Preparation method of high-strength tungsten alloy bar and high-strength tungsten alloy bar

Abstract

The invention discloses a preparation method of a high-strength tungsten alloy bar and the high-strength tungsten alloy bar. The technical problem that in the prior art, the strength of tungsten alloy is poor is solved. The preparation method of the high-strength tungsten alloy bar comprises the following steps: ball-milling and mixing four to eight metal oxides of titanium oxide, niobium oxide, hafnium oxide, zirconium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide and vanadium oxide with carbon black to obtain first mixed slurry; the first mixed slurry is placed in a nitrogen atmosphere for an in-situ carbon thermal reduction nitridation reaction, and multi-component carbonitride powder is obtained after cooling; tungsten powder, multi-component carbonitride powder and a forming agent are subjected to ball milling and mixing, and second mixed slurry is obtained; drying the second mixed slurry, and pressing the dried second mixed slurry into a pressed blank; and the pressed blank is subjected to high-temperature sintering treatment and high-temperature rotary swaging treatment, and the high-strength tungsten alloy bar is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of tungsten alloy rods, and in particular to a preparation method of a high-strength tungsten alloy rod and the high-strength tungsten alloy rod. Background Art

[0002] Metal tungsten has excellent properties such as high melting point, high specific gravity and low thermal expansion coefficient. It has been used in nuclear power equipment, welding electrodes, high-temperature thermal field equipment and other fields. With the development of nuclear energy, semiconductor manufacturing and other fields, metal tungsten, as a key core component in related equipment, has put forward more stringent requirements on its performance. The density, strength and service life of metal tungsten materials still need to be further improved.

[0003] In order to improve the strength of tungsten alloy, Chinese invention patent application CN102424941A uses rare earth lanthanum oxide particles as the second phase, which can improve the strength of tungsten alloy by adsorbing impurities at the grain boundaries. However, the properties of lanthanum oxide as a reinforcing phase in tungsten alloy are quite different from those of tungsten element, and the interface structure and bonding strength need to be improved, which will affect the strengthening effect of lanthanum oxide. Chinese invention patent application CN1445377A uses ZrC, NbC, TaC, HfC and other carbides mixed with tungsten to prepare composite materials, but the mechanical mixture of multiple carbides has the difficulty of homogenizing the reinforcing phase elements. Therefore, there is currently no simple and effective method for strengthening tungsten alloys. Summary of the invention

[0004] The main purpose of the present invention is to provide a preparation method of a high-strength tungsten alloy rod and a high-strength tungsten alloy rod to solve the technical problem of poor strength of tungsten alloy in the prior art.

[0005] In order to achieve the above object, the present invention first provides a method for preparing a high-strength tungsten alloy rod, and the technical scheme is as follows:

[0006] The method for preparing high-strength tungsten alloy rod comprises the following steps:

[0007] Mixing four to eight metal oxides selected from titanium oxide, niobium oxide, hafnium oxide, zirconium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, and vanadium oxide with carbon black by ball milling to obtain a first mixed slurry;

[0008] Placing the first mixed slurry in a nitrogen atmosphere for in-situ carbothermal reduction nitridation reaction, and obtaining a multi-component carbonitride powder after cooling;

[0009] The tungsten powder, the multi-component carbonitride powder and the forming agent are ball-milled and mixed to obtain a second mixed slurry;

[0010] drying the second mixed slurry and pressing it into a compact;

[0011] The pressed blank is subjected to high temperature sintering and high temperature rotary forging to obtain high strength tungsten alloy rods.

[0012] As a further improvement of the above-mentioned method for preparing the high-strength tungsten alloy rod: the selected metal oxides are titanium oxide, niobium oxide, hafnium oxide, zirconium oxide, tantalum oxide, chromium oxide, molybdenum oxide and tungsten oxide.

[0013] As a further improvement to the preparation method of the above-mentioned high-strength tungsten alloy rod: the selected metal oxides have the same number of metal atoms when used; the metal oxides and carbon black are ball-milled for 48 to 96 hours according to a ball-to-material mass ratio of (4 to 10):1 to obtain a first mixed slurry.

[0014] As a further improvement of the above-mentioned method for preparing high-strength tungsten alloy rods: the in-situ carbon thermal reduction nitridation reaction is carried out in a carbon tube furnace, the reaction temperature is 1500-1800° C., and the reaction time is 1-5 hours.

[0015] As a further improvement to the above-mentioned method for preparing high-strength tungsten alloy rods: in the mixture of tungsten powder and multi-component carbonitride powder, the mass fraction of the multi-component carbonitride powder is 1-3%.

[0016] As a further improvement of the above-mentioned method for preparing high-strength tungsten alloy rods: the particle size of tungsten powder is 200-700nm; the particle size of multi-component carbonitride is 200-500nm; and the molding agent is glycerol.

[0017] As a further improvement of the preparation method of the above-mentioned high-strength tungsten alloy rod: according to the ball-to-material mass ratio of (10-25):1, tungsten powder and multi-component carbonitride powder are ball-milled for 48-96 hours, and then a molding agent is added and the ball-milling is continued for 6-18 hours to obtain a second mixed slurry.

[0018] As a further improvement of the preparation method of the above-mentioned high-strength tungsten alloy rod: the high-temperature sintering treatment is: first placed in a tubular furnace with an argon protective atmosphere, and kept warm at 280-320°C for 1-3 hours; then placed in a vacuum sintering furnace, and sintered at 2000-2400°C for 3-5 hours.

[0019] As a further improvement to the above-mentioned method for preparing the high-strength tungsten alloy rod, the high-temperature rotary forging treatment is carried out at 1000-1600°C.

[0020] In order to achieve the above object, the present invention secondly provides a high-strength tungsten alloy rod, and the technical solution is as follows:

[0021] The high-strength tungsten alloy rod is prepared by the preparation method of the high-strength tungsten alloy rod described in the first aspect.

[0022] The preparation method of the high-strength tungsten alloy rod and the high-strength tungsten alloy rod of the present invention have the following advantages:

[0023] The present invention firstly obtains a multi-component carbonitride of four to eight kinds of titanium, niobium, hafnium, zirconium, tantalum, chromium, molybdenum, tungsten and vanadium with uniform distribution of elements as a raw material for strengthening tungsten alloy by in-situ carbon thermal reduction nitridation reaction, and diffuses a small amount of multi-component carbonitride in the tungsten matrix, while solid solution strengthening of tungsten alloy (especially a small amount of solid solution of carbon and nitrogen elements in the alloy can improve the strength of the material), and can also purify the grain boundary and improve the grain boundary strength by reacting with carbon, nitrogen and residual oxygen adsorbed on the surface of tungsten powder during the sintering process. In particular, when ultrafine multi-component carbonitride is used, the strength of the material can be further improved by dispersion strengthening, thereby achieving the improvement of the strength of tungsten alloy material.

[0024] Compared with Chinese invention patent application CN1445377A, the preparation method of the present invention does not directly mechanically mix multiple carbides and tungsten powder, but pre-carbothermally reduces and nitrides the metal oxides in situ, and introduces nitrogen into the composite, forming a multi-component carbonitride with uniform element distribution as a raw material for strengthening tungsten alloy, thereby achieving further optimization and improvement of the performance of the reinforcement phase.

[0025] The present invention is further described below by way of specific embodiments. Additional aspects and advantages of the present invention will be partially given in the following description, partially become apparent from the following description, or be learned through practice of the present invention. DETAILED DESCRIPTION

[0026] The present invention is described clearly and completely below. A person skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention, it should be noted that:

[0027] The technical solutions and technical features provided in each part of the present invention, including the following description, may be combined with each other if there is no conflict.

[0028] In addition, the embodiments of the present invention involved in the following description are generally only a part of the embodiments of the present invention, rather than all the embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0029] About the terms and units in the present invention: The terms "include", "have" and any variations thereof in the description and claims of the present invention and related parts are intended to cover non-exclusive inclusions.

[0030] Example 1

[0031] According to the same number of metal atoms in the multi-component carbonitride (Ti, Nb, Zr, Ta) (C, N), corresponding titanium oxide, niobium oxide, zirconium oxide and tantalum oxide are prepared, and then cemented carbide grinding balls, metal oxides and carbon black are added to a horizontal ball mill at a ball-to-material mass ratio of 6:1, and ball milled for 48 hours to obtain a first mixed slurry.

[0032] After the first mixed slurry is dried, an in-situ carbon thermal reduction nitridation reaction is carried out in a carbon tube furnace placed in a flowing nitrogen atmosphere. The reaction temperature is 1800° C. and the reaction time is 1 hour. After cooling, a multi-component carbonitride powder is obtained.

[0033] Weigh multi-component carbonitride and tungsten powder according to the mass fraction of multi-component carbonitride of 1% and the mass fraction of tungsten powder of 99%, then add carbide grinding balls and weighed tungsten powder and multi-component carbonitride powder into a horizontal ball mill according to the ball-to-material mass ratio of 10:1, and ball mill for 48 hours; then add glycerol as a molding agent and continue ball milling for 12 hours according to the mass ratio of ball-milled mixed powder (the sum of the mass of tungsten powder and multi-component carbonitride) to glycerol of 100:3 to obtain a second mixed slurry. Among them, the particle size of tungsten powder is 200-700nm, and the particle size of multi-component carbonitride is 200-500nm.

[0034] After the second mixed slurry is dried, it is placed in a cold isostatic press and pressed at a pressure of 350 MPa into a tungsten alloy rod-shaped compact with a diameter of 10 mm.

[0035] The obtained tungsten alloy rod-shaped compact is placed in a tubular furnace with argon protection atmosphere and kept at 300℃ for 2 hours to remove glycerol; then placed in a vacuum sintering furnace, the furnace temperature is raised to 2400℃ and sintered for 3 hours to complete the densification sintering. Finally, it is subjected to rotary forging treatment at 1500℃ to obtain a tungsten alloy rod with high strength.

[0036] The test shows that the tensile strength of tungsten alloy rod is 2150MPa.

[0037] Example 2

[0038] According to the same number of metal atoms in the multi-component carbonitride (Ti, Nb, Hf, Zr, Ta) (C, N), corresponding titanium oxide, niobium oxide, hafnium oxide, zirconium oxide and tantalum oxide are prepared, and then cemented carbide grinding balls, metal oxides and carbon black are added to a horizontal ball mill at a ball-to-material mass ratio of 8:1, and ball milled for 72 hours to obtain a first mixed slurry.

[0039] After the first mixed slurry is dried, an in-situ carbon thermal reduction nitridation reaction is carried out in a carbon tube furnace placed in a flowing nitrogen atmosphere. The reaction temperature is 1600° C. and the reaction time is 2 hours. After cooling, a multi-component carbonitride powder is obtained.

[0040] Weigh multi-component carbonitride and tungsten powder according to the mass fraction of multi-component carbonitride of 1.5% and the mass fraction of tungsten powder of 98.5%, then add carbide grinding balls and weighed tungsten powder and multi-component carbonitride powder into a horizontal ball mill according to the ball-to-material mass ratio of 20:1, and ball mill for 96 hours; then add glycerol as a molding agent and continue ball milling for 12 hours according to the mass ratio of ball-milled mixed powder (the sum of the mass of tungsten powder and multi-component carbonitride) to glycerol of 100:3 to obtain a second mixed slurry. Among them, the particle size of tungsten powder is 200-700nm, and the particle size of multi-component carbonitride is 200-500nm.

[0041] After the second mixed slurry is dried, it is placed in a cold isostatic press and pressed at a pressure of 350 MPa into a tungsten alloy rod-shaped compact with a diameter of 10 mm.

[0042] The obtained tungsten alloy rod-shaped compact is placed in a tubular furnace with argon protection atmosphere and kept at 300℃ for 2 hours to remove glycerol; then placed in a vacuum sintering furnace, the furnace temperature is raised to 2200℃ and sintered for 5 hours to complete the densification sintering. Finally, it is subjected to rotary forging treatment at 1500℃ to obtain a tungsten alloy rod with high strength.

[0043] The test shows that the tensile strength of tungsten alloy rod is 2180MPa.

[0044] Example 3

[0045] According to the same number of metal atoms in the multi-component carbonitride (Ti, Nb, Hf, Zr, Ta, Cr, Mo) (C, N), corresponding titanium oxide, niobium oxide, hafnium oxide, zirconium oxide, tantalum oxide, chromium oxide and molybdenum oxide are prepared, and then cemented carbide grinding balls, metal oxides and carbon black are added to a horizontal ball mill at a ball-to-material mass ratio of 8:1, and ball milled for 96 hours to obtain a first mixed slurry.

[0046] After the first mixed slurry is dried, an in-situ carbon thermal reduction nitridation reaction is carried out in a carbon tube furnace placed in a flowing nitrogen atmosphere. The reaction temperature is 1700° C. and the reaction time is 3 hours. After cooling, a multi-component carbonitride powder is obtained.

[0047] Weigh multi-component carbonitride and tungsten powder according to the mass fraction of multi-component carbonitride of 2% and the mass fraction of tungsten powder of 98%, then add carbide grinding balls and weighed tungsten powder and multi-component carbonitride powder into a horizontal ball mill according to the ball-to-material mass ratio of 25:1, and ball mill for 96 hours; then add glycerol as a molding agent and continue ball milling for 12 hours according to the mass ratio of ball-milled mixed powder (the sum of the mass of tungsten powder and multi-component carbonitride) to glycerol of 100:3 to obtain a second mixed slurry. Among them, the particle size of tungsten powder is 200-700nm, and the particle size of multi-component carbonitride is 200-500nm.

[0048] After the second mixed slurry is dried, it is placed in a cold isostatic press and pressed at a pressure of 350 MPa into a tungsten alloy rod-shaped compact with a diameter of 10 mm.

[0049] The obtained tungsten alloy rod-shaped compact is placed in a tubular furnace with argon protection atmosphere and kept at 300℃ for 2 hours to remove glycerol; then placed in a vacuum sintering furnace, the furnace temperature is raised to 2300℃ and sintered for 5 hours to complete the densification sintering. Finally, it is subjected to rotary forging treatment at 1500℃ to obtain a tungsten alloy rod with high strength.

[0050] The test shows that the tensile strength of tungsten alloy rod is 2320MPa.

[0051] Embodiment 4 (optimum embodiment)

[0052] According to the same number of metal atoms in the multi-component carbonitride (Ti, Nb, Hf, Zr, Ta, Cr, Mo, W) (C, N), corresponding titanium oxide, niobium oxide, hafnium oxide, zirconium oxide, tantalum oxide, chromium oxide, molybdenum oxide and tungsten oxide are prepared, and then cemented carbide grinding balls, metal oxides and carbon black are added to a horizontal ball mill at a ball-to-material mass ratio of 10:1, and ball milled for 96 hours to obtain a first mixed slurry.

[0053] After the first mixed slurry is dried, an in-situ carbon thermal reduction nitridation reaction is carried out in a carbon tube furnace placed in a flowing nitrogen atmosphere. The reaction temperature is 1650° C. and the reaction time is 2 hours. After cooling, a multi-component carbonitride powder is obtained.

[0054] Weigh multi-component carbonitride and tungsten powder according to the mass fraction of multi-component carbonitride of 2.2% and the mass fraction of tungsten powder of 97.8%, then add carbide grinding balls and weighed tungsten powder and multi-component carbonitride powder into a horizontal ball mill according to the ball-to-material mass ratio of 22:1, and ball mill for 80 hours; then add glycerol as a molding agent and continue ball milling for 12 hours according to the mass ratio of ball-milled mixed powder (the sum of the mass of tungsten powder and multi-component carbonitride) to glycerol of 100:3 to obtain a second mixed slurry. Among them, the particle size of tungsten powder is 200-700nm, and the particle size of multi-component carbonitride is 200-500nm.

[0055] After the second mixed slurry is dried, it is placed in a cold isostatic press and pressed at a pressure of 350 MPa into a tungsten alloy rod-shaped compact with a diameter of 10 mm.

[0056] The obtained tungsten alloy rod-shaped compact is placed in a tubular furnace with argon protection atmosphere and kept at 300℃ for 2 hours to remove glycerol; then placed in a vacuum sintering furnace, the furnace temperature is raised to 2300℃ and sintered for 4 hours to complete the densification sintering. Finally, it is subjected to rotary forging treatment at 1500℃ to obtain a tungsten alloy rod with high strength.

[0057] The test shows that the tensile strength of the tungsten alloy rod is 2450MPa.

[0058] Example 5

[0059] According to the same number of metal atoms in the multi-component carbonitride (Nb, Hf, Zr, Ta, Cr, Mo, W, V) (C, N), corresponding niobium oxide, hafnium oxide, zirconium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide and vanadium oxide are prepared, and then cemented carbide grinding balls, metal oxides and carbon black are added to a horizontal ball mill at a ball-to-material mass ratio of 4:1, and ball milled for 72 hours to obtain a first mixed slurry.

[0060] After the first mixed slurry is dried, an in-situ carbon thermal reduction nitridation reaction is carried out in a carbon tube furnace placed in a flowing nitrogen atmosphere. The reaction temperature is 1500° C. and the reaction time is 5 hours. After cooling, a multi-component carbonitride powder is obtained.

[0061] Weigh multi-component carbonitride and tungsten powder according to the mass fraction of multi-component carbonitride of 3% and the mass fraction of tungsten powder of 97%, then add carbide grinding balls and weighed tungsten powder and multi-component carbonitride powder into a horizontal ball mill according to the ball-to-material mass ratio of 22:1, and ball mill for 80 hours; then add glycerol as a molding agent and continue ball milling for 12 hours according to the mass ratio of ball milled mixed powder (the sum of the mass of tungsten powder and multi-component carbonitride) to glycerol of 100:3 to obtain the second mixed slurry. Among them, the particle size of tungsten powder is 200-700nm, and the particle size of multi-component carbonitride is 200-500nm.

[0062] After the second mixed slurry is dried, it is placed in a cold isostatic press and pressed at a pressure of 350 MPa into a tungsten alloy rod-shaped compact with a diameter of 10 mm.

[0063] The obtained tungsten alloy rod-shaped compact is placed in a tubular furnace with argon protection atmosphere and kept at 300℃ for 2 hours to remove glycerol; then placed in a vacuum sintering furnace, the furnace temperature is raised to 2000℃ and sintered for 5 hours to complete the densification sintering. Finally, it is subjected to rotary forging treatment at 1500℃ to obtain a tungsten alloy rod with high strength.

[0064] The test shows that the tensile strength of tungsten alloy rod is 2270MPa.

[0065] Comparative Example 1

[0066] Compared with Example 1, the difference of this comparative example is that the corresponding titanium oxide, niobium oxide and zirconium oxide are prepared according to the same number of metal atoms in the multi-component carbonitride (Ti, Nb, Zr) (C, N).

[0067] The test shows that the tensile strength of the tungsten alloy rod is 1810MPa.

[0068] Comparative Example 2

[0069] Compared with Example 1, the difference of this comparative example is that the multi-component carbonitride and tungsten powder are weighed according to the mass fraction of the multi-component carbonitride being 0.7% and the mass fraction of the tungsten powder being 99.3%.

[0070] The test shows that the tensile strength of the tungsten alloy rod is 1750MPa.

[0071] Comparative Example 3

[0072] Compared with Example 5, the difference of this control example is: the corresponding titanium oxide, niobium oxide, hafnium oxide, zirconium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, and vanadium oxide are prepared according to the same number of metal atoms in the multi-component carbonitride (Ti, Nb, Hf, Zr, Ta, Cr, Mo, W, V) (C, N).

[0073] The test shows that the tensile strength of tungsten alloy rod is 2140MPa.

[0074] Comparative Example 4

[0075] Compared with Example 5, the difference of this comparative example is that the multi-component carbonitride and tungsten powder are weighed so that the mass fraction of the multi-component carbonitride is 3.3% and the mass fraction of the tungsten powder is 96.7%.

[0076] The test shows that the tensile strength of tungsten alloy rod is 2090MPa.

[0077] Comparative Example 5

[0078] Compared with Example 1, the difference of this comparative example is that the cemented carbide grinding balls and weighed tungsten powder and multi-component carbonitride powder are added into a horizontal ball mill for ball milling at a ball-to-material mass ratio of 8:1.

[0079] The test shows that the tensile strength of tungsten alloy rod is 1940MPa.

[0080] Comparative Example 6

[0081] Compared with Example 3, the difference of this comparative example is that the cemented carbide grinding balls and weighed tungsten powder and multi-component carbonitride powder are added into a horizontal ball mill for ball milling at a ball-to-material mass ratio of 27:1.

[0082] The test shows that the tensile strength of tungsten alloy rod is 2200MPa.

[0083] In the above embodiments and control examples, a universal mechanical testing machine was used to test the tensile strength of the molybdenum alloy wire according to "Tensile Test of Metallic Materials Part 1: Room Temperature Test Method" (GB / T 228.1-2021).

[0084] The above is a description of the relevant contents of the present invention. A person skilled in the art will be able to implement the present invention based on these descriptions. Based on the above contents of the present invention, all other embodiments obtained by a person skilled in the art without creative work shall fall within the scope of protection of the present invention.

Claims

1. The method for preparing high-strength tungsten alloy rod is characterized by: The following steps are involved: Mixing four to eight metal oxides selected from titanium oxide, niobium oxide, hafnium oxide, zirconium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, and vanadium oxide with carbon black by ball milling to obtain a first mixed slurry; Placing the first mixed slurry in a nitrogen atmosphere for in-situ carbothermal reduction nitridation reaction, and obtaining a multi-component carbonitride powder after cooling; The tungsten powder, the multi-component carbonitride powder and the forming agent are ball-milled and mixed to obtain a second mixed slurry; drying the second mixed slurry and pressing it into a compact; The pressed blank is subjected to high temperature sintering and high temperature rotary forging to obtain high strength tungsten alloy rods.

2. The method for preparing the high-strength tungsten alloy rod according to claim 1, wherein: The selected metal oxides are titanium oxide, niobium oxide, hafnium oxide, zirconium oxide, tantalum oxide, chromium oxide, molybdenum oxide and tungsten oxide.

3. The method for preparing the high-strength tungsten alloy rod according to claim 1, characterized in that: The selected metal oxides have the same number of metal atoms when used; the metal oxides and carbon black are ball-milled for 48 to 96 hours according to a ball-to-material mass ratio of (4 to 10):1 to obtain a first mixed slurry.

4. The method for preparing the high-strength tungsten alloy rod according to claim 1, characterized in that: The in-situ carbon thermal reduction nitridation reaction is carried out in a carbon tube furnace, the reaction temperature is 1500-1800° C., and the reaction time is 1-5 hours.

5. The method for preparing the high-strength tungsten alloy rod according to claim 1, characterized in that: In the mixture of tungsten powder and multi-component carbonitride powder, the mass fraction of the multi-component carbonitride powder is 1-3%.

6. The method for preparing the high-strength tungsten alloy rod according to claim 1, characterized in that: The particle size of the tungsten powder is 200-700 nm; the particle size of the multi-component carbonitride is 200-500 nm; and the molding agent is propylene glycol.

7. The method for preparing the high-strength tungsten alloy rod according to claim 1, characterized in that: According to the ball-to-material mass ratio of (10-25):1, tungsten powder and multi-component carbonitride powder are ball-milled for 48-96 hours, and then a molding agent is added and ball-milled for 6-18 hours to obtain a second mixed slurry.

8. The method for preparing the high-strength tungsten alloy rod according to claim 1, characterized in that: The high temperature sintering treatment is as follows: firstly, the steel sheet is placed in a tubular furnace with an argon protective atmosphere and kept at 280-320° C. for 1-3 hours; then, the steel sheet is placed in a vacuum sintering furnace and sintered at 2000-2400° C. for 3-5 hours.

9. The method for preparing the high-strength tungsten alloy rod according to claim 1, characterized in that: The high temperature rotary forging process is performed at 1000-1600°C.

10. High strength tungsten alloy rod, characterized by: The high-strength tungsten alloy rod is prepared by the preparation method of the high-strength tungsten alloy rod according to any one of claims 1 to 9.