Efficient valve seat machining process and quality control method
By combining ultrasonic flaw detection and overall heat treatment with standardized cutting parameters, the problems of insufficient consistency and precision in valve seat machining were solved, achieving efficient and stable valve seat machining that is suitable for the high temperature and high pressure conditions at oil wellheads.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TIANJIN LONGCHI MACHINERY MFG CO LTD
- Filing Date
- 2026-03-23
- Publication Date
- 2026-06-05
Smart Images
Figure CN122142691A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of quality control technology, and in particular to a high-efficiency valve seat processing technology and quality control method. Background Technology
[0002] In oilfield operations, firstly, the processing technology lacks systematic optimization, with cumbersome and poorly connected procedures. The traditional single-process model is still in use, failing to integrate processes and solidify parameters tailored to the valve seat's structural characteristics. Furthermore, the stress relief treatment after rough machining is substandard, leading to valve seat warping and deformation after finishing, reducing efficiency and yield. Secondly, cutting parameters rely heavily on operator experience, lacking standardized and automated control, resulting in poor product accuracy consistency, rapid tool wear, and surface defects. Thirdly, the sealing surface is crudely machined, with non-standard welding parameters and insufficiently graded grinding, leading to insufficient sealing surface precision and potential media leakage. Fourthly, the lack of dedicated clamping fixtures, uneven clamping force from general-purpose jaws, and low positioning accuracy easily cause valve seat deformation and positioning deviations, affecting fit accuracy. Fifthly, quality control is rudimentary, relying primarily on final inspection, lacking online inspection and feedback between processes. Defective workpieces easily flow into the next process, inspection data is untraceable, and the inspection process is cumbersome, with unclear standards and no personnel control or parameter locking mechanism, posing potential quality risks. Finally, existing processes do not fit actual working conditions and material characteristics, resulting in short valve seat lifespan and an imbalance between confidentiality and operability, making it difficult to meet the "high efficiency, high quality, confidentiality, and ease of operation" requirements of OEM scenarios, thus hindering industry development. Summary of the Invention
[0003] In view of this, the present invention provides a valve seat high-efficiency machining process and quality control method, which can effectively reduce deformation through flaw detection screening, heat treatment and graded stress relief, improve machining consistency and efficiency through standardized cutting parameters, ensure sealing performance through closed-loop repair of sealing surface, and significantly improve the pass rate through parameter optimization and full-process quality control, thereby achieving efficient and stable machining of valve seats.
[0004] This invention provides a high-efficiency machining process and quality control method for valve seats. The method includes: Step 1, selecting wear-resistant and corrosion-resistant alloy billets suitable for the target oil wellhead, detecting internal defects in the wear-resistant and corrosion-resistant alloy billets using ultrasonic flaw detection to remove unqualified billets containing porosity, cracks, and inclusions, and performing overall quenching and tempering treatment on qualified billets; Step 2, performing integrated rough machining on the overall quenched and tempered billets, simultaneously completing the standardized setting of rough machining cutting parameters, performing low-temperature aging treatment to relieve stress after rough machining, and performing standardized setting of semi-finishing cutting parameters based on the dimensions of the integrated rough-machined billet, judging based on the inner hole diameter. If the dimensions of the blank meet the acceptable working conditions, it is deemed acceptable and the sealing surface is precisely machined. If not, it is deemed unacceptable and does not proceed to the next process. In the third step, if any defects are detected during the precise machining of the sealing surface, an angle grinder is used to remove the defective area, and the welding and defect detection are repeated until the weld layer is free of defects. If the inspection is satisfactory, it proceeds to the finishing and finishing process. In the fourth step, during the finishing and finishing process, it is determined whether to perform solidified cutting parameter optimization. If so, a full-item final inspection is performed after optimization. If not, a full-item final inspection is performed directly. The qualified workpieces are labeled and put into storage, while the unacceptable workpieces are stored separately.
[0005] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:
[0006] By performing ultrasonic flaw detection and precise heat treatment on wear-resistant and corrosion-resistant alloy billets, internal defects can be effectively eliminated and initial internal stress can be removed, ensuring uniform and stable hardness of the billet and reducing the risk of deformation in subsequent processing from the source. Integrated roughing combined with standardized cutting parameters, along with dynamic adjustment of rotational speed, feed rate, and depth of cut, improves processing efficiency and reduces tool wear and surface defects. Low-temperature aging treatment after roughing completely releases processing stress and significantly improves dimensional stability. Semi-finishing, through the linkage control of speed and feed rate, further ensures processing accuracy and surface quality. Using the inner hole diameter as the acceptance criterion, process interception is achieved to prevent the flow of defective products. Sealing surface processing employs a defect detection-repair- The closed-loop re-inspection process eliminates welding defects and ensures that the sealing surface performance meets the high-pressure sealing requirements of the wellhead. The precision machining process is equipped with a fixed parameter optimization judgment mechanism, which can adaptively adjust according to real-time machining data. Combined with the final inspection of the entire project and unique code traceability management, it can not only ensure that the valve seat dimensional accuracy, form and position tolerance and sealing performance meet the standards, but also achieve process confidentiality, process control and quality stability in batch contract manufacturing. Ultimately, it can significantly improve the valve seat machining qualification rate, production efficiency and product service life, and adapt to the harsh working conditions of high temperature, high pressure and strong corrosion at oil wellheads. Attached Figure Description
[0007] Figure 1This is a flowchart of a high-efficiency valve seat processing technology and quality control method provided in an embodiment of the present invention;
[0008] Figure 2 This is a flowchart of a multi-point hardness testing process for a valve seat high-efficiency processing technology and quality control method provided in an embodiment of the present invention. Detailed Implementation
[0009] This invention provides a high-efficiency valve seat processing technology and quality control method, such as... Figure 1 The flowchart shown illustrates a high-efficiency machining process and quality control method for valve seats. The process flow of this method may include the following steps:
[0010] Step one involves selecting wear-resistant and corrosion-resistant alloy billets suitable for the target oil wellhead. Ultrasonic testing is used to detect internal defects in the billets, eliminating substandard billets with porosity, cracks, or inclusions. Qualified billets undergo overall quenching and tempering treatment. The tempering temperature is controlled at 880-920℃, held for 2-3 hours, then cooled in the furnace to below 300℃, followed by air cooling to room temperature. This ensures the billet hardness reaches HRC28-32, eliminating initial internal stress.
[0011] It should be understood that the material of the wear-resistant and corrosion-resistant alloy billet is adapted to the high pressure, high temperature, and strong corrosion conditions of the target oil wellhead. Chromium-nickel-molybdenum alloy and titanium alloy are selected, and ultrasonic flaw detection is carried out using a digital ultrasonic flaw detector, with the detection range covering the cross-section and end face of the billet. If any of the following defects are detected in the billet: a pore with a diameter greater than or equal to the preset diameter, a crack with a length greater than or equal to the preset length, or an inclusion with an area greater than or equal to the preset area, the billet is judged as unqualified and is rejected. If the billet passes the test and a qualified ultrasonic flaw detection report is issued, the billet undergoes overall heat treatment.
[0012] In this embodiment, firstly, based on the high pressure, high temperature, and strong corrosion requirements of the oil wellhead, a more adaptable chromium-nickel-molybdenum alloy or titanium alloy is selected as the wear-resistant and corrosion-resistant alloy billet. This ensures that the valve seat has excellent corrosion resistance, wear resistance, and high-temperature mechanical properties from the base material level, extending its downhole service life. Subsequently, a digital ultrasonic flaw detector is used to perform full-coverage non-destructive testing on the cross-section and end face of the billet, accurately identifying hidden defects inside the billet. When any defect is detected, such as a pore with a diameter not less than a preset diameter, a crack with a length not less than a preset length, or an inclusion with an area not less than a preset area, it is immediately judged as an unqualified billet and rejected. This prevents defective billets from flowing into subsequent processes from the source, avoiding problems such as processing cracking, finished product sealing failure, and early failure caused by internal defects. Only billets that pass the test and have a formal ultrasonic flaw detection certificate are subjected to overall heat treatment, which not only ensures the consistency of the incoming material quality but also lays a reliable foundation for subsequent cutting and dimensional stability, while reducing the cost losses caused by subsequent rework and scrap.
[0013] Further, the specific steps for overall conditioning are as follows:
[0014] The qualified billet is heat-treated by a box-type resistance furnace. The qualified billet is placed in the box-type resistance furnace, the furnace door is closed and the heating program is started to raise the temperature inside the furnace to the preset heat-treatment temperature range. Once the temperature inside the box-type resistance furnace is within the preset heat-treatment temperature range, it is kept at a constant temperature for the preset heat-treatment time.
[0015] After the constant temperature heat preservation is completed, turn off the furnace heating device and let the billet cool naturally with the furnace until the furnace temperature drops to the preset tempering temperature reference value. Then take out the billet and place it in a normal temperature environment to air cool to room temperature.
[0016] S101. After the overall heat treatment is completed, the Rockwell hardness tester is used to perform multi-point hardness testing on the billet. Test points are evenly selected along the cross-section and end face of the billet. The distance between any two adjacent test points is greater than or equal to the preset test point distance, and the test points avoid the edge of the billet.
[0017] In this embodiment, a box-type resistance furnace is used to perform overall quenching and tempering on billets that have passed ultrasonic flaw detection and have received a qualified report. First, the qualified billets are placed stably and evenly inside the box-type resistance furnace, ensuring that there is no stacking or contact between the billets. After closing the furnace door, the heating program is started, and the furnace temperature is slowly raised to the preset quenching and tempering temperature range of 880-920℃. This heating method avoids thermal stress caused by sudden local temperature increases in the billets, preventing deformation, cracking, and other problems. After the furnace temperature stabilizes within the preset quenching and tempering temperature range, it is maintained at a constant temperature for 2-3 hours. This constant temperature holding process ensures that the internal structure of the billets undergoes sufficient transformation, uniformly refines the grains, and improves the overall mechanical properties of the billets, providing a good material foundation for subsequent machining. After the constant temperature holding period, the furnace heating device is turned off, allowing the billets to cool naturally with the furnace until the furnace temperature drops below the preset quenching and tempering temperature benchmark value of 300℃. This stepped cooling method effectively releases the internal stress generated in the billets during heating and holding, avoiding excessively rapid cooling. Uneven hardness and cracks in the billet were caused by the initial heat treatment. The billet was then removed and air-cooled to room temperature to further stabilize its microstructure and hardness, ensuring consistent performance. After the overall heat treatment, a Rockwell hardness tester was used to perform multi-point hardness testing on the billet. During testing, test points were evenly selected along the cross-section and end face of the billet, with a minimum distance of 10mm between any two adjacent test points. The test points avoided the edges of the billet. This testing method can comprehensively and accurately reflect the overall hardness distribution of the billet, avoiding deviations in test results due to concentrated test points or proximity to edges, ensuring the authenticity and reliability of the test data. At the same time, multi-point testing can promptly detect uneven hardness in the billet, providing a basis for subsequent process adjustments, ensuring that the billet hardness meets the preset requirement of HRC28-32, completely eliminating initial internal stress in the billet, improving the dimensional stability and machinability of the billet, reducing problems such as billet deformation and excessive tool wear during subsequent processing, and providing a solid guarantee for the machining accuracy of the valve seat.
[0018] It should be understood that, such as Figure 2 The diagram shows a multi-point hardness testing flowchart of a valve seat high-efficiency processing technology and quality control method provided by an embodiment of the present invention. The specific process is as follows: After the overall heat treatment is completed, the test points are selected according to the specifications (S101), and then the single test point hardness test is performed (S102). The operation is repeated until all points are tested. Then, the average hardness is calculated and the hardness of each point is checked to see if it is within the preset range of HRC28-32 (S103). If all are qualified, the blank is judged to be qualified and enters the subsequent processing steps. If there are unqualified points (S104), the blank is judged to be unqualified, and the overall heat treatment is repeated. After rework, the test process is repeated until the hardness of all test points is qualified, thereby ensuring the uniformity of the blank hardness and processing performance, and controlling the valve seat processing quality from the source.
[0019] It should be further explained that the specific steps for multi-point hardness testing are as follows:
[0020] S102, start the hardness tester, control the indenter loading speed within the preset loading speed range, load to the preset load and hold for a preset time, then unload and record the hardness value of the test point;
[0021] S103, repeat steps S101-S102 to complete the hardness test of all test points, calculate the average value of the hardness values of all test points, and if the hardness values of all test points are within the preset hardness value range, the billet hardness test is deemed qualified.
[0022] S104 If the hardness value of any test point is outside the preset hardness value range, the billet hardness test is deemed unqualified. The billet is then subjected to overall tempering treatment again, and multi-point hardness testing is performed again until the test is qualified.
[0023] In this embodiment, a box-type resistance furnace is used to perform overall quenching and tempering treatment on billets that have passed ultrasonic testing. Specifically, qualified billets suitable for oilfield applications are first placed stably into the box-type resistance furnace, ensuring even placement and no stacking to avoid uneven stress in certain areas. Then, the heating program is started to precisely raise the furnace temperature to the preset quenching and tempering temperature range, achieving slow heating and stable temperature control. This effectively avoids billet deformation caused by sudden temperature increases in certain areas, ensuring the stability of subsequent processing. During the constant temperature holding stage, the temperature is continuously maintained to further refine the internal structure of the billet, improve the material's mechanical properties, and lay a solid foundation for subsequent processing. Simultaneously, through… A scientific heating and holding process reduces the impact of thermal stress on the billet, ensuring structural stability. After holding, the billet cools naturally with the furnace, avoiding structural damage caused by rapid cooling and further improving dimensional stability and processing adaptability. Multi-point testing with a Rockwell hardness tester ensures the billet hardness meets preset standards, providing strong support for subsequent machining and sealing performance. This effectively reduces deformation risks during processing, ensuring high-precision machining and stable product quality. Ultimately, it achieves precise matching of billet performance with oilfield scenarios, laying a core foundation for the reliable operation of subsequent valve seat products.
[0024] Step two involves performing integrated rough machining on the overall tempered billet, simultaneously standardizing the rough machining cutting parameters. After rough machining, a low-temperature aging treatment is applied to relieve stress. Based on the dimensions of the billet after integrated rough machining, standardized semi-finishing cutting parameters are set. The billet dimensions are judged according to the inner hole diameter to determine whether they meet the acceptable working conditions. If they do, the billet is deemed acceptable and the sealing surface is precisely machined; otherwise, it is deemed unacceptable and does not proceed to the next process. The standardized rough machining cutting parameters are: rotation speed 800-1000 r / min, feed rate 0.2-0.3 mm / r, and depth of cut 2-3 mm. After rough machining, a low-temperature aging treatment is immediately applied to relieve stress at a temperature of 180-220℃ for 4-6 hours, with the furnace temperature fluctuation controlled within ±5℃ throughout the process to completely release the internal stress generated during rough machining.
[0025] Furthermore, the specific steps to complete the standardized setting of roughing cutting parameters are as follows:
[0026] The correspondence between rotational speed, feed rate and depth of cut is established in advance to clarify the reference range of depth of cut that is suitable for different rotational speeds and feed rates. The actual rotational speed and actual feed rate of the current cutting process are collected in real time and compared with the preset reference values of rotational speed and feed rate. The depth of cut is dynamically adjusted according to the comparison results.
[0027] When the actual rotational speed is higher than the rotational speed reference value and the actual feed rate is not lower than the lower limit of the feed rate reference value, the actual rotational speed and actual feed rate are input into the pre-established correspondence between rotational speed, feed rate and depth of cut, and the depth of cut is reduced. This is to avoid excessive cutting load caused by excessive rotational speed and normal feed rate. The difference between the depth of cut reference value and the depth of cut reduction is processed to obtain the target depth of cut.
[0028] When the actual rotational speed is lower than the reference value and the actual feed rate is not higher than the upper limit of the reference value, the actual rotational speed and actual feed rate are input into the pre-established correspondence between rotational speed, feed rate and depth of cut, and the depth of cut is adjusted upwards. This avoids a decrease in machining efficiency due to excessively low rotational speed and normal feed rate. The reference value of depth of cut and the adjustment amount of depth of cut are superimposed to obtain the target depth of cut.
[0029] Completing the standardized settings for roughing cutting parameters also includes:
[0030] When the actual rotational speed is within the reference range and the actual feed rate is higher than the upper limit of the reference feed rate, the actual rotational speed and actual feed rate are input into the pre-established correspondence between rotational speed, feed rate and depth of cut, and the depth of cut is output to reduce the depth of cut. This prevents the surface of the workpiece from scratching or burrs due to excessive feed rate and normal rotational speed. The difference between the reference value of the depth of cut and the depth of cut reduction is processed to obtain the target depth of cut.
[0031] When the actual rotational speed is within the reference range and the actual feed rate is lower than the lower limit of the reference feed rate value, the actual rotational speed and actual feed rate are input into the pre-established correspondence between rotational speed, feed rate and depth of cut, and the depth of cut is adjusted upwards to balance machining accuracy and efficiency. The reference value of the depth of cut and the depth of cut adjustment upwards are superimposed to obtain the target depth of cut.
[0032] When the actual rotational speed and actual feed rate are both within the preset reference range, maintain the cutting depth reference value;
[0033] The system provides real-time feedback on dynamic data of rotational speed, feed rate, and depth of cut, and simultaneously monitors cutting force and tool temperature. If the cutting force exceeds the preset cutting force range, the system immediately pauses adjustment and stops the machine for inspection. After the fault is resolved, the linkage adjustment program is restarted to ensure accurate depth of cut adjustment and stable machining process.
[0034] In this embodiment, a pre-established relationship between rotational speed, feed rate, and depth of cut based on a BP neural network is first established. This model is trained and optimized through a large amount of machining data and can accurately output the corresponding depth of cut reference range according to different rotational speed and feed rate parameters. At the same time, a PID fuzzy control algorithm is embedded to realize dynamic closed-loop adjustment of the depth of cut, ensuring the scientific nature and accuracy of parameter adaptation. Subsequently, the standardization setting process for roughing cutting parameters is initiated, and the actual rotational speed and actual feed rate data of the current cutting process are collected in real time and compared with the preset rotational speed reference value and feed rate reference value. Meanwhile, the cutting force, tool vibration frequency, and workpiece surface temperature data during the cutting process are captured in real time by sensors, serving as the core basis for parameter adjustment. When the actual rotational speed is higher than the preset rotational speed reference value and the actual feed rate is not lower than the lower limit of the feed rate reference value, the actual rotational speed and actual feed rate are input into the BP neural network linkage model. The PID fuzzy control algorithm calculates the cutting depth adjustment amount and accurately outputs the adjustment parameters. The difference between the cutting depth reference value and the adjustment amount is calculated to obtain the target cutting depth, effectively avoiding excessive cutting load caused by excessive rotational speed and normal feed rate, and preventing excessive tool wear and workpiece deformation. When the actual rotational speed is lower than the preset rotational speed reference value and the actual feed rate is not higher than the upper limit of the feed rate reference value, the actual parameters are also input into the linkage model. The algorithm calculates and outputs the cutting depth adjustment amount. The cutting depth reference value and the adjustment amount are superimposed to obtain the target cutting depth adapted to the current working conditions, balancing machining efficiency and machining quality, and avoiding the problem of prolonged machining cycle caused by excessively low rotational speed. When the actual rotational speed is within the preset reference range, but the actual feed rate is higher than the upper limit of the feed rate reference value, the actual parameters are input into the linkage model. The algorithm analyzes and outputs a downward adjustment of the depth of cut to prevent excessive feed rate from causing scratches and burrs on the workpiece surface, ensuring the smoothness of the machined surface. When the actual rotational speed is within the reference range and the actual feed rate is lower than the lower limit of the feed rate reference value, the depth of cut is output after being input into the linkage model. This improves machining efficiency while ensuring machining accuracy and avoids ineffective machining losses. At the same time, the dynamic data of rotational speed, feed rate, and depth of cut are fed back in real time. The cutting force is monitored simultaneously to see if it exceeds the preset range and if the tool temperature is too high. If the cutting force fluctuation exceeds the allowable threshold or the tool temperature is abnormal, the parameter adjustment program is immediately paused, the machine is stopped to check the tool wear and workpiece clamping status, and the linkage adjustment program is restarted after troubleshooting to ensure that the depth of cut adjustment is accurate and controllable. When the actual rotational speed and actual feed rate are both within the preset reference range, the depth of cut reference value is maintained unchanged to ensure the stability of the machining process. The entire parameter setting process, through algorithm linkage and real-time monitoring, not only achieves standardization and precision of roughing cutting parameters, but also effectively reduces tool wear, minimizes machining defects, and improves roughing efficiency and quality, laying a solid foundation for subsequent finishing stages. At the same time, through algorithm optimization and real-time monitoring, the confidentiality and stability of the process are ensured, adapting to the quality control requirements of mass production.
[0035] It should be further explained that the specific steps for standardizing the semi-finishing cutting parameters are as follows:
[0036] S201, establish the correspondence between semi-finishing rate and feed rate in advance to clarify the reference range of semi-finishing rate and the corresponding feed rate reference range, collect the actual semi-finishing rate of the current semi-finishing process in real time, compare the actual semi-finishing rate with the preset semi-finishing rate reference range, and dynamically adjust the semi-finishing feed rate according to the comparison results in different scenarios.
[0037] S202, when the actual semi-finishing rate is higher than the upper limit of the rate reference range, the actual semi-finishing rate is input into the pre-established correspondence between the semi-finishing rate and the feed rate, and the feed rate reduction is output to avoid excessive cutting load due to excessively high rate and unchanged feed rate. The difference between the feed rate reference value and the feed rate reduction is processed to obtain the target feed rate.
[0038] Standardizing the cutting parameters for semi-finishing also includes:
[0039] S203, when the actual semi-finishing rate is lower than the lower limit of the rate reference range, the actual semi-finishing rate is input into the pre-established correspondence between the semi-finishing rate and the feed rate, and the feed rate adjustment is output to avoid the decrease in processing efficiency due to the low rate and unchanged feed rate. The feed rate reference value and the feed rate adjustment are superimposed to obtain the target feed rate.
[0040] S204, when the actual semi-finishing rate is within the rate reference range, the feed reference value is kept unchanged. The rate reference range refers to the closed interval formed by the lower limit of the rate reference range and the upper limit of the rate reference range.
[0041] Continuously monitor the actual semi-finishing rate and feed rate. If the actual semi-finishing rate deviates from the rate reference range, repeat steps S201-S204. If the actual semi-finishing rate still deviates from the rate reference range after adjustment, the machine will automatically stop and issue an alarm signal to prompt the operator to check the tool wear and blank clamping status. After the fault is eliminated, restart the linkage adjustment program to ensure the stability of the semi-finishing process and guarantee the blank processing quality and processing efficiency.
[0042] In this embodiment, when standardizing the semi-finishing cutting parameters, a semi-finishing rate and feed rate correspondence based on a fuzzy PID algorithm is first established in advance. This model integrates fuzzy control algorithm and PID adjustment algorithm, which can dynamically optimize parameters according to the actual working conditions of semi-finishing. At the same time, the reference range of semi-finishing rate (corresponding to the preset cutting speed standard mentioned above) and feed rate reference range are clearly defined. The blank that has passed the ultrasonic test is first placed stably on the machining table, the correspondence is started, and the actual semi-finishing rate data of the current semi-finishing process is collected in real time. The collected actual rate is accurately compared with the preset semi-finishing rate reference range. At the same time, the collected data is analyzed and processed by the fuzzy PID algorithm to achieve dynamic matching of rate and feed rate. When the actual semi-finishing rate is higher than the upper limit of the rate reference range, the actual rate data is input into the pre-established correspondence between the semi-finishing rate and the feed rate. The corresponding feed rate reduction is calculated using a fuzzy PID algorithm. The difference between the feed rate reference value and the reduction is processed to obtain the target feed rate adapted to the current high-rate working condition. This effectively avoids problems such as excessive cutting load and accelerated tool wear caused by excessively high rate and unchanged feed rate, ensuring a smooth machining surface and reducing defects such as burrs and cracks. When the actual semi-finishing rate is lower than the lower limit of the rate reference range, the actual rate data is also input into the correspondence. The corresponding feed rate increase is calculated using an algorithm. The feed rate reference value and the increase are superimposed to obtain the target feed rate adapted to the low-rate working condition. This avoids problems such as low machining efficiency and excessive surface roughness caused by excessively low rate and insufficient feed rate. When the actual semi-finishing rate is within the preset reference range, the original feed rate reference value is maintained unchanged to ensure the stability of the machining process. Throughout the parameter adjustment process, the dynamic changes in the actual semi-finishing rate and feed rate are continuously monitored. Simultaneously, data such as tool wear and surface finish quality are collected in real time. If the actual rate deviates from the reference range, the parameter adjustment process is immediately repeated. If the rate still cannot return to the reference range after adjustment, an alarm signal is automatically issued by the model, prompting the operator to check the tool wear and workpiece clamping status. This allows for timely troubleshooting, tool replacement, or adjustment of the clamping position, ensuring a stable and controllable semi-finishing process. This parameter setting method not only achieves precise adaptation of cutting parameters through the fuzzy PID algorithm, avoiding machining defects caused by unreasonable parameters, but also ensures the accuracy and efficiency of semi-finishing through real-time monitoring and dynamic adjustment, reducing rework losses and improving the controllability of the machining process. This lays a solid foundation for the quality of subsequent finished products, ensuring seamless connection between the semi-finishing stage and subsequent processes, further improving overall machining efficiency and product quality. It adapts to the high-pressure, high-temperature, and highly corrosive working conditions of oil wellheads, providing a stable and qualified workpiece base for subsequent finishing stages.
[0043] Step 3: During the precision machining of the sealing surface, if any defects are detected, an angle grinder is used to remove the defective area and the welding and defect detection are repeated until the weld layer is free of any defects. If the inspection is qualified, the process proceeds to finishing and finished product repair.
[0044] It should be understood that the specific steps for performing weld overlay and defect detection are as follows:
[0045] After the precision machining of the sealing surface is completed, the machining equipment is stopped immediately, the valve seat blank is removed, and all edges and corners of the valve seat are rounded using a special angle grinder. The rounding radius is standardized and set within the preset radius standard range to avoid damage to the sealing surface and the machined surface.
[0046] The valve seat surface is wiped with anhydrous ethanol to remove surface oil, iron filings, and residual cutting fluid. Then, compressed air is used to blow away any remaining dust on the surface to ensure that the valve seat surface is free of any burrs, scratches, impurities, and oxide layer.
[0047] High-precision micrometers, coaxiality testers, and perpendicularity testers are used to comprehensively inspect the key dimensions and geometric tolerances of the valve seat. At the same time, a roughness tester is used to inspect the roughness of the sealing surface and each machined surface to ensure that the surface roughness of the sealing surface is less than or equal to the preset roughness threshold.
[0048] If the inspection is qualified, the finishing and repair of the finished product is deemed qualified, and it will proceed to the subsequent final inspection process; if the inspection is unqualified, the finishing and repair will be carried out again according to the defect type, and the inspection will be carried out again until the inspection is qualified. Defect types include dimensional deviation, exceeding the form and position tolerance, surface defects, etc.
[0049] In this embodiment, the machine is stopped immediately after the sealing surface is precisely machined, and the valve seat blank is removed. A special angle grinder is used to perform standardized rounding treatment on all edges and corners of the valve seat, strictly controlling the rounding radius within a preset range. This removes sharp edges and corners to prevent scratching of the seal during subsequent assembly, and avoids excessive grinding that could damage the sealing surface and precision-machined surface, ensuring the structural integrity and operational safety of the valve seat. Subsequently, anhydrous ethanol is used to thoroughly wipe the surface of the valve seat, effectively removing oil stains, iron filings, and cutting fluid residue. Then, clean compressed air is used to thoroughly blow away fine dust and debris, ensuring that the valve seat surface is free of burrs, impurities, and oxide layers. This creates clean conditions for subsequent high-precision testing, preventing foreign objects from interfering with the test results or affecting the sealing performance of the finished product assembly. Finally, a high-precision micrometer, coaxiality tester, and perpendicularity tester are used to check the key dimensions of the valve seat. Dimensioning and geometric tolerances are fully inspected, and a roughness tester is used simultaneously to check the roughness of the sealing surface and each machined surface to ensure that the roughness of the sealing surface does not exceed the preset threshold. This accurately determines whether the valve seat machining accuracy meets the high-pressure sealing and assembly requirements of the wellhead. If all indicators are qualified, the finishing and repair are deemed qualified, and the product directly enters the final inspection of all items. If there are unqualified items such as dimensional deviations, excessive geometric tolerances, or surface defects, the product is re-finished and repaired according to the defect type. After repair, the full-item inspection is performed again. This cycle is repeated until the product is completely qualified, thereby achieving closed-loop defect control, significantly improving the finished product qualification rate and dimensional stability of the valve seat, ensuring that it can adapt to the harsh working conditions of high temperature, high pressure, and strong corrosion at the oil wellhead, while reducing rework waste and improving overall processing efficiency and product reliability.
[0050] Step 4: During the finishing and finishing process, determine whether to perform solidified cutting parameter optimization. If yes, perform a full-item final inspection after optimization. If not, perform a full-item final inspection directly, label the qualified workpieces and put them into the warehouse, and store the unqualified workpieces separately.
[0051] It should be noted that the specific steps for determining whether to perform solidified cutting parameter optimization are as follows:
[0052] The system collects data on cutting speed, feed rate, depth of cut, tool wear, and workpiece surface quality in real time during the machining process. It compares the collected data with pre-cured standard cutting parameters and automatically determines whether to perform optimization of the cured cutting parameters based on the comparison results.
[0053] When the deviation between the collected data and the solidified standard cutting parameters exceeds the preset allowable range, it is determined that the solidified cutting parameters need to be optimized. The cutting speed and feed rate are finely adjusted within the limited range and adjusted to the preset optimal range. After the optimization is completed, the finishing and finishing are re-executed. After the finishing is completed, the workpiece is subjected to a full-item final inspection.
[0054] When the deviation between the collected data and the solidified standard cutting parameters is within the preset allowable range, it is determined that there is no need to perform solidified cutting parameter optimization, and the workpiece with finished finishing and finished product repair is directly subjected to full-item final inspection.
[0055] Workpieces that pass the final inspection of all items are assigned a unique identification code and labeled, and then stored in the qualified warehouse according to batch.
[0056] Workpieces that fail the final inspection of the entire project are transferred to a dedicated non-conforming product area for separate storage, and the type of non-conformity and the corresponding workpiece code are recorded for subsequent traceability and disposal.
[0057] In this embodiment, during finishing and finishing processes, the equipment's built-in sensors collect multi-dimensional machining data in real time, including cutting speed, feed rate, depth of cut, tool wear, and workpiece surface quality. This data is then compared with pre-fixed and encrypted standard cutting parameters stored within the system. Based on data deviation thresholds, the system automatically determines whether to initiate the fixed cutting parameter optimization process, thereby achieving intelligent control of the machining process and ensuring consistency and confidentiality during mass production. When the deviation between the collected data and the standard parameters exceeds a preset allowable range, the system determines that parameter optimization is necessary. Authorized personnel then precisely fine-tune the cutting speed and feed rate within a defined safety range, correcting the parameters to the preset optimal range. This prevents dimensional deviations, surface quality degradation, or abnormal tool wear caused by parameter offsets. After optimization, finishing is performed again. After finishing and trimming the finished products to ensure that the processing quality meets the standards, a full-item final inspection is carried out. If the data deviation is within the allowable range, it is determined that no optimization is needed, and a full-item final inspection is carried out on the finished and trimmed workpieces. The dimensional accuracy, geometric tolerances, sealing performance and surface quality are fully verified to ensure that the valve seat meets the requirements of the high temperature, high pressure and strong corrosion conditions at the wellhead. Workpieces that pass the final inspection are assigned a unique identification code and labeled, and are classified into batches and managed in a qualified warehouse for unified management, so as to achieve full-process quality traceability. Workpieces that fail the final inspection are transferred to a special non-conforming product area for separate storage, and the non-conformity type and corresponding workpiece code are recorded at the same time. This facilitates the subsequent analysis of the cause of defects, optimization of processing technology and implementation of targeted rework, thereby effectively improving the finished product qualification rate, reducing production losses, and ensuring the stability and controllability of the processing process, which is suitable for the high efficiency and quality requirements of batch contract manufacturing.
Claims
1. A high-efficiency processing technology and quality control method for valve seats, characterized in that, The method includes: Step 1: Select wear-resistant and corrosion-resistant alloy billets suitable for the target oil wellhead. Use ultrasonic flaw detection to detect internal defects in the wear-resistant and corrosion-resistant alloy billets to remove unqualified billets with pores, cracks, and inclusions. Then, perform overall heat treatment on qualified billets. Step 2: Perform integrated rough machining on the billet after overall heat treatment, and simultaneously complete the standardized setting of rough machining cutting parameters. After rough machining, use low temperature aging treatment to relieve stress. Based on the dimensions of the billet after integrated rough machining, perform standardized setting of semi-finishing cutting parameters. Determine whether the billet dimensions meet the qualified working conditions based on the inner hole diameter. If yes, it is judged as qualified and the sealing surface is precisely machined. If not, it is judged as unqualified and does not flow into the next process. Step 3: During the precision machining of the sealing surface, if any defects are detected, an angle grinder is used to remove the defective area and the welding and defect detection are repeated until the weld layer is free of any defects. If the inspection is qualified, the process proceeds to fine machining and finished product finishing. Step 4: During the finishing and finishing process, determine whether to perform solidified cutting parameter optimization. If yes, perform a full-item final inspection after optimization. If not, perform a full-item final inspection directly, label the qualified workpieces and put them into the warehouse, and store the unqualified workpieces separately.
2. The valve seat high-efficiency machining process and quality control method as described in claim 1, characterized in that, In step one, the material of the wear-resistant and corrosion-resistant alloy billet is adapted to the high pressure, high temperature and strong corrosion conditions of the target oil wellhead. Chromium-nickel-molybdenum alloy and titanium alloy are selected, and the ultrasonic flaw detection adopts a digital ultrasonic flaw detector, with the detection range covering the cross-section and end face of the billet. If any of the following defects are detected in the billet: a pore with a diameter greater than or equal to the preset diameter, a crack with a length greater than or equal to the preset length, or an inclusion with an area greater than or equal to the preset area, the billet shall be deemed unqualified and rejected. If the billet passes the inspection and an ultrasonic flaw detection report is issued, then overall quenching and tempering treatment will be carried out.
3. The valve seat high-efficiency processing technology and quality control method as described in claim 2, characterized in that, The specific steps for the overall conditioning process are as follows: The qualified billet is subjected to overall quenching and tempering treatment using a box-type resistance furnace. The qualified billet is placed in the box-type resistance furnace, the furnace door is closed, and the heating program is started to raise the temperature inside the furnace to the preset quenching and tempering temperature range. Once the temperature inside the box-type resistance furnace is within the preset quenching and tempering temperature range, the temperature is kept constant for the preset holding time. After the constant temperature heat preservation is completed, turn off the furnace heating device and let the billet cool naturally with the furnace until the furnace temperature drops to the preset tempering temperature reference value. Then take out the billet and place it in a normal temperature environment to air cool to room temperature. S101. After the overall heat treatment is completed, the Rockwell hardness tester is used to perform multi-point hardness testing on the billet. Test points are evenly selected along the cross-section and end face of the billet. The distance between any two adjacent test points is greater than or equal to the preset test point distance, and the test points avoid the edge of the billet.
4. The valve seat high-efficiency processing technology and quality control method as described in claim 3, characterized in that, The specific steps for performing multi-point hardness testing are as follows: S102, start the hardness tester, control the indenter loading speed within the preset loading speed range, load to the preset load and hold for a preset time, then unload and record the hardness value of the test point; S103, repeat steps S101-S102 to complete the hardness test of all test points, calculate the average value of the hardness values of all test points, and if the hardness values of all test points are within the preset hardness value range, the billet hardness test is deemed qualified. S104 If the hardness value of any test point is outside the preset hardness value range, the billet hardness test is deemed unqualified. The billet is then subjected to overall tempering treatment again, and multi-point hardness testing is performed again until the test is qualified.
5. The valve seat high-efficiency machining process and quality control method as described in claim 1, characterized in that, The specific steps for completing the standardized setting of roughing cutting parameters are as follows: The correspondence between rotational speed, feed rate and depth of cut is established in advance to clarify the reference range of depth of cut that is suitable for different rotational speeds and feed rates. The actual rotational speed and actual feed rate of the current cutting process are collected in real time and compared with the preset reference values of rotational speed and feed rate. The depth of cut is dynamically adjusted according to the comparison results. When the actual rotational speed is higher than the rotational speed reference value and the actual feed rate is not lower than the lower limit of the feed rate reference value, the actual rotational speed and actual feed rate are input into the pre-established correspondence between rotational speed, feed rate and depth of cut, and the depth of cut is reduced. This is to avoid excessive cutting load caused by excessive rotational speed and normal feed rate. The difference between the depth of cut reference value and the depth of cut reduction is processed to obtain the target depth of cut. When the actual rotational speed is lower than the reference value and the actual feed rate is not higher than the upper limit of the reference value, the actual rotational speed and actual feed rate are input into the pre-established correspondence between rotational speed, feed rate and depth of cut, and the depth of cut is adjusted upwards. This avoids a decrease in machining efficiency due to excessively low rotational speed and normal feed rate. The reference value of depth of cut and the adjustment amount of depth of cut are superimposed to obtain the target depth of cut.
6. The valve seat high-efficiency machining process and quality control method as described in claim 5, characterized in that, The standardization setting of roughing cutting parameters also includes: When the actual rotational speed is within the reference range and the actual feed rate is higher than the upper limit of the reference feed rate, the actual rotational speed and actual feed rate are input into the pre-established correspondence between rotational speed, feed rate and depth of cut, and the depth of cut is output to reduce the depth of cut. This prevents the surface of the workpiece from scratching or burrs due to excessive feed rate and normal rotational speed. The difference between the reference value of the depth of cut and the depth of cut reduction is processed to obtain the target depth of cut. When the actual rotational speed is within the reference range and the actual feed rate is lower than the lower limit of the reference feed rate value, the actual rotational speed and actual feed rate are input into the pre-established correspondence between rotational speed, feed rate and depth of cut, and the depth of cut is adjusted upwards to balance machining accuracy and efficiency. The reference value of the depth of cut and the depth of cut adjustment upwards are superimposed to obtain the target depth of cut. When the actual rotational speed and actual feed rate are both within the preset reference range, maintain the cutting depth reference value; The system provides real-time feedback on dynamic data of rotational speed, feed rate, and depth of cut, and simultaneously monitors cutting force and tool temperature. If the cutting force exceeds the preset cutting force range, the system immediately pauses adjustment and stops the machine for inspection. After the fault is resolved, the linkage adjustment program is restarted to ensure accurate depth of cut adjustment and stable machining process.
7. The valve seat high-efficiency machining process and quality control method as described in claim 1, characterized in that, The specific steps for standardizing the semi-finishing cutting parameters are as follows: S201, establish the correspondence between semi-finishing rate and feed rate in advance to clarify the reference range of semi-finishing rate and the corresponding feed rate reference range, collect the actual semi-finishing rate of the current semi-finishing process in real time, compare the actual semi-finishing rate with the preset semi-finishing rate reference range, and dynamically adjust the semi-finishing feed rate according to the comparison results in different scenarios. S202, when the actual semi-finishing rate is higher than the upper limit of the rate reference range, the actual semi-finishing rate is input into the pre-established correspondence between the semi-finishing rate and the feed rate, and the feed rate reduction is output to avoid excessive cutting load due to excessively high rate and unchanged feed rate. The difference between the feed rate reference value and the feed rate reduction is processed to obtain the target feed rate.
8. The valve seat high-efficiency machining process and quality control method as described in claim 7, characterized in that, The standardization setting of semi-finishing cutting parameters also includes: S203, when the actual semi-finishing rate is lower than the lower limit of the rate reference range, the actual semi-finishing rate is input into the pre-established correspondence between the semi-finishing rate and the feed rate, and the feed rate adjustment is output to avoid the decrease in processing efficiency due to the low rate and unchanged feed rate. The feed rate reference value and the feed rate adjustment are superimposed to obtain the target feed rate. S204, when the actual semi-finishing rate is within the rate reference range, the feed reference value is kept unchanged, and the rate reference range refers to the closed interval formed by the lower limit of the rate reference range and the upper limit of the rate reference range; Continuously monitor the actual semi-finishing rate and feed rate. If the actual semi-finishing rate deviates from the rate reference range, repeat steps S201-S204. If the actual semi-finishing rate still deviates from the rate reference range after adjustment, the machine will automatically stop and issue an alarm signal to prompt the operator to check the tool wear and blank clamping status. After the fault is eliminated, restart the linkage adjustment program to ensure the stability of the semi-finishing process and guarantee the blank processing quality and processing efficiency.
9. The valve seat high-efficiency machining process and quality control method as described in claim 1, characterized in that, The specific steps for performing welding overlay and defect detection are as follows: After the precision machining of the sealing surface is completed, the machining equipment is stopped immediately, the valve seat blank is removed, and all edges and corners of the valve seat are rounded using a special angle grinder. The rounding radius is standardized and set within the preset radius standard range to avoid damage to the sealing surface and the machined surface. The valve seat surface is wiped with anhydrous ethanol to remove surface oil, iron filings, and residual cutting fluid. Then, compressed air is used to blow away any remaining dust on the surface to ensure that the valve seat surface is free of any burrs, scratches, impurities, and oxide layer. High-precision micrometers, coaxiality testers, and perpendicularity testers are used to comprehensively inspect the key dimensions and geometric tolerances of the valve seat. At the same time, a roughness tester is used to inspect the roughness of the sealing surface and each machined surface to ensure that the surface roughness of the sealing surface is less than or equal to the preset roughness threshold. If the inspection is qualified, the finishing and repair of the finished product is deemed qualified, and it will proceed to the subsequent final inspection process; if the inspection is unqualified, the finishing and repair will be carried out again according to the defect type, and the inspection will be carried out again until the inspection is qualified. The defect types include dimensional deviation, exceeding the form and position tolerance, surface defects, etc.
10. The valve seat high-efficiency machining process and quality control method as described in claim 1, characterized in that, The specific steps for determining whether to perform solidification cutting parameter optimization are as follows: The system collects data on cutting speed, feed rate, depth of cut, tool wear, and workpiece surface quality in real time during the machining process. It compares the collected data with pre-cured standard cutting parameters and automatically determines whether to perform optimization of the cured cutting parameters based on the comparison results. When the deviation between the collected data and the solidified standard cutting parameters exceeds the preset allowable range, it is determined that the solidified cutting parameters need to be optimized. The cutting speed and feed rate are finely adjusted within the limited range and adjusted to the preset optimal range. After the optimization is completed, the finishing and finishing are re-executed. After the finishing is completed, the workpiece is subjected to a full-item final inspection. When the deviation between the collected data and the solidified standard cutting parameters is within the preset allowable range, it is determined that there is no need to perform solidified cutting parameter optimization, and the workpiece with finished finishing and finished product repair is directly subjected to full-item final inspection. Workpieces that pass the final inspection of all items are assigned a unique identification code and labeled, and then stored in the qualified warehouse according to batch. Workpieces that fail the final inspection of the entire project are transferred to a dedicated non-conforming product area for separate storage, and the type of non-conformity and the corresponding workpiece code are recorded for subsequent traceability and disposal.