Preparation method of low-nickel silicon bronze alloy material and application thereof

Abstract

The application discloses a preparation method of a low-nickel silicon bronze alloy material, which comprises the following steps: S1, melting; S2, casting; S3, hot forging; S4, solid solution treatment; S5, cold forging; and S6, aging treatment. The copper alloy contains 1-1.6 wt.% of Ni, 0.1-0.25 wt.% of Cr, 0.2-0.35 wt.% of Si, 0.01-0.03 wt.% of P, and the balance of Cu. The application has the advantages that the grain is small, the precipitation phase and the distribution of the structure are more uniform, the strength and the conductivity of the product are improved, the product still has high strength and appropriate conductivity after brazing, and the application is suitable for squirrel cage asynchronous motors and continuous casting devices and other parts.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of copper alloy, in particular to a preparation method of low-nickel silicon bronze alloy material and application thereof. BACKGROUND

[0002] Cu-Ni-Si alloy is a precipitation-strengthened high-strength and medium-conductive nickel-silicon bronze alloy with excellent comprehensive performance, which can replace high-elasticity beryllium copper in many occasions and has become a special material for high-speed electrified railway catenary components, motor slot wedge, lead frame, etc. Cu-Ni-Si alloy has high strength, and its tensile strength can still be maintained at about 500 MPa after simulated brazing treatment. However, Cu-Ni-Si alloy cannot meet the requirements of electrical conductivity and thermal conductivity of some parts due to its low electrical conductivity, and its application is greatly limited.

[0003] In recent years, the research on Cu-Ni-Si alloy mainly focuses on the combination optimization of multi-element alloying, heat treatment and processing technology. For example, the Chinese patents with publication numbers CN 101717877A and CN 108193080A disclosed in the prior art have high nickel content and contain rare earth elements, which are high in cost but still low in electrical conductivity; the Chinese patents with publication numbers CN 112853149 and CN 115652135 improve the electrical conductivity by adding other alloying elements, but still cannot meet the requirement of electrical conductivity ≥ 60% IACS.

[0004] After brazing, the electrical conductivity and hardness of copper alloy will decrease, for example, the electrical conductivity and hardness of chromium bronze after brazing will decrease by 50%; but the performance of Cu-Ni-Si alloy after brazing has not been reported. The electrical conductivity of high-strength and medium-conductive Cu-Ni-Si alloy is generally below 50% IACS, and the electrical conductivity will decrease by about 25% after brazing. In order to meet the requirements of electrical conductivity and thermal conductivity of some parts, the electrical conductivity of Cu-Ni-Si alloy needs to be improved. SUMMARY

[0005] To solve the above technical problems, the present application provides a preparation method of low-nickel silicon bronze alloy material and application thereof.

[0006] The technical scheme of the present application is: a preparation method of low-nickel silicon bronze alloy material, comprising the following steps:

[0007] S1, melting:

[0008] The raw materials include, by mass percentage: 1-1.6 wt.% of Ni, 0.1-0.25 wt.% of Cr, 0.2-0.35 wt.% of Si, 0.01-0.03 wt.% of P, and the balance of Cu;

[0009] The above raw materials are placed in a vacuum induction furnace for melting. The melting temperature is 1300~1450℃, the vacuum degree is <5Pa, and the melting process is kept degassing and deoxidizing.

[0010] S2, Casting:

[0011] The alloy melt is cast at a temperature of 1250~1350℃ and is cast using a bottom casting system to obtain an alloy ingot, which is then machined.

[0012] S3, Hot Forging:

[0013] The alloy ingot obtained in step S2 is heated to 900~950℃, the forging fixture is preheated to 250~350℃, and the alloy ingot is hot forged 3 times. The initial forging temperature of the hot forging is 850~900℃, and the final forging temperature is 640~660℃. After the hot forging is completed, the alloy billet is obtained.

[0014] S4. Solution treatment:

[0015] The billet obtained in step S3 is heated to 850~900℃ at a heating rate of 19~22℃ / min and held for 60~90min. After the holding period, the billet is removed from the furnace and cooled to room temperature with water.

[0016] S5, Cold Forging:

[0017] The billet obtained in step S4 is cold forged, and the billet is trimmed after the cold forging is completed;

[0018] S6. Time-sensitive processing:

[0019] The billet obtained in step S5 is heated to 450~500℃ at a heating rate of 5~8℃ / min and held for 3~5 hours. After the holding period, the billet is cooled to 90~100℃ and then removed from the furnace and air-cooled to room temperature.

[0020] Furthermore, the Cu, Cr, and P are placed in the vacuum induction furnace in the form of electrolytic copper plates, copper-chromium master alloys, copper-silicon master alloys, and phosphorus-copper master alloys, and the Ni is placed in the form of electrolytic nickel plates.

[0021] Note: By melting the raw materials in the above manner, the purity of the main elements can be improved and the content of impurities can be reduced.

[0022] Furthermore, the Cr content in the raw material is 0.1~0.2 wt.%.

[0023] Note: By narrowing the range of chromium content, the properties of the prepared alloy are placed within a more superior and stable range.

[0024] Furthermore, the Ni content in the raw material is 1.3~1.5 wt.%.

[0025] Note: By narrowing the range of nickel content, the properties of the prepared alloy are placed within a more superior and stable range.

[0026] Furthermore, in step S3, the hot forging includes upsetting and drawing.

[0027] Explanation: Upsetting and drawing alter the as-cast structure, breaking down coarse as-cast structures into fine grains and reducing defects in the as-cast structure.

[0028] Furthermore, in step S5, the cold forging is upsetting, and the deformation of the billet is 20-30%.

[0029] Note: The upsetting cold forging process significantly improves the hardness and strength of the resulting billet.

[0030] Further, in step S1, degassing and deoxygenation includes the following steps:

[0031] During the first half of the melting process, inert gas is uniformly introduced into the vacuum induction furnace at a flow rate of 350~400 NL / min, and a purifying agent accounting for 0.5~1.5% of the alloy melt mass is added uniformly at the same time as the inert gas is introduced.

[0032] In the latter half of the melting process, the inert gas flow rate is gradually reduced from 15 to 25 NL / min. For every 60 NL / min reduction in the inert gas flow rate, the amount of purifying agent added per minute is reduced by 0.05 to 0.08 wt.%, until the melting process is completed.

[0033] Explanation: By controlling the inert gas introduction rate in stages, the uniformity and stability of the melting process can be promoted. Inert gas provides good thermal conductivity and thermal stability during the melting process, making the molten pool temperature more uniform, which helps the alloy to mix evenly and grow crystals. The purification agent is added in stages while the gas is being introduced, and the addition rate of the purification agent is adjusted with the gas introduction rate, so that the purification agent can stably and efficiently remove impurities from the metal, thereby improving the purity and quality of the metal.

[0034] Furthermore, the purifying agent comprises zinc oxide, silicon carbide, sodium fluoride, and sodium potassium silicate in a mass ratio of 1~2:1:0.5:0.02; the inert gas is nitrogen.

[0035] Note: Zinc oxide has high adsorption capacity and chemical reactivity, and can react with some metallic impurities to achieve a purification effect; silicon carbide has good stability at high temperatures and is inorganic, so it will not produce additional effects during the purification process; sodium fluoride has the advantages of strong oxidizing properties, rapid and efficient operation, multifunctionality, and low cost.

[0036] Furthermore, in step S2, while maintaining a constant casting temperature, variable-speed casting is employed, as follows:

[0037] The initial casting rate is 0.15~0.20 kg / s, and an initial magnetic field is applied during casting. After casting for 20~25 seconds, a first dispersion treatment is performed. Then, the casting rate is increased to 1.2~1.4 times the initial rate, and the magnetic field strength is increased by 2~3 times compared to the initial magnetic field for a second dispersion treatment. Finally, the casting rate is reduced to the initial rate and the magnetic field is turned off until casting is completed.

[0038] The initial magnetic field has a pulse frequency of 350~750Hz and a magnetic field strength of 4~6T.

[0039] Explanation: During the first dispersion process, a higher pouring speed is used to promote more uniform solidification of the casting, avoid the formation of porosity and inclusions, and a higher magnetic field is applied at the same time to improve the uniformity of the casting dispersion and make the solidification more uniform. During the second dispersion process, the pouring speed and magnetic field strength are further increased to avoid problems such as stress concentration and hot cracking. Finally, the initial pouring speed is returned and the magnetic field is removed to promote final solidification and cooling, which helps the casting shrink and shape stability, and reduces deformation and stress.

[0040] The application of the low-nickel silicon bronze alloy material prepared by any of the above-mentioned methods, wherein the low-nickel silicon bronze alloy material is used in squirrel-cage asynchronous motors and continuous casting machines.

[0041] The beneficial effects of this invention are:

[0042] (1) The low-nickel silicon bronze alloy obtained by the present invention through the composition design of low nickel content and phosphorus deoxidation and the preparation process of this application has a yield strength >500MPa, conductivity ≥60%IACS, and precipitate size below 100nm; it can achieve the advantages of fine grains, more uniform distribution of precipitates and microstructure in the alloy, while improving the strength and conductivity of the alloy, and can still maintain high strength and conductivity after the alloy is brazed, and is suitable for parts such as squirrel cage asynchronous motors and continuous casting machines.

[0043] (2) The low-nickel silicon bronze alloy prepared by the present invention strengthens the alloy by adding a certain amount of Ni and Cr. On the one hand, Ni atoms and Cu atoms are infinitely miscible and can form solid solution strengthening in the alloy, thereby improving the strength of the alloy. On the other hand, Ni atoms and Si atoms, and Cr atoms and Si atoms form nanoscale intermetallic compounds Ni2Si phase and Cr3Si phase. The addition of Cr can promote the precipitation of Ni2Si and improve the conductivity. Trace amounts of P exist as deoxidizers, which can improve the fluidity of the melt and improve the weldability and corrosion resistance of copper and alloys. Detailed Implementation

[0044] The present invention will now be described in more detail with reference to specific embodiments, so as to better demonstrate the advantages of the present invention.

[0045] Example 1

[0046] A method for preparing a low-nickel silicon bronze alloy material includes the following steps:

[0047] S1, Smelting:

[0048] The raw materials, by mass percentage, include: 1.4 wt.% Ni, 0.15 wt.% Cr, 0.25 wt.% Si, 0.02 wt.% P, 0.05 wt.% Fe, 0.05 wt.% Mn, 0.02 wt.% Pb, with the balance being Cu;

[0049] The Cu, Cr and P are in the form of electrolytic copper plates, copper-chromium master alloys, copper-silicon master alloys and phosphorus copper master alloys, and the Ni is in the form of electrolytic nickel plates. They are placed in a vacuum induction furnace for melting. The melting temperature is 1375℃, the vacuum degree is 4Pa, the melting time is 80min, and the melting process is maintained by degassing and deoxidation.

[0050] S2, Casting:

[0051] The alloy melt is cast at a temperature of 1300℃ and is cast using a bottom casting system at a rate of 0.15 kg / s for 80 seconds to obtain an alloy ingot with a diameter of Ф200 mm, which is then machined.

[0052] S3, Hot Forging:

[0053] The alloy ingot obtained in step S2 is heated to 925°C, the forging fixture is preheated to 300°C, and the alloy ingot is hot-forged 3 times. The hot forging includes upsetting and drawing. The initial forging temperature of the hot forging is 875°C and the final forging temperature is 650°C. After the hot forging is completed, an alloy billet is obtained.

[0054] S4. Solution treatment:

[0055] The billet obtained in step S3 is heated to 875°C at a heating rate of 20°C / min and held for 75 minutes. After the holding period, the billet is removed from the furnace and cooled to room temperature with water.

[0056] S5, Cold Forging:

[0057] The billet obtained in step S4 is cold forged, the cold forging is upsetting, the deformation of the billet is 25%, and the billet is trimmed after the cold forging is completed.

[0058] S6. Time-sensitive processing:

[0059] The billet obtained in step S5 is heated to 475°C at a heating rate of 6°C / min and held for 4 hours. After the holding period, the billet is cooled to 95°C and then removed from the furnace and air-cooled to room temperature.

[0060] The aforementioned low-nickel silicon bronze alloy material is used in squirrel-cage asynchronous motors and continuous casting machines.

[0061] Example 2

[0062] The difference between this embodiment and Embodiment 1 is that the raw materials, by mass percentage, include: 1 wt.% Ni, 0.1 wt.% Cr, 0.2 wt.% Si, 0.01 wt.% P, 0.05 wt.% Fe, 0.05 wt.% Mn, 0.02 wt.% Pb, with the balance being Cu.

[0063] Example 3

[0064] The difference between this embodiment and Embodiment 1 is that the raw materials, by mass percentage, include: 1.6 wt.% Ni, 0.25 wt.% Cr, 0.35 wt.% Si, 0.03 wt.% P, 0.05 wt.% Fe, 0.05 wt.% Mn, 0.02 wt.% Pb, with the balance being Cu.

[0065] Example 4

[0066] The difference between this embodiment and Embodiment 1 is that the Cr content in the raw materials is 0.2 wt.%.

[0067] Example 5

[0068] The difference between this embodiment and Embodiment 1 is that the Ni content in the raw materials is 1.3 wt.%.

[0069] Example 6

[0070] The difference between this embodiment and Embodiment 1 is that the Ni content in the raw materials is 1.5 wt.%.

[0071] Example 7

[0072] The difference between this embodiment and Embodiment 1 is that in step S1, the melting temperature is 1300℃ and the melting time is 75min.

[0073] Example 8

[0074] The difference between this embodiment and Embodiment 1 is that in step S1, the melting temperature is 1450℃ and the melting time is 85min.

[0075] Example 9

[0076] The difference between this embodiment and Embodiment 1 is that, in step S2, the casting temperature of the alloy melt is 1250°C.

[0077] Example 10

[0078] The difference between this embodiment and Embodiment 1 is that, in step S2, the casting temperature of the alloy melt is 1350℃.

[0079] Example 11

[0080] The difference between this embodiment and embodiment 1 is that in step S3, the alloy ingot obtained in step S2 is heated to 900°C, the forging fixture is preheated to 250°C, and the alloy ingot is hot-forged 3 times. The initial forging temperature is 850°C and the final forging temperature is 640°C.

[0081] Example 12

[0082] The difference between this embodiment and embodiment 1 is that in step S3, the alloy ingot obtained in step S2 is heated to 950°C, the forging fixture is preheated to 350°C, and the alloy ingot is hot-forged 3 times. The initial forging temperature is 900°C and the final forging temperature is 660°C.

[0083] Example 13

[0084] The difference between this embodiment and embodiment 1 is that in step S4, the billet obtained in step S3 is heated to 850°C at a heating rate of 19°C / min and held for 60min.

[0085] Example 14

[0086] The difference between this embodiment and embodiment 1 is that in step S4, the billet obtained in step S3 is heated to 900°C at a heating rate of 22°C / min and held at that temperature for 90min.

[0087] Example 15

[0088] The difference between this embodiment and embodiment 1 is that in step S5, the deformation of the billet is 20%.

[0089] Example 16

[0090] The difference between this embodiment and embodiment 1 is that in step S5, the deformation of the billet is 30%.

[0091] Example 17

[0092] The difference between this embodiment and embodiment 1 is that in step S6, the billet obtained in step S5 is heated to 450°C at a heating rate of 5°C / min and held for 3 hours. After the holding period, the billet is cooled to 90°C and then removed from the furnace and air-cooled to room temperature.

[0093] Example 18

[0094] The difference between this embodiment and embodiment 1 is that in step S6, the billet obtained in step S5 is heated to 500°C at a heating rate of 8°C / min and held for 5 hours. After the holding period, the billet is cooled to 100°C and then removed from the furnace and air-cooled to room temperature.

[0095] Example 19

[0096] The difference between this embodiment and Embodiment 1 is that, in step S1, degassing and deoxygenation include the following steps:

[0097] During the first half of the melting process, inert gas is introduced into the vacuum induction furnace at a constant flow rate of 375 NL / min, and a purifying agent accounting for 1.0% of the alloy melt mass is added at the same constant flow rate while the inert gas is introduced.

[0098] During the latter half of the melting process, the inert gas flow rate was gradually reduced to 20 NL / min, and the amount of purifying agent added per minute was reduced by 0.07 wt.% for every 60 NL / min reduction in the inert gas flow rate until the melting process was completed.

[0099] The purifying agent comprises zinc oxide, silicon carbide, sodium fluoride, and sodium potassium silicate in a mass ratio of 1.5:1:0.5:0.02; the inert gas is nitrogen.

[0100] Example 20

[0101] The difference between this embodiment and embodiment 19 is that, during the first half of the melting process, nitrogen gas is introduced into the vacuum induction furnace at a constant flow rate of 350 NL / min.

[0102] Example 21

[0103] The difference between this embodiment and embodiment 19 is that, during the first half of the melting process, nitrogen gas is introduced into the vacuum induction furnace at a constant flow rate of 400 NL / min.

[0104] Example 22

[0105] The difference between this embodiment and embodiment 19 is that, during the first half of the melting process, a purifying agent accounting for 0.5% of the mass of the alloy melt is added at a uniform rate while nitrogen is introduced.

[0106] Example 23

[0107] The difference between this embodiment and embodiment 19 is that, during the first half of the melting process, a purifying agent accounting for 1.5% of the alloy melt mass is added at a uniform rate while nitrogen is introduced.

[0108] Example 24

[0109] The difference between this embodiment and embodiment 19 is that, in the latter half of the melting process, the nitrogen flow rate is gradually reduced from 15 NL / min.

[0110] Example 25

[0111] The difference between this embodiment and Embodiment 19 is that, in the latter half of the melting process, the nitrogen flow rate is gradually reduced from 25 NL / min.

[0112] Example 26

[0113] The difference between this embodiment and Embodiment 19 is that, in the latter half of the melting process, for every 60 NL / min decrease in the nitrogen flow rate, the amount of purifying agent added per minute is reduced by 0.05 wt.%, until the melting process is completed.

[0114] Example 27

[0115] The difference between this embodiment and Embodiment 19 is that, in the latter half of the melting process, for every 60 NL / min decrease in the nitrogen flow rate, the amount of purifying agent added per minute is reduced by 0.08 wt.%, until the melting process is completed.

[0116] Example 28

[0117] The difference between this embodiment and Embodiment 19 is that the purifying agent comprises zinc oxide, silicon carbide, sodium fluoride, and sodium potassium silicate in a mass ratio of 1:1:0.5:0.02.

[0118] Example 29

[0119] The difference between this embodiment and Embodiment 19 is that the purifying agent comprises zinc oxide, silicon carbide, sodium fluoride, and sodium potassium silicate in a mass ratio of 2:1:0.5:0.02.

[0120] Example 30

[0121] The difference between this embodiment and Embodiment 1 is that in step S2, the casting temperature is kept constant, and variable speed casting is used. The steps are as follows:

[0122] The initial casting rate is 0.18 kg / s, and an initial magnetic field is applied during casting. After 23 seconds of casting, a first dispersion treatment is performed. Then, the casting rate is increased to 1.3 times the initial rate, and the magnetic field strength is increased by 2.5 times compared to the initial magnetic field, which is maintained for 18 seconds for a second dispersion treatment. Finally, the casting rate is reduced to the initial rate and the magnetic field is turned off until casting is completed.

[0123] The initial magnetic field has a pulse frequency of 550 Hz and a magnetic field strength of 5 T.

[0124] Example 31

[0125] The difference between this embodiment and embodiment 30 is that, during the single dispersion process, the initial casting rate is 0.15 kg / s, the pulse frequency of the initial magnetic field is 350 Hz, the magnetic field strength is 4 T, and the casting time is 20 s.

[0126] Example 32

[0127] The difference between this embodiment and embodiment 30 is that, during the single dispersion process, the initial casting rate is 0.20 kg / s, the pulse frequency of the initial magnetic field is 750 Hz, the magnetic field strength is 6 T, and the casting time is 25 s.

[0128] Example 33

[0129] The difference between this embodiment and embodiment 30 is that during the secondary dispersion process, the casting rate is increased to 1.2 times the initial rate, and the magnetic field strength is increased by 2 times compared to the initial magnetic field, lasting for 15 seconds.

[0130] Example 34

[0131] The difference between this embodiment and embodiment 30 is that during the secondary dispersion process, the casting rate is increased to 1.4 times the initial rate, and the magnetic field strength is increased by 3 times compared to the initial magnetic field, lasting for 20 seconds.

[0132] Experimental Example

[0133] For the low-nickel silicon bronze alloy materials prepared in each embodiment, five samples from each embodiment were taken to test the performance of the low-nickel silicon bronze alloy materials. The average value of the performance measurement results of the five samples in each embodiment was taken as the performance measurement result of that embodiment. The specific investigation is as follows:

[0134] 1. Investigate the effect of elemental composition on the hardness and conductivity of low-nickel silicon bronze alloy materials.

[0135] Table 1. Effects of Examples 1-6 and Comparative Examples 1-2 on the hardness (HB) and conductivity (%IACS) of low-nickel silicon bronze alloy materials before and after brazing.

[0136]

[0137] The difference between Comparative Example 1 and Example 1 is that the raw materials, by mass percentage, include Ni: 2.05 wt.%, Cr: 0.13 wt.%, Zr: 0.2 wt.%, Si: 0.67 wt.%, P: 0.0004 wt.%, and the balance Cu.

[0138] The difference between Comparative Example 2 and Example 1 is that the raw materials, by mass percentage, include Ni: 1.36 wt.%, Cr: 0.546 wt.%, Si: 0.456 wt.%, P: 0.01 wt.%, and the balance Cu.

[0139] As can be seen from Table 1, the Ni content in Comparative Example 1 was too high, and although the hardness increased, the electrical conductivity decreased significantly. The increase in hardness was less than the decrease in electrical conductivity. In Comparative Example 2, the Cr content was too high and Zr was lacking. The hardness was improved compared to Examples 1-6, but the effect decreased significantly after brazing, and the electrical conductivity was poor before and after brazing. Therefore, Comparative Example 1 and Comparative Example 2 were not as good as Examples 1-6 in general.

[0140] Comparing Examples 1-6, it can be seen that the Ni and Cr content affects the hardness and electrical conductivity of the low-nickel silicon bronze alloy material. The overall effect of Examples 4-6 is better than that of Examples 2-3, but the improvement is small. The effect of Ni and Cr being too high or too low will be reduced compared to Example 1. Therefore, the element content distribution of Example 1 is better.

[0141] 2. To investigate the effects of each step in the preparation process on the hardness and conductivity of low-nickel silicon bronze alloy materials.

[0142] Table 2. Effects of Examples 7-18 on the hardness (HB) and conductivity (%IACS) of copper-zirconium alloy rings.

[0143]

[0144] As shown in Table 2, the hardness of Examples 8, 10, 14 and 18 is improved compared to Example 1, but the improvement is less than the decrease in conductivity. Therefore, overall, the parameter effect of Example 1 is relatively better.

[0145] 3. Investigate the effects of degassing and deoxidation on the hardness and conductivity of low-nickel silicon bronze alloy materials.

[0146] Table 3. Effects of Examples 19-29 and Comparative Examples 3-5 on the hardness (HB) and conductivity (%IACS) of low-nickel silicon bronze alloy materials.

[0147]

[0148] The difference between Comparative Example 3 and Example 19 is that the nitrogen flow rate remained constant during the latter half of the melting process.

[0149] The difference between Comparative Example 4 and Example 19 is that the rate at which the purifying agent is added remains constant during the latter half of the melting process.

[0150] The difference between Comparative Example 5 and Example 19 is that the purifying agent comprises zinc oxide, silicon carbide, and sodium fluoride in a mass ratio of 1.502:1:0.5.

[0151] As can be seen from the results in Table 3, Comparative Example 3 lacked the change in airflow rate, Comparative Example 4 lacked the change in the addition rate of purifying agent, and the purifying agent in Comparative Example 5 lacked sodium potassium silicate. Therefore, the overall effect of Comparative Examples 3 to 5 was reduced compared with Examples 19 to 29.

[0152] Comparing Examples 19-29, it can be seen that excessively slow or fast nitrogen flow rate, insufficient or excessive amount of purifying agent, excessively slow or fast nitrogen flow rate reduction, excessively slow or fast purifying agent addition rate reduction, and insufficient or excessive proportion of potassium sodium silicate in the purifying agent will all reduce the improvement effect on the hardness or conductivity of low-nickel silicon bronze alloy materials. Therefore, considering all factors, Example 19 has a relatively better effect.

[0153] Table 4. Average hardness (HB) and average conductivity (%IACS) of low-nickel silicon bronze alloy materials after brazing, compared with Examples 1-18 and Examples 19-29.

[0154]

[0155] As shown in Table 4, the average hardness and average conductivity of Examples 1-18 after brazing are higher in Examples 1-19-29 than in Examples 1-18. Therefore, Examples 19-29 are more effective in further removing impurities and purifying low-nickel silicon bronze alloy materials during degassing and deoxidation.

[0156] 4. Investigate the effect of variable speed casting on the hardness and conductivity of low-nickel silicon bronze alloy materials.

[0157] Table 5. Effects of Examples 30-34 and Comparative Example 6 on the hardness (HB) and conductivity (%IACS) of low-nickel silicon bronze alloy materials.

[0158]

[0159] The difference between Comparative Example 6 and Example 30 is that the magnetic field strength remains unchanged;

[0160] As shown in Table 5, the hardness and conductivity of the control example 6, which lacks the change of magnetic field, are lower than those of examples 30-34. Therefore, the change of magnetic field has a certain impact on improving the hardness and conductivity of low-nickel silicon bronze alloy materials. Comparing examples 30-34, it can be seen that if the parameters during the first dispersion treatment are too low or too high, or the parameters during the second dispersion treatment are too low or too high, the hardness or conductivity will be reduced, thereby reducing the overall performance of the low-nickel silicon bronze alloy materials. Therefore, in summary, the effect of example 30 is relatively better.

Claims

1. A method for preparing a low-nickel silicon bronze alloy material, characterized in that, Includes the following steps: S1, Smelting: The raw materials, by mass percentage, include: 1~1.6 wt.% Ni, 0.1~0.25 wt.% Cr, 0.2~0.35 wt.% Si, 0.01~0.03 wt.% P, with the balance being Cu; The above raw materials are placed in a vacuum induction furnace for melting. The melting temperature is 1300~1450℃, the vacuum degree is <5Pa, and the melting time is 75~85min. During the melting process, degassing and deoxidation are maintained. Degassing and deoxygenation include the following steps: During the first half of the melting process, inert gas is uniformly introduced into the vacuum induction furnace at a flow rate of 350~400 NL / min, and a purifying agent accounting for 0.5~1.5% of the alloy melt mass is added uniformly at the same time as the inert gas is introduced. In the latter half of the melting process, the inert gas flow rate is gradually reduced from 15 to 25 NL / min, and for every 60 NL / min reduction in the inert gas flow rate, the amount of purifying agent added per minute is reduced by 0.05 to 0.08 wt.%, until the melting process is completed. The purifying agent comprises zinc oxide, silicon carbide, sodium fluoride, and sodium potassium silicate in a mass ratio of 1~2:1:0.5:0.02; the inert gas is nitrogen. S2, Casting: The alloy melt is cast at a temperature of 1250~1350℃ and is cast using a bottom casting system to obtain an alloy ingot, which is then machined. S3, Hot Forging: The alloy ingot obtained in step S2 is heated to 900~950℃, the forging fixture is preheated to 250~350℃, and the alloy ingot is hot forged 3 times. The initial forging temperature of the hot forging is 850~900℃, and the final forging temperature is 640~660℃. After the hot forging is completed, the alloy billet is obtained. S4. Solution treatment: The billet obtained in step S3 is heated to 850~900℃ at a heating rate of 19~22℃ / min and held for 60~90min. After the holding period, the billet is removed from the furnace and cooled to room temperature with water. S5, Cold Forging: The billet obtained in step S4 is cold forged, and the billet is trimmed after the cold forging is completed; S6. Time-sensitive processing: The billet obtained in step S5 is heated to 450~500℃ at a heating rate of 5~8℃ / min and held for 3~5 hours. After the holding period, the billet is cooled to 90~100℃ and then removed from the furnace and air-cooled to room temperature.

2. The method for preparing a low-nickel silicon bronze alloy material according to claim 1, characterized in that, The Cu, Cr, Si, and P are placed in the vacuum induction furnace in the form of electrolytic copper plates, copper-chromium master alloys, copper-silicon master alloys, and phosphorus-copper master alloys, and the Ni is placed in the form of electrolytic nickel plates.

3. The method for preparing a low-nickel silicon bronze alloy material according to claim 1, characterized in that, The Cr content in the raw materials is 0.1~0.2 wt.%.

4. The method for preparing a low-nickel silicon bronze alloy material according to claim 1, characterized in that, The Ni content in the raw material is 1.3~1.5 wt.%.

5. The method for preparing a low-nickel silicon bronze alloy material according to claim 1, characterized in that, In step S3, the hot forging includes upsetting and drawing.

6. The method for preparing a low-nickel silicon bronze alloy material according to claim 1, characterized in that, In step S5, the cold forging is upsetting, and the deformation of the billet is 20-30%.

7. The method for preparing a low-nickel silicon bronze alloy material according to claim 1, characterized in that, In step S2, the casting temperature is kept constant, and variable speed casting is used. The steps are as follows: The initial casting rate is 0.15~0.20 kg / s, and an initial magnetic field is applied during casting. After casting for 20~25 seconds, a first dispersion treatment is performed. Then, the casting rate is increased to 1.2~1.4 times the initial rate, and the magnetic field strength is increased by 2~3 times compared to the initial magnetic field, which is maintained for 15~20 seconds for a second dispersion treatment. Finally, the casting rate is reduced to the initial rate and the magnetic field is turned off until casting is completed. The initial magnetic field has a pulse frequency of 350~750Hz and a magnetic field strength of 4~6T.

8. The application of the low-nickel silicon bronze alloy material prepared by the preparation method according to any one of claims 1 to 7, characterized in that, The low-nickel silicon bronze alloy material is used in squirrel-cage asynchronous motors and continuous casting machines.

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