CN109778046A - A kind of preparation method of low-cost and high-performance duplex grain structure WC-Co hard alloy - Google Patents
A kind of preparation method of low-cost and high-performance duplex grain structure WC-Co hard alloy Download PDFInfo
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Abstract
The invention discloses a kind of preparation methods of low-cost and high-performance duplex grain structure WC-Co hard alloy, prepare mixed powder by raw material of ammonium metatungstate, WC powder, graphite powder and cobalt powder；Add deionized water；By mixture after ball mill mixing, addition forming agent, compression moulding, degreasing and calcination process, it is sintered, obtains the WC-Co hard alloy with duplex grain structure.WC-Co hard alloy hardness prepared by the present invention, bending strength and fracture toughness are higher, have preferable comprehensive mechanical property.The preparation method simple process, to production equipment without particular/special requirement, lower production costs have broad application prospects.
Description
Technical field
The present invention relates to the preparation methods of low-cost and high-performance duplex grain structure WC-Co hard alloy, belong to powder metallurgy skill
Art field.
Background technique
WC-Co hard alloy is because having that hardness is high, wearability is good, red hardness is high and chemical stability is preferably etc. a series of excellent
Good characteristic has been widely used as cutting element, geology and mine tool, mold, constitutional detail, wear part, high-temperature-resistant structure part etc.,
It is known as " tooth of modern industry ".However, being a pair of shifting lance in cemented carbide material, between hardness and toughness
Shield relationship.In the identical situation of Co content, when the WC grain of material is thinner, Cemented Carbide Hardness is higher, and wearability is preferable,
But toughness is obviously relatively low, brittleness is larger；And when the WC grain of material is thicker, toughness is preferable, but its hardness and wearability
Then it is decreased obviously.However, with the appearance of difficult-to-machine material, and it is complicated, harsh work condition environment increase, to hard alloy material
More stringent requirements are proposed for the comprehensive mechanical property of material, it is clear that traditional hard alloy is not able to satisfy such demand, this restriction
The development of cemented carbide industry.
To solve the contradiction between Cemented Carbide Hardness and toughness, the excellent hard alloy material of comprehensive mechanical property is prepared
Material, scientific research personnel propose the duplex grain structure hard alloy for preparing that a kind of hard-phase particles size is in bimodal distribution, can integrate
The advantage of both coarse-grain and fine grained cemented carbide.Liu Chao et al. (preparation of mixed crystal WC-8Co hard alloy and performance study, it is Central-South
University, 2014) by the way that a certain proportion of thick WC powder is added in thin WC powder, hard-phase particles size has been prepared in double
The duplex grain structure hard alloy of peak distribution, improves the comprehensive mechanical property of material.However, thick WC in duplex grain structure hard alloy
Particle while improving toughness so that it is decreased obviously relative to fine grained cemented carbide hardness.Chinese patent
CN102212731A discloses " a kind of industrialized process for preparing for having both high-intensitive and high tenacity twin crystal hard alloy ", the party
Method is with WO2.9, Co3O4, carbon black is raw material, first prepares WC-Co mixed-powder in a vacuum furnace, then carries out under protection of argon gas
Reunite pretreatment, compression molding finally carried out to the pretreated powder of reuniting and final liquid-phase sintering to prepare twin crystal structure hard
Matter alloy.However, such preparation method process flow is complicated, and it is cumbersome, it is readily incorporated impurity, Mechanical Fluctuation is larger.
106756391 A of Chinese patent CN discloses " a kind of WC-Co hard alloy preparation method with duplex grain structure ", this method
It is based on carbon thermal reduction WO in situ3Duplex grain structure hard alloy is prepared, but is difficult to be carbonized since in-between process product lacks carbon phase
Completely, so that being usually present brittleness third phase in final sintered body, reduce the obdurability of material so that the performance inconsistency of material compared with
Greatly.
In view of the foregoing, in order to enable WC-Co hard alloy preferably to be applied in more areas, it is necessary to this
Kind material conducts further research, and developing one kind has duplex grain structure WC-Co hard alloy novel preparation method, makes it not only
Hardness and strength with higher, it may have higher fracture toughness, and it is suitable for industrialized production.
Summary of the invention
The purpose of the present invention is to provide a kind of preparation method of low-cost and high-performance duplex grain structure WC-Co hard alloy,
To prepare not only hardness and strength with higher, it may have the WC-Co hard alloy of higher fracture toughness, and technique mistake
Journey is simple, manufacturing cost is cheap.
To achieve the above object, the technical solution adopted by the present invention are as follows:
A kind of preparation method of low-cost and high-performance duplex grain structure WC-Co hard alloy, comprising the following steps:
Step 1, mixed powder is prepared by raw material of ammonium metatungstate, WC powder, graphite powder and cobalt powder；According to mass fraction, institute
State WC-Co hard alloy to be made of following element: it be 0.18~0.19, O is that 4.41~4.68, W is that N, which is 0.58~0.61, H,
76.01~80.68, C are that 7.78~8.35, Co is 5.49~11.04；Wherein, N, H and O are introduced by ammonium metatungstate；W a part
It is introduced by ammonium metatungstate, a part is introduced by WC；C a part is introduced by graphite powder, and a part is introduced by WC；Co is drawn by cobalt powder
Enter；
Step 2, in mixed powder deionized water addition step 1 obtained；
Step 3, mixture step 2 obtained is through ball mill mixing, addition forming agent, compression moulding, degreasing and calciner
It after sequence, is sintered, obtains the WC-Co hard alloy with duplex grain structure；
The sintering process is completed in a complete thermal cycle, including following four stage:
(1) first by degreasing and calcined green compact continues to be warming up to 800 DEG C with 0.4~0.8 DEG C/min；
(2) 1180~1220 DEG C then are warming up to the rate of 4 DEG C/min, and in 90~150min of this temperature；
(3) 1380~1420 DEG C then are warming up to the rate of 3 DEG C/min, then first vacuum-sintering 20min is passed through again
CH4With Ar mixed gas, pressure is 500~1000Pa, keeps the temperature 20~60min；
(4) 1300 DEG C then are cooled to the rate of 3 DEG C/min again, and are passed through CH4With Ar mixed gas, pressure 500
~1000Pa keeps the temperature 20~60min, then furnace cooling；
In above-mentioned sintering process, in addition to sintering stage of ventilating, remaining heating, sintering stage vacuum degree be higher than 1.0 ×
10-1It is carried out under conditions of Pa.
As optimal technical scheme, in the step 1, the granularity of WC powder is 0.5~0.8 μm, and the granularity of graphite powder is 3
~4 μm, the granularity of cobalt powder is 1~2 μm.
In degreasing and calcination process, in the case where removing forming agent completely, it should also make ammonium metatungstate by calcining
WO3 is resolved into completely.Therefore, as optimal technical scheme, in the step 1, O of the C of addition in complete removing system is simultaneously
After generating WC by carbonization, should also make in sintered body remaining total C content between (6.13%~0.085 × Co%) and
Between (6.13%~0.080 × Co%), to guarantee that the microscopic structure of the gained alloy after being finally sintered is in normal two-phase section,
It is not in remaining graphite-phase or harmful brittleness η phase；Wherein Co% is the mass fraction of Co in corresponding component system.
As optimal technical scheme, in the step 2, the weight ratio of deionized water and mixed powder is 1:1~2.
As optimal technical scheme, in the step 3, ball mill mixing process carries out in tumbling ball mill, and revolving speed is
30~50rpm, ratio of grinding media to material 5:1, Ball-milling Time are 36~48h.
As optimal technical scheme, in the step 3, forming agent is that concentration is 7wt.% polyvinyl alcohol water solution, is added
Ratio is 4~6wt% of mixture.
As optimal technical scheme, in the step 3, pressure applied in compression moulding process is 120~180MPa.
As optimal technical scheme, in the step 3, degreasing and calcine process vacuum degree higher than 10Pa vacuum/
It is carried out in atmosphere all-in-one oven, is to slowly warm up to 600 DEG C from room temperature, carried out degreasing and calcine, wherein being risen between 200~600 DEG C
Warm speed is 0.2~0.4 DEG C/min.
As optimal technical scheme, in the step 3, CH that (3) stage of sintering process is filled with4With Ar mixed gas
Middle CH4Volume ratio with Ar is 1:1~2, and uses pendulum-type aeration, and the pendulum-type period is 20min；
As optimal technical scheme, in the step 3, CH that (4) stage of sintering process is filled with4With Ar mixed gas
Middle CH4Volume ratio with Ar is 1:1~2, and uses pendulum-type aeration, and the pendulum-type period is 20min.
The principle of the present invention is:
All the time, oxygen is considered as the objectionable impurities in hard alloy, because they can make firmly in liquid sintering process
Angle of wetting between matter phase and Binder Phase becomes larger, and reduces its wetability, to deteriorate materials microstructure and performance, so existing at present
The oxygen content in powder is all reduced when preparing hard alloy as far as possible.Although present invention introducing portion in the form of ammonium metatungstate
A large amount of O has also been introduced while W, but metatungstic acid can be made while 200~600 DEG C of degreasings by rationally control technique
Ammonium is completely decomposed into WO3, and the graphite powder by introducing corresponding content and controlling sintering process can make O at 600~800 DEG C
Between by reaction WO3+ 3C → W+3CO is removed completely, and by WO3In-situ reducing is W.And sintered body is still in early period at this time
In the solid-phase sintering stage, relative density is lower, and hole is in aperture state, and the gas for reacting generation under vacuum conditions can be smooth
Evolution.In the follow-up sintering stage, continue to increase with temperature, reduction gained W powder will continue to suitable with remaining graphite powder and Co powder
Following reaction: xW+yC+zCo → Co occurs for sequencexWyCz, CoxWyCz+ C → WC+Co, CoxWyCzIt is formed in Xiang Yu carbon reaction process
Twin, to form the thick WC grain of plate.Crack propagation approach occurs when the thick WC grain of one side plate makes material bear outer carry
Deflection, to effectively improve the fracture toughness of material.On the other hand, WC grain is close-packed hexagonal crystallographic system, and (0001) basal plane is hard
Degree close to 2 times of cylinder hardness.Since plate-like shape WC grains are along (0001) basal plane preferential growth, thus
(0001) ratio shared by basal plane increases, and therefore, a large amount of thick WC grains of plate are also beneficial to improve the hardness of material.Also, carbon
The reducibility gas CO discharged during thermal reduction can make other original powder WC powder and the absorption oxygen removal on Co powder surface more
Thoroughly, the interface between ceramic phase and metallic binding phase is purified, the bond strength of phase interface is enhanced, its is tough to reach raising
The purpose of property.
The present invention has a characteristic that using deionized water as ball-milling medium, due to ammonium metatungstate can be dissolved in from
Stablizing solution is formed in sub- water, so as to improve it in the distributing homogeneity of mixture, on the other hand replaces alcohol with deionized water
It can be with save the cost and environmentally protective.Degreasing and calcining are carried out in vacuum/atmosphere all-in-one oven of the vacuum degree higher than 10Pa,
Green compact is warming up to 600 DEG C with the rate of 0.2~0.4 DEG C/min, it is therefore an objective to while degreasing, make ammonium metatungstate calcining complete
It is decomposed into WO3.Sintering carries out in vacuum/atmosphere all-in-one oven, including four-stage: first by degreasing and calcined green compact after
It is continuous to be warming up to 800 DEG C with 0.4~0.8 DEG C/min, it is therefore an objective to carry out carbothermic reduction reaction, sufficiently remove contained in tungstic acid
Oxygen, while so that the gas generated is passed through aperture and being escaped from sintered body；Then it is warming up to the rate of 4 DEG C/min
1180~1220 DEG C, and in 90~150min of this temperature, it is therefore an objective to make the further carbonization of tungsten powder obtained by carbon thermal reduction
For tungsten carbide；Then it is warming up to the rate of 3 DEG C/min and burns 1380~1420 DEG C of temperature eventually, heat preservation 20min carries out final liquid
Phase sintering simultaneously obtains fine and close duplex grain structure sintered body, is then re-filled with CH4With Ar mixed gas, pressure is 500~1000Pa,
Keep the temperature 20~60min；1300 DEG C finally are cooled to the rate of 3 DEG C/min, and is passed through CH herein4With Ar mixed gas, pressure
For 500~1000Pa, 20~60min, then furnace cooling are kept the temperature.Two stages are filled with CH after sintering4With Ar mixed gas
Purpose be in order to make in hard alloy may the scarce carbon phase of remaining react to form twin with carbon, be further formed plate WC crystalline substance
Grain, to guarantee that there is no harmful scarce carbon phases in final sintered body, improve the stabilization of hard alloy mechanical property and performance
Property.
The invention has the following beneficial effects:
(1) duplex grain structure WC-Co hard alloy provided by the invention, the thick WC grain of plate can effectively improve the tough of material
Property, it can also be improved the hardness of material, thin WC grain can guarantee the hardness and bending strength of material.Thus material has higher
Comprehensive mechanical property.
(2) present invention replaces alcohol as primary raw material, and using deionized water using cheap ammonium metatungstate
As ball-milling medium, on the one hand form stablizing solution since ammonium metatungstate can be dissolved in deionized water, so as to improve its
The distributing homogeneity of mixture, another aspect save the cost and environmentally protective.
(3) WO is generated completely after ammonium metatungstate calcining and decomposing3, carbothermic reduction reaction further, which is carried out, with graphite powder generates also
Originality gas CO can purify the interface between WC hard phase and Co Binder Phase, enhance the bond strength of phase interface, be conducive to improve
The obdurability of material.
(4) present invention process process is simple, completes in a complete thermal cycle, can significant energy saving, reduction life
It produces cost, improve productivity.
(5) present invention only needs conventional equipment, is conducive to commercial introduction application to production equipment without particular/special requirement.
Specific embodiment
Further explanation is done to the present invention below with reference to embodiment.
According to following embodiments, the present invention can be better understood.However, as it will be easily appreciated by one skilled in the art that real
It applies specific material proportion, process conditions and its result described in example and is merely to illustrate the present invention, without that should will not limit
The present invention described in detail in claims processed.
Raw material used by following embodiment is WC powder, ammonium metatungstate, Co powder and graphite powder.
Table 1 is the mixture of 4 kinds of component prescriptions used by following embodiments.It is different using 3 kinds in Examples 1 to 3
Technological parameter is prepared into duplex grain structure hard alloy, and it is tough to measure its bending strength, hardness and palmqvist fracture respectively
Property.
The mixing situation of each component in the case of 1 four kinds of table
| Ingredient | N | H | O | W | C | Co |
| 1# | 0.61 | 0.19 | 4.68 | 80.68 | 8.35 | 5.49 |
| 2# | 0.60 | 0.19 | 4.59 | 79.13 | 8.16 | 7.33 |
| 3# | 0.59 | 0.18 | 4.50 | 77.58 | 7.97 | 9.18 |
| 4# | 0.58 | 0.18 | 4.41 | 76.01 | 7.78 | 11.04 |
It wherein, is each element in table 1 according to the proportion of mass fraction.
Embodiment 1:
(1) 4 kinds of mixed powders are prepared according to table 1, raw materials used is ammonium metatungstate, WC powder, graphite powder and Co powder, WC powder
The granularity at end is 0.5~0.8 μm, and the granularity of graphite powder is 3~4 μm, and the granularity of cobalt powder is 1~2 μm；
(2) deionized water is added in above-mentioned mixed powder, the weight ratio of deionized water and mixed powder is 1:1；
(3) mixture that step (2) obtains is placed in ball milling in tumbling ball mill, revolving speed 30rpm, ratio of grinding media to material 5:1,
Ball-milling Time is 48h；
(4) forming agent is added, forming agent uses concentration for the polyvinyl alcohol water solution of 7wt.%, and additional amount is mixture
4wt%；
(5) compression moulding, pressure used in compression moulding are 120MPa；
(6) deviate from forming agent and calcine, deviate from forming agent and calcination process carries out in vacuum/atmosphere all-in-one oven,
Vacuum degree is higher than 10Pa, is to slowly warm up to 600 DEG C from room temperature, carries out degreasing and calcines, wherein the liter between 200~600 DEG C
Warm speed is 0.2 DEG C/min；
(7) it is sintered, is carried out in vacuum/atmosphere all-in-one oven.First by degreasing and calcined green compact continue with 0.4 DEG C/
Min is warming up to 800 DEG C；1180 DEG C then are warming up to the rate of 4 DEG C/min, and in this temperature 150min；Then with 3
DEG C/rate of min is warming up to 1380 DEG C, then first vacuum-sintering 20min is passed through CH again4With Ar mixed gas, volume ratio is
1:1, pressure 500Pa keep the temperature 20min；Then 1300 DEG C are cooled to the rate of 3 DEG C/min again, and are passed through CH herein4And Ar
Mixed gas, volume ratio 1:1, pressure 1000Pa keep the temperature 60min, then furnace cooling.In above-mentioned sintering process, remove
It clearly states outside ventilation sintering stage, remaining heating, sintering stage are higher than 1.0 × 10 in vacuum degree-1It is carried out under conditions of Pa.
Under above-mentioned preparation process condition, the mechanical property of the hard alloy of heterogeneity proportion is shown in Table 2.
The mechanical property for the different hardness alloy that table 2 is prepared using technique 1
| Ingredient | 1# | 2# | 3# | 4# |
| Bending strength σb(MPa) | 2369 | 2574 | 2662 | 2866 |
| Hardness (HRA) | 91.3 | 90.6 | 89.7 | 88.3 |
| Fracture toughness (MPam1/2) | 14.6 | 16.7 | 20.4 | 24.3 |
Embodiment 2:
(1) 4 kinds of mixed powders are prepared according to table 1, raw materials used is ammonium metatungstate, WC powder, graphite powder and Co powder, WC powder
The granularity at end is 0.5~0.8 μm, and the granularity of graphite powder is 3~4 μm, and the granularity of cobalt powder is 1~2 μm；
(2) deionized water is added in above-mentioned mixed powder, the weight ratio of deionized water and mixture is 1:1.5；
(3) mixture that step (2) obtains is placed in ball milling in tumbling ball mill, revolving speed 40rpm, ratio of grinding media to material 5:1,
Ball-milling Time is 42h；
(4) forming agent is added, forming agent uses concentration for the polyvinyl alcohol water solution of 7wt.%, and additional amount is mixture
5wt%；
(5) compression moulding, pressure used in compression moulding are 150MPa；
(6) deviate from forming agent and calcine, deviate from forming agent and calcination process carries out in vacuum/atmosphere all-in-one oven,
Vacuum degree is higher than 10Pa, is to slowly warm up to 600 DEG C from room temperature, carries out degreasing and calcines, wherein the liter between 200~600 DEG C
Warm speed is 0.3 DEG C/min；
(7) it is sintered, is carried out in vacuum/atmosphere all-in-one oven.First by degreasing and calcined green compact continue with 0.6 DEG C/
Min is warming up to 800 DEG C；1200 DEG C then are warming up to the rate of 4 DEG C/min, and in this temperature 120min；Then with 3
DEG C/rate of min is warming up to 1400 DEG C, then first vacuum-sintering 20min is passed through CH again4With Ar mixed gas, volume ratio is
1:1.5, pressure 800Pa keep the temperature 40min；Then 1300 DEG C are cooled to the rate of 3 DEG C/min again, and are passed through CH herein4With
Ar mixed gas, volume ratio 1:1.5, pressure 800Pa keep the temperature 40min, then furnace cooling.In above-mentioned sintering process,
In addition to clearly stating ventilation sintering stage, remaining heating, sintering stage are higher than 1.0 × 10 in vacuum degree-1Under conditions of Pa into
Row.
Under above-mentioned preparation process condition, the mechanical property of the hard alloy of heterogeneity proportion is shown in Table 3.
The mechanical property for the different hardness alloy that table 3 is prepared using technique 2
| Ingredient | 1# | 2# | 3# | 4# |
| Bending strength σb(MPa) | 2456 | 2578 | 2703 | 2857 |
| Hardness (HRA) | 91.1 | 90.4 | 89.4 | 88.1 |
| Fracture toughness (MPam1/2) | 14.4 | 17.3 | 21.6 | 25.3 |
Embodiment 3:
(1) 4 kinds of mixed powders are prepared according to table 1, raw materials used is ammonium metatungstate, WC powder, graphite powder and Co powder, WC powder
The granularity at end is 0.5~0.8 μm, and the granularity of graphite powder is 3~4 μm, and the granularity of cobalt powder is 1~2 μm；
(2) deionized water is added in above-mentioned mixed powder, the weight ratio of deionized water and mixture is 1:2；
(3) mixture that step (2) obtains is placed in ball milling in tumbling ball mill, revolving speed 50rpm, ratio of grinding media to material 5:1,
Ball-milling Time is 36h.
(4) forming agent is added, forming agent uses concentration for the polyvinyl alcohol water solution of 7wt.%, and additional amount is mixture
6wt%；
(5) compression moulding, pressure used in compression moulding are 180MPa；
(6) deviate from forming agent and calcine, deviate from forming agent and calcination process carries out in vacuum/atmosphere all-in-one oven,
Vacuum degree is higher than 10Pa, is to slowly warm up to 600 DEG C from room temperature, carries out degreasing and calcines, wherein the liter between 200~600 DEG C
Warm speed is 0.4 DEG C/min；
(7) it is sintered, is carried out in vacuum/atmosphere all-in-one oven.First by degreasing and calcined green compact continue with 0.8 DEG C/
Min is warming up to 800 DEG C；1220 DEG C then are warming up to the rate of 4 DEG C/min, and in this temperature 90min；Then with 3 DEG C/
The rate of min is warming up to 1420 DEG C, then first vacuum-sintering 20min is passed through CH again4With Ar mixed gas, volume ratio 1:
2, pressure 1000Pa keep the temperature 60min；Then 1300 DEG C are cooled to the rate of 3 DEG C/min again, and are passed through CH herein4And Ar
Mixed gas, volume ratio 1:2, pressure 500Pa keep the temperature 20min, then furnace cooling.In above-mentioned sintering process, except bright
Really illustrate to ventilate outside sintering stage, remaining heating, sintering stage are higher than 1.0 × 10 in vacuum degree-1It is carried out under conditions of Pa.
Under above-mentioned preparation process condition, the mechanical property of the hard alloy of heterogeneity proportion is shown in Table 4.
The mechanical property for the different hardness alloy that table 4 is prepared using technique 3
| Ingredient | 1# | 2# | 3# | 4# |
| Bending strength σb(MPa) | 2412 | 2558 | 2673 | 2862 |
| Hardness (HRA) | 91.2 | 90.5 | 89.5 | 88.2 |
| Fracture toughness (MPam1/2) | 15.0 | 16.9 | 21.7 | 26.5 |
In value range of the invention, the technological parameter in the first two stage of sintering process is opposite to Effect on Mechanical Properties
Larger, only when the carbon thermal reduction in this stage and carbonisation carry out complete, the hard alloy of above-mentioned each component prescription can be obtained
Obtain relatively good comprehensive mechanical property.In short, being influenced on the performance of hard alloy limited in value range of the present invention.
The above is only a preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art
For member, various improvements and modifications may be made without departing from the principle of the present invention, these improvements and modifications are also answered
It is considered as protection scope of the present invention.
Claims (10)
1. a kind of preparation method of low-cost and high-performance duplex grain structure WC-Co hard alloy, it is characterised in that: including following step
It is rapid:
Step 1, mixed powder is prepared by raw material of ammonium metatungstate, WC powder, graphite powder and cobalt powder；According to mass fraction, the WC-
Co hard alloy is made of following element: N be 0.58~0.61, H be 0.18~0.19, O be 4.41~4.68, W be 76.01~
80.68, C be 7.78~8.35, Co be 5.49~11.04；Wherein, N, H and O are introduced by ammonium metatungstate；W a part is by metatungstic acid
Ammonium introduces, and a part is introduced by WC；C a part is introduced by graphite powder, and a part is introduced by WC；Co is introduced by cobalt powder；
Step 2, in mixed powder deionized water addition step 1 obtained；
Step 3, mixture step 2 obtained after ball mill mixing, addition forming agent, compression moulding, degreasing and calcination process,
It is sintered, obtains the WC-Co hard alloy with duplex grain structure；
The sintering process is completed in a complete thermal cycle, including following four stage:
(1) first by degreasing and calcined green compact continues to be warming up to 800 DEG C with 0.4~0.8 DEG C/min；
(2) 1180~1220 DEG C then are warming up to the rate of 4 DEG C/min, and in 90~150min of this temperature；
(3) 1380~1420 DEG C then are warming up to the rate of 3 DEG C/min, then first vacuum-sintering 20min is passed through CH again4And Ar
Mixed gas, pressure are 500~1000Pa, keep the temperature 20~60min；
(4) 1300 DEG C then are cooled to the rate of 3 DEG C/min again, and are passed through CH4With Ar mixed gas, pressure be 500~
1000Pa keeps the temperature 20~60min, then furnace cooling；
In above-mentioned sintering process, in addition to sintering stage of ventilating, remaining heating, sintering stage are higher than 1.0 × 10 in vacuum degree-1Pa
Under conditions of carry out.
2. the preparation method of low-cost and high-performance duplex grain structure WC-Co hard alloy according to claim 1, feature exist
In: in the step 1, the granularity of WC powder is 0.5~0.8 μm, and the granularity of graphite powder is 3~4 μm, and the granularity of cobalt powder is 1~2
μm。
3. the preparation method of low-cost and high-performance duplex grain structure WC-Co hard alloy according to claim 1, feature exist
In: in the step 1, the C of addition should also make to remain in sintered body after the O in complete removing system and by carbonization generation WC
Remaining total C content is between (6.13%~0.085 × Co%) and (6.13%~0.080 × Co%), to guarantee through final
The microscopic structure of gained alloy is in normal two-phase section after sintering, and wherein Co% is the mass fraction of Co in corresponding component system.
4. the preparation method of low-cost and high-performance duplex grain structure WC-Co hard alloy according to claim 1, feature exist
In: in the step 2, the weight ratio of deionized water and mixed powder is 1:1~2.
5. the preparation method of low-cost and high-performance duplex grain structure WC-Co hard alloy according to claim 1, feature exist
In: in the step 3, ball mill mixing process carries out in tumbling ball mill, revolving speed be 30~50rpm, ratio of grinding media to material 5:1,
Ball-milling Time is 36~48h.
6. the preparation method of low-cost and high-performance duplex grain structure WC-Co hard alloy according to claim 1, feature exist
In: in the step 3, forming agent is that concentration is 7wt.% polyvinyl alcohol water solution, and additional proportion is 4~6wt% of mixture.
7. the preparation method of low-cost and high-performance duplex grain structure WC-Co hard alloy according to claim 1, feature exist
In: in the step 3, pressure applied in compression moulding process is 120~180MPa.
8. the preparation method of low-cost and high-performance duplex grain structure WC-Co hard alloy according to claim 1, feature exist
In: in the step 3, the process of degreasing and calcining carries out in vacuum/atmosphere all-in-one oven of the vacuum degree higher than 10Pa, from room temperature
600 DEG C are warming up to, degreasing is carried out and is calcined, wherein heating rate is 0.2~0.4 DEG C/min between 200~600 DEG C.
9. the preparation method of low-cost and high-performance duplex grain structure WC-Co hard alloy according to claim 1, feature exist
In: in the step 3, CH that (3) stage of sintering process is filled with4With CH in Ar mixed gas4Volume ratio with Ar is 1:1
~2, and pendulum-type aeration is used, the pendulum-type period is 20min.
10. the preparation method of low-cost and high-performance duplex grain structure WC-Co hard alloy according to claim 1, feature
It is: in the step 3, CH that (4) stage of sintering process is filled with4With CH in Ar mixed gas4Volume ratio with Ar is 1:
1~2, and pendulum-type aeration is used, the pendulum-type period is 20min.
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| CN111069619A (en) * | 2019-12-12 | 2020-04-28 | 湖南博云东方粉末冶金有限公司 | Preparation method of extra-coarse grain hard alloy mixture |
| CN112063905A (en) * | 2020-08-28 | 2020-12-11 | 南京航空航天大学 | High-performance WC-WCoB-Co complex phase hard alloy and preparation method thereof |
| CN114752835A (en) * | 2022-03-18 | 2022-07-15 | 南京航空航天大学 | Ti (C, N) -based metal ceramic with honeycomb structure and preparation method thereof |
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| CN111069619A (en) * | 2019-12-12 | 2020-04-28 | 湖南博云东方粉末冶金有限公司 | Preparation method of extra-coarse grain hard alloy mixture |
| CN111069619B (en) * | 2019-12-12 | 2023-04-07 | 湖南博云东方粉末冶金有限公司 | Preparation method of extra-coarse grain hard alloy mixture |
| CN112063905A (en) * | 2020-08-28 | 2020-12-11 | 南京航空航天大学 | High-performance WC-WCoB-Co complex phase hard alloy and preparation method thereof |
| CN114752835A (en) * | 2022-03-18 | 2022-07-15 | 南京航空航天大学 | Ti (C, N) -based metal ceramic with honeycomb structure and preparation method thereof |
| CN114752835B (en) * | 2022-03-18 | 2022-10-25 | 南京航空航天大学 | Ti (C, N) -based metal ceramic with honeycomb structure and preparation method thereof |
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