CN114653948B - Preparation method of tungsten alloy beads - Google Patents
Preparation method of tungsten alloy beads Download PDFInfo
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- CN114653948B CN114653948B CN202210320537.0A CN202210320537A CN114653948B CN 114653948 B CN114653948 B CN 114653948B CN 202210320537 A CN202210320537 A CN 202210320537A CN 114653948 B CN114653948 B CN 114653948B
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- 229910001080 W alloy Inorganic materials 0.000 title claims abstract description 178
- 239000011324 bead Substances 0.000 title claims abstract description 159
- 238000002360 preparation method Methods 0.000 title abstract description 15
- 238000005245 sintering Methods 0.000 claims abstract description 51
- 239000000843 powder Substances 0.000 claims abstract description 46
- 238000005238 degreasing Methods 0.000 claims abstract description 42
- 239000000463 material Substances 0.000 claims abstract description 26
- 238000000137 annealing Methods 0.000 claims abstract description 21
- 239000011812 mixed powder Substances 0.000 claims abstract description 21
- 239000002994 raw material Substances 0.000 claims abstract description 21
- 239000010941 cobalt Substances 0.000 claims abstract description 16
- 229910017052 cobalt Inorganic materials 0.000 claims abstract description 16
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000008187 granular material Substances 0.000 claims abstract description 15
- 239000003292 glue Substances 0.000 claims abstract description 11
- 238000000227 grinding Methods 0.000 claims abstract description 11
- 239000002245 particle Substances 0.000 claims abstract description 9
- 238000012216 screening Methods 0.000 claims abstract description 8
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 8
- 239000010937 tungsten Substances 0.000 claims abstract description 8
- 238000002156 mixing Methods 0.000 claims abstract description 7
- 238000000034 method Methods 0.000 claims description 35
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 32
- 239000004576 sand Substances 0.000 claims description 32
- 239000001257 hydrogen Substances 0.000 claims description 22
- 229910052739 hydrogen Inorganic materials 0.000 claims description 22
- 238000011068 loading method Methods 0.000 claims description 20
- 230000008569 process Effects 0.000 claims description 19
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 13
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 12
- 238000002844 melting Methods 0.000 claims description 12
- 230000008018 melting Effects 0.000 claims description 12
- 150000002431 hydrogen Chemical class 0.000 claims description 11
- 229910052757 nitrogen Inorganic materials 0.000 claims description 6
- 238000004140 cleaning Methods 0.000 claims description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 4
- 238000009933 burial Methods 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- UGKDIUIOSMUOAW-UHFFFAOYSA-N iron nickel Chemical compound [Fe].[Ni] UGKDIUIOSMUOAW-UHFFFAOYSA-N 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 125000006850 spacer group Chemical group 0.000 claims 2
- 230000000694 effects Effects 0.000 abstract description 9
- 238000004519 manufacturing process Methods 0.000 abstract description 7
- 230000006866 deterioration Effects 0.000 abstract description 4
- 230000008595 infiltration Effects 0.000 abstract description 3
- 238000001764 infiltration Methods 0.000 abstract description 3
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 18
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 12
- 229910052750 molybdenum Inorganic materials 0.000 description 11
- 239000011733 molybdenum Substances 0.000 description 11
- 238000011049 filling Methods 0.000 description 6
- 239000010935 stainless steel Substances 0.000 description 6
- 229910001220 stainless steel Inorganic materials 0.000 description 6
- 229910000831 Steel Inorganic materials 0.000 description 5
- 239000010959 steel Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000005453 pelletization Methods 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- 238000004663 powder metallurgy Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000003213 activating effect Effects 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000000748 compression moulding Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007123 defense Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000001746 injection moulding Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
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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
- B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
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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
- B22F3/02—Compacting only
-
- 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
- B22F3/1017—Multiple heating or additional steps
- B22F3/1021—Removal of binder or filler
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/24—After-treatment of workpieces or articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
- B65B31/00—Packaging articles or materials under special atmospheric or gaseous conditions; Adding propellants to aerosol containers
- B65B31/04—Evacuating, pressurising or gasifying filled containers or wrappers by means of nozzles through which air or other gas, e.g. an inert gas, is withdrawn or supplied
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C27/00—Alloys based on rhenium or a refractory metal not mentioned in groups C22C14/00 or C22C16/00
- C22C27/04—Alloys based on tungsten or molybdenum
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
- C22F1/18—High-melting or refractory metals or alloys based thereon
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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
- B22F3/24—After-treatment of workpieces or articles
- B22F2003/247—Removing material: carving, cleaning, grinding, hobbing, honing, lapping, polishing, milling, shaving, skiving, turning the surface
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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
- B22F3/24—After-treatment of workpieces or articles
- B22F2003/248—Thermal after-treatment
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- Organic Chemistry (AREA)
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Abstract
The invention discloses a preparation method of tungsten alloy beads, which comprises the following steps: 1. adding cobalt element into the tungsten alloy powder to obtain tungsten alloy bead raw material mixed powder; 2. mixing tungsten alloy bead raw material mixed powder with glue, granulating, screening and grading to obtain granules with different granularity grades; 3. forming the granulated materials with different granularity grades according to the same granularity grade respectively to obtain tungsten alloy bead pressed blanks; 4. thermally degreasing the tungsten alloy bead compact; 5. sintering to obtain a tungsten alloy bead sintered blank; 6. and grinding the tungsten alloy bead sintered blank, and then carrying out stress relief annealing treatment to obtain the tungsten alloy bead. According to the invention, cobalt element is added into tungsten alloy powder, so that the infiltration performance of tungsten particles is improved, the sintering activity is increased, the flowability of the prepared particles is improved, the single weight and the size fluctuation of tungsten alloy bead pressed blanks are reduced, the thermal degreasing and the stress relief annealing are combined, the pressed blank damage and the performance deterioration are avoided, and the forming quality and the production efficiency of tungsten alloy beads are improved.
Description
Technical Field
The invention belongs to the technical field of tungsten alloy material manufacturing, and particularly relates to a preparation method of tungsten alloy beads.
Background
Tungsten alloy beads are tungsten alloy articles for counterweights or killing components, known as smallest high density balls in the tungsten alloy field, and are widely used in numerous fields such as golf clubs, fishing weights, balancing forces for military defenses, and the like. Particularly, the tungsten alloy beads have the advantages of high density, good storage speed performance, strong armor piercing capability and the like, and are widely applied to killing warheads in recent years.
The tungsten alloy beads are produced in a powder metallurgy mode, however, the tungsten alloy beads are easy to be influenced by powder fluidity during pressing and have the phenomena of single pressed blank and size fluctuation due to small volume and high tungsten alloy powder density, the tungsten alloy beads are subjected to a boat loading mode during sintering, the whole production efficiency of the tungsten alloy beads is limited by the sintering productivity, and the crushing performance of the tungsten alloy beads is poor due to work hardening in the grinding process after sintering, so that the contradiction with the large demand of the tungsten alloy beads and the high performance demand is increasingly prominent.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a preparation method of tungsten alloy beads aiming at the defects in the prior art. According to the method, cobalt element is added into tungsten alloy powder, so that the infiltration performance of tungsten particles is improved, the sintering activity is increased, the tungsten alloy bead raw material mixed powder is mixed with glue, granulated and screened for classification, the fluidity of the granulated material is improved, the single weight and the size fluctuation of tungsten alloy bead pressed blanks are reduced, the thermal degreasing and the stress relief annealing are combined, the pressed blank damage during sintering and boat loading and material placing is avoided, the performance deterioration caused by processing stress is reduced, and the forming quality and the production efficiency of tungsten alloy beads are improved.
In order to solve the technical problems, the invention adopts the following technical scheme: a method for preparing tungsten alloy beads, comprising the steps of:
adding cobalt element into tungsten alloy powder to obtain tungsten alloy bead raw material mixed powder; the tungsten alloy powder comprises the following components in percentage by mass: 93% or 95% of tungsten element, the balance being nickel-iron element, and the ratio of nickel to iron is 7:3;
step two, mixing the tungsten alloy bead raw material mixed powder obtained in the step one with glue, granulating, and then screening and grading to obtain granules with different granularity grades;
step three, forming the granulated materials with different granularity grades obtained in the step three according to the same granularity grade respectively to obtain tungsten alloy bead pressed blanks;
pushing the tungsten alloy bead pressed compact obtained in the third step into a continuous degreasing furnace for thermal degreasing;
step five, placing the tungsten alloy bead pressed blank subjected to thermal degreasing in the step four in a muffle furnace for sintering to obtain a tungsten alloy bead sintered blank;
and step six, grinding the tungsten alloy bead sintered blank obtained in the step five, and then carrying out stress relief annealing treatment to obtain the tungsten alloy bead.
According to the invention, the tungsten alloy beads are prepared by adopting a powder metallurgy method, firstly, cobalt element is added into tungsten alloy powder, so that the wettability of bonding formed in a subsequent sintering process relative to tungsten particles is improved, the tungsten particles are completely embedded in a bonding phase matrix, meanwhile, the sintering activity is increased, the forming quality of the tungsten alloy beads is improved, and the production efficiency of the tungsten alloy beads is improved; secondly, the tungsten alloy bead raw material mixed powder is mixed with glue, granulated, screened and graded, and then molded according to the same granularity grade, and steel die compression molding or injection molding is generally adopted, so that the fluidity of the granulated material is improved, the stable and consistent weight of the granulated material compression is ensured, and the single weight and the size fluctuation of a tungsten alloy bead pressed compact are reduced; thirdly, the tungsten alloy bead pressed compact is thermally degreased to remove the glue added during glue mixing and granulating, so that the strength of the tungsten alloy bead pressed compact after thermal degreasing is improved while the degumming effect is ensured, the pressed compact is not damaged in the sintering boat loading and arranging process, the single weight and size difference of the tungsten alloy beads are further reduced, and the quality performance of the tungsten alloy beads is improved; and finally, carrying out stress relief annealing on the tungsten alloy bead sintered blank after grinding processing, thereby improving the performance deterioration of the tungsten alloy bead caused by processing stress, ensuring the crushing performance of the tungsten alloy bead and further improving the quality performance of the tungsten alloy bead.
The preparation method of the tungsten alloy bead is characterized in that the mass content of cobalt element in the tungsten alloy bead raw material mixed powder in the first step is 0.25% -0.35%. The preferable cobalt element addition ensures the complete wettability of bonding relative to tungsten particles, plays a role in activating sintering, and further improves the quality and performance of tungsten alloy beads.
The preparation method of the tungsten alloy beads is characterized in that the screen mesh adopted in the screening classification in the second step comprises 80-mesh, 100-mesh and 120-mesh screen meshes, and the corresponding obtained granulating material comprises four granularity grades of +80- +100-100- +120-mesh and-120-mesh. According to the invention, the tungsten alloy bead raw material mixed powder is divided into the four particle size grades, so that the fluidity of the prepared granules is improved, and therefore, when the steel mould forming by a capacity filling method is adopted in the follow-up process, the fluidity and consistency of the prepared granules are good, when the powder filling volumes of the capacity filling method are the same, the powder filling amount is the same, and the weight and the dimensional stability of the tungsten alloy bead pressed compact are improved.
The preparation method of the tungsten alloy beads is characterized in that in the second step, the granulated materials with different granularity grades are packaged by plastic bags according to the same granularity grade, nitrogen is filled for protection, and the weight of each bag of granulated materials is not more than 20kg. The invention adopts plastic bags for powder and controls the weight of the pelleting materials with different granularity grades, so as to avoid the reduction of the fluidity of the pelleting materials caused by the compression deformation of the pelleting materials due to overlarge dead weight, and the invention combines the protection of nitrogen filling to discharge air in the plastic bags, prevent the pelleting materials from absorbing water and enhancing the viscosity, destroy the fluidity of the pelleting materials and adhere to a die.
The preparation method of the tungsten alloy bead is characterized in that the tungsten alloy bead pressed compact obtained in the third step is placed on a screen, surface floating powder is removed through soft brush cleaning, and then the next thermal degreasing process is carried out. The surface floating powder of the tungsten alloy bead pressed compact is removed in advance, so that the surface floating powder is prevented from adhering to the surface of the tungsten alloy bead sintered compact after subsequent sintering, and grinding equipment is prevented from being damaged during subsequent grinding processing.
The preparation method of the tungsten alloy beads is characterized in that the thermal degreasing is carried out by adopting a four-belt continuous degumming furnace in the fourth step, wherein the temperature of the first region is 340-360 ℃, the temperature of the second region is 490-510 ℃, the temperature of the third region is 640-660 ℃, the temperature of the fourth region is 740-760 ℃, and the boat pushing speed is 3.5-10.5 mm/min. According to the invention, the degumming temperature and the boat pushing speed of each zone are reasonably designed in the thermal degreasing process, so that the degumming effect of the tungsten alloy bead pressed compact is ensured, the strength of the tungsten alloy bead pressed compact after thermal degreasing is improved, and the pressed compact is prevented from being damaged during sintering and charging.
The preparation method of the tungsten alloy beads is characterized in that alumina sand is paved at the bottom of the tungsten alloy bead compact in the thermal degreasing process in the fourth step, and the air flow is 4m 3 /h～6m 3 And/h, the air inlet mode is reverse hydrogen, namely, the direction of the air inlet is opposite to the pushing direction. According to the invention, aluminum oxide sand is paved at the bottom of the tungsten alloy bead pressed compact, so that adhesion of the tungsten alloy bead pressed compact in the thermal degreasing process is avoided, meanwhile, the gas flow is controlled by adopting a reverse hydrogen gas inlet mode, so that gas is filled in a hearth, all tungsten alloy bead pressed compact is ensured to be fully contacted with the gas, the carbon potential in a discharge end of thermal degreasing is ensured to be low by utilizing the reverse hydrogen, and the full degumming is facilitated.
The preparation method of the tungsten alloy beads is characterized in that in the fifth step, sintering temperature is 1470-1510 ℃, boat pushing speed is 5-6 mm/min, hydrogen atmosphere is adopted, air inlet mode is reverse hydrogen, namely, opposite to the pushing direction, and flow rate of the hydrogen atmosphere is 2.0m 3 /h～3.0m 3 And/h. According to the invention, by adopting the reverse hydrogen gas inlet mode and controlling the gas flow, and combining the sintering temperature and the boat pushing speed, the impurity atmosphere generated by the exhaust impurity removal in the initial stage of sintering is effectively removed, the impurity atmosphere is prevented from polluting the product at the sintering discharge end, and the performance of the tungsten alloy beads is ensured.
The method for preparing the tungsten alloy bead is characterized in that in the fifth step, the loading mode of the tungsten alloy bead pressed blank after thermal degreasing is alumina sand or electric melting alumina powder multilayer imbedding and burning, a spacing layer formed by alumina sand or electric melting alumina powder is adopted to completely separate adjacent tungsten alloy bead pressed blanks after thermal degreasing, and the thickness of the spacing layer is more than 0.25 times of the diameter of the tungsten alloy bead pressed blank after thermal degreasing. According to the invention, the aluminum oxide sand or the electric melting aluminum oxide powder is used for embedding and burning in a multi-layer manner, so that the adjacent tungsten alloy bead pressed billets after thermal degreasing are completely separated by the spacing layer formed by the aluminum oxide sand or the electric melting aluminum oxide powder, the direct contact of the tungsten alloy bead pressed billets after thermal degreasing is avoided, meanwhile, the thickness of the spacing layer is controlled, the direct contact of the aluminum oxide sand or the electric melting aluminum oxide powder is prevented when the tungsten alloy bead pressed billets are scattered around due to the sintering shrinkage of the tungsten alloy bead pressed billets in the sintering process, the pores generated by the sintering shrinkage of the scattered aluminum oxide sand or the electric melting aluminum oxide powder are filled in the tungsten alloy bead pressed billets, the isolation effect of the tungsten alloy bead pressed billets is further ensured, the sintering adhesion phenomenon generated by the direct contact of the tungsten alloy bead pressed billets is effectively prevented, and the preparation efficiency of the tungsten alloy beads is improved while the quality of the tungsten alloy beads is improved.
The preparation method of the tungsten alloy beads is characterized in that the temperature of the stress relief annealing treatment in the step six is 1350-1400 ℃, the boat pushing speed is 10-30 mm/min, and the loading mode is alumina sand or electric melting alumina powder burying and burning. By the limitation, the stress is effectively removed, and meanwhile, solid solution strengthening is realized, so that the performance of the tungsten alloy bead is further improved.
In the invention, alumina sand or electric melting alumina powder is preferably adopted for paving and burying burning during thermal degreasing, sintering and stress relief annealing, and electric melting alumina powder is more preferably adopted, so that sand sticking or scratch on the surface of the tungsten alloy bead is avoided, and the surface quality of the tungsten alloy bead is further improved.
Compared with the prior art, the invention has the following advantages:
1. according to the invention, the cobalt element is added into the tungsten alloy powder, so that the infiltration performance of tungsten particles is improved, the sintering activity is increased, the tungsten alloy bead raw material mixed powder is mixed with glue, granulated and sieved for classification, the fluidity of granulated materials is improved, the stable and consistent weight of the granulated materials pressed is ensured, the single weight and size fluctuation of tungsten alloy bead pressed blanks are reduced, the thermal degreasing and stress relief annealing are combined, the pressed blank damage during sintering, boat loading and material arrangement is avoided, the performance deterioration caused by processing stress is reduced, and the forming quality and the production efficiency of tungsten alloy beads are improved.
2. The invention prevents the compression deformation and the water absorption and viscosity change of the granules from influencing the fluidity by limiting the split charging and preserving conditions of the granules, ensures the stable filling weight of the granules during the compacting, and further reduces the singleness and the size fluctuation of the tungsten alloy bead compacting.
3. The invention always adopts a reverse hydrogen mode in the thermal degreasing and sintering processes, ensures the clean atmosphere of a high temperature area and a discharge end, further ensures the degumming effect, ensures complete impurity removal and improves the performance of tungsten alloy bead pressed billets.
4. According to the invention, alumina sand or electric melting alumina powder is adopted for multilayer burial sintering in the sintering process, so that the sintering loading quantity is greatly improved on the premise of ensuring the sintering effect, the production efficiency is improved, and the sintering productivity bottleneck of tungsten alloy bead products is solved.
5. The invention removes the processing stress and improves the comprehensive performance of the tungsten alloy bead product by carrying out stress relief annealing after grinding processing, thereby ensuring the appearance of the tungsten alloy bead product.
6. The preparation method is simple, the tungsten alloy beads with different specifications are used, the practicability is high, the sintering process can be performed in a conventional continuous molybdenum wire sintering furnace, the requirements on sintering equipment are low, and the method is easy to popularize and apply.
The technical scheme of the invention is further described in detail through the drawings and the embodiments.
Drawings
FIG. 1 is a loading diagram of the stress free annealing process according to example 2 of the present invention.
FIG. 2 is a physical view of the tungsten alloy bead prepared in example 2 of the present invention.
Fig. 3 is a charge diagram of the sintering process of example 3 of the present invention.
FIG. 4a is a physical diagram of a sintered compact of tungsten alloy beads prepared by multi-layer sintering of alumina sand in example 3 of the present invention.
FIG. 4b is a schematic representation of a sintered compact of tungsten alloy beads prepared by multilayer burn-in of electrofused alumina powder in example 3 of the present invention.
Detailed Description
Example 1
The embodiment comprises the following steps:
adding cobalt element into tungsten alloy powder to obtain tungsten alloy bead raw material mixed powder; the tungsten alloy powder comprises the following element components in percentage by mass: w93%, ni 4.9%, fe 2.1%, and cobalt element in the tungsten alloy bead raw material mixed powder is 0.35%;
step two, mixing the tungsten alloy bead raw material mixed powder obtained in the step one, granulating by means of glue, and screening and grading by adopting screens with 80 meshes, 100 meshes and 120 target standard meshes to obtain granules with four granularity grades of +80 meshes, -80 meshes to +100 meshes, -100 meshes to +120 meshes and-120 meshes; the granulating materials with different granularity grades are packaged by plastic bags according to the granularity grades, and are protected by nitrogen, and the weight of each bag of granulating materials is not more than 20kg;
step three, respectively adopting a steel die to press and mold the pelletization materials obtained in the step three according to the same granularity, obtaining tungsten alloy bead pressed blanks with the sphere diameter of Sphi 11.5mm, placing the tungsten alloy bead pressed blanks on a screen, cleaning with a soft brush to remove surface floating powder, and then transferring to a next thermal degreasing process;
loading the tungsten alloy bead pressed compact obtained in the step III into a stainless steel box with aluminum oxide sand paved at the bottom and with the thickness of more than 5mm, pushing the stainless steel box into a four-belt continuous degumming furnace, wherein the temperature of a first area is 340-360 ℃, the temperature of a second area is 490-510 ℃, the temperature of a third area is 640-660 ℃, the temperature of a fourth area is 740-760 ℃, the boat pushing speed is 3.5mm/min, and the air flow is 4m 3 /h～6m 3 And/h, the air inlet mode is reverse hydrogen, namely, the direction of the air inlet is opposite to the pushing direction;
step five, loading the tungsten alloy bead pressed compact after thermal degreasing in the step four into a molybdenum box, pushing the molybdenum box into a two-belt muffle furnace for sintering, wherein the loading mode is that aluminum oxide sand is used for multi-layer imbedding and sintering, a spacing layer formed by the aluminum oxide sand is adopted to completely separate adjacent tungsten alloy bead pressed compact after thermal degreasing, and the thickness of the spacing layer is that after thermal degreasingThe diameter of the pressed tungsten alloy bead is more than 0.25 times, the sintering temperature is 1485 ℃, the boat pushing speed is 6mm/min, a hydrogen atmosphere is adopted, the air inlet mode is reverse hydrogen, namely, the direction is opposite to the pushing direction, and the flow rate of the hydrogen atmosphere is 2.0m 3 /h～3.0m 3 And/h, obtaining a tungsten alloy bead sintered blank;
and step six, grinding the tungsten alloy bead sintered blank obtained in the step five, uniformly stirring with alumina sand, loading the mixture into a molybdenum box, pushing the molybdenum box into a double-belt muffle furnace for stress relief annealing treatment, wherein the temperature of the stress relief annealing treatment is 1360 ℃, and the boat pushing speed is 20mm/min, so as to obtain the tungsten alloy bead.
In the fifth embodiment, the fused alumina powder may be used to replace alumina sand during sintering and stress relief annealing in the sixth step.
Example 2
The embodiment comprises the following steps:
adding cobalt element into tungsten alloy powder to obtain tungsten alloy bead raw material mixed powder; the tungsten alloy powder comprises the following element components in percentage by mass: w93%, ni 4.9%, fe 2.1%, and cobalt element in the tungsten alloy bead raw material mixed powder is 0.3%;
step two, mixing the tungsten alloy bead raw material mixed powder obtained in the step one, granulating by means of glue, and screening and grading by adopting screens with 80 meshes, 100 meshes and 120 target standard meshes to obtain granules with four granularity grades of +80 meshes, -80 meshes to +100 meshes, -100 meshes to +120 meshes and-120 meshes; the granulating materials with different granularity grades are packaged by plastic bags according to the granularity grades, and are protected by nitrogen, and the weight of each bag of granulating materials is not more than 20kg;
step three, respectively adopting a steel die to press and mold the pelletization materials obtained in the step three according to the same granularity to obtain tungsten alloy bead pressed blanks with the sphere diameter of Sphi 5mm, placing the tungsten alloy bead pressed blanks on a screen, cleaning with a soft brush to remove surface floating powder, and then transferring to a next thermal degreasing process;
step four, putting the tungsten alloy bead compact obtained in the step three into a stainless steel box with aluminum oxide sand with the thickness of more than 5mm paved at the bottom, and then pushing the stainless steel box into a four-belt continuous degumming furnaceThe process is carried out, the temperature of the first area is 340-360 ℃, the temperature of the second area is 490-510 ℃, the temperature of the third area is 640-660 ℃, the temperature of the fourth area is 740-760 ℃, the boat pushing speed is 10.5mm/min, and the air flow is 4m 3 /h～6m 3 And/h, the air inlet mode is reverse hydrogen, namely, the direction of the air inlet is opposite to the pushing direction;
step five, loading the tungsten alloy bead pressed compact after thermal degreasing in the step four into a molybdenum box, pushing the tungsten alloy bead pressed compact into a two-belt muffle furnace for sintering, wherein the loading mode is that aluminum oxide sand is used for multi-layer burying and sintering, a spacing layer formed by the aluminum oxide sand is used for completely separating adjacent tungsten alloy bead pressed compacts after thermal degreasing, the thickness of the spacing layer is more than 0.25 times of the diameter of the tungsten alloy bead pressed compact after thermal degreasing, the sintering temperature is 1470 ℃, the boat pushing speed is 5.5mm/min, hydrogen atmosphere is adopted, the air inlet mode is reverse hydrogen, namely, the direction is opposite to the pushing direction, and the flow of the hydrogen atmosphere is 2.0m 3 /h～3.0m 3 And/h, obtaining a tungsten alloy bead sintered blank;
and step six, grinding the tungsten alloy bead sintered blank obtained in the step five, uniformly stirring with alumina sand, loading the mixture into a molybdenum box, pushing the molybdenum box into a two-belt muffle furnace to perform stress relief annealing treatment, wherein the temperature of the stress relief annealing treatment is 1350 ℃, and the boat pushing speed is 30mm/min, so as to obtain the tungsten alloy bead, as shown in fig. 2.
In the fifth embodiment, the fused alumina powder may be used to replace alumina sand during sintering and stress relief annealing in the sixth step.
Example 3
The embodiment comprises the following steps:
adding cobalt element into tungsten alloy powder to obtain tungsten alloy bead raw material mixed powder; the tungsten alloy powder comprises the following element components in percentage by mass: w95%, ni 3.5%, fe 1.5%, the mass content of cobalt element in the tungsten alloy bead raw material mixed powder is 0.25%;
step two, mixing the tungsten alloy bead raw material mixed powder obtained in the step one, granulating by means of glue, and screening and grading by adopting screens with 80 meshes, 100 meshes and 120 target standard meshes to obtain granules with four granularity grades of +80 meshes, -80 meshes to +100 meshes, -100 meshes to +120 meshes and-120 meshes; the granulating materials with different granularity grades are packaged by plastic bags according to the granularity grades, and are protected by nitrogen, and the weight of each bag of granulating materials is not more than 20kg;
step three, respectively adopting a steel die to press and mold the pelletization materials obtained in the step three according to the same granularity, obtaining tungsten alloy bead pressed blanks with the sphere diameter of Sphi 5.5mm, placing the tungsten alloy bead pressed blanks on a screen, cleaning with a soft brush to remove surface floating powder, and then transferring to a next thermal degreasing process;
loading the tungsten alloy bead pressed compact obtained in the step III into a stainless steel box with aluminum oxide sand paved at the bottom and with the thickness of more than 5mm, pushing the stainless steel box into a four-belt continuous degumming furnace, wherein the temperature of a first area is 340-360 ℃, the temperature of a second area is 490-510 ℃, the temperature of a third area is 640-660 ℃, the temperature of a fourth area is 740-760 ℃, the boat pushing speed is 6.4mm/min, and the air flow is 4m 3 /h～6m 3 And/h, the air inlet mode is reverse hydrogen, namely, the direction of the air inlet is opposite to the pushing direction;
step five, loading the tungsten alloy bead pressed compact after thermal degreasing in the step four into a molybdenum box, pushing the molybdenum box into a two-belt muffle furnace for sintering, wherein the loading mode is that aluminum oxide sand is used for multi-layer burying and sintering, a spacing layer formed by the aluminum oxide sand is used for completely separating adjacent tungsten alloy bead pressed compacts after thermal degreasing, the thickness of the spacing layer is more than 0.25 times of the diameter of the tungsten alloy bead pressed compact after thermal degreasing, as shown in figure 3, the sintering temperature is 1510 ℃, the boat pushing speed is 5mm/min, a hydrogen atmosphere is adopted, the air inlet mode is reverse hydrogen, namely, the direction is opposite to the pushing direction, and the flow of the hydrogen atmosphere is 2.0m 3 /h～3.0m 3 And/h, obtaining a tungsten alloy bead sintered blank, as shown in fig. 4 a;
and step six, grinding the tungsten alloy bead sintered blank obtained in the step five, uniformly stirring with alumina sand, loading the mixture into a molybdenum box, pushing the molybdenum box into a double-belt muffle furnace for stress relief annealing treatment, wherein the temperature of the stress relief annealing treatment is 1400 ℃, and the boat pushing speed is 10mm/min, so as to obtain the tungsten alloy bead.
In the fifth embodiment, the fused alumina powder may be used to replace alumina sand during sintering and stress relief annealing in the sixth embodiment, wherein a physical diagram of a tungsten alloy bead sintered blank prepared by using the fused alumina powder in a multilayer buried sintering manner is shown in fig. 4 b.
Comparing fig. 4a with fig. 4b, it can be seen that the use of the electrofused alumina powder prevents the surface of the tungsten alloy bead from being burnt or scratched, and further improves the surface quality of the tungsten alloy bead.
The above description is only of the preferred embodiments of the present invention, and is not intended to limit the present invention. Any simple modification, variation and equivalent variation of the above embodiments according to the technical substance of the invention still fall within the scope of the technical solution of the invention.
Claims (9)
1. A method for preparing tungsten alloy beads, comprising the steps of:
adding cobalt element into tungsten alloy powder to obtain tungsten alloy bead raw material mixed powder; the tungsten alloy powder comprises the following components in percentage by mass: 93% or 95% of tungsten element, the balance being nickel-iron element, and the ratio of nickel to iron is 7:3; the mass content of cobalt element in the tungsten alloy bead raw material mixed powder is 0.25% -0.35%;
step two, mixing the tungsten alloy bead raw material mixed powder obtained in the step one with glue, granulating, and then screening and grading to obtain granules with different granularity grades;
step three, forming the granulated materials with different granularity grades obtained in the step three according to the same granularity grade respectively to obtain tungsten alloy bead pressed blanks;
pushing the tungsten alloy bead pressed compact obtained in the third step into a continuous degreasing furnace for thermal degreasing;
step five, placing the tungsten alloy bead pressed blank subjected to thermal degreasing in the step four in a muffle furnace for sintering to obtain a tungsten alloy bead sintered blank;
and step six, grinding the tungsten alloy bead sintered blank obtained in the step five, and then carrying out stress relief annealing treatment to obtain the tungsten alloy bead.
2. The method for preparing tungsten alloy beads according to claim 1, wherein the screen mesh adopted in the screening classification in the second step comprises 80 mesh, 100 mesh and 120 mesh screens, and the corresponding obtained granulated material comprises four particle size grades of +80 mesh, -80 mesh to +100 mesh, -100 mesh to +120 mesh and-120 mesh.
3. The method for preparing tungsten alloy beads according to claim 1, wherein the granulated materials with different granularity grades in the second step are packaged by plastic bags according to the same granularity grade, and are protected by nitrogen, and the weight of each bag of granulated materials is not more than 20kg.
4. The method of producing tungsten alloy beads according to claim 1, wherein the tungsten alloy bead compact obtained in the third step is placed on a screen, and the surface powder is removed by brush cleaning, and then transferred to the next thermal degreasing step.
5. The method for preparing tungsten alloy beads according to claim 1, wherein the thermal degreasing is performed in a four-belt continuous degumming furnace, the temperature of the first area is 340 ℃ to 360 ℃, the temperature of the second area is 490 ℃ to 510 ℃, the temperature of the third area is 640 ℃ to 660 ℃, the temperature of the fourth area is 740 ℃ to 760 ℃, and the boat pushing speed is 3.5mm/min to 10.5mm/min.
6. The method for preparing tungsten alloy beads according to claim 1, wherein alumina sand is laid at the bottom of the tungsten alloy bead compact in the thermal degreasing process in the fourth step, and the air flow is 4m 3 /h~6m 3 And/h, the air inlet mode is reverse hydrogen, namely, the direction of the air inlet is opposite to the pushing direction.
7. The method of claim 1, wherein in the fifth step, sintering is performed at 1470-1510 ℃, the boat pushing speed is 5-6 mm/min, a hydrogen atmosphere is adopted, the air intake mode is reverse hydrogen, namely, the direction opposite to the pushing direction, and the flow rate of the hydrogen atmosphere is 2.0m 3 /h~3.0m 3 /h。
8. The method for preparing tungsten alloy beads according to claim 1, wherein in the fifth step, the tungsten alloy bead pressed blank after thermal degreasing is filled with alumina sand or electric melting alumina powder in a multilayer embedding manner, a spacer layer formed by the alumina sand or the electric melting alumina powder is adopted to completely separate adjacent tungsten alloy bead pressed blanks after thermal degreasing, and the thickness of the spacer layer is more than 0.25 times of the diameter of the tungsten alloy bead pressed blank after thermal degreasing.
9. The method for preparing tungsten alloy beads according to claim 1, wherein the temperature of the stress relief annealing treatment in the sixth step is 1350 ℃ -1400 ℃, the boat pushing speed is 10 mm/min-30 mm/min, and the loading mode is alumina sand or fused alumina powder burial.
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