Preparation process of alloy powder for fracturing pump plunger spraying

Abstract

The present application relates to the technical field of alloy powder preparation, and specifically to a preparation process for alloy powder for fracturing pump plunger spraying, the process comprising: selecting high-purity Ni, Fe, Cr, Si, B, and C as raw materials; sequentially adding the raw materials into a furnace to melt and alloy them; then extracting the slag and keeping it warm before taking it out of the furnace to obtain molten steel; using high-pressure water atomization equipment to allow high-speed water flow to impact the molten steel to break it into droplets, which are then cooled and solidified in an atomization tower to form powder and collected; and adjusting the feedback signal of the PLC system feedback controller in real time to adjust the high-pressure water temperature and the atomization chamber temperature based on the distribution characteristics of various temperature data collected and analyzed in real time during the atomization powder making process; dehydrating the water-powder mixture after taking it out of the furnace, drying it, airing it, and screening it. The present application accurately captures the impact of abnormal instantaneous temperature fluctuations on the powder making process, realizes dynamic closed-loop control of temperature parameters, and improves the sphericity and particle size uniformity of the powder.

Description

Technical Field

[0001] The present application relates to the technical field of alloy powder preparation, and in particular to a process for preparing alloy powder for spraying on a fracturing pump plunger. Background Art

[0002] In the oil and gas industry, the performance of the fracturing pump plunger, a key component, directly impacts production efficiency and costs. As the mining environment becomes increasingly complex, demands for fracturing pump plungers, such as those with increased wear and corrosion resistance, continue to rise. Alloy powder spraying technology has become an important means of improving plunger performance. By spraying alloy powder on the plunger surface, a coating with specialized properties is formed, enhancing its wear, corrosion, and erosion resistance.

[0003] However, the quality of alloy powders currently used for fracturing pump plunger spraying on the market varies greatly. In actual use scenarios, alloy powders prepared by existing processes have defects in particle size distribution, sphericity, and composition uniformity, resulting in unstable quality of the plunger coating after spraying, making it difficult to meet the requirements of suppressing acid corrosion and wear resistance, and unable to meet the needs of long-term, efficient mining. In the harsh working conditions of the fracturing pump plunger system, it is necessary to further improve the powder sphericity, working surface hardness, plunger service life, and surface roughness of the prepared alloy powder. However, in the existing preparation process, the high-pressure water temperature and the atomization chamber temperature are difficult to accurately control, resulting in uneven particle size distribution and poor sphericity of the powder, which in turn affects the flatness and density of the coating after spraying, limiting the development of fracturing pump plunger spraying technology and making it difficult to meet the oil extraction industry's demand for high-quality fracturing pump plungers. Summary of the Invention

[0004] In order to solve the above technical problems, the present application provides a preparation process of alloy powder for fracturing pump plunger spraying to solve the existing problems.

[0005] The preparation process of alloy powder for spraying fracturing pump plunger in the present application adopts the following technical solution:

[0006] One embodiment of the present application provides a process for preparing alloy powder for spraying a fracturing pump plunger, the process comprising the following steps:

[0007] S1, raw material preparation: select high-purity Ni, Fe, Cr, Si, B, and C as raw materials for preparing Ni65A alloy powder;

[0008] S2, smelting process: raw materials are added to the furnace in sequence to melt and alloy them; the slag is then removed from the furnace to obtain molten steel after heat preservation;

[0009] S3, atomization powder making: using high-pressure water atomization equipment to make high-speed water flow impact the molten steel to break it into droplets, which are then cooled and solidified in the atomization tower to form powder and collected;

[0010] During the atomization powder making process, the temperature of high-pressure water and the temperature at different positions in the atomization chamber are collected in real time;

[0011] The average anomaly score of all temperature data types at each collection moment is used as the ordinate, and the average similarity between the temperature vector formed by all temperature data types at each collection moment and the temperature vectors at all other moments is used as the abscissa to construct a rectangular coordinate system. The abscissa and ordinate values ​​of all collection moments are mapped to the coordinate system for clustering.

[0012] The comprehensive response deviation value of each temperature data is calculated by combining the average adjacent time intervals between elements in different clusters and the average difference between each temperature data and the preset target value;

[0013] At each monitoring point arranged at a preset equal time interval, the comprehensive response deviation value of each temperature data is compared with a preset deviation threshold to determine the feedback signal of the PLC system feedback controller;

[0014] Compare the various temperature data collected in real time with the pre-set values, and adjust the high-pressure water temperature and the atomization chamber temperature in real time;

[0015] S4, subsequent treatment of powder: dehydrating the water-powder mixture after it comes out of the oven, drying it, air-drying it, and screening it.

[0016] Preferably, the components of the Ni65A alloy powder are respectively arranged in weight percentage as follows: C: 0.7-0.85, B: 2.5-2.75, Si: 4.0-4.3, Cr: 16-17, Fe: ≤5, and Ni: balance.

[0017] Preferably, in the process of sequentially adding materials into the furnace, recycled materials are added once at the beginning and end of the addition.

[0018] Preferably, during alloying, the power is adjusted to 130 kW and the smelting is continued for 10 minutes.

[0019] Preferably, the calculation method of the comprehensive response deviation value of each temperature data is:

[0020]

[0021] in, Indicates the The comprehensive response deviation value of the temperature data; Indicates the The temperature data is The measured deviation value under the instantaneous fluctuation abnormal characteristics corresponding to each cluster; Indicates the The discontinuous characteristic value of the instantaneous fluctuation anomaly corresponding to the cluster, The sum of the discontinuous eigenvalues ​​of the instantaneous fluctuation anomalies corresponding to all clusters; Indicates the number of clusters divided by clustering; x represents the number of different temperature data, and i represents the number of different clusters;

[0022] The discontinuous characteristic value of the instantaneous fluctuation anomaly of each cluster is determined by the average adjacent time interval of all elements in the corresponding cluster after sorting according to the acquisition time;

[0023] The measured deviation value of each temperature data under the instantaneous fluctuation abnormal characteristics corresponding to each cluster is determined by the average difference between the corresponding temperature data in the corresponding cluster and the preset target value.

[0024] Preferably, the method for determining the feedback signal of the PLC system feedback controller is: if the comprehensive response deviation value of each temperature data at each monitoring point is greater than the corresponding deviation threshold, the comprehensive response deviation value is used as the feedback signal of the PLC system feedback controller; otherwise, the difference between the actual temperature value and the set value at the corresponding monitoring point is used as the feedback signal.

[0025] Preferably, the preset deviation threshold for each temperature data is determined by the average of the differences between each temperature data calculated in the previous batch preparation process and the preset value.

[0026] Preferably, the process of comparing the various temperature data collected in real time with pre-set values ​​and adjusting the high-pressure water temperature and the atomization chamber temperature in real time includes:

[0027] When the high-pressure water temperature is higher than the upper limit of the set value, the PLC controls the electric regulating valve to increase the opening of the cooling water pipeline, increase the cooling water volume, and reduce the high-pressure water temperature; when the temperature is lower than the lower limit of the set value, the PLC controls the electric regulating valve to decrease the opening of the cooling water pipeline, reduce the cooling water volume, and increase the high-pressure water temperature; at the same time, if the current point is the set monitoring point, the comprehensive response deviation value is judged based on the above judgment, and the feedback signal of the controller in the PLC system is corrected and adjusted;

[0028] For the temperature of the atomizing chamber, if it is higher than the upper limit of the set value, the PLC system controls to increase the flow rate of the tower jacket cooling water or reduce the cooling water temperature according to the output signal of the feedback controller; if it is lower than the lower limit of the set value, the jacket cooling water flow rate is controlled to be reduced or the cooling water temperature is increased; at the same time, if it is currently at the set monitoring point, the comprehensive response deviation value is judged based on the above judgment, and the feedback signal of the controller in the PLC system is corrected and adjusted.

[0029] Preferably, the screening is divided into: preliminary screening using an ultrasonic vibrating screen and final screening using an air flow classifier.

[0030] Preferably, the preliminary screening is divided into two steps. The first step is to use a 150-mesh upper sieve and a 260-mesh lower sieve for the first screening; the second step is to use a 150-mesh upper sieve and a 270-mesh lower sieve for the second screening.

[0031] In the above scheme, the beneficial effects are:

[0032] To meet the application requirements of fracturing pump plunger systems under extreme operating conditions, this application proposes a process for preparing alloy powder for fracturing pump plunger spray coating, as traditional spray-coated alloy powders struggle to meet key performance requirements such as sphericity, oxygen content, working surface hardness, service life, and surface roughness. Using high-purity nickel (Ni), chromium (Cr), boron (B), silicon (Si), and carbon (C) as base raw materials, this process addresses existing technical bottlenecks through alloying, slag extraction, thermal insulation, atomization, powder production, dehydration, and drying. In the core powder production process, water atomization technology is used to achieve powder formation, and a PLC intelligent control system is introduced to optimize temperature management. By establishing dynamic monitoring points during high-pressure water impingement and atomization chamber temperature monitoring, combined with a local outlier factor (LOF) algorithm and density clustering (DBSCAN) analysis, the impact of transient temperature fluctuations on the powder production process is accurately captured, enabling dynamic closed-loop control of temperature parameters. This improves powder sphericity and particle size uniformity, ensuring the stability and consistency of the powder production process. After process optimization, the hardness of the Ni65A alloy powder prepared in this application is increased to above 65HRC on the working surface, the service life of the plunger is extended to 400-500 hours, and the surface roughness is controlled within Ra0.4μm, effectively meeting the wear resistance requirements under harsh working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0034] Figure 1 A flowchart of a process for preparing alloy powder for spraying a fracturing pump plunger according to one embodiment of the present application;

[0035] Figure 2 A flow chart of the optimized control process of the high-pressure water temperature and the atomization chamber temperature during the atomization powder making process provided in one embodiment of the present application. DETAILED DESCRIPTION

[0036] To further illustrate the technical means and effectiveness of this application's implementation of the intended invention, the following, in conjunction with the accompanying drawings and preferred embodiments, details the preparation process for an alloy powder for spray coating a fracturing pump plunger, including its specific implementation, structure, features, and effectiveness. In the following description, references to different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0037] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0038] The preparation process of the alloy powder for fracturing pump plunger spraying adopted in the present application includes raw material preparation, smelting process, atomization powder making and subsequent powder processing.

[0039] An embodiment of the present application provides a preparation process of alloy powder for spraying on a fracturing pump plunger. For the preparation flow chart, please refer to Figure 1 , the specific preparation process is as follows:

[0040] Example 1:

[0041] S1, raw material preparation: select high-purity Ni, Fe, Cr, Si, B, and C as raw materials for preparing Ni65A alloy powder.

[0042] According to the composition requirements of Ni65A alloy powder, the amount of each raw material is prepared according to the weight percentage of C: 0.7, B: 2.5, Si: 4.0, Cr: 16, Fe: 3, and Ni: balance.

[0043] For example, if a furnace capacity of 100-150 kg is required to produce 100 kg of alloy powder, the amount of each raw material must be calculated based on the component ratio and raw material purity. During actual production, precise adjustments must be made based on the actual purity of the raw materials.

[0044] S2, smelting process: raw materials are added into the furnace in sequence to melt and alloy them; the slag is then removed from the furnace to obtain molten steel after heat preservation.

[0045] Charging: Using atmospheric smelting, the process is carried out in a 100-150kg furnace. First, add 5kg of small nickel plates for ignition, followed by approximately 10kg of recycled material. Subsequently, add the remaining nickel plates, metallic silicon, carbon granules, ferroboron, boron carbide, approximately 10kg of recycled powder, and finally, metallic chromium. After charging, turn on the power. As the raw materials melt, the power gradually increases, ranging from approximately 145 to 200kW. Furthermore, as the furnace capacity increases, the melting time will increase accordingly, typically to around 20 minutes.

[0046] Alloying: Reduce the power to 130KW and continue melting for 10 minutes to ensure that the raw materials in the molten steel are completely melted and fully alloyed.

[0047] Slag extraction and heat preservation: When the slag in the molten steel completely floats and covers the surface of the molten steel, reduce the power, add a small amount of glass to extract the slag in the molten steel, then add a small amount of recycled powder, and then fully open the power for heat preservation. The heat preservation time is 5~10 minutes, and the power variation range is 0~210KW.

[0048] Unloading: Wait until the molten steel is completely clear, remove the slag remaining on the surface of the molten steel, reduce the power to 80KW, and start unloading. The unloading time is 5~10 minutes.

[0049] S3, atomization powder making: high-pressure water atomization equipment is used to make high-speed water flow impact the molten steel to break it into droplets, which are then cooled and solidified in the atomization tower to form powder and collected.

[0050] The molten steel is converted into powder using a water atomization process. High-pressure water atomization equipment, including a high-pressure water pump, atomizing nozzle, atomizing tower, and powder collection device, is used. The high-pressure water pump pressurizes the water, causing the high-speed water flow to impact the molten steel, breaking the molten steel into fine droplets. The droplets cool and solidify in the atomizing tower to form powder, which is then collected in the powder collection device.

[0051] Specifically, a multi-stage centrifugal pump is used, with an operating pressure range set to 15 MPa. By adjusting the speed of the pump's variable-frequency motor, the water pressure and flow rate are precisely controlled to ensure that the high-speed water flow has sufficient kinetic energy to impact the molten steel. A two-stream pressure nozzle with a 5 mm diameter and a 60° contraction angle is used. The distance between the nozzle and the molten steel outlet is set at 100 mm, ensuring that the high-speed water flow impacts the molten steel at the optimal angle and position, breaking the molten steel into fine, uniform droplets.

[0052] The atomization tower used in this embodiment is 5m high and 1.5m in diameter. Multi-layer guide plates are set inside the tower to guide the droplets to be evenly dispersed and cooled in the tower. The tower body adopts a double-layer jacket structure, and cooling water is passed through the jacket to maintain the tower wall temperature at 40-60°C to prevent powder from adhering to the tower wall. The internal temperature of the atomization tower is controlled at 80-120°C. The temperature is monitored in real time by temperature sensors installed at different positions in the tower. The flow rate and temperature of the cooling water in the tower jacket are adjusted according to temperature changes to maintain a stable temperature in the tower.

[0053] Powder is collected using a combination of a cyclone separator and a bag dust collector. The cyclone separator's inlet velocity is controlled at 18 m / s, achieving a separation efficiency of 80% to 90%. The bag dust collector's filtration velocity is 0.8 m / min, with a filtration efficiency of no less than 99%, ensuring that the collected powder particle size meets the requirements and that dust emissions comply with standards.

[0054] In the process of water atomization powder making, the high-pressure water temperature and the atomization chamber temperature significantly affect the sphericity and particle size distribution of the powder. The high-pressure water temperature affects the metal liquid crushing effect and powder particle size by changing the water viscosity, surface tension, vaporization degree and cooling capacity: when the temperature is high, the water viscosity and surface tension decrease, which is conducive to the crushing of the metal liquid into fine powder, but too high a temperature will trigger vaporization, weaken the stability of the water jet, and lead to uneven particle size; low-temperature high-pressure water can accelerate the solidification of the metal liquid, refine the grains, and reduce the escape of oxidizing gases, reducing powder oxidation. The temperature of the atomization chamber determines the flying cooling speed of the metal droplets, which directly affects the powder particle growth, solidification process and oxidation degree. Therefore, strict control of these two temperature parameters is the key to improving powder quality. The process flow chart for optimizing the control of the high-pressure water temperature and the atomization chamber temperature in the atomization powder making process is shown in the attached figure. Figure 2 As shown, the details are as follows:

[0055] (1) During the atomization powder making process, the temperature of high-pressure water and the temperature at different positions in the atomization chamber are collected in real time.

[0056] Specifically, a Pt100 thermistor temperature sensor is installed on the outlet pipe of the high-pressure water pump to collect the temperature of the high-pressure water in real time. The sensor accuracy is ±0.5°C, and the sampling frequency is 1 time / second; a K-type thermocouple temperature sensor is installed at the top, middle and bottom of the atomization chamber to monitor the temperature at different positions in the atomization chamber in real time. The sensor accuracy is ±1°C, and the sampling frequency is also 1 time / second.

[0057] The signal collected by the temperature sensor is transmitted to the analog input module of the PLC (Programmable Logic Controller) via a shielded cable. After filtering and amplifying the signal, the PLC converts the temperature data into a digital signal and stores it in an internal register.

[0058] (2) Analyze the distribution characteristics of different temperature data and adjust the feedback signal of the PLC system feedback controller in real time.

[0059] In the atomization powder production process, the stability of the high-pressure water shock temperature and the temperature within the atomization chamber are crucial to the process and product quality. Temperature and flow rate changes during the high-pressure shock process directly affect the crushing of the molten metal, while temperature fluctuations within the atomization chamber interfere with the growth, solidification, and oxidation of the crushed powder particles. Therefore, in actual production, control decisions are typically made based on the difference between the measured temperature and the set temperature. However, due to the natural fluctuations in temperature data, relying solely on this difference for judgment can easily lead to frequent and excessive adjustments, which in turn affects the quality of the atomized powder.

[0060] To optimize the temperature monitoring and control strategy, this application first sorts the various types of collected temperature data into time series and uses them as input data. The local outlier factor (LOF) anomaly detection algorithm is used to calculate the LOF value of each temperature data in each type of temperature data. The larger the LOF value, the higher the possibility of abnormal instantaneous temperature fluctuations. At the same time, considering the stable correlation between the high-pressure water temperature and the temperature changes in the atomization chamber, this application comprehensively evaluates the abnormal characteristics of the instantaneous fluctuations in the atomization powder temperature at different collection times. Specifically, the average LOF value of each type of temperature data at each collection time is used as the characteristic value for the comprehensive judgment of the abnormal instantaneous fluctuation. The higher the characteristic value, the more accurate the judgment of the abnormal characteristics of the instantaneous fluctuation at the current moment is, under the premise of comprehensively considering the stable consistency of the high-pressure water and the temperature in the atomization chamber.

[0061] When analyzing the time series characteristics of temperature data, this application calculates the cosine similarity between the temperature vector composed of all temperature data at each acquisition moment and the temperature vector at other moments, and uses the mean of all cosine similarities as the consistency judgment eigenvalue. The smaller the eigenvalue, the greater the possibility that there is a consistency difference in the temperature stability between the monitoring positions at the current moment from the perspective of temperature comparison at different moments and different monitoring positions. When the same temperature stability difference characteristics of the monitoring positions appear at different moments and have a higher instantaneous fluctuation abnormality characteristic, the temperature fluctuation at the current moment has a significant impact on the temperature control of atomized powder making.

[0062] In order to achieve effective classification of instantaneous temperature fluctuation characteristics at different moments, this application uses the consistency judgment characteristic value as the horizontal coordinate and the instantaneous fluctuation anomaly comprehensive judgment characteristic value as the vertical coordinate to construct a two-dimensional rectangular coordinate system, and maps the temperature data samples at all acquisition moments to the coordinate system. The mapping results are used as input and the DBSCAN algorithm is used for clustering. In order to further quantify the impact of different instantaneous fluctuation anomaly characteristics on actual temperature control, for each cluster, the samples in the cluster are arranged in ascending order according to the acquisition time, and the mean of the absolute value of the difference between the acquisition times of adjacent samples is calculated, which is used as the discontinuity characteristic value of the instantaneous fluctuation anomaly. The larger the discontinuity characteristic value, the longer the interval time of the instantaneous fluctuation anomaly change corresponding to the current cluster, indicating that in the actual atomization powder making process, the temperature fluctuation at the acquisition moment corresponding to the cluster has a more prominent impact on the regulation and control.

[0063] Furthermore, after completing the cluster division, a comparative analysis is conducted on the transient fluctuation abnormal change characteristics of each cluster. First, the difference between each temperature data in each cluster and the preset target value is calculated, and the mean of all the differences under the same temperature data is used as the measured deviation value corresponding to the transient fluctuation abnormal characteristics of the current cluster. ; Combine the discontinuity eigenvalues ​​of different clusters (Reflecting the time interval characteristics of abnormal temperature fluctuations), calculate the comprehensive response deviation value of each temperature data. The specific formula is as follows:

[0064]

[0065] in, Indicates the The comprehensive response deviation value of the temperature data; Indicates the The temperature data is The measured deviation value under the instantaneous fluctuation abnormal characteristics corresponding to each cluster; Indicates the The discontinuous characteristic value of the instantaneous fluctuation anomaly corresponding to the cluster, The sum of the discontinuous eigenvalues ​​of the instantaneous fluctuation anomalies corresponding to all clusters; = represents the number of clusters in the clustering division; x represents the number of different types of temperature data, and i represents the number of different clusters. The calculated comprehensive response deviation value can effectively quantify the degree of real-time control response lag and actual control deviation at the current temperature monitoring location.

[0066] To achieve precise closed-loop control of temperatures at various locations, dynamic monitoring and calibration points are implemented throughout the atomization process. Specifically, monitoring points are spaced at equal intervals based on the overall production duration, with the intervals set to the mean of all intermittent characteristic values ​​from the previous production run of the same batch. This aims to leverage the time-varying characteristics of historical temperature fluctuations, improving the timeliness and relevance of monitoring and calibration.

[0067] At each monitoring point, the comprehensive response deviation value of each temperature data is calculated in real time and compared with the pre-set deviation threshold: if the comprehensive response deviation value of each temperature data at each monitoring point is greater than the corresponding deviation threshold, the comprehensive response deviation value is used as the feedback signal of the PLC system feedback controller; otherwise, the difference between the actual temperature value and the set value at the corresponding monitoring point is used as the feedback signal.

[0068] Among them, the pre-set deviation threshold of each of the above-mentioned temperature data is determined by the average of the difference between each temperature data and the pre-set value calculated during the preparation process of the previous batch. Its purpose is to optimize and adjust the monitoring judgment of the actual equipment during the preparation process based on the preparation differences in the same batch of preparation processes. It should be noted that the larger the comprehensive response deviation value, the more serious the cumulative impact of abnormal instantaneous temperature fluctuations in various historical stages on the actual control process, resulting in significant current control deviations. Through the above-mentioned feedback signal selection mechanism, the temperature fluctuation characteristics up to the current monitoring point can be dynamically integrated to achieve adaptive correction of feedback control parameters, thereby effectively improving the dynamic response capability and steady-state control accuracy of temperature control in the atomization powder making process.

[0069] (3) Compare the various temperature data collected in real time with the pre-set values, and adjust the high-pressure water temperature and the atomization chamber temperature in real time.

[0070] The operator sets the temperature setpoints for the high-pressure water and atomizing chamber through the HMI (human-machine interface). The high-pressure water temperature setting range is 20-40°C, and the atomizing chamber temperature setting range is 80-120°C based on the above parameters. The PLC compares the various temperature data collected in real time with the pre-set values:

[0071] When the high-pressure water temperature is higher than the upper limit of the set value, the PLC controls the electric control valve to increase the opening of the cooling water pipeline, increase the cooling water volume, and reduce the high-pressure water temperature; when the temperature is lower than the lower limit of the set value, the PLC controls the electric control valve to reduce the opening of the cooling water pipeline, reduce the cooling water volume, and increase the high-pressure water temperature; at the same time, if the current point is at the set monitoring point, the comprehensive response deviation value is judged based on the above judgment, and the feedback signal of the controller in the PLC system is corrected and adjusted.

[0072] If the atomization chamber temperature exceeds the upper setpoint, the PLC system increases the tower jacket cooling water flow rate or lowers the cooling water temperature based on the feedback controller's output signal. If it falls below the lower setpoint, the system decreases the jacket cooling water flow rate or raises the cooling water temperature. Furthermore, if the temperature is currently at the set monitoring point, the system determines the overall response deviation based on this determination and adjusts the PLC system's controller feedback signal to ensure a stable atomization process and produce uniform, high-quality Ni65A alloy powder.

[0073] S4, subsequent treatment of powder: dehydrating the water-powder mixture after it comes out of the oven, drying it, air-drying it, and screening it.

[0074] Dehydration after baking: The water-powder mixture after baking is dehydrated by a centrifugal dehydrator to remove excess water in the powder. The dehydration time is 30 minutes.

[0075] Drying and Air-drying: The dehydrated powder is placed in an SZG double-cone rotary vacuum dryer for drying. The drying time is controlled within 40-60 minutes to ensure that the powder is completely dry and no wet particles are present. The dried powder is evenly placed on a drying tray, flattened and thinned, and then placed separately according to brand. A fan can be used to speed up the drying process. The drying time is approximately 120 minutes.

[0076] Sieving: After drying to room temperature, the powder is initially screened using an ultrasonic vibrating screen. This initial screening process is divided into two steps: the first step uses a 150-mesh upper sieve and a 260-mesh lower sieve for initial screening; the second step uses a 150-mesh upper sieve and a 270-mesh lower sieve for secondary screening. The product that has undergone initial screening on the vibrating screen is then sent to an air classifier for final screening. After screening, the product is weighed and stored. The entire screening process takes approximately 60 minutes.

[0077] Example 2:

[0078] In the raw material preparation of step S1, different from the composition requirements of the Ni65A alloy powder in Example 1, the raw materials in this embodiment are prepared according to the weight percentages of C: 0.85, B: 2.75, Si: 4.3, Cr: 17, Fe: 5, and Ni: the balance.

[0079] In step S3, the operating pressure range of the multi-stage centrifugal pump used in Example 1 was set to 30 MPa; the two-stream pressure nozzle used had a nozzle diameter of 3 mm and a contraction angle of 45°; and the distance between the nozzle and the molten steel outlet was set to 150 mm. The atomization tower used in this example was 3 m tall and 1.5 m in diameter; the inlet air velocity of the cyclone separator was controlled at 22 m / s, and the filtration air velocity of the bag filter was 1.2 m / min.

[0080] The remaining steps of the preparation process of the alloy powder for fracturing pump plunger spraying used in this embodiment are the same as those in Example 1.

[0081] Example 3:

[0082] In the raw material preparation of step S1, different from the composition requirements of the Ni65A alloy powder in Example 1 and Example 2, in this embodiment, the amount of each raw material is prepared according to the weight percentages of C: 0.8, B: 2.6, Si: 4.2, Cr: 16.5, Fe: 4, and Ni: the balance.

[0083] In step S3, the operating pressure range of the multi-stage centrifugal pump used in Example 1 was set to 25 MPa; the two-stream pressure nozzle used had a nozzle diameter of 4 mm and a contraction angle of 55°; and the distance between the nozzle and the molten steel outlet was set to 125 mm. The atomization tower used in this example was 4 m tall and 1 m in diameter; the inlet air velocity of the cyclone separator was controlled at 20 m / s, and the filtration air velocity of the bag filter was 1 m / min.

[0084] The remaining steps of the preparation process of the alloy powder for spraying the fracturing pump plunger used in this embodiment and the parts not mentioned are the same as those in Example 1.

[0085] The remaining steps of the preparation process of the alloy powder for fracturing pump plunger spraying used in this embodiment are the same as those in Example 1.

[0086] The various embodiments in this application are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0087] It should be noted that, unless otherwise specified and limited, terms such as "include", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a circuit structure, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such article or device. In the absence of further restrictions, the phrase "including a ..." defines an element, does not exclude the presence of other identical elements in the article or device including the element. In addition, the term "and\or" used herein includes any and all combinations of one or more related listed items.

[0088] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of the present application and include common knowledge or customary techniques in the art not invented herein.

[0089] It will be understood that the present application is not limited to the exact construction that has been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof.

Claims

1. A process for preparing alloy powder for spraying on fracturing pump plunger, characterized in that: The process The following steps are involved: S1, raw material preparation: select high-purity Ni, Fe, Cr, Si, B, and C as raw materials for preparing Ni65A alloy powder; S2, smelting process: raw materials are added to the furnace in sequence to melt and alloy them; the slag is then removed from the furnace to obtain molten steel after heat preservation; S3, atomization powder making: using high-pressure water atomization equipment to make high-speed water flow impact the molten steel to break it into droplets, which are then cooled and solidified in the atomization tower to form powder and collected; During the atomization powder making process, the temperature of high-pressure water and the temperature at different positions in the atomization chamber are collected in real time; The average anomaly score of all temperature data types at each collection moment is used as the ordinate, and the average similarity between the temperature vector formed by all temperature data types at each collection moment and the temperature vectors at all other moments is used as the abscissa to construct a rectangular coordinate system. The abscissa and ordinate values ​​of all collection moments are mapped to the coordinate system for clustering. Combined with the average adjacent time intervals between elements in different clusters and the average difference between each temperature data and the preset target value, the comprehensive response deviation value of each temperature data is calculated. The calculation method of the comprehensive response deviation value of each temperature data is: in, Indicates the The comprehensive response deviation value of the temperature data; Indicates the The temperature data is The measured deviation value under the instantaneous fluctuation abnormal characteristics corresponding to each cluster; Indicates the The discontinuous characteristic value of the instantaneous fluctuation anomaly corresponding to the cluster, The sum of the discontinuous eigenvalues ​​of the instantaneous fluctuation anomalies corresponding to all clusters; Indicates the number of clusters for clustering; x represents the number of different types of temperature data, and i represents the number of different clusters; the discontinuity characteristic value of the instantaneous fluctuation anomaly of each cluster is determined by the average adjacent time interval of all elements in the corresponding cluster after sorting according to the acquisition time; the measured deviation value of each type of temperature data under the corresponding instantaneous fluctuation anomaly characteristic of each cluster is determined by the average difference between the corresponding type of temperature data in the corresponding cluster and the preset target value; At each monitoring point arranged at a preset equal time interval, the comprehensive response deviation value of each temperature data is compared with a preset deviation threshold value to determine the feedback signal of the PLC system feedback controller. The method for determining the feedback signal of the PLC system feedback controller is as follows: if the comprehensive response deviation value of each temperature data at each monitoring point is greater than the corresponding deviation threshold value, the comprehensive response deviation value is used as the feedback signal of the PLC system feedback controller; otherwise, the difference between the actual temperature value at the corresponding monitoring point and the set value is used as the feedback signal; Compare the various temperature data collected in real time with the pre-set values, and adjust the high-pressure water temperature and the atomization chamber temperature in real time; S4, subsequent treatment of powder: dehydrating the water-powder mixture after it comes out of the oven, drying it, air-drying it, and screening it.

2. The process for preparing alloy powder for spraying fracturing pump plunger according to claim 1, characterized in that: The components of the Ni65A alloy powder are respectively arranged in weight percentage as follows: C: 0.7-0.85, B: 2.5-2.75, Si: 4.0-4.3, Cr: 16-17, Fe: ≤5, and Ni: balance.

3. The process for preparing alloy powder for spraying fracturing pump plunger according to claim 1, characterized in that: In the process of adding raw materials into the furnace in sequence, return materials are added once at the beginning and end of the addition.

4. The process for preparing alloy powder for spraying fracturing pump plunger according to claim 1, characterized in that: During alloying, the power was adjusted to 130KW and smelting was continued for 10 minutes.

5. The process for preparing alloy powder for spraying fracturing pump plunger according to claim 1, characterized in that: The preset deviation threshold of each temperature data is determined by the average of the difference between each temperature data calculated in the preparation process of the previous batch and the preset value.

6. The process for preparing alloy powder for spraying fracturing pump plunger according to claim 1, characterized in that: Compare the various temperature data collected in real time with the pre-set values, and adjust the high-pressure water temperature and the atomization chamber temperature in real time, including: When the high-pressure water temperature is higher than the upper limit of the set value, the PLC controls the electric regulating valve to increase the opening of the cooling water pipeline, increase the cooling water volume, and reduce the high-pressure water temperature; when the temperature is lower than the lower limit of the set value, the PLC controls the electric regulating valve to decrease the opening of the cooling water pipeline, reduce the cooling water volume, and increase the high-pressure water temperature; at the same time, if the current point is the set monitoring point, the comprehensive response deviation value is judged based on the above judgment, and the feedback signal of the controller in the PLC system is corrected and adjusted; For the temperature of the atomizing chamber, if it is higher than the upper limit of the set value, the PLC system controls to increase the flow rate of the tower jacket cooling water or reduce the cooling water temperature according to the output signal of the feedback controller; if it is lower than the lower limit of the set value, the jacket cooling water flow rate is controlled to be reduced or the cooling water temperature is increased; at the same time, if it is currently at the set monitoring point, the comprehensive response deviation value is judged based on the above judgment, and the feedback signal of the controller in the PLC system is corrected and adjusted.

7. The process for preparing alloy powder for spraying fracturing pump plunger according to claim 1, characterized in that: Screening is divided into: preliminary screening using ultrasonic vibrating screen and final screening using air flow classifier.

8. The process for preparing alloy powder for spraying fracturing pump plunger according to claim 7, characterized in that: The preliminary screening is divided into two steps. The first step is to use a 150-mesh upper sieve and a 260-mesh lower sieve for the first screening; the second step is to use a 150-mesh upper sieve and a 270-mesh lower sieve for re-screening.

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