative density of not less than 99.8%.
3. The cemented carbide material for press molding of a precision glass lens according to claim 1 or 2, wherein the cemented carbide material has a hardness of 2400HV 30 ～2700HV 30 Preferably 2500HV 30 ～2700HV 30 More preferably 2550HV 30 ～2700HV 30 ；
Preferably, the grain size of the cemented carbide material is not more than 0.2 μm;
preferably, the fracture toughness of the cemented carbide material is 6.5 MPa-m 1/2 ～8.5MPa·m 1/2 More preferably 7.0 MPa.m 1/2 ～8.0MPa·m 1/2 。
4. A method for producing a cemented carbide material for press molding a precision glass lens according to any one of claims 1 to 3, comprising the steps of:
1) Powder mixing: respectively placing WC powder, A powder and B powder into a hard alloy ball milling tank for ball milling and powder mixing, and carrying out vacuum drying on the obtained mixed powder; wherein the WC powder is present in an amount of 97.0wt.% to 99.7wt.%, preferably 98.0wt.% to 99.6wt.%, based on 100wt.% of the mixed powder; the total content of a+b powder is 0.3wt.% to 3.0wt.%, preferably 0.4wt.% to 2.0wt.%, a being Cr 3 C 2 B is VC;
2) And (5) die filling: placing the mixed powder obtained in the step 1) into a graphite female die, prepressing by adopting a hydraulic press, wherein the axial prepressing pressure is 10-20 MPa, and the pressure maintaining time is 5-15 min;
3) Sintering: placing the assembled graphite mold in a spark plasma sintering system, setting the axial pressure to be 10-50 MPa, vacuumizing to be less than 10Pa, and starting to electrify and sinter; the heating rate is set to 20-100 ℃/min, the sintering temperature is 1700-1950 ℃, and the preferred temperature is 1750-1900 ℃; preserving heat for 1-10 min, and cooling with a furnace;
4) Sampling: and taking out the sample by using a hydraulic press, and adopting sand blasting to treat graphite on the surface of the sample to obtain the hard alloy material.
5. The preparation method according to claim 4, wherein,
the purity of the WC powder is more than 99.9%, and the granularity of the powder is 0.1-1.0 mu m;
the purity of the powder A is more than 99.9%, and the granularity of the powder A is 0.1-1.0 mu m;
the purity of the powder B is more than 99.9%, and the granularity of the powder B is 0.1-1.0 mu m.
6. The preparation method according to claim 4, wherein,
the graphite female die and the graphite pressure head are separated from the powder by graphite paper or a graphite lining/gasket; and wrapping the thermal insulation graphite felt around the assembled graphite mold.
7. The preparation method according to claim 4, wherein,
the mixed powder is placed in the center of the graphite female die, and the depths of the upper graphite pressing head and the lower graphite pressing head pressed into the graphite female die are the same.
8. The preparation method according to claim 4, wherein,
in the step 3), when the sintering temperature is less than 1400 ℃, the axial pressure is 10-20 MPa; pressurizing to 20-50 MPa, preferably 30-50 MPa, at a sintering temperature of more than 1400 ℃ and less than or equal to 1500 ℃; constant pressure sintering is carried out at the target pressure until the sintering is completed.
9. The preparation method according to claim 4, wherein,
in the step 3), the heating rate is set to 20-80 ℃/min; cooling at 20-80 deg.c/min, preferably 40-80 deg.c/min; the temperature is kept at 1600 ℃ and 1500 ℃, 1400 ℃, 1300 ℃ and 1200 ℃ for 1-3 min, preferably 1600 ℃ and 1400 ℃ for 1-2 min respectively; cooling to 1000-1200 deg.c, eliminating axial pressure, closing sintering current and cooling with furnace.
10. A mold for precision glass lens compression molding, which is prepared from the cemented carbide material according to any one of claims 1 to 3.
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