CN115404366A - Environment-friendly preparation method of fine-grain copper-chromium electrical contact material - Google Patents
Environment-friendly preparation method of fine-grain copper-chromium electrical contact material Download PDFInfo
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- CN115404366A CN115404366A CN202210954024.5A CN202210954024A CN115404366A CN 115404366 A CN115404366 A CN 115404366A CN 202210954024 A CN202210954024 A CN 202210954024A CN 115404366 A CN115404366 A CN 115404366A
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Abstract
The invention discloses an environment-friendly preparation method of a fine-grain copper-chromium electrical contact material, which comprises the following steps: s1, deoiling, vacuum cleaning and drying, S2, environmental-friendly weak acid deoxidation, S3, liquid nitrogen low-temperature cooling and pre-crushing, S4, mechanical crushing, S5, vibrating, sieving and magnetic separation, S6, copper sheet wrapping, cold isostatic pressing and prefabricating electrode bars, S7, turning outer circles, vacuum sintering, S8, arc melting, and S9, sawing and slicing. The method directly utilizes the crushed copper-chromium alloy scraps to smelt, well solves the problems of high cost, long period and high energy consumption of the conventional atomized copper-chromium alloy powder making process, and the prepared copper-chromium contact material has the advantages of low gas content, less impurities and high purity, improves the material segregation to a certain extent, has more uniform tissue and fine and dispersed chromium phase, and further improves the material performance.
Description
Technical Field
The invention relates to the technical field of copper-chromium electrical contact materials, in particular to an environment-friendly preparation method of a fine-grain copper-chromium electrical contact material.
Background
At present, in the field of medium and high voltage, vacuum technology is mature day by day, and a vacuum switch has a plurality of advantages: excellent explosion-proof performance and high safety and reliability; excellent environmental protection performance; the overhaul period is long; the operation power is small, and the environmental noise is small; excellent low temperature performance, etc. The copper-chromium contact material has the characteristics of excellent electric conductivity, heat conduction, voltage resistance, arc ablation resistance and the like, and is widely applied to a medium-high voltage vacuum arc extinguishing chamber as a core component contact material. The preparation of the copper-chromium contact product mainly comprises two parts, namely material preparation and finished product processing. The prior preparation process of the copper-chromium contact material comprises four processes of mixed powder sintering, vacuum infiltration, vacuum casting and electric arc melting; the finished product is mainly processed by turning and milling. However, due to the high standard technical performance requirements of the materials of the copper-chromium contact products, the waste is often serious in the finished product processing process, and particularly after the materials are prepared, the scraps produced in the finished product processing process cannot be well recycled. In addition, the four existing material preparation processes basically need pure copper and pure chromium for smelting, the raw material cost is high, the selectivity of each process to the raw material is different, and the problems of material segregation, large chromium phase particles, dendrites and the like exist in the process of smelting due to process limitations, so that the material utilization rate is further reduced, and excessive waste materials are generated.
At present, 3 methods are mainly used for recovering scraps generated in the copper-chromium contact processing process. The conventional mechanical crushing and pulverizing process often needs to be carried out for multiple times due to the fact that the use requirement cannot be met, so that scraps are seriously heated and oxidized in the crushing process, and most impurities in the prepared powder cannot be recycled or used for preparing contact materials; when the copper-chromium alloy waste is recovered by a chemical method, the copper is generally separated and purified by adopting electrochemistry, and then the residual chromium is subjected to hydrogen reduction and ball milling for powder making, although the purity of the recovered powder is higher, a large amount of waste liquid and wastewater can be generated because some chemical solvents are used in the electrochemical separation and purification procedure, the treatment difficulty is high, the treatment cost outside the treatment is also high, the problems of environmental protection, safety, large pollution and the like exist, and the development requirement of environmental protection is not met. In recent years, the vacuum induction atomization method is used for recycling the copper-chromium alloy powder in the industry to prepare the alloy powder, but the problems of high cost, long preparation period and high energy consumption are not widely popularized.
Under the trend, the invention develops an environment-friendly preparation method of the high-performance fine-grain copper-chromium electrical contact material through continuous experimental research.
Disclosure of Invention
In order to solve the technical problems, the technical scheme of the invention is as follows:
an environment-friendly preparation method of a fine-grain copper-chromium electrical contact material comprises the following steps:
s1, deoiling, vacuum cleaning and drying:
carrying out deoiling, vacuum cleaning and drying treatment on copper-chromium alloy scraps generated in the copper-chromium contact processing process in a vacuum environment;
s2, environmental-friendly weak acid deoxidation:
carrying out environmental-friendly weak acid washing and ultrasonic cleaning on the copper-chromium alloy scrap material treated in the step S1 to remove local oxidation on the surface of the alloy scrap material, then carrying out deionized water ultrasonic cleaning, dehydrating and hydrocarbon cleaning, and carrying out vacuum drying for later use;
s3, liquid nitrogen low-temperature cooling pre-crushing:
immersing the copper-chromium alloy scraps processed in the step S2 into liquid nitrogen for cooling, and matching with a low-temperature crusher to ensure that the copper-chromium alloy scraps are synchronously pre-crushed while being embrittled at a low temperature;
s4, mechanical crushing:
mechanically crushing the copper-chromium alloy scraps after the S3 pre-crushing to prepare copper-chromium alloy particles with the average thickness of less than 0.5mm and the average length of less than 2mm;
s5, vibrating, sieving and magnetic separating:
the copper-chromium alloy particles obtained after the mechanical crushing of the S4 pass through an 80-mesh vibrating screen, a spiral magnetic separation device (such as an SQ-101 spiral magnetic separator) is added at the bottom of the screen, and the spiral magnetic separation device is added at the bottom of the screen so as to remove most of Fe powder impurities in the original copper-chromium alloy scraps and introduced in the mechanical crushing process;
s6, copper sheet wrapping, cold isostatic pressing and electrode bar prefabricating:
smoothly spreading a layer of high-purity oxygen-free copper sheet on the inner side of the rubber sleeve, uniformly filling the copper-chromium alloy particles treated by S5 into the rubber sleeve, compacting, wherein the thickness of the copper sheet is 0.05-3.0 mm, the specification of the rubber sleeve is 50-200 mm, the powder filling weight is 10-50 kg/root, and then performing cold isostatic pressing to obtain a prefabricated electrode bar, wherein the cold isostatic pressing pressure is 100-600 Mpa, and the pressure maintaining time is 1-60 min;
s7, turning an outer circle and vacuum sintering:
removing copper sheets from the prefabricated electrode bar obtained in the step S6 by turning, primarily heating and drying in a vacuum drying box at the drying temperature of 50-120 ℃, then loading the dried prefabricated electrode bar into a sintering mold, then performing vacuum sintering degassing, and synchronously utilizing the mold for straightening; after sintering, introducing argon for blowing and cooling when the temperature is reduced to 400 ℃, and discharging and naturally cooling to room temperature when the temperature is 60 ℃;
s8, arc melting:
carrying out arc melting on the electrode rod subjected to vacuum sintering in the S7 consumable arc melting furnace by adopting low voltage and large current to obtain an ingot;
s9, sawing and slicing:
and (4) roughly turning the outer circle, sawing a riser and a negative plate on the cast ingot obtained after the S8 electric arc melting, thus obtaining the environment-friendly fine-grain copper-chromium electrical contact material.
Description of the drawings: the method effectively utilizes the copper-chromium alloy scraps or powder after pretreatment to carry out vacuum consumable arc melting, mainly uses copper-chromium alloy sawdust as a main material, removes surface oil contamination impurities and oxidation through pretreatment, carries out low-temperature liquid nitrogen cooling and embrittlement pre-crushing, carries out mechanical primary crushing, obtains alloy scraps or powder with high purity and low gas through sieving and magnetic separation, and prepares the high-performance copper-chromium contact material through cold isostatic pressing, vacuum sintering and arc melting.
Further, in the above scheme, in step S1, the deoiling vacuum cleaning and drying process specifically includes: the method adopts an environment-friendly hydrocarbon cleaning machine to carry out vacuum negative pressure cleaning in a vacuum environment, and the cleaning parameters are as follows: primary steam degreasing for 30-120 s, ultrasonic cleaning for 30-180 s, spraying for 30-90 s, secondary steam degreasing for 30-180 s, and then vacuum drying for 150-480 s.
Further, in the above scheme, in the step S2, the cleaning agent used for the environmental-friendly weak acid washing and ultrasonic cleaning is prepared from an activation cleaning agent stock solution and deionized water according to a volume ratio of 1; the activating cleaning agent stock solution comprises the following components in percentage by mass: 1-10% of brightener, 1-6% of alkyl glycoside, 1-3% of acetic acid, 1-10% of citric acid, 5-30% of fatty alcohol-polyoxyethylene ether and the balance of water; the method for environmental-friendly weak acid washing and ultrasonic cleaning comprises the following steps: placing the copper-chromium alloy scraps into a cleaning frame, then placing the copper-chromium alloy scraps into an activation tank together, so that the liquid surface of an activation cleaning agent is submerged over the surface of the copper-chromium alloy scraps, the temperature of activation cleaning is 25-60 ℃, the time of activation cleaning is 60-300 s, the water dripping time is 15-90 s, and the pH value of the activation cleaning agent is kept at 1-2.
Further, in the above scheme, in the step S3, the cooling temperature is-140 ℃ to-75 ℃, the time is 1 to 3 hours, the rotation speed of the low-temperature pulverizer is 15 to 100r/min, the average thickness of the pre-crushed copper-chromium alloy scraps is less than 1mm, and the average length is less than 3mm.
Further, in the above scheme, in the step S4, argon with a purity of 99.9% is introduced during the mechanical crushing process, the scraps are protected from being oxidized by the inert gas of argon, the flow rate of argon purging is adjusted to be 20-80 m/S, a part of heat is taken away, it is ensured that the contact is not overheated during the crushing process, and the quality is stable.
Further, in the above scheme, in the step S5, the frequency of the vibrating screen is controlled by a variable frequency motor, and the inclination angle of the screen surface of the vibrating screen is controlled to be 10 to 25 °; the frequency of the spiral magnetic separation device is 15-60 Hz, and the translation frequency is 10-30 Hz; the feeding frequency is 5 to 50Kg/h.
Further, in the above scheme, in the step S7, the copper sheet is removed by turning, and the turning thickness is 0.5 to 3mm, and is determined according to the straightness of the electrode rod.
Further, in the above scheme, in the step S7 of vacuum sintering degassing, the charging amount per time does not exceed 1500kg, sintering is performed by adopting a gradient heating manner, the maximum sintering temperature is 900-1080 ℃, the heat preservation time is 1-10 h, the argon pressure is 0.1-0.8 Mpa, and the vacuum degree is controlled to be higher than 1 × 10 in the sintering process -1 pa。
Further, in the above scheme, in the step S8, when the arc melting is performed with low voltage and large current, the melting point current is 1.0K to 20KA, the arc voltage is 5V to 50V, and the number of short circuits in the melting process is less than or equal to 3 times.
Further, in the above scheme, in step S8, after the arc melting is completed, water cooling is performed, and meanwhile 100-600mba argon is charged to cool for 1-120min, and the furnace is taken out, where the environmental temperature and humidity requirements are as follows: temperature is less than or equal to 30 ℃, humidity is less than or equal to 60 percent RH.
Compared with the prior art, the beneficial effects of the invention are embodied in the following points:
firstly, the alloy scraps produced in the machining process of finished products are effectively treated and recycled, so that the production cost is reduced, the performance of the contact material is effectively improved, the market competitiveness is realized, the industrial mass production is realized, the national green circular economy development requirement is met, and the popularization significance is great.
Secondly, the method of the invention directly utilizes the crushed copper-chromium alloy scraps or powder for smelting, thereby well solving the problems of high cost, long period and large energy consumption of the existing atomized copper-chromium alloy powder preparation; the problems that the traditional machine is seriously oxidized when repeatedly crushing and pulverizing, the impurities are too much, the recovery and the utilization cannot be realized, and the problems of environmental pollution, high pollution and the like caused by the separation and recovery of the copper-chromium alloy waste by a chemical method are solved.
Thirdly, the copper-chromium contact material prepared by the method has the advantages of low gas content, less impurities, high purity, improvement on material segregation to a certain extent, more uniform structure, fine and dispersed chromium phase distribution and further improvement on material performance.
Drawings
FIG. 1 is an SEM 100-fold morphology of copper-chromium alloy particles obtained after the treatment of steps S1-S5 in example 1 of the present invention;
FIG. 2 is an appearance diagram of a product obtained by processing in steps S6, S7 and S8 in sequence in example 1 of the present invention;
wherein a is an appearance diagram of a product after copper clad and cold isostatic pressing;
b is an appearance diagram of a product after cylindrical turning and vacuum sintering;
c is an appearance diagram of a product obtained after electric arc melting;
FIG. 3 is a phase diagram of 50 times the gold phase of the Cu-Cr electrical contact material prepared in example 2 of the present invention;
fig. 4 is a 100-fold gold phase diagram of the cu-cr electrical contact material prepared in example 2 of the present invention.
Detailed Description
Example 1
An environment-friendly preparation method of a fine-grain copper-chromium electrical contact material comprises the following steps:
s1, deoiling, vacuum cleaning and drying:
carrying out deoiling, vacuum cleaning and drying treatment on copper-chromium alloy scraps generated in the copper-chromium contact processing process in a vacuum environment, and specifically comprising the following steps: the method adopts an environment-friendly hydrocarbon cleaning machine to carry out vacuum negative pressure cleaning in a vacuum environment, and the cleaning parameters are as follows: degreasing for 30s by primary steam, cleaning for 30s by ultrasonic, spraying for 30s, degreasing for 30s by secondary steam, and then drying for 150s in vacuum;
s2, environmental-friendly weak acid deoxidation:
carrying out environment-friendly weak acid washing and ultrasonic cleaning on the copper-chromium alloy scrap material treated in the step S1 to remove local oxidation on the surface of the alloy scrap material, then carrying out deionized water ultrasonic cleaning, dehydrating and hydrocarbon cleaning, and carrying out vacuum drying for later use;
the cleaning agent adopted by the environmental-friendly weak acid washing ultrasonic cleaning is prepared from an activation cleaning agent stock solution and deionized water according to the volume ratio of 1; the activating cleaning agent stock solution comprises the following components in percentage by mass: 1% of brightener, 1% of alkyl glycoside, 1% of acetic acid, 1% of citric acid, 5% of fatty alcohol-polyoxyethylene ether and the balance of water; the method for environmental-friendly weak acid washing and ultrasonic cleaning comprises the following steps: placing the copper-chromium alloy scraps into a cleaning frame, then placing the copper-chromium alloy scraps into an activation tank together, so that the liquid surface of an activation cleaning agent is submerged over the surface of the copper-chromium alloy scraps, the temperature of activation cleaning is 25 ℃, the time of activation cleaning is 60s, the water dripping time is 15s, and the pH value of the activation cleaning agent is kept to be 1;
s3, liquid nitrogen low-temperature cooling pre-crushing:
immersing the copper-chromium alloy scraps treated in the step S2 into liquid nitrogen for cooling, and matching with a low-temperature crusher to ensure that the copper-chromium alloy scraps are synchronously pre-crushed while embrittling at low temperature;
wherein the cooling temperature is-140 ℃, the cooling time is 1h, the rotating speed of the low-temperature pulverizer is 15r/min, the average thickness of the pre-crushed copper-chromium alloy scraps is 0.8mm, and the average length is 1.2mm;
s4, mechanical crushing:
mechanically crushing the copper-chromium alloy scraps after the S3 pre-crushing to prepare copper-chromium alloy particles with the average thickness of 0.3mm and the average length of 0.8 mm;
wherein, argon with the purity of 99.9 percent is introduced in the mechanical crushing process, the scraps are protected from being oxidized by argon inert gas, the flow velocity of argon purging is adjusted to be 20m/s, a part of heat is taken away, the contact crushing process is ensured not to be overheated, and the quality is stable;
s5, vibrating, sieving and magnetic separating:
the copper-chromium alloy particles obtained after the mechanical crushing of the S4 pass through an 80-mesh vibrating screen, and a spiral magnetic separation device (such as an SQ-101 spiral magnetic separator) is added at the bottom of the screen to remove most of Fe powder impurities in the original copper-chromium alloy scraps and introduced in the mechanical crushing process; the SEM topography of the obtained copper-chromium alloy particles is shown in figure 1;
the frequency of the vibrating screen is controlled by a variable frequency motor, and the inclination angle of the screen surface of the vibrating screen is controlled to be 10 degrees; the frequency of the spiral magnetic separation device is 15Hz, the translation frequency is 10Hz, and the feeding frequency is 5Kg/h;
s6, copper sheet wrapping, cold isostatic pressing and electrode bar prefabricating:
smoothly spreading a layer of high-purity oxygen-free copper sheet on the inner side of the rubber sleeve, uniformly filling the copper-chromium alloy particles treated by S5 into the rubber sleeve, compacting, wherein the thickness of the copper sheet is 0.05mm, the specification of the rubber sleeve is 50mm, the powder loading weight is 10 kg/root, and then performing cold isostatic pressing to obtain a prefabricated electrode rod, wherein the cold isostatic pressing pressure is 100MPa, and the pressure maintaining time is 1min;
s7, turning an outer circle and vacuum sintering:
removing copper sheets of the prefabricated electrode bar obtained in the step S6 through turning, wherein the turning thickness is 0.5mm and is determined according to the straightness of the electrode bar; then primarily heating and drying in a vacuum drying box at the drying temperature of 50 ℃, then loading the dried prefabricated electrode rod into a sintering mold, then carrying out vacuum sintering and degassing, wherein the furnace loading amount is 1200kg each time, sintering is carried out by adopting a gradient heating mode, the maximum sintering temperature is 900 ℃, the heat preservation time is 1h, the argon pressure is 0.1Mpa, and the vacuum degree is controlled to be 1.3 multiplied by 10 in the sintering process -1 pa; synchronously utilizing a die to straighten; after sintering, introducing argon for blowing and cooling when the temperature is reduced to 400 ℃, and discharging from the furnace and naturally cooling to room temperature when the temperature is 60 ℃;
s8, arc melting:
arc melting the electrode rod subjected to vacuum sintering in the S7 in a vacuum consumable arc melting furnace by adopting low voltage and large current, wherein the melting point current is 1.0KA, the arc voltage is 5V, and the short circuit frequency in the melting process is less than or equal to 3 times to obtain an ingot; and (3) performing water cooling after the electric arc melting is finished, simultaneously filling 100mba argon gas for cooling for 1min, and discharging the furnace, wherein the environmental temperature and humidity requirements are as follows: RH at 20 deg.C and humidity of 40%;
s9, sawing and slicing:
and (4) roughly turning the outer circle, sawing a riser and a negative plate on the cast ingot obtained after the S8 electric arc melting, thus obtaining the environment-friendly fine-grain copper-chromium electrical contact material.
Example 2
An environment-friendly preparation method of a fine-grain copper-chromium electrical contact material comprises the following steps:
s1, deoiling, vacuum cleaning and drying:
carrying out deoiling, vacuum cleaning and drying treatment on copper-chromium alloy scraps generated in the copper-chromium contact processing process in a vacuum environment, and specifically comprising the following steps: the method adopts an environment-friendly hydrocarbon cleaning machine to carry out vacuum negative pressure cleaning in a vacuum environment, and the cleaning parameters are as follows: carrying out primary steam degreasing for 80s, carrying out ultrasonic cleaning for 110s, spraying for 60s, carrying out secondary steam degreasing for 120s, and then carrying out vacuum drying for 320s;
s2, environmental-friendly weak acid deoxidation:
carrying out environmental-friendly weak acid washing and ultrasonic cleaning on the copper-chromium alloy scrap material treated in the step S1 to remove local oxidation on the surface of the alloy scrap material, then carrying out deionized water ultrasonic cleaning, dehydrating and hydrocarbon cleaning, and carrying out vacuum drying for later use;
the cleaning agent adopted by the environmental-friendly weak acid washing ultrasonic cleaning is prepared from an activation cleaning agent stock solution and deionized water according to the volume ratio of 1; the activating cleaning agent stock solution comprises the following components in percentage by mass: 5% of brightener, 4% of alkyl glycoside, 2% of acetic acid, 6% of citric acid, 20% of fatty alcohol-polyoxyethylene ether and the balance of water; the method for cleaning the steel plate by the environment-friendly weak acid washing and ultrasonic cleaning comprises the following steps: placing the copper-chromium alloy scraps into a cleaning frame, then placing the copper-chromium alloy scraps into an activation tank together, so that the liquid surface of an activation cleaning agent is submerged over the surface of the copper-chromium alloy scraps, the temperature of activation cleaning is 45 ℃, the time of activation cleaning is 200s, the water dripping time is 50s, and the pH value of the activation cleaning agent is kept to be 1;
s3, liquid nitrogen low-temperature cooling pre-crushing:
immersing the copper-chromium alloy scraps processed in the step S2 into liquid nitrogen for cooling, and matching with a low-temperature crusher to ensure that the copper-chromium alloy scraps are synchronously pre-crushed while being embrittled at a low temperature;
wherein the cooling temperature is-100 ℃, the cooling time is 2h, the rotating speed of the low-temperature pulverizer is 60r/min, the average thickness of the pre-crushed copper-chromium alloy scraps is 0.6mm, and the average length is 2mm;
s4, mechanical crushing:
mechanically crushing the copper-chromium alloy scraps after the pre-crushing in the step S3 to prepare copper-chromium alloy particles with the average thickness of 0.2mm and the average length of 1 mm;
wherein, argon with the purity of 99.9 percent is introduced in the mechanical crushing process, the scraps are protected from being oxidized by argon inert gas, the flow velocity of argon purging is adjusted to be 50m/s, a part of heat is taken away, the contact crushing process is ensured not to be overheated, and the quality is stable;
s5, vibrating, sieving and magnetic separating:
the copper-chromium alloy particles obtained after the mechanical crushing of the S4 pass through an 80-mesh vibrating screen, and a spiral magnetic separation device (such as an SQ-101 spiral magnetic separator) is added at the bottom of the screen to remove most of Fe powder impurities in the original copper-chromium alloy scraps and introduced in the mechanical crushing process;
the frequency of the vibrating screen is controlled by a variable frequency motor, and the inclination angle of the screen surface of the vibrating screen is controlled at 15 degrees; the frequency of the spiral magnetic separation device is 40Hz, the translation frequency is 20Hz, and the feeding frequency is 30Kg/h;
s6, copper sheet cladding and cold isostatic pressing of the prefabricated electrode bar:
smoothly spreading a layer of high-purity oxygen-free copper sheet on the inner side of the rubber sleeve, uniformly filling the copper-chromium alloy particles treated by S5 into the rubber sleeve, compacting, wherein the thickness of the copper sheet is 1.5mm, the specification of the rubber sleeve is 130mm, the powder loading weight is 30 kg/root, and then performing cold isostatic pressing to obtain a prefabricated electrode rod, wherein the cold isostatic pressing pressure is 350MPa, and the pressure maintaining time is 30min; the appearance of the obtained material is shown in FIG. 2 a;
s7, turning an outer circle and vacuum sintering:
removing copper sheets of the prefabricated electrode rod obtained in the step S6 through turning, wherein the turning thickness is 2mm, and is determined according to the straightness of the electrode rod; then primarily heating and drying in a vacuum drying box at the drying temperature of 100 ℃, then loading the dried prefabricated electrode rod into a sintering mold, then carrying out vacuum sintering and degassing, wherein the charging amount is 1300kg each time, sintering is carried out by adopting a gradient heating mode, the highest sintering temperature is 1000 ℃, the heat preservation time is 5h, the argon pressure is 0.5Mpa, and the vacuum degree is controlled to be 1.2 multiplied by 10 in the sintering process -1 pa; synchronously utilizing a die to straighten; after sintering, introducing argon for blowing and cooling when the temperature is reduced to 400 ℃, and discharging and naturally cooling to room temperature when the temperature is 60 ℃; the appearance of the resulting material is shown in FIG. 2 b;
s8, arc melting:
arc melting the electrode rod subjected to vacuum sintering in the S7 in a vacuum consumable arc melting furnace by adopting low voltage and large current, wherein the melting point current is 12KA, the arc voltage is 30V, and the short circuit frequency in the melting process is less than or equal to 3 times to obtain an ingot; and (3) performing water cooling after the electric arc melting is finished, simultaneously filling 400mba argon gas for cooling for 60min, and discharging the furnace, wherein the environmental temperature and humidity requirements are as follows: RH at 23 deg.C and humidity of 45%; the appearance of the resulting material is shown in FIG. 2 c;
s9, sawing and slicing:
and (4) roughly turning the outer circle, sawing a riser and a negative plate on the cast ingot obtained after the S8 electric arc melting, thus obtaining the environment-friendly fine-grain copper-chromium electrical contact material.
Example 3
An environment-friendly preparation method of a fine-grain copper-chromium electrical contact material comprises the following steps:
s1, deoiling, vacuum cleaning and drying:
carrying out deoiling, vacuum cleaning and drying treatment on a copper-chromium alloy scrap (CuCr 30) generated in the copper-chromium contact processing process in a vacuum environment, and specifically comprising the following steps: the method adopts an environment-friendly hydrocarbon cleaning machine to carry out vacuum negative pressure cleaning in a vacuum environment, and the cleaning parameters are as follows: degreasing for 120s by primary steam, cleaning for 180s by ultrasonic, spraying for 90s, degreasing for 180s by secondary steam, and then drying for 480s in vacuum;
s2, environmental-friendly weak acid deoxidation:
carrying out environmental-friendly weak acid washing and ultrasonic cleaning on the copper-chromium alloy scrap material treated in the step S1 to remove local oxidation on the surface of the alloy scrap material, then carrying out deionized water ultrasonic cleaning, dehydrating and hydrocarbon cleaning, and carrying out vacuum drying for later use;
the cleaning agent adopted by the environmental-friendly weak acid-washing ultrasonic cleaning is prepared from an activation cleaning agent stock solution and deionized water according to a volume ratio of 1; the activating cleaning agent stock solution comprises the following components in percentage by mass: 10% of brightener, 6% of alkyl glycoside, 3% of acetic acid, 10% of citric acid, 30% of fatty alcohol-polyoxyethylene ether and the balance of water; the method for environmental-friendly weak acid washing and ultrasonic cleaning comprises the following steps: placing the copper-chromium alloy scraps into a cleaning frame, then placing the cleaning frame and the copper-chromium alloy scraps into an activation tank together, so that the liquid surface of an activation cleaning agent is submerged on the surface of the copper-chromium alloy scraps, the activation cleaning temperature is 60 ℃, the activation cleaning time is 300s, the water dropping time is 90s, and the pH value of the activation cleaning agent is kept to be 2;
s3, liquid nitrogen low-temperature cooling pre-crushing:
immersing the copper-chromium alloy scraps treated in the step S2 into liquid nitrogen for cooling, and matching with a low-temperature crusher to ensure that the copper-chromium alloy scraps are synchronously pre-crushed while embrittling at low temperature;
wherein the cooling temperature is-75 ℃, the cooling time is 3h, the rotating speed of the low-temperature pulverizer is 100r/min, the average thickness of the pre-crushed copper-chromium alloy scraps is 0.9mm, and the average length is 2.8mm;
s4, mechanical crushing:
mechanically crushing the copper-chromium alloy scraps after the S3 pre-crushing to prepare copper-chromium alloy particles with the average thickness of 0.2mm and the average length of 0.6 mm;
wherein, argon with the purity of 99.9 percent is introduced in the mechanical crushing process, the scraps are protected from being oxidized by argon inert gas, the flow velocity of argon purging is adjusted to be 80m/s, a part of heat is taken away, the contact crushing process is ensured not to be overheated, and the quality is stable;
s5, vibrating, sieving and magnetically separating:
the copper-chromium alloy particles obtained after the mechanical crushing of the S4 pass through an 80-mesh vibrating screen, and a spiral magnetic separation device (such as an SQ-101 spiral magnetic separator) is added at the bottom of the screen to remove most of Fe powder impurities in the original copper-chromium alloy scraps and introduced in the mechanical crushing process;
the frequency of the vibrating screen is controlled by a variable frequency motor, and the inclination angle of the screen surface of the vibrating screen is controlled to be 25 degrees; the frequency of the spiral magnetic separation device is 60Hz, the translation frequency is 30Hz, and the feeding frequency is 50Kg/h;
s6, copper sheet wrapping, cold isostatic pressing and electrode bar prefabricating:
smoothly spreading a layer of high-purity oxygen-free copper sheet on the inner side of the rubber sleeve, uniformly filling the copper-chromium alloy particles treated by S5 into the rubber sleeve, compacting, wherein the thickness of the copper sheet is 3.0mm, the specification of the rubber sleeve is 200mm, the powder filling weight is 50 kg/root, and then performing cold isostatic pressing to obtain a prefabricated electrode rod, wherein the cold isostatic pressing pressure is 600MPa, and the pressure maintaining time is 60min;
s7, turning an outer circle and vacuum sintering:
obtaining S6The copper sheet of the prefabricated electrode rod is removed by turning, the turning thickness is 3mm, and the turning thickness is determined according to the straightness of the electrode rod; then primarily heating and drying in a vacuum drying box at 120 ℃, then loading the dried prefabricated electrode rod into a sintering mold, then carrying out vacuum sintering and degassing, wherein the charging amount is 1460kg each time, sintering is carried out by adopting a gradient heating mode, the highest sintering temperature is 1080 ℃, the heat preservation time is 10 hours, the argon pressure is 0.8Mpa, and the vacuum degree is controlled to be 2 multiplied by 10 in the sintering process -1 pa; synchronously utilizing a die to straighten; after sintering, introducing argon for blowing and cooling when the temperature is reduced to 400 ℃, and discharging and naturally cooling to room temperature when the temperature is 60 ℃;
s8, arc melting:
carrying out arc melting on the electrode rod subjected to vacuum sintering in S7 in a vacuum consumable arc melting furnace by adopting low voltage and large current, wherein the melting point current is 20KA, the arc voltage is 50V, and the short circuit frequency in the melting process is less than or equal to 3 times to obtain an ingot; and (3) performing water cooling after the electric arc melting is finished, simultaneously filling 600mba argon for cooling for 120min, and discharging the furnace, wherein the environmental temperature and humidity requirements are as follows: RH at 28 ℃ and 52% humidity;
s9, sawing and slicing:
and (4) roughly turning the outer circle, sawing a riser and a negative plate on the cast ingot obtained after the S8 electric arc melting, thus obtaining the environment-friendly fine-grain copper-chromium electrical contact material.
The environment-friendly fine-grain copper-chromium electrical contact material prepared by the method of embodiment 2 of the invention is sampled and detected, the content of the measured product elements is shown in table 1, and the performance parameters of the product are shown in table 2:
table 1 elemental content of product
TABLE 2 product Performance parameters Table
| Conductivity Ms/m | Hardness HB | Density g/cm 3 |
| 29.7～31.3 | 87.0～87.9 | 8.27 |
And the gold phase diagram of the obtained environment-friendly fine-grain copper-chromium electrical contact material is shown in figures 2 and 3.
As can be seen from tables 1 and 2, the copper-chromium contact material prepared by the preparation method disclosed by the invention is low in gas content, less in impurity and high in purity.
As can be seen from the figures 3 and 4 and the table 2, the copper-chromium contact material prepared by the preparation method has uniform tissue, fine and dispersed chromium phase, certain improvement on material segregation and further improvement on material performance.
Claims (10)
1. An environment-friendly preparation method of a fine-grain copper-chromium electrical contact material is characterized by comprising the following steps:
s1, deoiling, vacuum cleaning and drying:
carrying out deoiling, vacuum cleaning and drying treatment on copper-chromium alloy scraps generated in the copper-chromium contact processing process in a vacuum environment;
s2, environmental-friendly weak acid deoxidation:
carrying out environmental-friendly weak acid washing and ultrasonic cleaning on the copper-chromium alloy scrap material treated in the step S1 to remove local oxidation on the surface of the alloy scrap material, then carrying out deionized water ultrasonic cleaning, dehydrating and hydrocarbon cleaning, and carrying out vacuum drying for later use;
s3, liquid nitrogen low-temperature cooling pre-crushing:
immersing the copper-chromium alloy scraps processed in the step S2 into liquid nitrogen for cooling, and matching with a low-temperature crusher to ensure that the copper-chromium alloy scraps are synchronously pre-crushed while being embrittled at a low temperature;
s4, mechanical crushing:
mechanically crushing the copper-chromium alloy scraps after the S3 pre-crushing to prepare copper-chromium alloy particles with the average thickness of less than 0.5mm and the average length of less than 2mm;
s5, vibrating, sieving and magnetically separating:
enabling the copper-chromium alloy particles obtained after the mechanical crushing in the step S4 to pass through an 80-mesh vibrating screen, and adding a spiral magnetic separation device at the bottom of the screen to remove most of Fe powder impurities in the original copper-chromium alloy scraps and introduced in the mechanical crushing process;
s6, copper sheet wrapping, cold isostatic pressing and electrode bar prefabricating:
smoothly spreading a layer of high-purity oxygen-free copper sheet on the inner side of the rubber sleeve, uniformly filling the copper-chromium alloy particles treated by S5 into the rubber sleeve, compacting, wherein the thickness of the copper sheet is 0.05-3.0 mm, the specification of the rubber sleeve is 50-200 mm, the powder filling weight is 10-50 kg/root, and then performing cold isostatic pressing to obtain a prefabricated electrode bar, wherein the cold isostatic pressing pressure is 100-600 Mpa, and the pressure maintaining time is 1-60 min;
s7, turning an outer circle and vacuum sintering:
removing copper sheets from the prefabricated electrode bar obtained in the step S6 by turning, primarily heating and drying in a vacuum drying box at the drying temperature of 50-120 ℃, then loading the dried prefabricated electrode bar into a sintering mold, then performing vacuum sintering degassing, and synchronously utilizing the mold for straightening; after sintering, introducing argon for blowing and cooling when the temperature is reduced to 400 ℃, and discharging and naturally cooling to room temperature when the temperature is 60 ℃;
s8, arc melting:
carrying out arc melting on the electrode rod subjected to vacuum sintering in the S7 consumable arc melting furnace by adopting low voltage and large current to obtain an ingot;
s9, sawing and slicing:
and (4) roughly turning the outer circle, sawing a riser and a negative plate on the cast ingot obtained after the S8 electric arc melting, thus obtaining the environment-friendly fine-grain copper-chromium electrical contact material.
2. The environment-friendly preparation method for the fine-grained copper-chromium electrical contact material according to claim 1, wherein in the step S1, the deoiling, vacuum cleaning and drying treatment specifically comprises the following steps: the method adopts an environment-friendly hydrocarbon cleaning machine to carry out vacuum negative pressure cleaning in a vacuum environment, and the cleaning parameters are as follows: primary steam degreasing for 30-120 s, ultrasonic cleaning for 30-180 s, spraying for 30-90 s, secondary steam degreasing for 30-180 s, and then vacuum drying for 150-480 s.
3. The environment-friendly preparation method of the fine-grained copper chromium electrical contact material as claimed in claim 1, wherein in the step S2, the cleaning agent adopted for the environment-friendly weak acid washing and ultrasonic cleaning is prepared from an activated cleaning agent stock solution and deionized water according to a volume ratio of 1; the activating cleaning agent stock solution comprises the following components in percentage by mass: 1-10% of brightener, 1-6% of alkyl glycoside, 1-3% of acetic acid, 1-10% of citric acid, 5-30% of fatty alcohol-polyoxyethylene ether and the balance of water; the method for environmental-friendly weak acid washing and ultrasonic cleaning comprises the following steps: placing the copper-chromium alloy scraps into a cleaning frame, then placing the copper-chromium alloy scraps into an activation tank together, so that the liquid surface of an activation cleaning agent is submerged over the surface of the copper-chromium alloy scraps, the temperature of activation cleaning is 25-60 ℃, the time of activation cleaning is 60-300 s, the water dripping time is 15-90 s, and the pH value of the activation cleaning agent is kept at 1-2.
4. The environment-friendly preparation method of the fine-grained copper chromium electrical contact material as claimed in claim 1, wherein in the step S3, the cooling temperature is-140 ℃ to-75 ℃, the time is 1 to 3 hours, the rotating speed of the low-temperature crusher is 15 to 100r/min, the average thickness of the pre-crushed copper chromium alloy scraps is less than 1mm, and the average length is less than 3mm.
5. The environment-friendly preparation method of the fine-grained copper chromium electrical contact material as claimed in claim 4, wherein in the step S4, argon with the purity of 99.9% is introduced in the mechanical crushing process, and the flow rate of argon purging is adjusted to be 20-80 m/S.
6. The environment-friendly preparation method of the fine-grained copper chromium electrical contact material as claimed in claim 1, wherein in the step S5, the frequency of the vibrating screen is controlled by a variable frequency motor, and the inclination angle of the screen surface of the vibrating screen is controlled to be 10-25 °; the frequency of the spiral magnetic separation device is 15-60 Hz, and the translation frequency is 10-30 Hz; the feeding frequency is 5 to 50Kg/h.
7. The environment-friendly preparation method of the fine-grained copper-chromium electrical contact material as claimed in claim 1, wherein in the step S7, the copper skin is removed by turning, and the turning thickness is 0.5-3 mm, and is determined according to the straightness of the electrode rod.
8. The environment-friendly preparation method of the fine-grained copper chromium electrical contact material according to claim 1, characterized in that in the step S7 of vacuum sintering degassing, the charging amount is not more than 1500kg each time, the sintering is carried out by adopting a gradient heating mode, the highest sintering temperature is 900-1080 ℃, the heat preservation time is 1-10 h, the argon pressure is 0.1-0.8 Mpa, and the vacuum degree is controlled to be higher than 1 x 10 in the sintering process -1 pa。
9. The method of claim 1, wherein in step S8, when arc melting is performed with low voltage and large current, the melting point current is 1.0K-20 KA, the arc voltage is 5-50V, and the number of short circuits during melting is less than or equal to 3.
10. The environment-friendly preparation method of the fine-grained copper chromium electrical contact material as claimed in claim 1, wherein in the step S8, water cooling is performed after the electric arc melting is completed, and 100-600mba argon is simultaneously charged for cooling for 1-120min and then discharged from the furnace, and the environmental temperature and humidity requirements are as follows: temperature is less than or equal to 30 ℃, humidity is less than or equal to 60 percent RH.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108441670A (en) * | 2018-03-19 | 2018-08-24 | 陕西斯瑞新材料股份有限公司 | The method for preparing 50 contact material of copper chromium using vacuum consumable electrode arc furnace |
| CN111822725A (en) * | 2020-09-21 | 2020-10-27 | 陕西斯瑞新材料股份有限公司 | Preparation method of alloy powder for recycling copper-chromium alloy |
| CN112974810A (en) * | 2021-05-07 | 2021-06-18 | 陕西斯瑞新材料股份有限公司 | Preparation method of high-performance copper-chromium alloy contact |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108441670A (en) * | 2018-03-19 | 2018-08-24 | 陕西斯瑞新材料股份有限公司 | The method for preparing 50 contact material of copper chromium using vacuum consumable electrode arc furnace |
| CN111822725A (en) * | 2020-09-21 | 2020-10-27 | 陕西斯瑞新材料股份有限公司 | Preparation method of alloy powder for recycling copper-chromium alloy |
| CN112974810A (en) * | 2021-05-07 | 2021-06-18 | 陕西斯瑞新材料股份有限公司 | Preparation method of high-performance copper-chromium alloy contact |
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