CN115305398B - Alloy molybdenum wire for ultra-large current wire-cut electrical discharge machining and preparation method thereof - Google Patents

Alloy molybdenum wire for ultra-large current wire-cut electrical discharge machining and preparation method thereof Download PDF

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CN115305398B
CN115305398B CN202210818518.0A CN202210818518A CN115305398B CN 115305398 B CN115305398 B CN 115305398B CN 202210818518 A CN202210818518 A CN 202210818518A CN 115305398 B CN115305398 B CN 115305398B
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wire
molybdenum
ultra
alloy
large current
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CN115305398A (en
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蔡协勇
吴维嘉
王平
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XIAMEN HONGLU TUNGSTEN MOLYBDENUM INDUSTRY CO LTD
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XIAMEN HONGLU TUNGSTEN MOLYBDENUM INDUSTRY CO LTD
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    • 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
    • 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
    • B22F3/04—Compacting only by applying fluid pressure, e.g. by cold isostatic pressing [CIP]
    • 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
    • B22F3/17—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces by forging
    • 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
    • B22F3/18—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces by using pressure rollers
    • 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
    • B22F5/12—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of wires
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
    • B23H7/00—Processes or apparatus applicable to both electrical discharge machining and electrochemical machining
    • B23H7/02—Wire-cutting
    • B23H7/08—Wire electrodes
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C22C1/05—Mixtures of metal powder with non-metallic powder
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C32/00—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
    • C22C32/001—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides
    • C22C32/0015—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides with only single oxides as main non-metallic constituents
    • C22C32/0031—Matrix based on refractory metals, W, Mo, Nb, Hf, Ta, Zr, Ti, V or alloys thereof
    • 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
    • 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
    • B22F3/18—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces by using pressure rollers
    • B22F2003/185—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces by using pressure rollers by hot rolling, below sintering temperature

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Abstract

The invention relates to the technical field of wire-electrode cutting, in particular to an alloy molybdenum wire for ultra-large current wire-electrode cutting and a preparation method thereof. The alloy molybdenum wire for ultra-large current wire cut electrical discharge machining is prepared from molybdenum powder doped with rare earth oxide; the doping amount of the rare earth oxide is 0.7-2% of the total weight in percentage by weight; the granularity of the rare earth oxide is 0.5-4.0 mu m; the rare earth oxide is at least one of lanthanum oxide or cerium oxide. According to the invention, the rare earth oxide with high doping amount is added to refine molybdenum billet grains, so that uniform fine grain structure is obtained, the work hardening speed is improved, and meanwhile, the technological process is optimized, so that the finally prepared alloy molybdenum wire for wire cut electrical discharge machining with ultra-large current can obtain room temperature tensile strength exceeding 3000MPa, and thus, the wire cut electrical discharge machining service condition of ultra-large current greater than 12A is satisfied.

Description

Alloy molybdenum wire for ultra-large current wire-cut electrical discharge machining and preparation method thereof
Technical Field
The invention relates to the technical field of wire cut electrical discharge machining, in particular to an alloy molybdenum wire for ultra-large current wire cut electrical discharge machining and a preparation method thereof.
Background
The wire electrode for wire-electrode cutting is mainly molybdenum wire, which is an ideal wire electrode for wire-electrode cutting machine tool, can cut various steels and hard alloys, and can machine parts with extremely complex shapes, and the wire electrode for wire-electrode cutting is stable in electric discharge machining and can effectively improve the precision of the die. The electrode tool is usually selected as an ideal electrode tool for high-speed wire cutting processing by virtue of the advantages of low cost, good toughness, high strength, good conductivity, low elongation and the like.
Along with the change of the international situation and the development of domestic economy, the proposal of green economy is that in order to adapt to the existing environment-friendly requirement and the continuously rising labor and material cost, the domestic manufacturers are urgently required to greatly improve the wire cutting processing efficiency and reduce the waste, thereby improving the use requirement of wire cutting molybdenum wires and providing the concept of wire cutting under ultra-large current. Therefore, the high-temperature tensile property of the molybdenum wire is greatly improved by domestic manufacturers, and the molybdenum wire is required to withstand the ultra-large current of more than 12A, so that the ultra-large current wire-cut electric discharge machining is realized, and the machining efficiency is further improved.
The prior domestic manufacturers adopt rare earth oxide such as La with low doping amount (about 2500 ppm-7000 ppm) added in molybdenum 2 O 3 、Y 2 O 3 Etc. by adding La 2 O 3 、Y 2 O 3 The dispersion strengthening effect is achieved, so that the strength of the molybdenum wire can be improved; however, with La 2 O 3 、Y 2 O 3 The increase of the content of the equal rare earth oxide can lead the crack rate to be rapidly increased, and the occurrence of the crack easily leads to the phenomena of abnormal wire breakage, short cutting life and the like in the use process of the wire cutting molybdenum wire. The problem of crack rapid increase caused by the increase of the content of the rare earth oxide cannot be broken through, so that the strength of the molybdenum wire cannot be further improved by the further increase of the content of the rare earth oxide in the prior art, and therefore, the room-temperature tensile strength of the doped molybdenum wire on the market is generally smaller than 2800Mpa, and the use condition of ultra-large current wire-cut electric discharge machining cannot be met.
Disclosure of Invention
In order to solve the problems of high crack rate and insufficient strength of the conventional doped molybdenum wire, the invention provides an alloy molybdenum wire for ultra-large current wire cut electrical discharge machining, which is prepared from molybdenum powder doped with rare earth oxide;
the doping amount of the rare earth oxide is 0.7-2% of the total weight in percentage by weight; the granularity of the rare earth oxide is 0.5-4.0 mu m; the rare earth oxide is at least one of lanthanum oxide or cerium oxide.
In some embodiments, the process can operate properly in the range of 2A to a maximum process current of at least 12A. Specifically, the alloy molybdenum wire for ultra-large current wire cut electrical discharge machining can bear more than 8A and can keep normal work even under the machining current of more than 12A on the basis of meeting the conventional wire cut electrical discharge machining current of 2-8A, so that the alloy molybdenum wire is particularly suitable for ultra-large current wire cut electrical discharge machining of more than 12A.
The preparation method of the alloy molybdenum wire for the ultra-large current wire-cut electric discharge machining comprises the following steps:
doping molybdenum powder and rare earth oxide according to a proportion to prepare uniform alloy powder, carrying out isostatic pressing forming and sintering, and cooling along with a furnace to obtain a molybdenum alloy blank;
performing hot continuous rolling on the sintered molybdenum alloy billet through a two-roller mill to obtain a molybdenum wire rod;
and performing rotary forging, hot drawing, annealing and high-speed cold drawing on the molybdenum wire rod at least once again to obtain the alloy molybdenum wire for the ultra-large current wire cut electrical discharge machining.
In some embodiments, the doping is dry doping or solid-liquid doping.
Specifically, dry doping is: mixing a proper amount of molybdenum powder and rare earth oxide according to a certain weight ratio, and uniformly mixing the powder by a high-speed powder mixer to dope the first doped powder; mixing the first doped powder and the rest molybdenum powder in a doping way, and sieving to obtain secondary doped powder; mixing and sieving the secondary doped powder again to obtain tertiary doped powder; the solid-liquid doping is as follows: calcining ammonium molybdate at 500 ℃ to obtain molybdenum trioxide, and reducing the molybdenum trioxide by hydrogen to obtain solid molybdenum dioxide; uniformly doping solid molybdenum dioxide and proper amount of lanthanum nitrate/cerium in a solution form; reducing lanthanum/cerium-doped molybdenum dioxide powder into molybdenum-lanthanum alloy powder with proper granularity in a four-temperature zone reduction furnace at one time;
in some embodiments, the isostatic compaction further comprises adding alloy doped powder into the rubber sleeve for compaction, pumping out air in the rubber sleeve and sealing, then pressurizing the rubber sleeve to 150-180 MPa by isostatic pressure, maintaining the pressure for 3-6 min, and taking out the rubber sleeve after the pressure is reduced to normal pressure, thus obtaining the blank to be sintered.
In some embodiments, the sintering process is performed under a hydrogen atmosphere.
In some embodiments, the sintering process has a sintering temperature of 1850-2200 ℃ and a holding time of 4-9 hours.
In some embodiments, the two-roll hot rolling employs an "oval-round" pass, with a rolling temperature of 1550-1700 ℃ and a final speed of 20m/s. Specifically, the oval-round "hole pattern is shown in fig. 7.
In some embodiments, the rotary forging process adopts at least three rotary forging tandem forging processes, the processing temperature is 1000-1500 ℃, the speed is 2-15m/min, and the deformation per pass is 20-40%.
In some embodiments, the swaging process employs a bi-directional conical cemented carbide swaging die.
Specifically, the bidirectional conical hard alloy rotary forging die adopts the bidirectional conical GA80 hard alloy rotary forging die shown in fig. 2, and compared with the stellite rotary hammer die adopted in the conventional process shown in fig. 1, the surface of the produced bar has no obvious hammer mark, and a specific object is shown in fig. 3. The processing temperature is 1000-1500 ℃, and the rotary forging speed is 2-15 m/min.
In some embodiments, the hot drawing process includes a coarse gauge stage and a fine gauge stage; the rough specification stage is heated by a long-fire-groove heating zone with the length of 1-3 meters, the processing temperature is 650-1050 ℃, the speed is 5-33 m/min, and the deformation of the hot drawing pass is 10-30%; the thin specification stage adopts multimode serial drawing processing, the processing temperature is 650-1050 ℃, the speed is 8-50 m/min, and the deformation of the hot drawing pass is 10-30%.
Specifically, the coarse specification stage is phi 1.5-phi 4.0mm, and the fine specification stage is less than phi 1.5mm. The long heating area shown in fig. 4 is adopted in the thick specification stage, the long heating area adopts a four-section hearth design with the length of 1-3 meters, and the mixing proportion of air and liquefied gas can be independently adjusted in a segmented manner through a single gas-saving body adjusting knob, so that the slow temperature rise control is realized.
In some embodiments, the annealing is at a temperature of 980-1850 ℃ and a speed of 0.5-9 m/min.
In some embodiments, the high-speed cold drawing process is performed at room temperature, the wire drawing speed is 200-400 m/min, and the cold drawing pass deformation is 10-25%.
In some embodiments, the high-speed cold drawing process is to coat a graphite emulsion solution on the wire material after the last-pass multimode serial drawing in the fine specification stage and dry the wire material to obtain a drawn wire material with a dried graphite emulsion coating attached to the surface. And then the prepared drawn wire with the dried graphite emulsion coating is dipped with oil through a vegetable oil circulation groove and enters a cold drawing die for high-speed cold drawing processing. Specifically, the graphite emulsion solution comprises graphite emulsion colloid and water; the specific gravity of the graphite emulsion solution is 1.0-1.06 g/cm 3 。
Preferably, the drying process of the graphite emulsion solution and the multimode serial drawing at the fine specification stage share a heating area, namely, the wire is dried through the heating area of multimode serial drawing after being coated with the graphite emulsion solution, and the dried wire directly enters the subsequent oil dipping cold drawing process without passing through a hot drawing multimode serial drawing die.
Based on the above, compared with the prior art, the invention has the following beneficial effects:
1. the invention is realized by adding more than 7000ppm of rare earth oxide La 2 O 3 Or Ce 2 O 3 The method can further refine blank grains to obtain uniform fine grain structure, improves the work hardening speed, and can obtain room-temperature tensile strength of more than 3000MPa for molybdenum wires under the same processing technology and deformation degree, thereby meeting the use condition of wire cut electrical discharge machining with ultra-large current of more than 12A.
2. The invention adopts an oval-round hole pattern to carry out two-roller hot rolling processing, the rolling temperature is 1550-1700 ℃, and the problems that the middle pass is out of the ear when the hole pattern is improperly used, the subsequent pass rolling causes folding and crack expansion caused by the pressing of the ear and the generation of corner or edge cracks are avoided. The elliptic-square hole system adopted by the original process is easy to generate long lugs in the middle pass, so that the problem of folding and crack expansion caused by the pressing of the lugs in the subsequent pass rolling is caused; the triangular-hexagonal hole type system forming the Y-shaped rolling mill is easy to generate corner and edge cracks; the full-system elliptical-circular two-roller hot continuous rolling technology adopted by the technology well solves the cracking problem caused by the two rolling technologies, and simultaneously the rolling temperature of 1550-1700 ℃ is adopted by groping, so that the generation of rolling cracks can be effectively reduced, and a foundation is laid for the subsequent obtaining of crack-free molybdenum wires.
3. Compared with the original conventional rotary hammer mould, the rotary hammer mould adopts a bidirectional conical structure on the hole pattern, is changed from original stellite into hard alloy of GA80 (tungsten carbide brand) material in material, and solves the difficult processing problem caused by high rare earth oxide content by optimizing the hole pattern of the mould and adopting a special mould of the hard alloy material, thereby optimizing the surface quality of the bar after rotary forging and avoiding the generation of surface microcracks.
4. The invention adopts a multi-section long heating zone of 1-3 meters to heat, can realize independent adjustment of the mixing proportion of air and liquefied gas, realizes different temperature control, carries out slow temperature rise control, avoids the problem of wire drawing deep grooves caused by the damage of the graphite emulsion coating due to the wire drawing graphite emulsion coating caused by scouring of large gas flow because large gas flow is required to quickly rise in a short hot zone, and avoids the problem of cracks caused by the further expansion of the wire drawing deep grooves.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
For a clearer description of embodiments of the invention or of the solutions of the prior art, the drawings that are needed in the description of the embodiments or of the prior art will be briefly described, it being obvious that the drawings in the description below are some embodiments of the invention, and that other drawings can be obtained from them without inventive effort for a person skilled in the art; the positional relationships described in the drawings in the following description are based on the orientation of the elements shown in the drawings unless otherwise specified.
FIG. 1 is a schematic diagram of a hole pattern of an original stellite alloy rotary hammer mold;
FIG. 2 is a schematic diagram of a hole pattern of a bidirectional conical GA80 hard alloy rotary forging die adopted by the invention;
FIG. 3 is a diagram showing the comparison of the bar material object (left) produced by the hard alloy die and the bar material object (right) produced by the stellite alloy die;
FIG. 4 is a schematic diagram of a long heating zone for use in the heavy gauge hot drawing process of the present invention;
FIG. 5 is a schematic diagram of an oval-square pass system in a rolling mill pass system;
FIG. 6 is a schematic diagram of a "triangle-hexagon" pass system for a Y-mill;
FIG. 7 is a schematic diagram of an "oval-round" pass used in the present invention after optimization of the oval-square aperture in the original rolling mill pass train;
FIG. 8 is a schematic view of a metallographic microstructure of a composite molybdenum wire for wire cutting according to example 1 of the present invention;
FIG. 9 is a schematic view of a metallographic microstructure of a composite molybdenum wire for wire cutting according to example 4 of the present invention;
FIG. 10 is a schematic view of a metallographic microstructure of a composite molybdenum wire for wire cutting according to example 7 of the present invention;
FIG. 11 is a schematic view of a metallographic microstructure of a composite molybdenum wire for wire cutting according to example 10 of the present invention;
FIG. 12 is a schematic illustration of crack class A after eddy current inspection of a phi 0.18mm molybdenum wire finished product;
FIG. 13 is a schematic illustration of eddy current flaw detection cracks of the phi 0.18mm molybdenum wire finished product of comparative example 3;
FIG. 14 is a microscopic schematic view of the fracture of comparative example 3;
FIG. 15 is a schematic illustration of eddy current flaw detection cracks in a finished phi 0.18mm molybdenum wire of comparative example 4;
FIG. 16 is a microscopic view of the fracture of comparative example 4;
FIG. 17 is a schematic illustration of eddy current flaw detection cracks in a finished phi 0.18mm molybdenum wire of comparative example 5;
FIG. 18 is a schematic view of the surface of a rolling section of comparative example 5;
FIG. 19 is a schematic view of a metallographic microstructure after rolling in comparative example 5;
FIG. 20 is a microscopic schematic view of the fracture of comparative example 5;
FIG. 21 is a microscopic schematic of the foaming of the dried graphite emulsion coating of comparative example 6;
FIG. 22 is a schematic view showing that the surface of comparative example 6 is severely oxidized;
FIG. 23 is a microscopic schematic view showing the occurrence of grooves on the surface of comparative example 6;
FIG. 24 is a schematic illustration of eddy current flaw detection cracks in a 0.18mm phi molybdenum wire finished product of comparative example 6;
FIG. 25 is a microscopic schematic view of the fracture of comparative example 6;
reference numerals:
2.1 Long heating zone 2.2 Single throttle body adjusting knob 2.3 wire
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention; the technical features designed in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other; all other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be noted that all terms used in the present invention (including technical terms and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs and are not to be construed as limiting the present invention; it will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Example 1
Doped with 7000 to 9000ppm of La 2 O 3
A1, preparing molybdenum-doped raw material powder, which comprises the following steps:
a. calcining ammonium molybdate at 500 ℃ to obtain molybdenum trioxide, and reducing the molybdenum trioxide by hydrogen to obtain solid molybdenum dioxide;
b. solid-liquid doping by solid molybdenum dioxide and liquid lanthanum nitrate to obtain La-containing alloy 2 O 3 Molybdenum dioxide doped;
c. reducing the lanthanum-doped molybdenum dioxide powder into molybdenum-lanthanum alloy powder with proper granularity in a four-temperature zone reducing furnace, wherein the granularity is 4.0 mu m, la 2 O 3 The content is 8000ppm;
a2, filling the molybdenum-doped raw material powder prepared in the step A1 into a rubber sleeve, and pressing the molybdenum-lanthanum alloy powder into a pressed compact with the diameter phi of 70-90 mm by adopting an isostatic pressing mode through the pressure of 150-200 MPa;
a3, sintering the pressed compact obtained in the step A2 at a high temperature in a certain temperature raising and preserving mode by using an intermediate frequency furnace sintering mode to obtain a sintered compact strip with the density of 9.5-10.0 g/cm < 3 > and the diameter phi of 60-80 mm;
a4, rolling the molybdenum blank strip sintered in the step A3 into a molybdenum wire rod with the diameter of 5.5mm by adopting a two-roller hot rolling technology of an oval-round hole type, wherein the rolling temperature is 1600 ℃, and the final speed is 20m/s;
a5, carrying out at least one multi-pass rotary hammer serial beating, at least one hot drawing and at least one cold drawing on the molybdenum wire rod manufactured in the step A4, and carrying out annealing treatment in the middle to manufacture the composite doped wire-cut molybdenum wire with the diameter of phi 0.18mm, wherein the rotary forging adopts a bidirectional conical GA80 hard alloy rotary forging die for processing, the temperature is 1500 ℃, the speed is 3m/min, the thick-specification hot drawing adopts a 1.5m four-section temperature-adjustable long furnace chamber for heating slowly, the hot drawing temperature is 700 ℃, the hot drawing speed is 10m/min, the thin-specification hot drawing adopts multi-mode serial drawing, the hot drawing temperature is 700 ℃, the hot drawing speed is 40m/min, the average deformation of the hot drawing pass is 20%, the high-speed cold drawing speed is 380m/min, the deformation of the cold drawing pass is 18%, and the middle is subjected to medium-frequency induction heating annealing to adjust the tissue uniformity and the strength of a finished product, and the annealing temperature is 1500 ℃ and the speed is 2m/min. The finished wire-cut molybdenum wire is not limited to phi 0.18mm, but can be as thin as phi 0.12mm.
The finished product flaw detection grade of the composite doped wire-cut molybdenum wire prepared by the embodiment is A0 level (PPM value of 15% alarm threshold is less than 2000 PPM), the room temperature strength of the finished product is 3210Mpa, the high temperature strength (1300 ℃) is 978Mpa, the metallographic picture is shown in figure 8, the composite doped wire-cut molybdenum wire is put on a wire-cut machine tool to carry out cutting test, the high cutting current can be born more than 12A, and the processing efficiency reaches 1.49 ten thousand mm 2 /h。
Example 2:
9000-12000 ppm of La is doped in the molybdenum powder 2 O 3
Example 2 differs from example 1 in that: doped with 9000-12000 ppm of La 2 O 3 The remaining steps are the same.
The finished product flaw detection grade of the composite doped wire-cut molybdenum wire prepared by the embodiment is A0 level (the PPM value of 15% alarm threshold is smaller than 2000 PPM), the room temperature strength of the finished product is 3409Mpa, the high temperature strength (1300 ℃) is 999Mpa, the composite doped wire-cut molybdenum wire is put on a wire-cut machine tool to carry out cutting test, the high cutting current can be born to be more than 13A, and the processing efficiency reaches 1.55 ten thousand mm 2 /h。
Example 3:
la of 17000-20000 ppm is doped in molybdenum powder 2 O 3
The finished product flaw detection grade of the composite doped wire-cut molybdenum wire prepared by the embodiment is A1 level (PPM value of 15% alarm threshold is less than 2000 PPM), the room temperature strength of the finished product is 3710Mpa, the high temperature strength (1300 ℃) is 1042Mpa, and the composite doped wire-cut molybdenum wire is put on a wire-cut machine tool to carry out cutting test, so that the composite doped wire-cut molybdenum wire can bear high cutting forceCutting current is more than 14A, and processing efficiency reaches 1.65 ten thousand mm 2 /h。
Example 4:
doped with 7000 to 9000ppm of Ce 2 O 3
B1, preparing molybdenum-doped raw material powder, which comprises the following steps:
a. calcining ammonium molybdate at 500 ℃ to obtain molybdenum trioxide, and reducing the molybdenum trioxide by hydrogen to obtain solid molybdenum dioxide;
b. solid-liquid doping by solid molybdenum dioxide and liquid cerium nitrate to obtain a cerium-containing material 2 O 3 Molybdenum dioxide doped;
c. reducing cerium-doped molybdenum dioxide powder into molybdenum-cerium alloy powder with proper granularity in a four-temperature zone reducing furnace, wherein the granularity is 4.0 mu m and Ce 2 O 3 The content is 8000ppm;
b2, filling the molybdenum-doped raw material powder prepared in the step B1 into a rubber sleeve, and pressing the molybdenum-cerium alloy powder into a pressed compact with the diameter phi 70-90 mm by adopting an isostatic pressing mode through the pressure of 150-200 MPa, wherein the pressed compact is 20-30 kg in single weight;
b3, sintering the pressed compact obtained in the step B2 at a high temperature in a certain temperature raising and preserving mode by using an intermediate frequency furnace sintering mode to obtain a sintered compact strip with the density of 9.5-10.0 g/cm < 3 > and the diameter phi of 60-80 mm;
b4, rolling the molybdenum blank strip sintered in the step B3 into a molybdenum wire rod with the diameter of 5.5mm by adopting a two-roller hot rolling technology of an oval-round hole type, wherein the rolling temperature is 1600 ℃, and the final speed is 20m/s;
and B5, performing at least one multi-pass rotary hammer serial beating, at least one hot drawing and at least one cold drawing on the molybdenum wire rod manufactured in the step B4, and performing annealing treatment in the middle to manufacture the composite doped wire-cut molybdenum wire with the diameter phi of 0.18mm, wherein the rotary forging is processed by adopting a bidirectional conical GA80 hard alloy rotary forging die, the temperature is 1500 ℃, the speed is 3m/min, the thick-specification hot drawing is heated by adopting a 1.5m four-section temperature-adjustable long furnace chamber in a slow heating manner, the hot drawing temperature is 700 ℃, the hot drawing speed is 10m/min, the thin-specification hot drawing is processed by adopting a multi-mode serial drawing, the hot drawing temperature is 700 ℃, the hot drawing speed is 40m/min, the average deformation of the hot drawing pass is 20%, the high-speed cold drawing speed is 380m/min, the deformation of the cold drawing pass is 18%, and the middle is annealed by medium-frequency induction heating to adjust the tissue uniformity and the strength of a finished product, and the annealing temperature is 1500 ℃ and the speed is 2m/min. The finished wire-cut molybdenum wire is not limited to phi 0.18mm, but can be as thin as phi 0.12mm. A schematic of a specific microscopic metallographic microstructure is shown in fig. 9.
The finished product flaw detection grade of the composite doped wire-cut molybdenum wire prepared by the embodiment is A0 level (PPM value of 15% alarm threshold is less than 2000 PPM), the room temperature strength of the finished product is 3204Mpa, the high temperature strength (1300 ℃) is 965Mpa, the composite doped wire-cut molybdenum wire is put on a wire-cut machine tool to carry out cutting test, the high cutting current can be born more than 12A, and the processing efficiency is up to 1.46 ten thousand mm 2 /h。
Example 5:
9000-12000 ppm of Ce is doped in the molybdenum powder 2 O 3 。
Example 5 differs from example 4 in that: doped with 9000-12000 ppm of Ce 2 O 3 The remaining steps are the same.
The finished product flaw detection grade of the composite doped wire-cut molybdenum wire prepared by the embodiment is A1 level (the PPM value of 15% alarm threshold is less than 2000 PPM), the room temperature strength of the finished product is 3349Mpa, the high temperature strength (1300 ℃) is 990Mpa, the composite doped wire-cut molybdenum wire is put on a wire-cut machine tool to carry out cutting test, the high cutting current can be born to be more than 13A, and the processing efficiency is up to 1.52 ten thousand mm 2 /h。
Example 6:
doping 17000-20000 ppm Ce into molybdenum powder 2 O 3
Example 6 differs from example 4 in that: doped with 17000-20000 ppm of Ce 2 O 3 The remaining steps are the same.
The finished product flaw detection grade of the composite doped wire-cut molybdenum wire prepared by the embodiment is A1 level (PPM value of 15% alarm threshold is less than 2000 PPM), the room temperature strength of the finished product is 3685Mpa, the high temperature strength (1300 ℃) is 1031Mpa, and the composite doped wire-cut molybdenum wire is put on a wire-cut machine tool to carry out cutting test, so that the composite doped wire-cut molybdenum wire can bear high cutting current14A, the processing efficiency reaches 1.63 ten thousand mm 2 /h。
Example 7:
the La of 7000-9000 ppm is doped in the molybdenum powder 2 O 3 ：
Dry doping:
c1, preparing molybdenum-doped raw material powder, which comprises the following steps:
by using a high-speed powder mixer, adopting a solid-solid doping mode to uniformly dope proper amount of lanthanum oxide powder into pure molybdenum powder through at least 3 times of repeated powder mixing, and weighing to obtain La 2 O 3 A doped molybdenum powder having a content of 8000ppm;
c2, filling the molybdenum-doped raw material powder prepared in the step C1 into a rubber sleeve, and pressing the molybdenum-lanthanum alloy powder into a pressed compact with the diameter phi of 70-90 mm by adopting an isostatic pressing mode through 150-200 MPa pressure;
carrying out high-temperature sintering on the pressed compact obtained in the step C2 in a certain temperature raising and preserving mode by utilizing an intermediate frequency furnace sintering mode to obtain a sintered compact strip with the density of 9.5-10.0 g/cm < 3 > and the diameter phi of 60-80 mm;
c4, rolling the molybdenum blank strip sintered in the step C3 into a molybdenum wire rod with the diameter of 5.5mm by adopting a two-roller hot rolling technology of an oval-round hole type, wherein the rolling temperature is 1600 ℃, and the final speed is 20m/s;
and C5, performing at least one multi-pass rotary hammer serial beating, at least one hot drawing and at least one cold drawing on the molybdenum wire rod manufactured in the step C4, and performing annealing treatment in the middle to manufacture the composite doped wire-cut molybdenum wire with the diameter of phi 0.18mm, wherein the rotary forging is processed by adopting a bidirectional conical GA80 hard alloy rotary forging die, the temperature is 1500 ℃, the speed is 3m/min, the thick-specification hot drawing is heated by adopting four sections of adjustable temperature long furnace chambers with the temperature of 1.5m slowly, the hot drawing temperature is 700 ℃, the hot drawing speed is 10m/min, the thin-specification hot drawing is processed by adopting multi-mode serial drawing, the hot drawing temperature is 700 ℃, the speed is 40m/min, the average deformation of the hot drawing passes is 20%, the high-speed cold drawing speed is 380m/min, the deformation of the cold drawing passes is 18%, and the middle is annealed by medium-frequency induction heating to adjust the uniformity of tissues and the strength of finished products, and the annealing temperature is 1500 ℃ and the speed is 2m/min. The finished wire-cut molybdenum wire is not limited to phi 0.18mm, but can be as thin as phi 0.12mm. A schematic of a specific microscopic metallographic microstructure is shown in fig. 10.
The finished product flaw detection grade of the composite doped wire-cut molybdenum wire prepared by the embodiment is A0 level (PPM value of 15% alarm threshold is less than 2000 PPM), the room temperature strength of the finished product is 3252Mpa, the high temperature strength (1300 ℃) is 972Mpa, the metallographic structure is shown in figure 4, the composite doped wire-cut molybdenum wire is cut on a wire-cut machine for cutting test, can bear more than 12A of high cutting current, and the processing efficiency is up to 1.47 ten thousand mm 2 /h。
Example 8:
example 8 differs from example 7 in that: doped with 9000-120000 ppm of La 2 O 3 The remaining steps are the same.
The finished product flaw detection grade of the composite doped wire-cut molybdenum wire prepared by the embodiment is A0 level (the PPM value of 15 percent of alarm threshold is smaller than 2000 PPM), the room temperature strength of the finished product is 3427Mpa, the high temperature strength (1300 ℃) is 995Mpa, the composite doped wire-cut molybdenum wire is put on a wire-cut machine tool to carry out cutting test, the high cutting current can be born to be more than 13A, and the processing efficiency is up to 1.54 ten thousand mm 2 /h。
Example 9:
the finished product flaw detection grade of the composite doped wire-cut molybdenum wire prepared by the embodiment is A2 level (PPM value of 15% alarm threshold is less than 2000 PPM), the room temperature strength of the finished product is 3746Mpa, the high temperature strength (1300 ℃) is 1045Mpa, the composite doped wire-cut molybdenum wire is put on a wire-cut machine tool to carry out cutting test, the high cutting current can be born to be more than 13A, and the processing efficiency is up to 1.65 ten thousand mm 2 /h。
Example 10:
doped with 7000 to 9000ppm of Ce 2 O 3 ：
D1, preparing molybdenum-doped raw material powder, which comprises the following steps:
by using a high-speed powder mixer, a proper amount of cerium oxide powder is mixed by repeated powder mixing for at least 3 times in a solid-solid doping mode, and is uniformly doped into pure molybdenum powder, and Ce is obtained after weighing 2 O 3 A doped molybdenum powder having a content of 8000ppm;
d2, filling the molybdenum-doped raw material powder prepared in the step D1 into a rubber sleeve, and pressing the molybdenum-cerium alloy powder into a pressed compact with the diameter phi 70-90 mm by adopting an isostatic pressing mode through the pressure of 150-200 MPa, wherein the pressed compact is 20-30 kg in single weight;
d3, sintering the pressed compact obtained in the step D2 at a high temperature in a certain temperature raising and preserving mode by using an intermediate frequency furnace sintering mode to obtain a sintered compact strip with the density of 9.5-10.0 g/cm < 3 > and the diameter phi of 60-80 mm;
d4, rolling the molybdenum blank strip sintered in the step D3 into a molybdenum wire rod with the diameter of 5.5mm by adopting a two-roller hot rolling technology of an oval-round hole type, wherein the rolling temperature is 1600 ℃, and the final speed is 20m/s;
and D5, performing at least one multi-pass rotary hammer serial beating, at least one hot drawing and at least one cold drawing on the molybdenum wire rod manufactured in the step D4, and performing annealing treatment in the middle to manufacture the composite doped wire-cut molybdenum wire with the diameter phi of 0.18mm, wherein the rotary forging is processed by adopting a bidirectional conical GA80 hard alloy rotary forging die, the temperature is 1500 ℃, the speed is 3m/min, the thick-specification hot drawing is heated by adopting a 1.5m four-section temperature-adjustable long furnace chamber in a slow heating manner, the hot drawing temperature is 700 ℃, the hot drawing speed is 10m/min, the thin-specification hot drawing is processed by adopting a multi-mode serial drawing, the hot drawing temperature is 700 ℃, the hot drawing speed is 40m/min, the average deformation of the hot drawing pass is 20%, the high-speed cold drawing speed is 380m/min, the deformation of the cold drawing pass is 18%, and the middle is annealed by medium-frequency induction heating to adjust the tissue uniformity and the strength of a finished product, and the annealing temperature is 1500 ℃ and the speed is 2m/min. The finished wire-cut molybdenum wire is not limited to phi 0.18mm, but can be as thin as phi 0.12mm. A schematic of a specific microscopic metallographic microstructure is shown in fig. 11.
The finished product flaw detection grade of the composite doped wire-cut molybdenum wire prepared by the embodiment is A0 level (PPM value of 15% alarm threshold is less than 2000 PPM), the room temperature strength of the finished product is 3223Mpa, the high temperature strength (1300 ℃) is 967Mpa, the composite doped wire-cut molybdenum wire is put on a wire-cut machine tool to carry out cutting test, the high cutting current can be born above 12A, and the processing efficiency reaches 1.42 ten thousand mm 2 /h。
Example 11:
example 11The difference from example 10 is that: doped with 9000-120000 ppm of Ce 2 O 3 The remaining steps are the same.
The finished product flaw detection grade of the composite doped wire-cut molybdenum wire prepared by the embodiment is A0 level (the PPM value of 15 percent of alarm threshold is smaller than 2000 PPM), the room temperature strength of the finished product is 3387Mpa, the high temperature strength (1300 ℃) is 992Mpa, the composite doped wire-cut molybdenum wire is put on a wire-cut machine tool to carry out cutting test, the high cutting current can be born to be more than 13A, and the processing efficiency is up to 1.51 ten thousand mm 2 /h。
Example 12:
example 12 differs from example 10 in that: doped with 17000-20000 ppm of Ce 2 O 3 The remaining steps are the same.
The finished product flaw detection grade of the composite doped wire-cut molybdenum wire prepared by the embodiment is A0 level (the PPM value of 15 percent of alarm threshold is smaller than 2000 PPM), the room temperature strength of the finished product is 3735Mpa, the high temperature strength (1300 ℃) is 1035Mpa, the composite doped wire-cut molybdenum wire is put on a wire-cut machine tool to carry out cutting test, the high cutting current can be born more than 14A, and the processing efficiency is up to 1.62 ten thousand mm 2 /h。
Example 13:
example 13 differs from example 1 in that: doped with 3000-4000 ppm Ce 2 O 3 3000-4000 ppm La 2 O 3 The remaining steps are the same.
The finished product flaw detection grade of the composite doped wire-cut molybdenum wire prepared by the embodiment is A1 level (PPM value of 15% alarm threshold is less than 2000 PPM), the room temperature strength of the finished product is 3220Mpa, the high temperature strength (1300 ℃) is 975Mpa, the composite doped wire-cut molybdenum wire is put on a wire-cut machine tool to carry out cutting test, the high cutting current can be born above 12A, and the processing efficiency reaches 1.41 ten thousand mm 2 /h。
Comparative example 1:
comparative example 1 illustrates the performance of a commercially available 3-wire cut molybdenum wire, specifically as follows:
the flaw detection grade of the finished product of the A wire cutting molybdenum wire is A1 level (the PPM value of 15% alarm threshold is less than 2000 PPM), the room temperature strength of the finished product is 2469Mpa, and the temperature is highThe temperature strength (1300 ℃) is 657Mpa, the composite doped wire-cut molybdenum wire is put on a wire-cut machine tool to carry out cutting test, only 4A of cutting current can be tolerated, and the processing efficiency reaches 0.63 ten thousand mm 2 /h。
The flaw detection grade of the finished product of the B-cut molybdenum wire is A1 level (PPM value of 15% alarm threshold is less than 2000 PPM), the room temperature strength of the finished product is 2303Mpa, the high temperature strength (1300 ℃) is 566Mpa, the composite doped wire-cut molybdenum wire is put on a wire-cut machine tool to carry out cutting test, only 4A of cutting current can be tolerated, and the processing efficiency reaches 0.65 ten thousand mm 2 /h。
The flaw detection grade of the finished product of the C wire cutting molybdenum wire is A1 level (PPM value of 15% alarm threshold is less than 2000 PPM), the room temperature strength of the finished product is 2519Mpa, the high temperature strength (1300 ℃) is 725Mpa, the composite doped wire cutting molybdenum wire is put on a wire cutting machine tool for cutting test, only 5A of cutting current can be tolerated, and the processing efficiency reaches 0.73 ten thousand mm 2 /h。
The room temperature strength, high temperature tensile strength (1300 ℃) of the 3 cut molybdenum wires of example 1 and comparative example 1 were measured, and the measurement results are shown in Table 1:
TABLE 1 detection results
Product(s) Room temperature strength (Mpa) High temperature tensile strength (Mpa)
Example 1 3210 978
A 2469 657
B 2303 566
C 2519 725
The 3 wire cut molybdenum wire of example 1 and comparative example 1 was selected and cut on a fast wire running apparatus.
The cutting conditions were as follows: the Perilla DK77 series fast wire feeding machine tool has the voltage of 90V, the working current of 12A, the tracking of intermediate gear, the power amplification tube 4, the pulse width of 60, the pulse width of 3, the working fluid of 'Baoma' water base, the liquid ratio of water prepared according to the ratio of 1:3, the workpiece material of 45# steel with the thickness of 100mm, and the processing test results are shown in Table 2:
table 2 processing test results
Number plate Room temperature strength (Mpa) Total cutting time (min) Total cutting area (mm) 2 ) Cutting efficiency (mm) 2 /h)
Example 1 3210 35 9230 14900
A 2469 5 525 6300
B 2303 8.5 920 6500
C 2519 12.5 1521 7300
Comparative example 2:
comparative example 2 differs from example 1 in that: doped with 5500ppm of La 2 O 3 The rest steps are the same.
The finished product flaw detection grade of the composite doped wire-cut molybdenum wire prepared in comparative example 2 is A1 grade (PPM value of 15% alarm threshold is less than 2000 PPM), the room temperature strength of the finished product is 2712Mpa, the high temperature strength (1300 ℃) is 765Mpa, the composite doped wire-cut molybdenum wire is put on a wire-cut machine tool to carry out cutting test, only the cutting current is capable of tolerating 8A, and the processing efficiency is up to 1.02 ten thousand mm 2 /h。
Comparative example 3:
comparative example 3 differs from example 1 in that: doped with La of more than 20000ppm 2 O 3 The rest steps are the same.
The composite doped wire-cut molybdenum wire prepared in comparative example 3 has the advantages of high difficulty in the processing process, high wire breakage rate, high die loss in the cold drawing stage, and high wireThe surface of the material is whitened (the graphite emulsion coating on the surface of the wire is damaged to form a whitened surface), and the flaw detection grade of the molybdenum wire finished product is C-level (the PPM value of 15% alarm threshold is more than 10000 PPM), as shown in figure 13, obvious intensive cracks exist. The room temperature strength of the finished product is 3852Mpa, and the high temperature strength (1300 ℃) is 1153Mpa. The composite doped wire-cut molybdenum wire is put on a wire-cut machine tool for cutting test, only 8A of cutting current can be tolerated, and the machining efficiency reaches 0.98 ten thousand mm 2 And/h. The cutting area reaches 1500mm 2 The broken wire is shown as a brittle fracture in fig. 14, and is characterized in that the fracture has no obvious ductile fossa, namely, the fracture leads to the brittle fracture.
Comparative example 4
Comparative example 4 differs from example 1 in that: the rotary hammer adopts a stellite alloy rotary hammer die, and the rest steps are the same.
The finished product flaw detection grade of the composite doped wire-cut molybdenum wire prepared in comparative example 4 is grade B (PPM value of 15% alarm threshold is more than 2000 PPM), dense cracks exist in the following chart 15, obvious hammer marks appear on the surface after rotary hammer processing, and 3 times of wire breakage appear in the multimode serial drawing processing process. The room temperature strength of the finished product is 3134Mpa, and the high temperature strength (1300 ℃) is 923Mpa. The composite doped wire-cut molybdenum wire is put on a wire-cut machine tool for cutting test, and only the cutting current 7A can be tolerated, and the machining efficiency reaches 1.02 ten thousand mm 2 And/h. The cutting area reaches 1800mm 2 The broken wire is shown in fig. 16, and the broken wire is a brittle broken wire, and is characterized in that the broken wire has no obvious ductile fossa, namely, the brittle broken wire is caused by a crack.
Comparative example 5
Comparative example 5 differs from example 1 in that: the rolling mill pass uses an oval-square hole pattern system (as shown in fig. 5) (or a triangular-hexagonal pattern system as shown in fig. 6), and the rest steps are the same.
The finished product flaw detection grade of the composite doped wire-cut molybdenum wire prepared in the proportion 5 is B grade (PPM value of 15% warning threshold is more than 2000 PPM), dense cracks exist as shown in figure 17, obvious surface folding occurs in a rolling section as shown in figure 18, and obvious cracks can be found in the cross section as shown in figure 19. The room temperature strength of the finished product is 3095Mpa, and the high temperature strength (1300 ℃) is 905Mpa. Blending the compositeThe mixed wire is cut on the molybdenum wire to a wire cutting machine tool for cutting test, and only the cutting current of 7A can be tolerated, and the processing efficiency reaches 0.95 ten thousand mm 2 And/h. The cutting area reaches 1900mm 2 The broken wire is shown as a brittle fracture in fig. 20, and is characterized in that the fracture has no obvious ductile fossa, namely, the fracture leads to the brittle fracture.
Comparative example 6
Comparative example 6 differs from example 1 in that: the rough-specification hot drawing process adopts a conventional long-fire tank for heating, and the rest steps are the same.
The finished product flaw detection grade of the composite doped wire-cut molybdenum wire prepared in comparative example 6 is grade B (PPM value of 15% alarm threshold is larger than 2000 PPM), a conventional fire tank (the length of a hot zone is 0.5-0.8 m) is adopted in the coarse-specification drawing process, and because the length of the hot zone is short, high-flow gas is adopted for heating to ensure the heating temperature of the wire, so that under the condition of high-flow gas flushing, graphite emulsion on the surface of the wire is blown and foamed as shown in fig. 21, uneven coating of the graphite emulsion is caused, surface oxidation after drawing is serious as shown in fig. 22, and obvious grooves appear as shown in fig. 23. Because deep grooves appear on the surface of the thick-gauge wire, cracks are formed and spread in the continuous processing process, the room temperature strength of the finished wire flaw detection grade finished product is 3203Mpa, and the high temperature strength (1300 ℃) is 956Mpa, as shown in fig. 24. The composite doped wire-cut molybdenum wire is put on a wire-cut machine tool for cutting test, and only the cutting current 9A can be tolerated, and the machining efficiency reaches 1.12 ten thousand mm 2 And/h. The cutting area reaches 2600mm 2 The broken wire is shown in fig. 25 as a brittle fracture, and is characterized in that the fracture has no obvious ductile fossa and is caused by crack expansion.
The doping test protocol components of examples 1 to 13 and comparative examples 1 to 6 are shown in Table 3
TABLE 3 doping test protocol ingredients
Test La 2 O 3 Content of Ce 2 O 3 Content of
Implementation of the embodiments 8000 0
Implementation of the embodiments 11000 0
Implementation of the embodiments 18000 0
Implementation of the embodiments 0 8000
Implementation of the embodiments 0 11000
Implementation of the embodiments 0 18000
Implementation of the embodiments 8000 0
Implementation of the embodiments 11000 0
Implementation of the embodiments 18000 0
Implementation of the embodiments 0 8000
Implementation of the embodiments 0 11000
Implementation of the embodiments 0 18000
Implementation of the embodiments 3500 3500
Comparison - -
Comparison 8000 0
Comparison 8000 0
Comparison 8000 0
Comparison 8000 0
Comparison 8000 0
Comprehensive evaluation was performed on the composite reinforced wire-cut molybdenum wire, wherein the indexes include the appearance of crack grade, room temperature strength, high temperature tensile strength (1300 ℃), cutting efficiency, etc., and the results are shown in table 4:
table 4 comprehensive evaluation of doping test
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Note that fig. 12 is a graph of an actual measurement pattern of crack detection, and crack levels are divided by PPM values of 15% alarm threshold: and (3) material A: < 2000; and (2) material B: 2000-10000; c material and above: > 10000. Wherein the A material in the crack grade is divided into 3 grades, A0: less than 1000; a1: 1000-1500; a2: 1500-2000, specifically as shown in Table 5 below:
TABLE 5 definition of crack class after vortex inspection for 0.18mm molybdenum wire finished product
Crack rating 15% alarm threshold/ppm
A0 ＜1000
A1 1000～1500
A2 1500～2000
B 2000～10000
C ＞10000
The data in tables 3 and 4 show that: from examples 1 to 13, the rare earth oxide (lanthanum oxide and/or cerium oxide) doped content was in the range of 7000 to 20000ppm, and it was possible to obtain a room temperature tensile strength exceeding 3200Mpa, an extreme value exceeding 3700Mpa, a high temperature tensile strength (1300 ℃) exceeding 900Mpa, and an extreme value exceeding 1000Mpa. Examples 1 to 13 all had crack grades A0 to A2 (no or few cracks). The invention can well solve the problem of cracks caused by high doping rare earth oxide (lanthanum oxide and/or cerium oxide), and can ensure that the prepared product has higher room temperature tensile strength and high temperature tensile strength.
And the cutting current tolerance of the examples 1 to 13 is more than 12A, and the processing efficiency is more than 1.4 ten thousand mm 2 /h。
From comparative example 1, the commercial 3-pattern wire-cut molybdenum wire has room temperature strength about 700MPa lower than that of example 1 of the present invention, and high temperature tensile strength (1300 ℃) about 300MPa lower, so that the withstand current is between 4 and 6A, and the withstand current of the present invention can exceed 12A. From comparative example 2, the doped lanthanum content of the composite doped wire-cut molybdenum wire is less than 7000ppm, and the room temperature strength of the finished product cannot reach 3000Mpa, the high temperature strength (1300 ℃) cannot reach 900Mpa, and the withstand current can only reach 8A due to the small doping amount.
From comparative example 3, the composite doped wire-cut molybdenum wire with the lanthanum content of more than 20000ppm can cause the phenomena of rapid increase of processing difficulty, frequent wire breakage, large mold loss of a cold drawing section, poor surface of a finished product, rising of crack rate and the like in the processing process due to the excessively high doping amount, the withstand current of the finished product is only 8A, and brittle fracture occurs.
From comparative example 4, the surface of the screw hammer, which is formed by rotary forging the doped wire-cut molybdenum wire by using a stellite screw hammer die, has obvious hammer marks, is processed by Cheng Duansi, has a withstand current of only 7A, and has brittle fracture
From comparative example 5, the rolling mill pass adopts the doped wire cutting molybdenum wire of an elliptic-square hole type system, surface folding occurs in the rolling section, the finished product has more cracks, the withstand current is only 7A, and brittle fracture occurs.
From comparative example 6, the doped wire-cut molybdenum wire heated by the conventional long-fire groove has uneven graphite emulsion coating in the course of rough-specification hot drawing processing, deep grooves appear on the surface of the rough-specification wire, the finished product has more cracks, the withstand current is only 9A, and brittle fracture appears.
In summary, the wire-cut molybdenum wire product produced by the invention effectively avoids the occurrence of crack problems on the premise that the content of doped rare earth oxide (lanthanum oxide and/or cerium oxide) is 7000-20000 ppm, and simultaneously has excellent material performance and compact metallographic structure that the room-temperature tensile strength exceeds 3200Mpa and the high-temperature tensile strength (1300 ℃) can reach more than 900Mpa, so that the wire-cut molybdenum wire product can bear more than 12A of heavy current in the wire-cut processing process, the cutting efficiency is higher, the wear resistance is improved, the service life is prolonged, and the loss of the molybdenum wire is greatly saved.
In addition, it should be understood by those skilled in the art that although many problems exist in the prior art, each embodiment or technical solution of the present invention may be modified in only one or several respects, without having to solve all technical problems listed in the prior art or the background art at the same time. Those skilled in the art will understand that nothing in one claim should be taken as a limitation on that claim.
Although terms such as rare earth oxide, molybdenum alloy, doping, isostatic pressing, sintering, etc. are more used herein, the possibility of using other terms is not precluded. These terms are used merely for convenience in describing and explaining the nature of the invention; they are to be interpreted as any additional limitation that is not inconsistent with the spirit of the present invention.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.

Claims (9)

1. An alloy molybdenum wire for ultra-large current wire cut electrical discharge machining, which is characterized in that: the alloy molybdenum wire for the ultra-large current wire cut electrical discharge machining is made of molybdenum powder doped with rare earth oxide; the doping amount of the rare earth oxide is 0.7-2% of the total weight in percentage by weight; the granularity of the rare earth oxide is 0.5-4.0 mu m; the rare earth oxide is at least one of lanthanum oxide or cerium oxide; the alloy molybdenum wire for ultra-large current wire cut electrical discharge machining can work normally within the range from 2A to the highest machining current, and the highest machining current is at least 12A;
the alloy molybdenum wire for ultra-large current wire cut electrical discharge machining is subjected to two-roller hot rolling machining by adopting an oval-round hole pattern, and the rolling temperature is 1550-1700 ℃; adopting a rotary hammer die of the bidirectional conical hard alloy for rotary forging; the rough-specification hot drawing process adopts a multi-section long heating zone with the length of 1-3 meters for heating.
2. A method for preparing the alloy molybdenum wire for ultra-large current wire cut electric discharge machining according to claim 1, characterized in that: the method comprises the following steps:
doping molybdenum powder and rare earth oxide to prepare uniform powder, performing isostatic compaction and sintering, and cooling along with a furnace to obtain molybdenum alloy blank strips;
performing hot continuous rolling on the sintered molybdenum alloy billet through a two-roller mill to obtain a molybdenum wire rod;
and performing rotary forging, hot drawing, annealing and high-speed cold drawing on the molybdenum wire rod at least once again to obtain the alloy molybdenum wire for the ultra-large current wire cut electrical discharge machining.
3. The preparation method according to claim 2, characterized in that: the doping mode is dry doping or solid-liquid doping.
4. The preparation method according to claim 2, characterized in that: the hot continuous rolling of the two-roller rolling mill adopts an oval-round hole type two-roller rolling mill, the rolling temperature is 1550-1700 ℃, and the final rolling speed is 20m/s.
5. The preparation method according to claim 2, characterized in that: the rotary forging process adopts at least three rotary forging tandem forging processes, the processing temperature is 1000-1500 ℃, the speed is 2-15m/min, and the pass deformation is 20-40%.
6. The method of manufacturing according to claim 5, wherein: the rotary forging process adopts a bidirectional conical hard alloy rotary forging die.
7. The preparation method according to claim 2, characterized in that: the hot drawing process comprises a coarse specification stage and a fine specification stage; the rough specification stage is heated by a long-fire-groove heating zone with the length of 1-3 meters, the processing temperature is 650-1050 ℃, the speed is 5-33 m/min, and the deformation of the hot drawing pass is 10-30%; the fine specification stage adopts multimode serial drawing processing, the processing temperature is 650-1050 ℃, the speed is 8-50 m/min, and the deformation of the hot drawing pass is 10-30%.
8. The preparation method according to claim 2, characterized in that: the annealing temperature is 980-1850 ℃ and the annealing speed is 0.5-9 m/min.
9. The preparation method according to claim 2, characterized in that: the high-speed cold drawing process is carried out at room temperature, the wire drawing speed is 200-400 m/min, and the cold drawing pass deformation is 10-25%.
CN202210818518.0A 2022-07-12 2022-07-12 Alloy molybdenum wire for ultra-large current wire-cut electrical discharge machining and preparation method thereof Active CN115305398B (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5028756A (en) * 1988-10-18 1991-07-02 Sumitomo Electric Industries, Ltd. Electrode wire for electric spark cutting
CN1876875A (en) * 2006-07-06 2006-12-13 金堆城钼业集团有限公司 Rare earth molybdenum alloy wire and preparation method thereof
CN101328550A (en) * 2008-07-25 2008-12-24 西安交通大学 Preparation of nano rare-earth oxide doping molybdenum alloys
CN106312456A (en) * 2016-08-31 2017-01-11 佛山朕华照明材料有限公司 Production method of linearly cut molybdenum wire
CN113186438A (en) * 2021-01-20 2021-07-30 厦门虹鹭钨钼工业有限公司 Alloy wire and preparation method and application thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5028756A (en) * 1988-10-18 1991-07-02 Sumitomo Electric Industries, Ltd. Electrode wire for electric spark cutting
CN1876875A (en) * 2006-07-06 2006-12-13 金堆城钼业集团有限公司 Rare earth molybdenum alloy wire and preparation method thereof
CN101328550A (en) * 2008-07-25 2008-12-24 西安交通大学 Preparation of nano rare-earth oxide doping molybdenum alloys
CN106312456A (en) * 2016-08-31 2017-01-11 佛山朕华照明材料有限公司 Production method of linearly cut molybdenum wire
CN113186438A (en) * 2021-01-20 2021-07-30 厦门虹鹭钨钼工业有限公司 Alloy wire and preparation method and application thereof

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