Preparation process of alloy powder for spraying fracturing pump plunger

Abstract

The invention relates to the technical field of alloy powder preparation, in particular to a preparation process of alloy powder for spraying a fracturing pump plunger, and the process comprises the following steps: selecting high-purity Ni, Fe, Cr, Si, B and C as raw materials; the raw materials are sequentially added into the smelting furnace to be melted and alloyed; extracting slag, preserving heat, and discharging to obtain molten steel; high-pressure water atomization equipment is adopted to enable high-speed water flow to impact the molten steel so as to crush the molten steel into liquid drops, and the liquid drops are cooled and solidified in an atomization tower to form powder and collected; according to the distribution characteristics of various temperature data collected and analyzed in real time in the atomization powder making process, feedback signals of a PLC system feedback controller are adjusted in real time so as to adjust the temperature of high-pressure water and the temperature of an atomization chamber; and carrying out dehydration treatment on the discharged water-powder mixture, and drying, airing and screening the water-powder mixture. According to the method, the influence of temperature instantaneous fluctuation abnormity on the powder preparation process is accurately captured, dynamic closed-loop control over the temperature parameters is achieved, and the sphericity degree and the granularity uniformity of the powder are improved.

Description

Technical Field

[0001] This application relates to the technical field of alloy powder preparation, and particularly relates to a preparation process of alloy powder for spraying on a fracturing pump plunger. Background Art

[0002] In the field of oil extraction, the fracturing pump plunger is a key component, and its performance directly affects the extraction efficiency and cost. With the increasingly complex extraction environment, the requirements for the wear resistance, corrosion resistance, etc. of the fracturing pump plunger are continuously increasing. The alloy powder spraying technology has become an important means to improve the performance of the plunger. By spraying alloy powder on the surface of the plunger, a coating with special properties can be formed to enhance its wear resistance, corrosion resistance and erosion resistance.

[0003] However, at present, the quality of alloy powders used for spraying on fracturing pump plungers in the market is uneven. In actual use scenarios, the alloy powders prepared by existing processes have defects in terms of particle size distribution, sphericity and composition uniformity, resulting in unstable quality of the sprayed plunger coating, making it difficult to meet the requirements of inhibiting acid erosion and wear resistance, and unable to meet the long-term and efficient extraction needs. Among them, under the harsh working conditions of the fracturing pump plunger system, it is necessary to further improve the powder sphericity, working surface hardness, service life of the plunger and surface roughness of the prepared alloy powder. However, in the existing water atomization process for preparation, the high-pressure water temperature and 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 sprayed coating, limiting the development of the fracturing pump plunger spraying technology and making it difficult to meet the needs of the oil extraction industry for high-quality fracturing pump plungers. Summary of the Invention

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

[0005] The preparation process of alloy powder for spraying on a fracturing pump plunger in this application adopts the following technical solutions: An embodiment of this application provides a preparation process of alloy powder for spraying on a fracturing pump plunger, and this process includes the following steps: S1, Raw material preparation: Select high-purity Ni, Fe, Cr, Si, B, C as raw materials for preparing Ni65A alloy powder; S2, Melting process: Add the raw materials into the furnace in sequence to melt and alloy them; then skim the slag and keep warm before taking out the furnace to obtain molten steel; S3, Atomization powder making: Use a high-pressure water atomization device to make high-speed water flow impact the molten steel to break it into droplets, so as to cool and solidify in the atomization tower to form powder and collect it; During the atomization powder making process, the temperature of the high-pressure water and the temperatures at different positions in the atomization chamber are collected in real time; Taking the average anomaly score of all types of temperature data at each acquisition moment as the ordinate and the average similarity between the temperature vector composed of all types of temperature data at each acquisition moment and the temperature vectors at all other moments as the abscissa, a rectangular coordinate system is constructed; mapping the abscissa and ordinate values of all acquisition moments into the coordinate system for clustering division; Combining the average adjacent time interval between elements within different clustering clusters and the average difference between each type of temperature data and a preset target value, calculate the comprehensive response deviation value of each type of temperature data; At each monitoring point arranged at a preset equal time interval, compare the comprehensive response deviation value of each type of temperature data with a preset deviation threshold to determine the feedback signal of the feedback controller of the PLC system; Compare various temperature data collected in real time with preset values, and adjust the high-pressure water temperature and atomization chamber temperature in real time; S4, subsequent processing of the powder: dehydrate the water-powder mixture after it comes out of the furnace, and then dry, air-dry, and screen it.

[0006] Preferably, the composition of the Ni65A alloy powder is equipped by weight percentage as follows: C: 0.7 - 0.85, B: 2.5 - 2.75, Si: 4.0 - 4.3, Cr: 16 - 17, Fe: ≤5, Ni: the balance.

[0007] Preferably, during the process of sequentially adding materials into the furnace, return materials are added once at the initial stage and the end of the material addition.

[0008] Preferably, during alloying, the power is adjusted to 130KW and melting is continued for 10 minutes.

[0009] Preferably, the calculation method of the comprehensive response deviation value of each type of temperature data is as follows: Among them, represents the comprehensive response deviation value of the th type of temperature data; represents the measured deviation value under the instantaneous fluctuation anomaly feature corresponding to the th type of temperature data in the th clustering cluster; represents the discontinuous feature value of the instantaneous fluctuation anomaly corresponding to the th clustering cluster, represents the sum of the discontinuous feature values of the instantaneous fluctuation anomalies corresponding to all clustering clusters; represents the number of clustering clusters in the clustering division; x represents the number of different types of temperature data, and i represents the number of different clustering clusters; Among them, the discontinuous eigenvalue of the instantaneous fluctuation anomaly of each clustering cluster is determined by the average adjacent time interval of all elements within the corresponding clustering cluster sorted according to the acquisition time; The measured deviation value of each type of temperature data under the corresponding instantaneous fluctuation anomaly feature of each clustering cluster is determined by the average difference between the corresponding type of temperature data within the corresponding clustering cluster and the preset target value.

[0010] Preferably, the method for determining the feedback signal of the feedback controller of the PLC system is as follows: If the comprehensive response deviation value of each type of temperature data at each monitoring point is greater than the corresponding deviation threshold, use this comprehensive response deviation value as the feedback signal of the feedback controller of the PLC system; otherwise, use the difference between the measured temperature value and the set value at the corresponding monitoring point as the feedback signal.

[0011] Preferably, the preset deviation threshold for each type of temperature data is determined by the average value of the difference between each type of temperature data and the preset value calculated during the previous batch preparation process.

[0012] Preferably, comparing the various temperature data collected in real time with the preset values and adjusting the high-pressure water temperature and the atomization chamber temperature in real time includes: 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; meanwhile, if the current is at the set monitoring point, based on the above judgment, judge the comprehensive response deviation value and correct and adjust the feedback signal of the controller in the PLC system; For the atomization chamber temperature, 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, control to reduce the jacket cooling water flow rate or increase the cooling water temperature; meanwhile, if the current is at the set monitoring point, based on the above judgment, judge the comprehensive response deviation value and correct and adjust the feedback signal of the controller in the PLC system.

[0013] Preferably, the screening is divided into: preliminary screening using an ultrasonic vibrating screen and final screening using an air classifier.

[0014] Preferably, the preliminary screening is divided into two steps. In the first step, use a sieve mesh with 150 meshes on the upper sieve and 260 meshes on the lower sieve for the first screening; in the second step, use a sieve mesh with 150 meshes on the upper sieve and 270 meshes on the lower sieve for re-screening.

[0015] In the above solution, its beneficial effects are as follows: In view of the application requirements of the fracturing pump plunger system under extreme working conditions, since traditional alloy powders for spraying are difficult to meet the requirements in terms of key performance indicators such as sphericity, oxygen content, working surface hardness, service life, and surface roughness, this application proposes a preparation process for alloy powders for spraying fracturing pump plungers. This application uses high-purity nickel (Ni), chromium (Cr), boron (B), silicon (Si), and carbon (C) as basic raw materials, and through processes such as alloying, slag removal, heat preservation, atomization powder making, dehydration, and drying, it solves the bottlenecks of the existing technology. In the core powder-making process, water atomization technology is used to form the powder, and a PLC intelligent control system is introduced to optimize temperature management. By setting dynamic monitoring points during the high-pressure water impact and atomization chamber temperature monitoring, combined with the local outlier factor (LOF) algorithm and density-based spatial clustering of applications with noise (DBSCAN) analysis, the impact of instantaneous temperature fluctuations on the powder-making process is accurately captured, realizing dynamic closed-loop control of temperature parameters, improving the sphericity and particle size uniformity of the powder, and ensuring the stability and consistency of the powder-making process. After process optimization, the Ni65A alloy powder prepared in this application has a working surface hardness increased to above 65 HRC, the service life of the plunger is extended to 400 - 500 hours, and the surface roughness is controlled within Ra0.4 μm, effectively meeting the wear-resistant requirements under harsh working conditions. Brief Description of the Drawings

[0016] To more clearly illustrate the technical solutions and advantages in the embodiments of this application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 It is a process flow diagram of a preparation process for alloy powders for spraying fracturing pump plungers provided by an embodiment of this application; Figure 2 It is an optimized control process flow diagram of the high-pressure water temperature and atomization chamber temperature during the atomization powder-making process provided by an embodiment of this application. Detailed Embodiments

[0018] To further elaborate on the technical means and effects adopted by this application to achieve the intended invention purpose, the following, in combination with the drawings and preferred embodiments, details the specific embodiments, structures, features, and effects of a preparation process for alloy powders for spraying fracturing pump plungers proposed according to this application. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs.

[0020] The preparation process steps of the alloy powder for spraying the fracturing pump plunger adopted in this application include raw material preparation, melting process, atomization powder making, and subsequent powder treatment.

[0021] A preparation process of an alloy powder for spraying a fracturing pump plunger provided by an embodiment of this application. For the preparation flow chart, please refer to Figure 1 , and the specific preparation process is as follows: Example 1: S1. Raw material preparation: Select high-purity Ni, Fe, Cr, Si, B, and C as the raw materials for preparing the Ni65A alloy powder.

[0022] According to the composition requirements of the Ni65A alloy powder, the usage amounts of each raw material are prepared according to the weight percentages: C: 0.7, B: 2.5, Si: 4.0, Cr: 16, Fe: 3, Ni: the balance.

[0023] For example, when the furnace capacity is 100 - 150 kg, if 100 kg of alloy powder needs to be prepared, the usage amounts of each raw material need to be calculated based on the composition ratio and raw material purity, and precise adjustment should be made according to the actual purity of the raw materials during actual production.

[0024] S2. Melting process: Add the raw materials into the furnace in sequence to melt and alloy them; then skim the slag and keep it warm before taking the molten steel out of the furnace.

[0025] Feeding: Adopt the atmospheric melting method and operate in a furnace with a capacity of 100 - 150 kg. First, add 5 kg of small nickel plates for ignition, and then add about 10 kg of return materials. Subsequently, add the remaining nickel plates, metallic silicon, carbon particles, ferroboron, boron carbide in sequence, then add about 10 kg of return powder, and finally add metallic chromium. After the feeding is completed, turn the power to full. As the raw materials gradually melt, the power will gradually increase, and the power range is about 145 - 200 KW. In addition, when the furnace capacity increases, the melting time of the raw materials will be correspondingly extended, usually about 20 min.

[0026] Alloying: Lower the power to 130 KW and keep melting for 10 min to ensure that the raw materials in the molten steel are completely melted and fully alloyed.

[0027] Skimming the slag and keeping it warm: When the slag in the molten steel completely floats up and covers the surface of the molten steel, lower the power, add a small amount of glass to extract the slag in the molten steel, then add a small amount of return powder, and then turn the power fully on for heat preservation. The heat preservation time is 5 - 10 min, and the power change range is 0 - 210 KW.

[0028] Tap out: Wait until the molten steel is completely melted, remove the slag remaining on the surface of the molten steel, reduce the power to 80KW, and start tapping out. The tapping time is 5 - 10 minutes.

[0029] S3, Atomization and powder making: Use a high-pressure water atomization device to make high-speed water flow impact the molten steel to break it into droplets, and cool and solidify in the atomization tower to form powder and collect it.

[0030] Use the water atomization process to make the molten steel tapped out into powder. Employ a high-pressure water atomization device, including a high-pressure water pump, atomization nozzles, an atomization tower, and a powder collection device, etc. Pressurize the water through the high-pressure water pump to make the high-speed water flow impact the molten steel flow, break the molten steel into fine droplets, the droplets cool and solidify in the atomization tower to form powder, and finally complete the collection in the powder collection device.

[0031] Specifically, use a multistage centrifugal pump, and set the working pressure range to 15MPa. Precisely control the water pressure and flow rate by adjusting the rotational speed of the variable-frequency motor of the water pump to ensure that the high-speed water flow has sufficient kinetic energy to impact the molten steel flow. Select a two-fluid pressure nozzle with a nozzle diameter of 5mm and a contraction angle of 60°. Set the distance between the nozzle and the outlet of the molten steel flow to 100mm to ensure that the high-speed water flow can impact the molten steel at the best angle and position, breaking the molten steel into fine and uniform droplets.

[0032] In this embodiment, the height of the atomization tower used is 5m, and the diameter is 1.5m. Multiple layers of guide plates are arranged inside the tower to guide the droplets to disperse and cool evenly in the tower. The tower body adopts a double-layer jacket structure, and cooling water is introduced into the jacket to keep the temperature of the tower wall 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, and the flow rate and temperature of the cooling water in the tower body jacket are adjusted according to the temperature change to maintain the stability of the temperature inside the tower.

[0033] Collect the powder by combining a cyclone separator and a bag filter. Control the inlet air velocity of the cyclone separator at 18m / s, and the separation efficiency can reach 80% - 90%; the filtration air velocity of the bag filter is 0.8m / min, and the filtration efficiency is not less than 99%, ensuring that the collected powder particle size meets the requirements and the dust emission reaches the standard.

[0034] During the water atomization powder making process, the high-pressure water temperature and the atomization chamber temperature significantly affect the powder sphericity and particle size distribution. The high-pressure water temperature affects the metal liquid fragmentation effect and powder particle size by changing the viscosity, surface tension, vaporization degree, and cooling capacity of water: when the temperature is relatively high, the water viscosity and surface tension decrease, which is conducive to the fragmentation of the metal liquid into fine powder, but too high a temperature will cause vaporization, weaken the stability of the water jet, and result in 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, thereby reducing powder oxidation. The atomization chamber temperature determines the flight cooling speed of the metal liquid droplets and directly affects the growth, solidification process, and oxidation degree of the powder particles. Therefore, strictly controlling these two temperature parameters is the key to improving the powder quality. The process flow chart for the optimal control of the high-pressure water temperature and the atomization chamber temperature during the atomization powder making process is as attached Figure 2 as shown below: (1)During the atomization powder making process, the temperature of the high-pressure water and the temperatures at different positions in the atomization chamber are collected in real time.

[0035] Specifically, a Pt100 thermal resistance temperature sensor is installed on the outlet pipeline of the high-pressure water pump to collect the temperature of the high-pressure water in real time. The accuracy of the sensor is ±0.5°C, and the sampling frequency is 1 time per second; a K-type thermocouple temperature sensor is installed at the top, middle, and bottom of the atomization chamber to monitor the temperatures at different positions in the atomization chamber in real time. The accuracy of the sensor is ±1°C, and the sampling frequency is also 1 time per second.

[0036] The signals collected by the temperature sensors are transmitted to the analog input module of the PLC (programmable logic controller) through shielded cables. After the PLC processes the signals such as filtering and amplification, the temperature data is converted into digital signals and stored in the internal register.

[0037] (2)Analyze the distribution characteristics of different temperature data and adjust the feedback signal of the PLC system feedback controller in real time.

[0038] In the atomization powder making process, the stability of the high-pressure water impact temperature and the temperature in the atomization chamber is crucial for the process and product quality. Among them, the temperature and flow rate changes during the high-pressure impact process directly affect the fragmentation effect of the metal liquid, while the temperature fluctuations in the atomization chamber will interfere with the growth, solidification, and oxidation processes of the fragmented powder particles. Therefore, in actual production, the regulation and judgment are usually based on the difference between the measured temperature value and the set value. However, due to the natural fluctuations of the temperature data, simply relying on this difference for judgment is extremely likely to cause frequent and excessive adjustment operations, thereby affecting the powder quality of the atomization powder making.

[0039] To optimize the temperature monitoring and control strategy, this application first sorts various types of collected temperature data in time series, uses the obtained data as input data, and applies the Local Outlier Factor (LOF) anomaly detection algorithm to calculate the LOF value of each temperature data among various types of temperature data. The larger the LOF value, the higher the possibility that the instantaneous temperature fluctuation appears abnormal. At the same time, considering the stable correlation characteristics between the high-pressure water temperature and the temperature change in the atomization chamber, this application comprehensively evaluates the abnormal characteristics of the instantaneous temperature fluctuation during atomization powder making at different collection times. Specifically, the mean value of the LOF values of various types of temperature data at each collection time is used as the characteristic value for comprehensive judgment of instantaneous fluctuation abnormality. The higher this characteristic value is, 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 between the high-pressure water and the temperature in the atomization chamber.

[0040] 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 collection time and the temperature vectors at other times, and uses the mean value of all cosine similarities as the characteristic value for consistency judgment. The smaller this characteristic value is, the greater the possibility that there is a consistency difference in the temperature stability among the current monitoring positions from the perspective of temperature comparison at different times and different monitoring positions. When there are the same temperature stability difference characteristics at different times and a high instantaneous fluctuation abnormality characteristic, the temperature fluctuation at the current moment has a significant impact on the temperature control of atomization powder making.

[0041] To effectively classify the instantaneous fluctuation characteristics of temperature at different times, this application constructs a two-dimensional rectangular coordinate system with the characteristic value of consistency judgment as the abscissa and the characteristic value of comprehensive judgment of instantaneous fluctuation abnormality as the ordinate, maps the temperature data samples at all collection times to this coordinate system, uses the mapping result as input, and adopts the DBSCAN algorithm for clustering division; to further quantify the impact of different instantaneous fluctuation abnormality characteristics on the actual temperature control, for each clustering cluster, the samples within the cluster are arranged in ascending order of collection time, and the mean value of the absolute values of the differences in collection time between adjacent samples is calculated as the discontinuous characteristic value of the instantaneous fluctuation abnormality. The larger this discontinuous characteristic value is, the longer the interval time of the corresponding instantaneous fluctuation abnormality change of the current clustering cluster, indicating that in the actual atomization powder making process, the temperature fluctuation at the collection time corresponding to the clustering cluster has a more prominent impact on the adjustment control.

[0042] Furthermore, after completing the clustering division, a comparative analysis is conducted on the abnormal change characteristics of the instantaneous fluctuation of each clustering cluster. First, calculate the difference between each type of temperature data within each clustering cluster and the preset target value, and use the mean value of all these differences for the same type of temperature data as the measured deviation value of the corresponding type of temperature data under the abnormal characteristics of the instantaneous fluctuation of the current clustering cluster ; combined with the discontinuous characteristic values of different clustering clusters (Reflecting the time interval characteristics of temperature fluctuation anomalies), calculate the comprehensive response deviation value of each temperature data. The specific formula is as follows: Wherein, represents the comprehensive response deviation value of the th type of temperature data; represents the measured deviation value under the instantaneous fluctuation anomaly feature corresponding to the th type of temperature data in the th clustering cluster; represents the discontinuous feature value of the instantaneous fluctuation anomaly corresponding to the th clustering cluster, represents the sum of the discontinuous feature values of the instantaneous fluctuation anomalies corresponding to all clustering clusters; represents the number of clustering clusters for clustering division; x represents the number of different types of temperature data, and i represents the number of different clustering clusters. The calculated comprehensive response deviation value can effectively quantify the real-time control response lag degree and actual control deviation of the current temperature monitoring position.

[0043] To achieve precise closed-loop control of temperatures at different positions, dynamic monitoring and correction points are set during the atomization powder-making process. Specifically, based on the overall preparation duration, monitoring points are arranged at equal time intervals, and the interval time is set as the average value of all discontinuous feature values in the previous preparation process of the same batch. The purpose is to make full use of the time interval change characteristics of historical temperature fluctuation anomalies and improve the timeliness and pertinence of monitoring and correction.

[0044] At each monitoring point, calculate the comprehensive response deviation value of each temperature data in real time and compare it with a 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, use this comprehensive response deviation value as the feedback signal of the PLC system feedback controller; otherwise, use the difference between the measured temperature value and the set value at the corresponding monitoring point as the feedback signal.

[0045] Among them, the pre-set deviation threshold for each type of temperature data is determined by the average value of the differences between each type of temperature data and the pre-set value calculated during the previous batch preparation process. The purpose is to optimize and adjust the monitoring and judgment during the preparation process of the actual equipment used based on the preparation differences in the same batch preparation process. It should be noted that the larger the comprehensive response deviation value, the more severely the actual control process is affected by the cumulative influence of temperature instantaneous fluctuation anomalies at each historical stage, resulting in a significant current control deviation. Through the above 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 ability and steady-state control accuracy of temperature control in the atomization powder-making process.

[0046] (3) Compare the various temperature data collected in real time with the preset values, and adjust the high-pressure water temperature and atomization chamber temperature in real time.

[0047] The operator sets the temperature set values of the high-pressure water and the atomization chamber through the HMI (human-machine interface). The high-pressure water temperature setting range is 20~40°C, and the atomization chamber temperature set value is set at 80~120°C according to the above parameters. The PLC compares the various temperature data collected in real time with the preset values: 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 is at the set monitoring point, based on the above judgment, the judgment of the comprehensive response deviation value is carried out, and the feedback signal of the controller in the PLC system is corrected and adjusted.

[0048] For the atomization chamber temperature, 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, it controls to reduce the jacket cooling water flow rate or increase the cooling water temperature. At the same time, if the current is at the set monitoring point, based on the above judgment, the judgment of the comprehensive response deviation value is carried out, and the feedback signal of the controller in the PLC system is corrected and adjusted to ensure the stable progress of the atomization process and produce Ni65A alloy powder with uniform particle size and qualified quality.

[0049] S4, subsequent treatment of the powder: dehydrate the water-powder mixture after leaving the furnace, and then dry, air-dry, and screen it.

[0050] Dehydration after leaving the furnace: The water-powder mixture after leaving the furnace is dehydrated by a centrifugal dehydrator to remove the excess water in the powder, and the dehydration time is 30 min.

[0051] Drying and air-drying: The dehydrated powder is loaded into an SZG double-cone rotary vacuum dryer for drying. The drying time is controlled within 40~60 min to ensure that the powder is completely dry and there are no wet block particles. The dried powder is evenly placed in the powder drying tray, spread out and thinly air-dried, and placed separately according to the grade. A fan can be used to accelerate the air-drying speed, and the air-drying time is about 120 min.

[0052] Screening: For the powder dried to room temperature, initial screening is first carried out using an ultrasonic vibrating screen. The initial screening is divided into two operations. In the first step, the first screening is carried out using a 150-mesh upper screen and a 260-mesh lower screen; in the second step, the second screening is carried out using a 150-mesh upper screen and a 270-mesh lower screen. The product after initial screening by the vibrating screen is then sent to an air classifier for final screening. After screening, the product is weighed and stored in the warehouse. The entire screening process takes about 60 minutes.

[0053] Example 2: In the raw material preparation of step S1, different from the composition requirements of the Ni65A alloy powder in Example 1, in this example, according to the weight percentages C: 0.85, B: 2.75, Si: 4.3, Cr: 17, Fe: 5, Ni: the balance, the amounts of each raw material are prepared.

[0054] In step S3, different from the working pressure range of the multistage centrifugal pump set at 30 MPa in Example 1; the nozzle diameter of the two-fluid pressure nozzle selected is 3 mm, and the contraction angle is 45°; the distance between the nozzle and the molten steel flow outlet is set at 150 mm. The height of the atomization tower used in this example is 3 m, and the diameter is 1.5 m; the inlet wind speed of the cyclone separator is controlled at 22 m / s, and the filtration wind speed of the bag filter is 1.2 m / min.

[0055] The remaining steps of the preparation process of the alloy powder for spraying the fracturing pump plunger adopted in this example are the same as those in Example 1.

[0056] Example 3: 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 example, according to the weight percentages C: 0.8, B: 2.6, Si: 4.2, Cr: 16.5, Fe: 4, Ni: the balance, the amounts of each raw material are prepared.

[0057] In step S3, different from the working pressure range of the multistage centrifugal pump set at 25 MPa in Example 1; the nozzle diameter of the two-fluid pressure nozzle selected is 4 mm, and the contraction angle is 55°; the distance between the nozzle and the molten steel flow outlet is set at 125 mm. The height of the atomization tower used in this example is 4 m, and the diameter is 1 m; the inlet wind speed of the cyclone separator is controlled at 20 m / s, and the filtration wind speed of the bag filter is 1 m / min.

[0058] The remaining steps and the unmentioned parts of the preparation process of the alloy powder for spraying the fracturing pump plunger adopted in this example are the same as those in Example 1.

[0059] The remaining steps of the preparation process of the alloy powder for spraying the fracturing pump plunger adopted in this example are the same as those in Example 1.

[0060] Each embodiment in the present application is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other, and the differences between each embodiment and other embodiments are mainly described.

[0061] It should be noted that, unless otherwise specified and limited, terms such as "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a circuit structure, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or elements inherent to such article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of another identical element in the article or device including the said element. In addition, the term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0062] Those skilled in the art will readily conceive of other embodiments of the present application after considering the specification and practicing the invention herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common general knowledge or conventional technical means in the technical field not invented by the present application.

[0063] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A preparation process of alloy powder for spraying on a fracturing pump plunger, characterized in that, This process includes the following steps: S1, raw material preparation: Select high-purity Ni, Fe, Cr, Si, B, and C as raw materials for preparing Ni65A alloy powder; S2, melting process: Add the raw materials into the furnace in sequence, melt and alloyize them; then skim the slag and keep warm before discharging to obtain molten steel; S3, atomization powder making: Use high-pressure water atomization equipment to make high-speed water flow impact the molten steel to break it into droplets, which are 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 temperatures at different positions in the atomization chamber are collected in real time; Taking the average anomaly score of all types of temperature data at each collection moment as the ordinate and the average similarity between the temperature vector composed of all types of temperature data at each collection moment and the temperature vectors at all other moments as the abscissa, construct a rectangular coordinate system; map the abscissa and ordinate values of all collection moments into the coordinate system for clustering division; Combining the average adjacent time interval between elements within different clustering clusters and the average difference between each type of temperature data and the preset target value, calculate the comprehensive response deviation value of each type of temperature data; At each monitoring point arranged at a preset equal time interval, compare the comprehensive response deviation value of each type of temperature data with the preset deviation threshold to determine the feedback signal of the PLC system feedback controller; Compare the various temperature data collected in real time with the preset values, and adjust the high-pressure water temperature and the atomization chamber temperature in real time; S4, subsequent powder treatment: Dehydrate the water-powder mixture after discharging from the furnace, and then dry, air-dry, and screen it.

2. The preparation process of an alloy powder for spraying a fracturing pump plunger according to claim 1, wherein, The composition of Ni65A alloy powder is prepared by weight percentage as follows: C: 0.7 - 0.85, B: 2.5 - 2.75, Si: 4.0 - 4.3, Cr: 16 - 17, Fe: ≤5, Ni: the balance.

3. The preparation process of an alloy powder for spraying a fracturing pump plunger as described in claim 1, characterized in that, During the process of adding the raw materials into the furnace in sequence, return materials are added once at the beginning and the end of the feeding.

4. The preparation process of an alloy powder for spraying a fracturing pump plunger according to claim 1, characterized in that, During alloying, adjust the power to 130KW and keep melting for 10min.

5. The preparation process of an alloy powder for spraying a fracturing pump plunger as described in claim 1, characterized in that, The calculation method of the comprehensive response deviation value of each type of temperature data is as follows: Among them, represents the comprehensive response deviation value of the th temperature data; represents the measured deviation value under the instantaneous fluctuation anomaly feature corresponding to the th temperature data in the th clustering cluster; represents the discontinuous feature value of the instantaneous fluctuation anomaly corresponding to the th clustering cluster, represents the sum of the discontinuous feature values of the instantaneous fluctuation anomalies corresponding to all clustering clusters; represents the number of clustering clusters for clustering division; x represents the number of different types of temperature data, and i represents the number of different clustering clusters; Among them, the discontinuous characteristic value of the instantaneous fluctuation anomaly of each clustering cluster is determined by the average adjacent time interval of all elements within the corresponding clustering cluster sorted according to the collection moment; The measured deviation value of each type of temperature data under the corresponding instantaneous fluctuation anomaly characteristic of each clustering cluster is determined by the average difference between the corresponding type of temperature data within the corresponding clustering cluster and the preset target value.

6. The preparation process of an alloy powder for spraying on a fracturing pump plunger according to claim 1, characterized in that, The method for determining the feedback signal of the PLC system feedback controller is: If the comprehensive response deviation value of each type of temperature data at each monitoring point is greater than the corresponding deviation threshold, use this comprehensive response deviation value as the feedback signal of the PLC system feedback controller; otherwise, use the difference between the measured temperature value and the set value at the corresponding monitoring point as the feedback signal.

7. The preparation process of an alloy powder for spray coating a fracturing pump plunger according to claim 1, characterized in that, The preset deviation threshold of each type of temperature data is determined by the mean of the difference between each type of temperature data and the preset value calculated during the preparation process of the previous batch.

8. The preparation process of an alloy powder for spraying a fracturing pump plunger according to claim 1, characterized in that, The comparison of the various temperature data collected in real time with the preset values and the real-time adjustment of the high-pressure water temperature and the atomization chamber temperature include: When the temperature of the high-pressure water is higher than the upper limit of the set value, the PLC controls the electric control valve to increase the opening degree of the cooling water pipeline, increase the cooling water volume, and reduce the temperature of the high-pressure water; when the temperature is lower than the lower limit of the set value, the PLC controls the electric control valve to reduce the opening degree of the cooling water pipeline, reduce the cooling water volume, and increase the temperature of the high-pressure water; meanwhile, if it is currently at the set monitoring point, based on the above judgment, a judgment of the comprehensive response deviation value is made, and the feedback signal of the controller in the PLC system is corrected and adjusted. For the temperature of the atomization chamber, if it is higher than the upper limit of the set value, the PLC system controls to increase the flow rate of the cooling water in the tower jacket 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, it controls to reduce the flow rate of the jacket cooling water or increase the cooling water temperature; meanwhile, if it is currently at the set monitoring point, based on the above judgment, a judgment of the comprehensive response deviation value is made, and the feedback signal of the controller in the PLC system is corrected and adjusted.

9. The preparation process of an alloy powder for spraying a fracturing pump plunger as described in claim 1, wherein, The screening is divided into: preliminary screening using an ultrasonic vibrating screen and final screening using an air classifier.

10. The preparation process of an alloy powder for spraying a fracturing pump plunger according to claim 9, characterized in that, The preliminary screening is divided into two steps. In the first step, the first screening is carried out using a 150-mesh upper screen and a 260-mesh lower screen; in the second step, the screening is carried out again using a 150-mesh upper screen and a 270-mesh lower screen.

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