A processing method for improving the performance stability of high specific gravity tungsten alloy rods in the same batch

Abstract

The present application belongs to the field of powder metallurgy, and discloses a processing method for improving the performance stability of high specific gravity tungsten alloy rods in the same batch. The processing method is as follows: taking W powder, Ni powder and Fe powder as main raw materials, taking one or more of Mo powder, Re powder, Zr powder and Co powder as doping phase, mixing after adopting two-stage mixing process, pressing into a slab, after one-step densification and rolling, machining into several rod blanks, and after vacuum annealing, rotary swaging and vacuum heat treatment, W-Ni-Fe system high specific gravity alloy rods are obtained. The processing method can realize the preparation of high-performance W-Ni-Fe alloy rods, and effectively improve the stability of the rods in density and room temperature mechanical properties among the same batch.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of powder metallurgy, in particular to a processing method for improving the performance stability of high specific gravity tungsten alloy rods in the same batch. BACKGROUND

[0002] W-Ni-Fe high specific gravity tungsten alloy has the advantages of high strength, good plasticity, strong impact toughness and penetration ability, small thermal expansion coefficient, good electric and thermal conductivity, and strong radiation absorption ability, and is widely used in military, aerospace, machinery, atomic energy and other fields. Especially, W-Ni-Fe high specific gravity tungsten alloy has a relatively high density of 16.5g / cm 3 ~19.0g / cm 3 , which makes it an indispensable key material for gyro rotors, counterweights, shock absorbers and military cores.

[0003] With the continuous progress of science and technology, higher requirements are put forward for the comprehensive performance of high specific gravity tungsten alloy rods: high strength, high toughness, more uniform microstructure, high stability in the same batch, etc. have become the indicators for measuring the performance of high specific gravity tungsten alloy.

[0004] However, the traditional preparation method of high specific gravity tungsten alloy rods in the prior art is to mix W, Ni and Fe powders in proportion, press and form, obtain W-Ni-Fe sintered blanks after sintering process, and then obtain tungsten alloy rods by forging and heat treatment process. For example, the prior art CN104313377A provides a high-performance W-Ni-Fe alloy rod prepared by sintering W, Ni and Fe as raw materials into a rod blank and then using hot static liquid extrusion. In the patent of the prior art CN108315624A, the tungsten alloy powder raw material is activated by high-energy ball milling, and then tungsten alloy single-fire large deformation is carried out by continuous rolling deformation process, realizing the preparation of high-performance W-Ni-Fe alloy rod. The above preparation methods mainly improve the mechanical properties of W-Ni-Fe alloy rods by preparing high-quality powders, controlling the sintering process, and increasing the deformation amount of the rod blank. However, they cannot improve the stability of high specific gravity tungsten alloy rods in the same batch, and thus cannot meet the current requirements for the comprehensive performance of high specific gravity tungsten alloy rods, limiting the further application and development of high specific gravity tungsten alloy rods. SUMMARY

[0005] In order to solve the problem of stability fluctuation of W-Ni-Fe rod blanks in performance between batches, the application provides a processing method for improving the performance stability of high specific gravity tungsten alloy rods in the same batch. The application realizes the preparation of high-performance W-Ni-Fe alloy rods, and strictly controls the stability of the density and room temperature mechanical properties of the rods between batches.

[0006] The processing method for improving the performance stability of high specific gravity tungsten alloy rods in the same batch of the application is realized by the following technical scheme:

[0007] The processing method for improving the performance stability of high specific gravity tungsten alloy rods in the same batch comprises the following steps:

[0008] Step 1, preparing a slab blank:

[0009] According to the composition of the W-Ni-Fe high specific gravity tungsten alloy to be improved, the corresponding mass of W powder, Ni powder and Fe powder is weighed and prepared; after the weighed Ni powder and Fe powder are mixed, the doping phase powder is added and mixed to obtain a first mixed powder; the weighed W powder is added to the first mixed powder and mixed to obtain a second mixed powder; the second mixed powder is pressed into a blank to obtain a slab blank.

[0010] It should be noted that according to the actual W-Ni-Fe high specific gravity tungsten alloy rod to be improved, the composition of the corresponding grade W-Ni-Fe high specific gravity tungsten alloy rod is selected to weigh the main raw materials of W powder, Ni powder and Fe powder. For example, the W-Ni-Fe high specific gravity tungsten alloy rod of the application is a W-Ni-Fe high specific gravity tungsten alloy rod with a grade of 90W-7Ni-3Fe, 93W-4.9Ni-2.1Fe and 95W-3.5Ni-1.5Fe.

[0011] The application uses one or more of Mo powder, Re powder, Zr powder and Co powder as doping phase powder to purify impurity oxygen elements on the grain boundary and inhibit the abnormal growth behavior of the grain, effectively enhance the interface bonding force, and be beneficial to improve the mechanical properties of W-Ni-Fe alloy.

[0012] And the application controls the addition amount of the doping phase powder ≤1wt% of the total mass of W powder, Ni powder and Fe powder, so as to realize the performance strengthening effect on the basis of the existing W-Ni-Fe alloy without changing the composition range of the existing W-Ni-Fe grade.

[0013] The present application considers that if the raw materials are directly mixed together by ball milling, the grinding balls in the high rotation of the ball mill drive the powder to break, which is easy to introduce impurity elements. Therefore, in order to avoid the introduction of impurity elements in the mixing process, the present application preferably adopts a two-stage mixing process for mixing, and first mixes the Ni powder, the Fe powder and the doped phase powder, and then adds the W powder for mixing, so as to effectively disperse the doped phase in the main preparation raw materials of the W-Ni-Fe system high specific gravity tungsten alloy rod, and realizes the uniform distribution of each element in the raw material mixture.

[0014] In some preferred embodiments of the present application, when preparing the first mixed powder, intermittent dry ball milling is adopted for preparation. And in some more preferred embodiments of the present application, the ball-to-material ratio of each ball milling treatment is 1-3:1, the rotation speed is 100-200 r / min, the time of each ball milling treatment is 15-25 min, the interval between adjacent two ball milling treatments is 15-25 min, and the total ball milling time is 7-9 h, so as to first mix a small amount of doped phase with Ni powder and Fe powder at a low rotation speed, thereby avoiding the introduction of impurity elements in the mixing process.

[0015] In some preferred embodiments of the present application, when preparing the second mixed powder, intermittent dry ball milling is adopted for preparation. And in some more preferred embodiments of the present application, the ball-to-material ratio of each ball milling treatment is 1-2:1, the rotation speed is 50-70 r / min, the time of each ball milling treatment is 55-65 min, the interval between adjacent two ball milling treatments is 55-65 min, and the total ball milling time is 7-9 h, so as to effectively realize large-scale mixing of the first mixed powder and a large amount of W powder, and realize the uniform distribution of each element in the raw material mixture.

[0016] In some preferred embodiments of the present application, in order to ensure that the first mixed powder and the W powder are fully mixed, the mixture of the Ni powder, the Fe powder and the doped phase powder is sieved through a 200-mesh screen and then mixed with the W powder as the first mixed powder.

[0017] In some preferred embodiments of the present application, in order to improve the density of the slab, the mixture of the first mixed powder and the W powder is sieved through a 200-mesh screen and then pressed into a slab as the second mixed powder.

[0018] In some preferred embodiments of the present application, when the slab is pressed, the density of the slab should be greater than 75%.

[0019] Step 2, densification treatment:

[0020] The slab is subjected to densification treatment in a hydrogen atmosphere to obtain a sintered slab.

[0021] It should be noted that the present application improves the flatness and deformation of the slab by densification treatment. In some preferred embodiments of the present application, the densification process is completed in one furnace by first performing pre-sintering treatment on the slab to improve the density and strength of the sample, and then performing sintering treatment, thereby effectively improving the flatness and deformation of the sample. The present application directly completes the pre-sintering and sintering processes in the powder metallurgy process by two-stage heating in the same furnace, effectively shortens the process flow, and realizes the sintering preparation of large-size slabs.

[0022] In some more preferred embodiments of the present application, the densification treatment is specifically achieved by the following steps:

[0023] After the slab is heated to 1000-1200℃ and held for 1-4h, pre-sintering treatment is performed on the slab, and then the temperature is raised to 1420-1560℃ and held for 2-6h to perform sintering treatment on the slab, thereby directly completing the pre-sintering and sintering processes in one furnace by adjusting the process parameters, and obtaining a sintered slab with good shape and density.

[0024] Step 3: treating the slab into a plurality of rod blanks:

[0025] The sintered slab is subjected to hot rolling treatment and then machined into a plurality of rod blanks.

[0026] It should be noted that the present application preliminarily improves the deformation by hot rolling treatment, and the large-size slab after rough rolling is machined into a plurality of rod blanks of the same batch, so that the rod blanks of the same batch are all derived from the same slab blank, thereby laying a foundation for the stability of the final rod blank in density, mechanical properties, etc. by effectively controlling the source of the rod blanks of the same batch.

[0027] In some preferred embodiments of the present application, the hot rolling treatment is achieved by the following steps:

[0028] The sintered slab is heated to 800-1000℃ and held for 1h, and then subjected to rolling treatment, and the single-pass deformation is controlled to be ≤10% and the total deformation is controlled to be 15-50% during the rolling treatment.

[0029] In some preferred embodiments of the present application, the machining is achieved by the following steps: after the sintered slab after hot rolling treatment is cooled to room temperature, it is machined into a plurality of rod blanks along the rolling direction by using water jet cutting and lathe machining.

[0030] Step 4: post-treatment:

[0031] After vacuum annealing of the several rod blanks, a rotary swaging process is performed, and then vacuum heat treatment is performed, so as to effectively improve the stability of the high specific gravity tungsten alloy rods in the same batch.

[0032] It should be noted that the present application improves the deformation amount again by performing the rotary swaging process on the several rod blanks after vacuum annealing, and realizes the preparation of the high-performance W-Ni-Fe alloy rods in the same batch by combining the vacuum heat treatment, that is, effectively improves the stability of the W-Ni-Fe alloy rods in the same batch in terms of composition, density and mechanical properties.

[0033] In some preferred embodiments of the present application, during the rotary swaging process, the single-pass deformation amount is controlled to be less than or equal to 8%, and the total deformation amount is 10% to 35%, so as to strictly control the deformation amount of rotary swaging, and effectively reduce the performance difference between the rod blanks caused by rotary swaging. The present application performs preliminary deformation processing through hot rolling, and then performs secondary deformation processing through the rotary swaging process, and the total deformation amount during the hot rolling process is controlled to be 15% to 50%, and the total deformation amount during the rotary swaging process is set to be 10% to 35%, that is, the deformation amount during the hot rolling process is greater than the deformation amount set during the rotary swaging process, so as to effectively improve the stability of the rods in the same batch, and reduce the influence of the mechanical property fluctuation of the final rod during forging.

[0034] In some preferred embodiments of the present application, the temperature of the vacuum annealing is 550°C to 830°C.

[0035] In some preferred embodiments of the present application, the temperature of the vacuum heat treatment is 550°C to 830°C.

[0036] Compared with the prior art, the present application has the following beneficial effects:

[0037] The application takes one or more of Mo powder, Re powder, Zr powder and Co powder as doping phase powder, adopts two-stage mixing process for mixing, and first mixes Ni powder, Fe powder and doping phase powder, and then adds W powder for mixing, so as to effectively disperse the doping phase in the main raw material of W-Ni-Fe high specific gravity tungsten alloy rod, realize the uniform distribution of each element in the raw material mixture, and then improve the flatness and deformation of the slab through densification treatment. Then, the deformation amount is preliminarily improved through hot rolling treatment, and the large-size slab after rough rolling is machined into multiple rod blanks of the same batch, so as to effectively control the source of the rod blanks between the same batch, and lay a foundation for the stability of the final rod blank in density, mechanical properties and the like. Then, secondary deformation processing is carried out through the spinning process, so as to realize the step-by-step deformation processing of the rod blanks between the same batch through hot rolling and spinning process, thereby effectively improving the stability of the rod blanks between the same batch and reducing the influence of the mechanical property fluctuation of the final rod during forging. In combination with vacuum heat treatment, the preparation of high-performance W-Ni-Fe alloy rod of the same batch is realized, that is, the stability of the W-Ni-Fe alloy rod of the same batch in composition, density and mechanical properties and the like is effectively improved.

[0038] The preparation method of the application can realize the preparation of high-performance W-Ni-Fe alloy rod while effectively improving the stability of the rod between the same batch in density and room temperature mechanical properties. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 Metallographic structure image of high specific gravity tungsten alloy rod prepared for example 1 under 100 μm scale.

[0040] Figure 2 Metallographic structure image of high specific gravity tungsten alloy rod prepared for example 1 under 50 μm scale.

[0041] Figure 3 Metallographic structure image of high specific gravity tungsten alloy rod prepared for example 3 under 100 μm scale.

[0042] Figure 4 Metallographic structure image of high specific gravity tungsten alloy rod prepared for example 3 under 50 μm scale. DETAILED DESCRIPTION

[0043] The technical solutions in the examples of the application will be described clearly and completely.

[0044] Example 1

[0045] The embodiment provides a processing method for improving the performance stability of high specific gravity tungsten alloy rod of the same batch, which comprises the following steps:

[0046] Step 1, preparing a slab:

[0047] 1.1) This embodiment takes tungsten alloy with the brand of 93W-4.9Ni-2.1Fe as the high specific gravity tungsten alloy to be promoted, and the corresponding mass of W powder, Ni powder and Fe powder is weighed according to the composition of the tungsten alloy with the brand of 93W-4.9Ni-2.1Fe for standby.

[0048] 1.2) Co powder and Mo powder are taken as the doping phase together, and the corresponding mass of Co powder and Mo powder is weighed according to the ratio that the addition amount of Co powder is 0.3wt% of the total mass of W powder, Ni powder and Fe powder, and the addition amount of Mo powder is 0.3wt% of the total mass of W powder, Ni powder and Fe powder for standby.

[0049] 1.3) The mixed powder of Ni powder, Fe powder and doping phase powder is mixed and then subjected to intermittent dry ball milling, and the ball-to-material ratio of each ball milling treatment is controlled to be 2:1, the rotation speed is 100r / min, the time of each ball milling treatment is 20min, the interval between adjacent two ball milling treatments is 20min, and the total ball milling time is 8h. The ball milling product is passed through a 200 mesh screen to obtain a first mixed powder.

[0050] 1.4) The weighed W powder is added to the above first mixed powder, and then subjected to intermittent dry ball milling, and the ball-to-material ratio of each ball milling treatment is controlled to be 1.5:1, the rotation speed is 60r / min, the time of each ball milling treatment is 60min, the interval between adjacent two ball milling treatments is 60min, and the total ball milling time is 8h. The ball milling product is passed through a 200 mesh screen to obtain a second mixed powder.

[0051] 1.5) The above second mixed powder is pressed into a blank to obtain a plate blank.

[0052] Step 2, densification treatment:

[0053] The plate blank obtained in the above step 1.5) is placed in a hydrogen furnace, heated to 1050℃ under hydrogen atmosphere, and then held for 2h, and then heated to 1495℃ and held for 4h to obtain a sintered plate blank with a size of 216mm×305mm×60mm.

[0054] Step 3, processing the plate blank into a plurality of rod blanks:

[0055] 3.1) The sintered plate blank obtained in the above step 2 is heated to 910℃ in an air furnace and held for 1h, and then subjected to rolling treatment, and the single pass deformation amount is controlled to be 5% and the total deformation amount is controlled to be 20% during the rolling treatment.

[0056] 3.2) After the sintered plate blank after the hot rolling treatment in the above 3.1) is cooled to room temperature, it is machined into 9 rod blanks with a size of φ30mm×245mm along the rolling direction by using water jet cutting and lathe machining.

[0057] Step 4, post-processing:

[0058] 4.1) The nine bars with a size of φ30mmx245mm obtained in 3.2) above were placed in a vacuum annealing furnace, and heated to 830℃ and kept for 2h.

[0059] 4.2) The bars after vacuum annealing in 4.1) above were heated to 710℃ in an air furnace, and forged by rotary forging, with a single pass deformation of 5% and a total deformation of 30%.

[0060] 4.3) After surface finishing of the bars after rotary forging in 4.2) above, the bars were kept at 600℃ for 1h, and nine high specific gravity tungsten alloy bars with a size of φ23mmx280mm were obtained.

[0061] And through room temperature mechanical property detection of the nine high specific gravity tungsten alloy bars with a size of φ23mmx280mm obtained in the example, the tensile strength of the nine W-Ni-Fe alloy bars in the same batch was in the range of 1470MPa-1476MPa, the elongation was in the range of 14.4%-14.6%, and the density was 17.32g / cm 3 , which shows that the preparation method of the example has good stability of the bars in the same batch, i.e. the preparation method of the application can effectively improve the stability of the high specific gravity tungsten alloy bars in the same batch.

[0062] Example 2

[0063] The example provides a processing method for improving the performance stability of high specific gravity tungsten alloy bars in the same batch, which comprises the following steps:

[0064] Step 1, preparation of slab:

[0065] 1.1) In the example, the tungsten alloy with a grade of 90W-7Ni-3Fe was used as the high specific gravity tungsten alloy to be improved, and the corresponding mass of W powder, Ni powder and Fe powder was weighed according to the composition of the tungsten alloy with a grade of 90W-7Ni-3Fe for standby.

[0066] 1.2) Co powder, Mo powder and Re powder were used as doping phases, and the addition amount of Co powder was 0.2wt% of the total mass of W powder, Ni powder and Fe powder, the addition amount of Mo powder was 0.2wt% of the total mass of W powder, Ni powder and Fe powder, and the addition amount of Re powder was 0.2wt% of the total mass of W powder, Ni powder and Fe powder, and the corresponding mass of Co powder, Mo powder and Re powder was weighed according to the above ratio for standby.

[0067] 1.3) The weighed Ni powder, Fe powder and doped phase powder are mixed and then subjected to intermittent dry ball milling, the ball-to-material ratio in each ball milling process is controlled to be 2:1, the rotation speed is 150 r / min, the time for each ball milling process is 20 min, the interval between two adjacent ball milling processes is 20 min, the total ball milling time is 8 h, and the ball milling product is passed through a 200 mesh screen to obtain a first mixed powder.

[0068] 1.4) The weighed W powder is added to the first mixed powder, and then subjected to intermittent dry ball milling, the ball-to-material ratio in each ball milling process is controlled to be 1.5:1, the rotation speed is 60 r / min, the time for each ball milling process is 60 min, the interval between two adjacent ball milling processes is 60 min, the total ball milling time is 8 h, and the ball milling product is passed through a 200 mesh screen to obtain a second mixed powder.

[0069] 1.5) The second mixed powder is pressed into a green body to obtain a plate green body.

[0070] Step 2, densification treatment:

[0071] The plate green body obtained in step 1.5) is placed in a hydrogen furnace, heated to 1000°C under a hydrogen atmosphere, and then held for 4 h, and then heated to 1420°C and held for 6 h to obtain a sintered plate green body with a size of 184 mm x 302 mm x 40 mm.

[0072] Step 3, processing the plate green body into a plurality of rod green bodies:

[0073] 3.1) The sintered plate green body obtained in step 2 is heated to 810°C in an air furnace and held for 1 h, and then subjected to rolling treatment, and the single pass deformation is controlled to be 6% and the total deformation is controlled to be 30%.

[0074] 3.2) After the sintered plate green body after the hot rolling treatment in step 3.1) is cooled to room temperature, it is machined into 13 rod green bodies with a size of φ23 mm x 205 mm along the rolling direction by using a water jet cutting and a lathe.

[0075] Step 4, post-treatment:

[0076] 4.1) The 13 rod green bodies with a size of φ23 mm x 205 mm obtained in step 3.2) are placed in a vacuum annealing furnace, heated to 550°C and held for 3 h.

[0077] 4.2) The rod green bodies after vacuum annealing in step 4.1) are heated to 600°C in an air furnace, and then subjected to forging by using rotary forging, the single pass deformation is controlled to be 8%, and the total deformation is controlled to be 32%.

[0078] 4.3) After the bar blank treated in the swaging process of 4.2) is surface finished, the high specific gravity tungsten alloy bar with a size of φ18mmx230mm is obtained after being kept at 600℃ for 1h.

[0079] And through the room temperature mechanical property detection of the 13 high specific gravity tungsten alloy bars with a size of φ18mmx230mm obtained in the embodiment, the tensile strength of the 13 W-Ni-Fe alloy bars of the same batch in the embodiment is in the range of 1426MPa-1434MPa, and the elongation is in the range of 15.9%-16.4%, which shows that the stability of the bar blanks of the same batch prepared by the preparation method of the embodiment is good, that is, the preparation method of the embodiment can effectively improve the stability of the high specific gravity tungsten alloy bars of the same batch.

[0080] Embodiment 3

[0081] The embodiment provides a processing method for improving the performance stability of high specific gravity tungsten alloy bars of the same batch, which comprises the following steps:

[0082] Step 1, preparation of a slab blank:

[0083] 1.1) In the embodiment, the tungsten alloy with a brand of 95W-3.5Ni-1.5Fe is used as the high specific gravity tungsten alloy to be improved, and the corresponding mass of W powder, Ni powder and Fe powder according to the composition of the tungsten alloy with a brand of 95W-3.5Ni-1.5Fe is weighed for standby.

[0084] 1.2) Co powder and Re powder are used as doping phases, and the Co powder is added in an amount of 0.4wt% of the total mass of W powder, Ni powder and Fe powder, and the Re powder is added in an amount of 0.2wt% of the total mass of W powder, Ni powder and Fe powder, and the corresponding mass of Co powder and Re powder is weighed for standby.

[0085] 1.3) The mixed powder is obtained by mixing the weighed Ni powder, Fe powder and doping phase powder and then performing intermittent dry ball milling, and the ball-to-material ratio of each ball milling treatment is controlled to be 2:1, the rotation speed is 100r / min, the ball milling treatment time of each time is 20min, the interval between adjacent two ball milling treatments is 20min, and the total ball milling time is 8h, and the ball milling product is passed through a 200 mesh screen to obtain the first mixed powder.

[0086] 1.4) The W powder is added to the above-mentioned first mixed powder, and then intermittent dry ball milling is performed, and the ball-to-material ratio of each ball milling treatment is controlled to be 1.5:1, the rotation speed is 60r / min, the ball milling treatment time of each time is 60min, the interval between adjacent two ball milling treatments is 60min, and the total ball milling time is 8h, and the ball milling product is passed through a 200 mesh screen to obtain the second mixed powder.

[0087] 1.5) The second mixed powder is pressed into a blank to obtain a slab blank.

[0088] Step 2, densification treatment:

[0089] The slab obtained in step 1.5) above was placed in a hydrogen furnace, heated to 1200℃ under a hydrogen atmosphere, and held for 4h, and then heated to 1560℃ and held for 2h, to obtain a sintered slab with a size of 192mm x 302mm x 40mm.

[0090] Step 3, processing the slab into a plurality of rod blanks:

[0091] 3.1) The sintered slab obtained in step 2 above was heated to 1000℃ in an air furnace and held for 1h, and then subjected to rolling treatment using a rolling mill, with a single pass deformation of 6% and a total deformation of 42%.

[0092] 3.2) After the sintered slab obtained in step 3.1) above was cooled to room temperature, it was machined into 13 rod blanks with a size of φ18mm x 213mm using a water jet cutter and a lathe.

[0093] Step 4, post-treatment:

[0094] 4.1) The 13 rod blanks with a size of φ18mm x 213mm obtained in step 3.2) above were placed in a vacuum annealing furnace, heated to 700℃ and held for 2h.

[0095] 4.2) The rod blanks obtained in step 4.1) above were heated to 700℃ in an air furnace and subjected to swaging, with a single pass deformation of 5% and a total deformation of 35%.

[0096] 4.3) After the rod blanks obtained in step 4.2) above were subjected to surface finishing, they were held at 600℃ for 1h to obtain 13 high specific gravity tungsten alloy rods with a size of φ13mm x 225mm.

[0097] The room temperature mechanical properties of the 13 high specific gravity tungsten alloy rods with a size of φ13mm x 225mm obtained in this example were tested, and the tensile strength of 9 W-Ni-Fe alloy rods in the same batch was found to be in the range of 1504MPa to 1510MPa, and the elongation was in the range of 9.8% to 10.2%, which indicates that the preparation method of this example has good stability for the rod blanks in the same batch, i.e., the preparation method of the present application can effectively improve the stability of high specific gravity tungsten alloy rods in the same batch.

[0098] Comparative Example 1

[0099] This comparative example provides a treatment method for improving the performance stability of high specific gravity tungsten alloy rods in the same batch, comprising the following steps:

[0100] Step 1, preparation of rod blank:

[0101] 1.1) The tungsten alloy with the trade name of 93W-4.9Ni-2.1Fe was used as a comparative test, and the corresponding mass of W powder, Ni powder and Fe powder was weighed according to the composition of the tungsten alloy with the trade name of 93W-4.9Ni-2.1Fe, and was prepared for use.

[0102] 1.2) Co powder and Mo powder were used as doping phases, and the Co powder was added in an amount of 0.3wt% of the total mass of W powder, Ni powder and Fe powder, and the Mo powder was added in an amount of 0.3wt% of the total mass of W powder, Ni powder and Fe powder, and the corresponding mass of Co powder and Mo powder was weighed, and was prepared for use.

[0103] 1.3) The mixed powder was obtained by intermittent dry ball milling of the weighed Ni powder, Fe powder and doping phase powder, and the ball-to-material ratio of each ball milling treatment was controlled to be 2:1, the rotation speed was 100r / min, the ball milling time of each ball milling treatment was 20min, the interval between adjacent two ball milling treatments was 20min, and the total ball milling time was 8h. The ball milling product was sieved through a 200 mesh screen to obtain the first mixed powder.

[0104] 1.4) The W powder was added to the above-mentioned first mixed powder, and then intermittent dry ball milling was carried out, and the ball-to-material ratio of each ball milling treatment was controlled to be 1.5:1, the rotation speed was 60r / min, the ball milling time of each ball milling treatment was 60min, the interval between adjacent two ball milling treatments was 60min, and the total ball milling time was 8h. The ball milling product was sieved through a 200 mesh screen to obtain the second mixed powder.

[0105] 1.5) The above-mentioned second mixed powder was directly pressed into 10 rod blanks with the same size.

[0106] Step 2, densification treatment:

[0107] The rod blank obtained in step 1.5) was placed in a hydrogen furnace, and heated to 1050℃ under hydrogen atmosphere, and then held for 2h, and then heated to 1495℃ and held for 4h, to obtain 10 sintered rod blanks with a size of φ30x200mm.

[0108] Step 3, post-treatment:

[0109] 3.1) The 10 rod blanks with a size of φ30mmx200mm obtained in step 2 were placed in a vacuum annealing furnace, and heated to 830℃ and held for 2h.

[0110] 3.2) The rod blanks after vacuum annealing in 3.1) were again heated to 710℃ in an atmospheric furnace, and were forged by rotary forging, and the single pass deformation amount was controlled to be 5%, and the total deformation amount was 50%.

[0111] 3.3) After the bar blank treated in the above 4.2) swaging process is surface finished, 10 high specific gravity tungsten alloy rods with a size of φ20mmx370mm are obtained after being kept at 600℃ for 1h.

[0112] The difference between the present comparative example and Example 1 is that:

[0113] Directly pressing into 10 bar blanks with the same size and then performing densification treatment.

[0114] And through the room temperature mechanical property detection of the 10 high specific gravity tungsten alloy rods with a size of φ20mmx370mm obtained by the present comparative example, the tensile strength of the 10 W-Ni-Fe alloy rods of the same batch in the present comparative example is in the range of 1320MPa-1447MPa, and the elongation is in the range of 13.3%-14.8%, it can be seen that the fluctuation of the tensile strength and elongation of the rods of the same batch prepared by the present comparative example is large, which indicates that the stability of the bar blanks of the same batch prepared by the preparation method of the present comparative example is poor. Compared with Example 1, it can be known that the densification treatment after pressing into a plate blank, and then rolling the sintered plate blank after the densification treatment into a plurality of bar blanks, can effectively improve the stability of the rods of the same batch and reduce the influence of the mechanical property fluctuation of the final rod in the forging process.

[0115] The present application also takes the high specific gravity tungsten alloy rods prepared by Example 1 and Example 3 as examples, and the metallographic structures thereof are tested, and the test results are shown in Figures 1-4

[0116] Among them, Figure 1 is the metallographic structure image of the high specific gravity tungsten alloy rod prepared by Example 1 under the scale of 100μm, Figure 2 is the metallographic structure image of the high specific gravity tungsten alloy rod prepared by Example 1 under the scale of 50μm, it can be seen that the microstructure of the high specific gravity tungsten alloy rod prepared by Example 1 is uniform, the tungsten grains are uniformly distributed in the binder phase (Ni-Fe), and the tungsten grains are in the form of thin and long strips, which is beneficial to improve the tensile strength and other mechanical properties of the alloy material.

[0117] Figure 3 is the metallographic structure image of the high specific gravity tungsten alloy rod prepared by Example 3 under the scale of 100μm, Figure 4 is the metallographic structure image of the high specific gravity tungsten alloy rod prepared by Example 3 under the scale of 50μm, it can be seen that the tungsten grains are elongated in the same direction by the method of rolling first and then forging, and part of the tungsten grains are in the interlaced state, which is beneficial to improve the room temperature mechanical properties of the alloy material.

[0118] ​Obviously, the above embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative labor shall fall within the protection scope of the present application.

Claims

1. A processing method for improving the performance stability of high specific gravity tungsten alloy rods in the same batch, characterized in that, The method comprises the following steps: According to the composition of the W-Ni-Fe high specific gravity tungsten alloy to be lifted, W powder, Ni powder and Fe powder of corresponding mass are weighed and prepared; the mixed powder of Ni powder and Fe powder is mixed, and then doped phase powder is added and mixed to obtain a first mixed powder; the W powder is added to the first mixed powder and mixed to obtain a second mixed powder; the second mixed powder is pressed into a blank to obtain a slab blank; The doped phase powder is one or more of Mo powder, Re powder, Zr powder and Co powder; the addition amount of the doped phase powder is ≤1wt% of the total mass of W powder, Ni powder and Fe powder; The slab blank is subjected to densification treatment in a hydrogen atmosphere to obtain a sintered slab blank; The sintered slab blank is subjected to hot rolling treatment, and then is machined into a plurality of rod blanks; The plurality of rod blanks are subjected to vacuum annealing, then are subjected to rotary forging process treatment, and then are subjected to vacuum heat treatment to improve the stability of the high specific gravity tungsten alloy rods in the same batch; The W-Ni-Fe high specific gravity tungsten alloy rods are W-Ni-Fe high specific gravity tungsten alloy rods with grades of 90W-7Ni-3Fe, 93W-4.9Ni-2.1Fe and 95W-3.5Ni-1.5Fe; The densification treatment is realized by the following steps: In the same furnace batch, the slab blank is heated to 1000-1200℃ and held for 1-4h to realize pre-sintering treatment of the slab blank, and then is heated to 1420-1560℃ and held for 2-6h to realize sintering treatment of the slab blank.

2. The method of claim 1, wherein the method is characterized by: The hot rolling treatment is realized by the following steps: The sintered slab blank is heated to 800-1000℃ and held for 1h, and then is subjected to rolling treatment, and the single-pass deformation amount is controlled to be ≤10% and the total deformation amount is 15-50% during the rolling treatment.

3. The method of claim 1, wherein the method is characterized by: The single-pass deformation amount is ≤8% and the total deformation amount is 10-35% during the rotary forging process treatment.

4. The method of claim 1, wherein the method is characterized by: The first mixed powder is prepared by intermittent dry ball milling; During the intermittent dry ball milling, the ball-to-material ratio is 1-3:1, the rotation speed is 100-200r / min, the ball milling time is 15-25min, the interval between adjacent ball milling treatments is 15-25min, and the total ball milling time is 7-9h.

5. The method for improving the performance stability of high-density tungsten alloy rods in the same batch as described in claim 1, characterized in that, The second mixed powder is prepared by intermittent dry ball milling; During the intermittent dry ball milling, the ball-to-material ratio is 1-2:1, the rotation speed is 50-70r / min, the ball milling time is 55-65min, the interval between adjacent ball milling treatments is 55-65min, and the total ball milling time is 7-9h.

6. The method for improving the performance stability of high-density tungsten alloy bars in the same batch as described in claim 1, characterized in that, The temperature of the vacuum annealing is 550-830℃.

7. The method for improving the performance stability of high-density tungsten alloy rods in the same batch as described in claim 1, characterized in that, The temperature of the vacuum heat treatment is 550-830℃.

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