CN115652136A - Free-cutting copper-nickel-silicon bar and preparation method thereof - Google Patents
Free-cutting copper-nickel-silicon bar and preparation method thereof Download PDFInfo
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- 238000005520 cutting process Methods 0.000 title claims abstract description 39
- ZUPBPXNOBDEWQT-UHFFFAOYSA-N [Si].[Ni].[Cu] Chemical compound [Si].[Ni].[Cu] ZUPBPXNOBDEWQT-UHFFFAOYSA-N 0.000 title claims abstract description 25
- 238000002360 preparation method Methods 0.000 title description 6
- 239000000463 material Substances 0.000 claims abstract description 29
- 239000010949 copper Substances 0.000 claims abstract description 21
- 239000011159 matrix material Substances 0.000 claims abstract description 20
- 239000012535 impurity Substances 0.000 claims abstract description 3
- 238000001125 extrusion Methods 0.000 claims description 39
- 238000012545 processing Methods 0.000 claims description 31
- 238000000034 method Methods 0.000 claims description 29
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 29
- 238000005266 casting Methods 0.000 claims description 28
- 239000006104 solid solution Substances 0.000 claims description 22
- 230000032683 aging Effects 0.000 claims description 21
- 238000001816 cooling Methods 0.000 claims description 12
- 238000010438 heat treatment Methods 0.000 claims description 11
- 238000004321 preservation Methods 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 238000003723 Smelting Methods 0.000 claims description 4
- 239000000498 cooling water Substances 0.000 claims description 3
- 239000011869 silicon-nickel composite material Substances 0.000 claims 1
- 238000005728 strengthening Methods 0.000 abstract description 18
- 229910052802 copper Inorganic materials 0.000 abstract description 12
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 abstract description 10
- 229910021484 silicon-nickel alloy Inorganic materials 0.000 abstract description 3
- 229910045601 alloy Inorganic materials 0.000 description 35
- 239000000956 alloy Substances 0.000 description 35
- 230000000694 effects Effects 0.000 description 16
- 230000000052 comparative effect Effects 0.000 description 10
- 239000000047 product Substances 0.000 description 8
- 230000008023 solidification Effects 0.000 description 8
- 238000007711 solidification Methods 0.000 description 7
- PTVDYARBVCBHSL-UHFFFAOYSA-N copper;hydrate Chemical compound O.[Cu] PTVDYARBVCBHSL-UHFFFAOYSA-N 0.000 description 6
- 239000013078 crystal Substances 0.000 description 6
- 229910052759 nickel Inorganic materials 0.000 description 6
- 229910017876 Cu—Ni—Si Inorganic materials 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 5
- 238000001556 precipitation Methods 0.000 description 5
- 229910000881 Cu alloy Inorganic materials 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000005336 cracking Methods 0.000 description 4
- 238000009826 distribution Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 229910052710 silicon Inorganic materials 0.000 description 4
- 238000001514 detection method Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000007769 metal material Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 230000035882 stress Effects 0.000 description 3
- 238000000137 annealing Methods 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 229910052745 lead Inorganic materials 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000003754 machining Methods 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- 238000009864 tensile test Methods 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 1
- 239000005751 Copper oxide Substances 0.000 description 1
- 229910018030 Cu2Te Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 229910001215 Te alloy Inorganic materials 0.000 description 1
- 238000007545 Vickers hardness test Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 229910000431 copper oxide Inorganic materials 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000004626 scanning electron microscopy Methods 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000011856 silicon-based particle Substances 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000011895 specific detection Methods 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract
The invention discloses a free-cutting copper-nickel-silicon bar material, which is characterized in that: the copper-nickel-silicon alloy consists of the following components in percentage by mass: 3.5 to 5.5%, si:0.7 to 1.5%, te:0.1 to 1.0%, P:0.01 to 0.1%, mn:0 to 0.2%, mg:0.05 to 0.2 percent, and the balance of Cu and inevitable impurities. Adding Ni, si, te, P, mn and Mg to a copper matrix, controlling the addition amount of each, the matrix containing delta-Ni 2 Si strengthening phase and NiP strengthening phase, which can improve the strength of the matrix without reducing the matrixElectrical conductivity of body containing Cu 2 The Te cutting phase improves the machinability of the matrix, and finally realizes that the tensile strength of the copper-nickel-silicon rod is more than or equal to 750MPa, the yield strength is more than or equal to 700MPa, the elongation is more than or equal to 2 percent, the electric conductivity is more than or equal to 25 percent IACS, the hardness HV is more than or equal to 260 percent, and the cutting index is more than 80 percent of C36000.
Description
Technical Field
The invention belongs to the technical field of copper alloy, and particularly relates to an easy-cutting copper-nickel-silicon bar and a preparation method thereof.
Background
The high-strength and high-conductivity copper alloy is an important material applied to high and new fields in the future, and the basic principle of the design of the high-strength and high-conductivity copper alloy is that alloy elements with low solid solubility are added into a copper matrix, and the alloy elements form a supersaturated solid solution in the copper matrix through high-temperature solid solution treatment. After subsequent aging treatment, the supersaturated solid solution is decomposed, solid-dissolved alloy elements are separated out from the copper matrix in a precipitate phase form, and the strength and the electric conductivity of the alloy are improved.
Wherein Cu-Ni-Si series is dispersed delta-Ni as a precipitation-strengthened alloy 2 Si particles can be precipitated from the alloy matrix after heat treatment of solid solution and aging, so that the strength of the material is greatly improved, and the material has good conductivity. At present, the main grades of Cu-Ni-Si series alloy comprise C70250, C70260, C19010, C19005 and the like, wherein the contents of Ni and Si of the C70250 series are higher, and the mass ratio of Ni to Si is controlled to be about 4 2 The quantity of the Si strengthening phase is more than that of other grades, and the highest tensile strength of the material can stably reach more than 800 MPa.
However, cu-Ni-Si alloy bars have the problem of poor machinability, and particularly, the strength of the material is further improved after work hardening and aging strengthening. Because the alloy structure does not have a free-cutting phase, the material cutting resistance is extremely high, the cutter is seriously damaged, and the service life of the cutter is seriously reduced, so the cutting processing speed needs to be set very slow, and the production efficiency is influenced. In order to improve the cutting performance of the material, a certain amount of free-cutting elements must be added, but the negative effects are that the cold and hot processability of the alloy is reduced, and the mechanical property is reduced. If the conventional process is adopted, the negative effects are particularly remarkable, and the high strength and the easy cutting performance cannot be realized simultaneously. Therefore, to achieve high strength and easy machinability, the alloy composition must be optimized and the machining process adjusted to minimize the negative effects described above.
Aiming at the problems, the free-cutting alloy copper-nickel-silicon bar is developed on the basis of Cu-Ni-Si series components, the formation of a free-cutting phase is promoted on the premise of not remarkably reducing the strength and the electric conductivity of the alloy by optimizing the components of alloy elements, and meanwhile, the cold-hot processing and heat treatment process is optimized, so that the free-cutting alloy copper-nickel-silicon bar has both high-strength high-electric conductivity and good cutting processability of the Cu-Ni-Si series.
Disclosure of Invention
The invention aims to solve the first technical problem of providing a free-cutting copper-nickel-silicon bar material which has the advantages of strength, electric conduction and cold-hot processing performance.
The second technical problem to be solved by the invention is to provide a preparation method of the free-cutting copper-nickel-silicon bar.
The technical scheme adopted by the invention for solving the first technical problem is as follows: a free-cutting copper-nickel-silicon bar is characterized in that: the copper-nickel-silicon alloy consists of the following components in percentage by mass: 3.5 to 5.5%, si:0.7 to 1.5%, te:0.1 to 1.0%, P:0.01 to 0.1%, mn:0 to 0.2%, mg:0.05 to 0.2 percent, and the balance of Cu and inevitable impurities.
The invention is based on Cu-Ni-Si alloy series, wherein Ni element and Si element are used as main additive elements to promote delta-Ni 2 The Si precipitation strengthening phase is formed to ensure that the material has high strength and high conductivity. The lower limit of the Ni content is controlled to be more than 3.5 percent, on one hand, the Ni element can be dissolved in the Cu matrix in a solid solution manner to realize good solid solution strengthening effect, and on the other hand, the delta-Ni is ensured 2 The formation amount of the Si precipitation strengthening phase plays a good precipitation strengthening effect. The upper limit of the Ni element is controlled to be more than 5.5 percent, the purpose is to avoid deteriorating the processing performance of the alloy, if the Ni content is too high, the required extrusion force is greatly improved, and transverse cracks are easy to appear on the extruded blank. Meanwhile, the difficulty of the alloy solution treatment process is increased, the hardness of the blank after the solution treatment is high, the plasticity is low, and the subsequent cold processing cannot be normally carried out. The addition of Si element is related to the Ni content, and the mass ratio of Ni/Si is controlled within the range of 4-5, so that the optimal mechanical property and conductivity can be obtained. If the Si content is too high, on the one hand, the brittleness of the material is increased, and the subsequent processing is reducedPlasticity and on the other hand, the conductivity of the alloy is reduced.
The purpose of adding Te element is to improve the machinability of the material, the Te element has extremely low solubility in Cu, and Cu is used 2 The Te phase is dispersed in the crystal boundary, and the stress field strength is lower, so that the alloy keeps good conductivity. Compared with other free-cutting elements such as Pb, bi, S and the like, the addition of the Te element can not obviously reduce the mechanical property and the processing plasticity of the alloy. The above-mentioned elements of Pb, bi and S improve the machinability of the material to some extent, but they significantly increase the brittleness of the material, and thus fail to achieve good cold and hot workability, and also cause a problem that the strength of the material is significantly reduced as the amount of the above-mentioned elements is increased. In order to obtain good mechanical conductivity comprehensive performance and cutting performance, the addition amount of the Te element is controlled within the range of 0.1-1.0%.
The addition of the P element mainly promotes the formation of a NiP compound, and the NiP compound is used as a precipitated phase to further improve the strength of the material. Meanwhile, the content range of P is strictly controlled, if the content of P is too high, the conductivity and the processing plasticity of the material are obviously reduced, so that the addition amount of the P element is controlled to be in the range of 0.01-0.1%.
The Mn element is added to improve the fatigue strength of the material so as to further improve the service life of the material. If the Mn element is added too high, the viscosity of the copper water is increased in the smelting process, the fluidity is poor, and copper oxide slag is easily formed. Therefore, the amount of Mn element added in the present invention is controlled to be in the range of 0 to 0.2%, preferably 0.01 to 0.2%.
The Mg element is added for improving the quality of cast ingots, and because the casting temperature of the alloy is high, the molten copper is easy to absorb gas in the solidification process to form defects of looseness, air holes and the like. The above problems can be effectively improved by the addition of Mg element. Meanwhile, the addition of trace Mg element is also beneficial to improving the cutting processing performance of the material, and the addition amount of the Mg element is controlled to be within the range of 0.05-0.2%.
Preferably, the microstructure of the copper-nickel-silicon contains a matrix phase and a second phase, and the second phase comprises delta-Ni 2 Si phase, niP phase and Cu 2 Te phase, delta-Ni 2 Si phase equilibriumAverage size range: 0.01-0.5 μm, 0.5-5% area ratio, niP phase average size range: 0.05-1 μm, 0.1-2% area ratio, cu 2 Te phase average size range: 5-10 μm, and the area accounts for 5-20%. On the premise of certain content of the added elements, the smaller the size of the precipitated phase is, the more the distribution amount of the precipitated phase is, and the more remarkable the improvement of the mechanical property, the conductivity and the cutting effect are. On the contrary, the larger the precipitated phase size is, the smaller the distribution amount is, and the performance improvement is not significant. delta-Ni 2 The Si phase and the NiP belong to the same strengthening phase, if the area ratio is small, the strengthening effect is not obvious, if the area is increased, the cold deformation plasticity of the alloy is poor, the tensile deformation cracking is easy to occur, and the normal processing cannot be realized. Cu 2 The Te phase belongs to a free-cutting phase, and if the area ratio is small, the cutting performance cannot meet the requirement. If the area ratio is too large, the alloy has poor hot working plasticity, and cannot be prepared by a normal extrusion processing process.
The technical scheme adopted by the invention for solving the second technical problem is as follows: a preparation method of a free-cutting copper nickel silicon bar is characterized by comprising the following steps: the process flow comprises smelting → casting → extrusion → intermediate stretching → aging → finished product stretching; the casting temperature is as follows: 1200-1300 ℃, casting speed: 20-50 mm/min, and the temperature of the cast ingot discharged from the crystallizer is 600-800 ℃.
Because the alloy of the invention is added with Ni, si, mn, te, P and other elements on the basis of a copper matrix, the heat-conducting property is general, the solidification and crystallization rate of the alloy is slow in the solidification process, the central part of the ingot can still be in a liquid state after the outer layer of the ingot is solidified, and the addition amount of the Ni and Si elements is large, therefore, the alloy is easy to generate casting stress in the casting process, the ingot is easy to generate transverse central epitaxial cracks, after the Te element is added on the basis of the components of Ni and Si, brittle phases are formed and are easy to aggregate to form large-area brittle regions, the brittle fracture tendency of the material is increased, the probability of the ingot cracking and cold shut phenomenon is greatly increased, after the Mn element is added, the heat-conducting property of the alloy is further reduced, the crystallization rate is further reduced in the solidification process, the external solidification center is easy to be still in the liquid state, the phenomenon is easy to cause the alloy to form stress cracks, the casting property is further deteriorated, and the casting difficulty is greatly increased.
The casting temperature range is 1200-1300 ℃, the casting temperature is lower than 1200 ℃, the casting process is accompanied with the heat loss of copper water, the phenomenon of solidification and blockage of the copper water of the drainage tube is easy to occur, and the normal casting cannot be carried out. If the casting temperature is higher than 1300 ℃, the copper water is easy to absorb air due to overhigh temperature, and the cast ingot obtained by casting has the defects of air holes, shrinkage porosity and the like.
And (3) casting speed: 20-50 mm/min, if the casting speed is too high, the phenomenon of copper leakage caused by insufficient solidification of copper water is easily caused, if the casting speed is too low, the production efficiency is influenced, and meanwhile, the solidification section in the crystallizer moves upwards at too low speed, the frictional resistance between the ingot and the crystallizer is increased, so that the surface quality of the ingot is reduced.
The temperature of the ingot leaving the crystallizer is 600-800 ℃, and if the leading-out temperature is lower than 600 ℃, the section of the ingot is easy to have lateral cracks extending from the core part. If the extraction temperature is higher than 800 ℃, the phenomenon of leakage is easy to occur if the copper water is insufficiently solidified.
Preferably, in the casting process, the cooling water pressure of the crystallizer is: 0.4-1.0 MPa, water inlet temperature: 10-30 ℃, water outlet temperature: 20 to 45 ℃.
Preferably, the extrusion process is as follows: heating the cast ingot at 850-950 ℃, keeping the temperature for 1-4 h, extruding the cast ingot at 30-100, extruding the cast ingot at the speed: 5-15 mm/s, on-line solid solution of the extrusion blank, the solid solution temperature is 750-950 ℃, and the cooling speed is 200-600 ℃/s.
The cast ingot has a brittle phase containing Te, and is obviously brittle under the high-temperature condition, and the extrusion condition is more severe.
The heating temperature of the cast ingot is 850-950 ℃, if the heating temperature is lower than 850 ℃, the resistance to high-temperature extrusion deformation of the alloy is large, and the extrusion force exceeds the limit, so that smooth extrusion and discharging cannot be realized. The upper limit of the extrusion heating temperature is controlled at 950 ℃, the growth of alpha crystal grains and precipitated phases caused by overhigh heating temperature is avoided, if the precipitated phases of nickel and silicon grow (more than 5 mu m) and are aggregated, the plasticity of an extrusion blank is rapidly deteriorated, and the phenomena of blank cracking and fracture are easy to occur during the subsequent stretching plastic processing.
The extrusion ratio is 30-100, if the extrusion ratio is less than 30, the extrusion specification is increased, and one-time stretching to the required finished product cannot be realizedThe specification needs to adopt two-pass or multi-pass stretching and high-temperature softening annealing process. The adoption of high-temperature softening annealing process inevitably causes crystal grain growth, and delta-Ni can not be effectively realized 2 Si phase average size range: 0.01-0.5 μm, 0.5-5% area ratio, niP phase average size range: 0.05-1 μm, 0.1-2% area ratio, cu 2 Te phase average size range: 5-10 μm, 5-20% of area. If the extrusion ratio is more than 100, the extrusion specification is reduced, the extrusion force is greatly increased, on one hand, the material cannot be extruded normally, and on the other hand, annular cracks are easy to appear on the surface of the blank.
Extrusion speed: 5-15 mm/s, and the control of the extrusion speed is particularly critical on the premise of determining the extrusion temperature. If the extrusion speed is too high, continuous transverse cracks are easy to appear on the extruded wire blank. If the extrusion speed is low, the extrusion time is increased, the temperature loss of the cast ingot is accompanied in the extrusion process, the extrusion force is greatly increased when the extrusion is carried out to the tail stage, and the extrusion efficiency and the quality are influenced.
The extrusion billet is subjected to online solid solution at the solid solution temperature of 750-950 ℃, the cooling speed of 200-600 ℃/s, the temperature of the extrusion billet before cooling is controlled at 750-950 ℃, and reasonable cooling conditions are controlled, so that the aim of achieving good solid solution effect is fulfilled, precipitation and formation of a precipitated phase before an aging process are avoided, and the cold processing plasticity of the billet is greatly reduced. If the temperature of the extrusion billet is lower than 750 ℃ before cooling, a certain amount of precipitated phases are generated, the amount of the precipitated phases is increased along with the temperature reduction (above the aging temperature), the solid solution temperature is higher than 950 ℃, alpha crystal grains and other phases further grow up, the structure uniformity is reduced, and meanwhile, cu distributed in the grain boundary 2 The brittleness of the Te phase is further increased, and cracking is easily formed by extrusion. The cooling rate is lower than 200 ℃/s, the solid solution effect of the blank is not ideal, part of precipitated phases cannot be effectively dissolved in the copper matrix in a solid solution way, the plasticity of the subsequent processing of the alloy is poor, and the large-processing-rate drawing cold deformation processing cannot be realized, so that the problem of low strength of the finished product is indirectly caused, the cooling rate is higher than 600 ℃/s, the faster the solid solution cooling is, the better the solid solution cooling is, but the actual solid solution effect has the cooling limit.
Extrusion blank performance: hardness: 80-100 HV, tensile strength: 320-360 MPa, yield strength: 120 to 160MPa, elongation: 25-40%, conductivity: 10 to 12% iacs, matrix phase (α phase) average grain size: 40-80 μm.
Preferably, the intermediate stretching process is as follows: the stretching is carried out in multiple passes, the stretching processing rate of each pass is controlled to be 5-30%, and the total stretching processing rate is 50-80%.
The total processing rate of stretching is controlled between 50 and 80 percent, and the purpose is to realize good deformation strengthening effect. When the elongation of the extrusion blank reaches the ideal range of 25-40%, the cold machining plastic working rate of the material can reach 80%, if the working rate is lower than 50%, the deformation strengthening effect is not obvious, meanwhile, alpha-phase crystal grains are not broken sufficiently, fine grain strengthening cannot be realized, and the strength of the finished product processed by the process cannot meet the requirement. The single-pass processing rate is controlled to be in a range of 5-30%, if the single-pass processing rate is larger than 30%, the risk of breakage of a stretching chuck is easy to occur, meanwhile, the surface of the bar after stretching is seriously scalded, on one hand, the subsequent stretching processing is influenced, on the other hand, the surface temperature of the bar is increased, part of precipitated phases are precipitated from a solid solution state, the plasticity of the material is reduced, and meanwhile, the uniformity of the structure is deteriorated.
Preferably, the aging process comprises the following steps: and (3) adopting reducing atmosphere for protection, wherein the aging temperature is 380-450 ℃, the time for heating from room temperature to the aging temperature is 60-120 min, and the heat preservation time is 100-250 min.
The aging temperature is 380-450 ℃, and the purpose is to separate out more delta-Ni 2 Si and NiP precipitate strengthening phases. If the temperature is low, delta-Ni 2 The precipitation amount of Si phase and NiP compound is small, and the alloy strength is not obviously improved. If the temperature is too high, delta-Ni 2 Si phase and NiP compound are gathered and grown up, strengthening effect is weakened, and alloy strength is reduced.
The time from room temperature to aging temperature is 60-120 min, the production efficiency is influenced by too slow temperature rise, and the NiP compound and the delta-Ni are heated too fast 2 Si phase is easy to fully grow and gather, the aging strengthening effect is weakened, and simultaneously the size and distribution uniformity of precipitated phase are poor.
The heat preservation time is 100-250 min, the aging is insufficient when the heat preservation time is too short, precipitated phases cannot be completely precipitated, and the strengthening effect is weakened. If the heat preservation time is too long, overaging occurs, the alloy softens, and the strength is reduced.
Preferably, the final product stretch processing ratio is 5 to 20%. The processing rate is lower than 5%, the deformation strengthening effect is not obvious, and the alloy strength cannot be further increased. The processing rate is higher than 20%, the plasticity of the finished bar is easy to be reduced, the elongation is less than 2%, the subsequent straightening plasticity is poor, and the straightness of the finished product is influenced. Poor straightness affects the machinability of the material.
Compared with the prior art, the invention has the advantages that: adding Ni, si, te, P, mn, mg into copper matrix, controlling their addition amount, delta-Ni being contained in the matrix 2 Si reinforcing phase and NiP reinforcing phase, which can improve the strength of the matrix and simultaneously does not reduce the conductivity of the matrix, and the matrix contains Cu 2 The Te cutting phase improves the machinability of the matrix, and finally realizes that the tensile strength of the copper-nickel-silicon bar is more than or equal to 750MPa, the yield strength is more than or equal to 700MPa, the elongation is more than or equal to 2 percent, the electric conductivity is more than or equal to 25 percent IACS, the hardness HV is more than or equal to 260, and the cutting index is more than 80 percent of C36000.
Drawings
FIG. 1 is a photograph of a metallographic structure of a sample of example 1 of the present invention.
FIG. 2 is a photograph of a metallographic structure of a comparative example of the invention.
Detailed Description
The invention is described in further detail below with reference to the following examples of the drawings.
The invention provides 10 examples and 5 comparative examples, the specific compositions of which are shown in Table 1.
The examples include the following preparation steps:
1) Smelting: proportioning according to the requirements of required components.
2) Casting: and (3) performing pull casting on the ingot by using a semi-continuous casting mode, wherein the casting temperature is as follows: 1200-1300 ℃, cooling water pressure: 0.4-1.0 MPa, water inlet temperature: 10-30 ℃, water outlet temperature: 20-45 ℃, casting speed: 20-50 mm/min, and the temperature of the cast ingot discharged from the crystallizer is 600-800 ℃, thus obtaining the cast ingot with the specification of phi 180-200 mm.
3) Extruding: heating the cast ingot at 850-950 ℃, keeping the temperature for 1-4 h, and extruding the mixture according to the extrusion ratio of 30-100: 1, extrusion speed: 5-15 mm/s, on-line solid solution of the extrusion blank, wherein the solid solution temperature is 750-950 ℃, and the cooling speed is 200-600 ℃/s.
4) Intermediate stretching: the stretching is carried out in multiple passes, the stretching processing rate of each pass is controlled to be 5-30%, and the total stretching processing rate is 50-80%.
5) Aging: adopting reducing atmosphere for protection and introducing ammonia gas, wherein the aging temperature is 380-450 ℃, the temperature is increased from room temperature to the aging temperature for 60-120 min, and the heat preservation time is 100-250 min.
6) Stretching a finished product: the finished product has a stretch processing rate of 5-20%, and the key process parameters are shown in tables 2 and 3.
Comparative example 1 is a commercially available bar of C70250 alloy.
Comparative example 2 differs from example 1 in that: the temperature of the cast ingot discharged from the crystallizer is below 100 ℃.
Comparative example 3 differs from example 1 in that: the casting speed is 60mm/min.
Comparative example 4 differs from example 1 in that: the extruded billet is directly cooled to room temperature, i.e. without in-line solution treatment.
Comparative example 5 differs from example 1 in that: the ageing temperature is 500 ℃.
The mechanical property and/or microstructure detection is carried out on the obtained examples and comparative examples, and the specific detection indexes and detection standards are as follows:
1) Hardness HV5: GB/T4340.1-2009 Metal materials Vickers hardness test part 1: test methods.
2) Tensile strength and elongation: part 1 of the GB/T228.1-2010 tensile test of metallic materials: room temperature tensile test method.
3) And (3) metallographic microscopic test: YS/T449-2002 copper and copper alloy casting and processing product microstructure inspection method.
FIG. 1 is a photograph of a metallographic structure of a sample of example 1, in which white crystal grains are an α phase, fine and uniformly distributed. The black particles are Cu2Te phase and distributed in the grain boundary.
FIG. 2 is a photograph of a metallographic structure of a sample of comparative example 1, in which alpha-phase grains are coarse and the size and distribution uniformity are general.
4) Cutting index: the cutting index of C36000 (HPb 63-3) is set to be 100 percent according to the evaluation of a cutting performance detection method in appendix B of YS-T647-2007 copper-zinc-bismuth-tellurium alloy bar.
5) Conductivity: GB/T351-2019 metal material resistivity measurement method.
6) The size and area fraction of the second phase was photographed and measured by scanning electron microscopy.
TABLE 1 compositions/wt% of the inventive examples
Table 2 key process parameter control for embodiments of the invention
Table 3 key process parameter control for embodiments of the invention
TABLE 4 microstructures of examples of the invention
TABLE 5 Properties of inventive and comparative examples
Claims (8)
1. A free-cutting copper nickel silicon bar is characterized in that: the copper-nickel-silicon composite material comprises the following components in percentage by mass: 3.5 to 5.5%, si:0.7 to 1.5%, te:0.1 to 1.0%, P:0.01 to 0.1%, mn:0 to 0.2%, mg:0.05 to 0.2 percent, and the balance of Cu and inevitable impurities.
2. The free-cutting copper-nickel-silicon rod material of claim 1, wherein: the microstructure of the copper-nickel-silicon contains a matrix phase and a second phase, wherein the second phase comprises delta-Ni 2 Si phase, niP phase and Cu 2 Te phase, delta-Ni 2 Si phase average size range: 0.01-0.5 μm, 0.5-5% area ratio, niP phase average size range: 0.05-1 μm, 0.1-2% area ratio, cu 2 Te phase average size range: 5-10 μm, and 5-20% of area.
3. A method for preparing the free-cutting copper-nickel-silicon bar material of claim 1 or 2, wherein: the process flow comprises smelting → casting → extrusion → intermediate stretching → aging → finished product stretching; the casting temperature is as follows: 1200-1300 ℃, casting speed: 20-50 mm/min, and the temperature of the cast ingot discharged from the crystallizer is 600-800 ℃.
4. The method of producing a free-cutting copper-nickel-silicon rod according to claim 3, wherein: in the casting process, the cooling water pressure of the crystallizer is as follows: 0.4-1.0 MPa, water inlet temperature: 10-30 ℃, water outlet temperature: 20 to 45 ℃.
5. The method of producing a free-cutting copper-nickel-silicon rod according to claim 3, wherein: the extrusion process comprises the following steps: heating the cast ingot at 850-950 ℃, keeping the temperature for 1-4 h, extruding the cast ingot at 30-100, and extruding at the speed: 5-15 mm/s, on-line solid solution of the extrusion blank, the solid solution temperature is 750-950 ℃, and the cooling speed is 200-600 ℃/s.
6. The method of producing a free-cutting copper-nickel-silicon rod material of claim 3, wherein: the intermediate stretching process comprises the following steps: the stretching is carried out in multiple passes, the stretching processing rate of each pass is controlled to be 5-30%, and the total stretching processing rate is 50-80%.
7. The method of producing a free-cutting copper-nickel-silicon rod material of claim 3, wherein: the aging process comprises the following steps: and (3) adopting reducing atmosphere for protection, wherein the aging temperature is 380-450 ℃, the time for heating from room temperature to the aging temperature is 60-120 min, and the heat preservation time is 100-250 min.
8. The method of producing a free-cutting copper-nickel-silicon rod according to claim 3, wherein: the finished product stretch processing rate is 5-20%.
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| CN103643080A (en) * | 2013-12-25 | 2014-03-19 | 海门市江滨永久铜管有限公司 | High-strength, high-ductility and high-conductivity copper-nickel-silicon alloy bar and production method thereof |
| CN111778427A (en) * | 2020-06-16 | 2020-10-16 | 陕西斯瑞新材料股份有限公司 | Preparation method of CuNiSi alloy wire for electric connector |
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| GB1358055A (en) * | 1971-09-22 | 1974-06-26 | Langley Alloys Ltd | Copper-based alloys |
| CN101605917A (en) * | 2007-02-16 | 2009-12-16 | 株式会社神户制钢所 | Intensity and the copper alloy plate for electric and electronic parts that has excellent formability |
| CN102666891A (en) * | 2010-03-31 | 2012-09-12 | Jx日矿日石金属株式会社 | Cu-ni-si based alloy with excellent bendability |
| JP2012055947A (en) * | 2010-09-10 | 2012-03-22 | Furukawa Electric Co Ltd:The | Copper alloy material and copper alloy component |
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