Medium-frequency heat treatment process for thrust wheel

Abstract

The invention provides a thrust wheel medium-frequency heat treatment process, which belongs to the technical field of thrust wheel heat treatment, and comprises the following steps: carrying out stress relief annealing pretreatment on a thrust wheel; the thrust wheel is grabbed through the visual positioning manipulator and placed on the rotary quenching platform; a thrust wheel is conveyed to a scanning station through a feeding conveying line, the high-precision 3D visual system rapidly scans the surface of a workpiece, the mechanical arm conducts self-adaptive grabbing, the six-axis cooperative mechanical arm plans a collision-free path according to coordinate data provided by the visual system and stably moves to a grabbing point at the accelerated speed of 0.3 G, a tail end pneumatic clamping jaw stably grabs the thrust wheel at the contact pressure of 15 + / -2N, and then the thrust wheel is automatically grabbed. A built-in force sensor feeds back in real time to ensure non-damage clamping; through the coordination effect of variable-power medium-frequency heating and PAGE + quenching oil gradient cooling, deep diathermancy and grain refinement are achieved, the martensite phase transformation rate is accurately controlled, the surface hardness of the thrust wheel is improved, and the total cross-section hardness fluctuation is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of heat treatment of support wheel, and particularly relates to a support wheel medium-frequency heat treatment process. BACKGROUND

[0002] The support wheel is one of the four wheels and one belt of the chassis of the tracked engineering machinery, and mainly functions to support the weight of the excavator and the bulldozer and enable the tracked belt to move forward along the wheels, so that the support wheel needs to have strong strength, hardness and wear resistance. In the prior art, a quenching process is usually adopted to increase the hardness of the surface of the support wheel by quenching and tempering the surface of the support wheel. In the quenching process, an induction coil is usually used to heat the support wheel, and medium-frequency induction heating is used to ensure the hardness of the support wheel.

[0003] The conventional support wheel heat treatment process uses a fixed frequency for medium-frequency induction heating, which results in a large temperature difference between the surface layer and the core of the workpiece. Although high-frequency heating has a fast heating speed, the hardened layer is shallow, and cannot meet the requirements of heavy load working conditions. Moreover, high-frequency-medium-frequency segmented heating has high energy consumption and causes grain coarsening. In the cooling process after induction heating in quenching, single water cooling easily produces a steam film, resulting in uneven hardness. Salt water medium corrodes the equipment, and the cost of waste water treatment is high. Salt water cooling is too fast below 300 DEG C, and the deformation rate is increased. Oil cooling has low efficiency, and the hardness is difficult to reach the standard.

[0004] In view of the above problems, the application provides a support wheel medium-frequency heat treatment process, which breaks through the limitation of single frequency and medium by the coordination of variable power medium-frequency heating and PAG+quenching oil gradient cooling, significantly improves the efficiency while ensuring the hardening depth, and solves the industry problems of support wheel quenching deformation and uneven hardness. SUMMARY

[0005] The application aims to solve the above problems of the prior art, and provides a support wheel medium-frequency heat treatment process.

[0006] The application can be realized by the following technical scheme.

[0007] A support wheel medium-frequency heat treatment process, comprising the following steps:

[0008] S1, stress relief annealing pretreatment is performed on the support wheel;

[0009] S2, the support wheel is grabbed by a visual positioning manipulator and placed on a rotary quenching platform, and the positioning accuracy is less than or equal to 0.1mm;

[0010] In the step S2, the following steps are included.

[0011] S21, 3D visual scanning and positioning: The track rollers are transported from the loading conveyor line to the scanning station. The high-precision 3D vision system quickly scans the workpiece surface and calculates the center coordinates and tilt angle of the track rollers through a point cloud matching algorithm to determine the optimal gripping point, with a positioning accuracy of ±0.05mm.

[0012] S22, adaptive gripping by the robot. The six-axis collaborative robot plans a collision-free path based on the coordinate data provided by the vision system, moving smoothly to the gripping point at an acceleration of 0.3G. The pneumatic gripper at the end stably grasps the supporting roller with a contact pressure of 15±2N. The built-in force sensor provides real-time feedback to ensure damage-free gripping.

[0013] S23, high-precision placement and calibration: The robot moves the track rollers to the rotary quenching platform. After rough positioning by the end camera, eight groups of circular array laser displacement sensors synchronously detect the workpiece position. The system calculates the position deviation in real time and dynamically adjusts it until the positioning error between the track rollers and the platform is ≤0.1mm. Vacuum adsorption is then triggered to fix the workpiece.

[0014] S24, closed-loop verification and exception handling: Laser sensors recheck the radial runout of the track rollers. After confirming that the positioning accuracy meets the standard, the quenching process begins. If the detection exceeds the tolerance, the vacuum is immediately released and the grip is re-grasped. If three consecutive failures occur, an alarm is triggered and the machine is shut down to ensure process reliability. The entire process takes ≤4 seconds, and the positioning repeatability reaches 0.07mm.

[0015] S3, system settings for medium frequency induction heating;

[0016] S4, performing variable power medium frequency induction heating on the track roller through the induction coil;

[0017] Wherein, step S4 specifically includes the following steps:

[0018] S41, preheating stage: use medium frequency power supply at 1-3kHz frequency, 0.8-1.2kW / cm 2 Heat the track rollers to 480-500°C with a power density of 18-22 seconds;

[0019] S42, austenitizing stage: switch to 0.5-1kHz frequency, 1.5-2.0kW / cm 2 Heat to 865-875℃ with power density and keep warm for 85-95s;

[0020] S5, performing gradient composite cooling on the track roller after induction heating.

[0021] Preferably, the step S5 specifically includes the following steps:

[0022] S51, in the first stage, a PAG polymer aqueous solution with a mass fraction of 8-12% is sprayed onto the heated supporting roller for 18-22 seconds;

[0023] S52, in the second stage, spraying rapid quenching oil with a cooling rate of ≥80℃ / s, spraying for 25-30s;

[0024] S53, the third stage is to introduce 0.4-0.6MPa compressed air to cool to room temperature.

[0025] Preferably, the induction heating in step S4 uses a contoured induction coil, the gap between the induction coil and the surface of the track wheel is 1.5-2.0 mm, and a circulating cooling water channel is integrated inside the copper tube of the induction coil.

[0026] Preferably, in step S4, the temperature of the heating process is monitored in real time by a two-color infrared thermometer. When the monitored temperature deviates from the set value by ±5°C, the PID algorithm is triggered to dynamically adjust the power density to maintain the temperature fluctuation ≤±5°C.

[0027] Preferably, the PAG polymer aqueous solution in the first stage of step S5 contains a rust inhibitor and a defoamer, and its cooling rate in the high temperature zone above 300°C is ≥120°C / s, and its cooling rate in the low temperature zone below 200°C is ≤20°C / s.

[0028] Preferably, the rotation speed of the rotary quenching platform is 10-15 rpm, and it keeps rotating throughout the heating and cooling stages.

[0029] Preferably, the heating rate in the austenitization stage in S4 is controlled at ≤25°C / s, and the heating rate is automatically reduced when the temperature difference between the track roller surface and the core is greater than 50°C.

[0030] Preferably, the kinematic viscosity of the second-stage rapid quenching oil in step S5 is 12-15 cSt (40° C.) and the flash point is ≥180° C.

[0031] Preferably, the mass percentage of the PAG polymer aqueous solution is 8%-12%.

[0032] Preferably, the rust inhibitor is benzotriazole (BTA) with a mass percentage of 0.15%-0.25%, and the defoaming agent is polydimethylsiloxane (PDMS) with a mass percentage of 0.05%-0.10%.

[0033] Compared with the existing technology, this medium frequency heat treatment process for supporting rollers has the following beneficial effects:

[0034] 1. The medium-frequency heat treatment process for a supporting wheel provided by the application realizes deep heat penetration and grain refinement through the coordination of variable-power medium-frequency heating and PAG+quenching oil gradient cooling, accurately controls the martensite phase change rate, improves the surface hardness of the supporting wheel, and reduces the full cross-section hardness fluctuation.

[0035] 2. The medium-frequency heat treatment process for a supporting wheel provided by the application realizes rapid and uniform initial cooling through PAG solution spraying, avoids steam film effect, and significantly reduces the deformation and cracking risk through the synergistic effect of the three-stage cooling process.

[0036] 3. The medium-frequency heat treatment process for a supporting wheel provided by the application effectively controls the cooling rate through the gradient composite cooling process, and takes into account the hardness and deformation prevention requirements.

[0037] 4. The medium-frequency heat treatment process for a supporting wheel provided by the application realizes non-contact accurate temperature measurement through dual-color infrared temperature measurement, ensures temperature control accuracy through PID dynamic adjustment, and significantly improves process stability through closed-loop control.

[0038] 5. The medium-frequency heat treatment process for a supporting wheel provided by the application.

[0039] In summary, the medium-frequency heat treatment process for a supporting wheel provided by the application realizes a surface hardness of 58-63HRC and a full cross-section hardness fluctuation of ≤1.5HRC through the synergistic effect of variable-power medium-frequency heating and gradient composite cooling, and reduces the roundness error from 0.15mm to ≤0.05mm through three-stage cooling combined with high-precision positioning. DETAILED DESCRIPTION

[0040] The following is a specific embodiment of the application, which further describes the technical solutions of the application, but the application is not limited to these embodiments.

[0041] Example 1

[0042] A medium-frequency heat treatment process for a supporting wheel includes the following steps:

[0043] S1, stress relief annealing pretreatment is performed on the supporting wheel, a φ220mm supporting wheel made of 40CrMnMo material is selected, and stress relief annealing at 580℃×2h is performed first;

[0044] S2, the supporting wheel is grabbed by a visual positioning manipulator and placed on a rotary quenching platform, and the positioning accuracy is ≤0.1mm;

[0045] Specifically, step S2 includes the following steps:

[0046] S21, 3D visual scanning and positioning: The track rollers are transported from the loading conveyor line to the scanning station. The high-precision 3D vision system quickly scans the workpiece surface and calculates the center coordinates and tilt angle of the track rollers through a point cloud matching algorithm to determine the optimal gripping point, with a positioning accuracy of ±0.05mm.

[0047] S22, adaptive gripping by the robot. The six-axis collaborative robot plans a collision-free path based on the coordinate data provided by the vision system, moving smoothly to the gripping point at an acceleration of 0.3G. The pneumatic gripper at the end stably grasps the supporting roller with a contact pressure of 15±2N. The built-in force sensor provides real-time feedback to ensure damage-free gripping.

[0048] S23, high-precision placement and calibration: The robot moves the track rollers to the rotary quenching platform. After rough positioning by the end camera, eight groups of circular array laser displacement sensors synchronously detect the workpiece position. The system calculates the position deviation in real time and dynamically adjusts it until the positioning error between the track rollers and the platform is ≤0.1mm. Vacuum adsorption is then triggered to fix the workpiece.

[0049] S24, closed-loop verification and exception handling: Laser sensors recheck the radial runout of the track rollers. After confirming that the positioning accuracy meets the standard, the quenching process begins. If the detection exceeds the tolerance, the vacuum is immediately released and the grip is re-grasped. If three consecutive failures occur, an alarm is triggered and the machine is shut down to ensure process reliability. The entire process takes ≤4 seconds, and the positioning repeatability reaches 0.07mm.

[0050] S3, set up the medium-frequency induction heating system. The hardware system configuration includes the power supply system, sensors, cooling system, and temperature measurement feedback. The power supply system uses an IGBT medium-frequency power supply. Parameter settings include basic parameter input, entering workpiece parameters on the PLC interface, selecting the variable power process mode, setting the frequency-power curve, setting safety thresholds, temperature over-limit alarm: set value ±10°C (hard limit ±15°C), cooling water flow alarm: power reduction operation when <20L / min, emergency shutdown when <10L / min.

[0051] Table 1 Frequency-power curve setting

[0052]

[0053] S4, performing variable power medium frequency induction heating on the track rollers through the induction coil;

[0054] Wherein, step S4 specifically includes the following steps:

[0055] S41, preheating stage: use medium frequency power supply at 1-3kHz frequency, 0.8-1.2kW / cm 2 Heat the track rollers to 480-500°C with a power density of 18-22 seconds;

[0056] Table 2 Electromagnetic simulation results

[0057]

[0058] Table 3 Measured data of 40Cr track wheels

[0059]

[0060] Table 4 Residual stress test results

[0061]

[0062]

[0063] Table 5 Core-surface temperature difference monitoring results

[0064]

[0065] Electromagnetic simulation results show that at 2.5kHz, the heating efficiency (78%) and heat penetration depth (1.2mm) are balanced, avoiding edge overheating caused by high frequency; 1.0kW / cm 2 The efficiency and uniformity are the best, power>1.2kW / cm 2 The temperature difference of the roller surface was measured in different power density ranges, and the results showed that 1.0kW / cm 2 The efficiency and uniformity are the best, power>1.2kW / cm 2 The temperature difference increases. The residual stress under 480-500℃ temperature control was measured by X-ray diffraction method. The results showed that the stress was fully relieved at 490℃ and no phase transformation was triggered. The temperature difference between the core and the surface was monitored by FLIR A655sc thermal imager. The results showed that the temperature difference was less than 40℃ in 20s, which met the subsequent austenitization uniformity requirements. The results show that 1-3kHz medium frequency heating optimizes the skin effect and achieves rapid and uniform heating, 0.8-1.2kW / cm 2 The power density can balance heating efficiency and thermal stress control. The preheating temperature of 480-500℃ can fully eliminate machining stress and avoid microstructure phase change. The holding time of 18-22s can ensure that the temperature difference between the core and the surface is ≤40℃, reducing the risk of deformation.

[0066] S42, austenitizing stage: switch to 0.5-1kHz frequency, 1.5-2.0kW / cm 2 Heat to 865-875℃ with power density and keep warm for 85-95s;

[0067] Table 6 Electromagnetic simulation and measured data

[0068]

[0069] Table 740Cr track roller austenitization dynamics test

[0070]

[0071] Table 8 Infrared thermal imager and metallographic inspection

[0072]

[0073] The head heating effect of 0.5-1kHz was measured, and the results of electromagnetic simulation and measured data showed that the best hardening layer depth (9.2mm) and temperature uniformity (±10℃) were achieved at 0.8kHz. 2 The phase transformation efficiency was measured at a power density of 1.8kW / cm 2 The phase transformation is sufficient and the grain is refined (level 8.5), power>2.0kW / cm 2 The uniformity of the holding time in the range of 85-95s was verified by infrared thermal imaging and metallographic examination. The results showed that the core was completely austenitized at 90s and decarburization was controllable. The results showed that 0.5-1kHz low-frequency heating can achieve deep thermal penetration and structural homogenization, 1.5-2.0kW / cm 2 The power density can quickly penetrate the austenite phase transformation zone, inhibit grain coarsening, and 85-95s heat preservation can completely austenitize and the temperature difference between the core and the surface is ≤15℃.

[0074] S5, performing gradient composite cooling on the track roller after induction heating.

[0075] In step S4, the induction heating adopts a contoured induction coil, the gap between the induction coil and the surface of the supporting wheel is 1.5-2.0mm, and the copper tube of the contoured induction coil is integrated with a spiral guide cooling water channel with a cross-sectional area of ​​12-15mm. 2 , water flow rate ≥5m / s, the inner wall of the water channel is provided with turbulent protrusions, and the outer surface of the copper tube is plated with a 5-8μm silver layer.

[0076] In step S4, the temperature of the heating process is monitored in real time by a two-color infrared thermometer. When the monitored temperature deviates from the set value by ±5°C, the PID algorithm is triggered to dynamically adjust the power density to maintain the temperature fluctuation ≤±5°C.

[0077] The rotary quenching platform rotates at a speed of 10-15 rpm and keeps rotating throughout the heating and cooling stages. The platform surface is equipped with a vacuum adsorption array consisting of micropores with a diameter of 1 mm, a heat-resistant ceramic coating with a thickness of 0.2-0.3 mm, and a dynamic balancing module that monitors the platform vibration in real time and automatically compensates for imbalance.

[0078] The heating rate in the austenitization stage of S4 is controlled at ≤25℃ / s, and the heating rate is automatically reduced when the temperature difference between the supporting wheel surface and the core is greater than 50℃.

[0079] Example 2:

[0080] A medium frequency heat treatment process for a track roller comprises the following steps:

[0081] S1, stress relief annealing pretreatment is performed on the supporting rollers. φ220mm supporting rollers made of 40CrMnMo material are selected and stress relief annealing is performed at 580℃×2h first;

[0082] S2, the track roller is grabbed by the visual positioning manipulator and placed on the rotary quenching platform with a positioning accuracy of ≤0.1mm;

[0083] Wherein, step S2 specifically includes the following steps:

[0084] S21, 3D visual scanning and positioning: The track rollers are transported from the loading conveyor line to the scanning station. The high-precision 3D vision system quickly scans the workpiece surface and calculates the center coordinates and tilt angle of the track rollers through a point cloud matching algorithm to determine the optimal gripping point, with a positioning accuracy of ±0.05mm.

[0085] S22, adaptive gripping by the robot. The six-axis collaborative robot plans a collision-free path based on the coordinate data provided by the vision system, moving smoothly to the gripping point at an acceleration of 0.3G. The pneumatic gripper at the end stably grasps the supporting roller with a contact pressure of 15±2N. The built-in force sensor provides real-time feedback to ensure damage-free gripping.

[0086] S23, high-precision placement and calibration: The robot moves the track rollers to the rotary quenching platform. After rough positioning by the end camera, eight groups of circular array laser displacement sensors synchronously detect the workpiece position. The system calculates the position deviation in real time and dynamically adjusts it until the positioning error between the track rollers and the platform is ≤0.1mm. Vacuum adsorption is then triggered to fix the workpiece.

[0087] S24, closed-loop verification and exception handling: Laser sensors recheck the radial runout of the track rollers. After confirming that the positioning accuracy meets the standard, the quenching process begins. If the detection exceeds the tolerance, the vacuum is immediately released and the grip is re-grasped. If three consecutive failures occur, an alarm is triggered and the machine is shut down to ensure process reliability. The entire process takes ≤4 seconds, and the positioning repeatability reaches 0.07mm.

[0088] S3, set up the medium-frequency induction heating system. The hardware system configuration includes the power supply system, sensors, cooling system, and temperature measurement feedback. The power supply system uses an IGBT medium-frequency power supply. Parameter settings include basic parameter input, entering workpiece parameters on the PLC interface, selecting the variable power process mode, setting the frequency-power curve, setting safety thresholds, temperature over-limit alarm: set value ±10°C (hard limit ±15°C), cooling water flow alarm: power reduction operation when <20L / min, emergency shutdown when <10L / min.

[0089] Table 1 Frequency-power curve setting

[0090]

[0091] S4, performing variable power medium frequency induction heating on the track rollers through the induction coil;

[0092] Wherein, step S4 specifically includes the following steps:

[0093] S41, preheating stage: use medium frequency power supply at 1-3kHz frequency, 0.8-1.2kW / cm 2 Heat the track rollers to 480-500°C with a power density of 18-22 seconds;

[0094] Table 2 Electromagnetic simulation results

[0095]

[0096] Table 3 Measured data of 40Cr track wheels

[0097]

[0098] Table 4 Residual stress test results

[0099]

[0100] Table 5 Core-surface temperature difference monitoring results

[0101]

[0102] Electromagnetic simulation results show that at 2.5kHz, the heating efficiency (78%) and heat penetration depth (1.2mm) are balanced, avoiding edge overheating caused by high frequency; 1.0kW / cm 2 The efficiency and uniformity are the best, power>1.2kW / cm 2 The temperature difference of the roller surface was measured in different power density ranges, and the results showed that 1.0kW / cm 2 The efficiency and uniformity are the best, power>1.2kW / cm 2The temperature difference increases. The residual stress under 480-500℃ temperature control was measured by X-ray diffraction method. The results showed that the stress was fully relieved at 490℃ and no phase transformation was triggered. The temperature difference between the core and the surface was monitored by FLIR A655sc thermal imager. The results showed that the temperature difference was less than 40℃ in 20s, which met the subsequent austenitization uniformity requirements. The results show that 1-3kHz medium frequency heating optimizes the skin effect and achieves rapid and uniform heating, 0.8-1.2kW / cm 2 The power density can balance heating efficiency and thermal stress control. The preheating temperature of 480-500℃ can fully eliminate machining stress and avoid microstructure phase change. The holding time of 18-22s can ensure that the temperature difference between the core and the surface is ≤40℃, reducing the risk of deformation.

[0103] S42, austenitizing stage: switch to 0.5-1kHz frequency, 1.5-2.0kW / cm 2 Heat to 865-875℃ with power density and keep warm for 85-95s;

[0104] Table 6 Electromagnetic simulation and measured data

[0105]

[0106] Table 740Cr track roller austenitization dynamics test

[0107]

[0108]

[0109] Table 8 Infrared thermal imager and metallographic inspection

[0110]

[0111] The head heating effect of 0.5-1kHz was measured, and the electromagnetic simulation and measured data results showed that the best hardening layer depth (9.2mm) and temperature uniformity (±10℃) were achieved at 0.8kHz. 2 The phase transformation efficiency was measured at a power density of 1.8kW / cm 2 The phase transformation is sufficient and the grains are refined (level 8.5), power>2.0kW / cm 2 The uniformity of the holding time in the range of 85-95s was verified by infrared thermal imaging and metallographic examination. The results showed that the core was completely austenitized at 90s and decarburization was controllable. The results showed that 0.5-1kHz low-frequency heating can achieve deep thermal penetration and structural homogenization, 1.5-2.0kW / cm 2The power density can quickly penetrate the austenite phase transformation zone, inhibit grain coarsening, and 85-95s heat preservation can completely austenitize and the temperature difference between the core and the surface is ≤15℃.

[0112] S5, performing gradient composite cooling on the track roller after induction heating.

[0113] Step S5 specifically includes the following steps:

[0114] In the first stage, S51, an 8-12% by mass aqueous solution of PAG polymer was sprayed onto the heated roller for 18-22 seconds. As shown in Table 9, the cooling characteristics were tested. The results showed that a 10% PAG solution achieved an ideal balance between rapid cooling (austenite region) and slow cooling (martensite region).

[0115] Table 9 Cooling characteristics test

[0116]

[0117] S52, the second stage spray cooling rate ≥ 80 ° C / s rapid quenching oil, spraying 25-30s, as shown in Table 10 and Table 11, the quenching oil performance and microstructure uniformity were tested. The results show that the rapid quenching oil has the best hardness, and the core / surface hardness difference and retained austenite content of PAG + oil cooling are both lower than those of single oil cooling;

[0118] Table 10 Comparison of quenching oil properties

[0119]

[0120] Table 11 Tissue uniformity test

[0121]

[0122] S53, the third stage is to introduce 0.4-0.6MPa compressed air to cool to room temperature.

[0123] Table 12 Residual stress detection

[0124]

[0125] The above test data shows that PAG solution spraying (8-12%) reduces deformation by 60% compared with pure water cooling, can optimize the steam film stage, and achieve rapid and uniform cooling; rapid quenching oil (≥80℃ / s) is 3-5HRC harder than ordinary quenching oil, can accurately control the martensitic phase transformation rate, and reduce the risk of cracking; compressed air cooling saves 30% of subsequent cleaning costs compared with oil cooling, indicating that it can eliminate residual stress and avoid oil pollution.

[0126] The induction heating in step S4 adopts a profiled induction coil body, the gap between the induction coil body and the surface of the supporting wheel is 1.5-2.0mm, and the copper pipe of the induction coil body is internally integrated with a circulating cooling water channel.

[0127] The PAG polymer aqueous solution in the first stage of step S5 contains a rust inhibitor and a defoaming agent, the cooling speed of which is ≥120℃ / s in the high temperature zone above 300℃, and ≤20℃ / s in the low temperature zone below 200℃.

[0128] The kinematic viscosity of the rapid quenching oil in the second stage of step S5 is 12-15cSt (40℃), and the flash point is ≥180℃.

[0129] The mass percentage of the PAG polymer aqueous solution is 8%-12%.

[0130] The rust inhibitor is benzotriazole (BTA) with a mass percentage of 0.15%-0.25%, and the defoaming agent is polydimethylsiloxane (PDMS) with a mass percentage of 0.05%-0.10%.

[0131] The specific embodiments described herein are merely illustrative of the spirit of the present application. Those skilled in the art of the present application can make various modifications or supplements to the described specific embodiments or replace them with similar ways, without departing from the spirit of the present application or exceeding the scope defined by the appended claims.

Claims

1. A medium frequency heat treatment process for a track roller, characterized in that: The following steps are involved: S1, performing stress relief annealing pretreatment on the supporting roller; S2, grab the supporting wheel by a visual positioning manipulator and place it on a rotary quenching platform with a positioning accuracy of ≤0.1mm; Wherein, step S2 specifically includes the following steps: S21, 3D visual scanning and positioning: The track rollers are transported from the loading conveyor line to the scanning station. The high-precision 3D vision system quickly scans the workpiece surface and calculates the center coordinates and tilt angle of the track rollers through a point cloud matching algorithm to determine the optimal gripping point, with a positioning accuracy of ±0.05mm. S22, adaptive gripping by the robot. The six-axis collaborative robot plans a collision-free path based on the coordinate data provided by the vision system, moving smoothly to the gripping point at an acceleration of 0.3G. The pneumatic gripper at the end stably grasps the supporting roller with a contact pressure of 15±2N. The built-in force sensor provides real-time feedback to ensure damage-free gripping. S23, high-precision placement and calibration: The robot moves the track rollers to the rotary quenching platform. After rough positioning by the end camera, eight groups of circular array laser displacement sensors synchronously detect the workpiece position. The system calculates the position deviation in real time and dynamically adjusts it until the positioning error between the track rollers and the platform is ≤0.1mm. Vacuum adsorption is then triggered to fix the workpiece. S24, closed-loop verification and exception handling: Laser sensors recheck the radial runout of the track rollers. After confirming that the positioning accuracy meets the standard, the quenching process begins. If the detection exceeds the tolerance, the vacuum is immediately released and the grip is re-grasped. If three consecutive failures occur, an alarm is triggered and the machine is shut down to ensure process reliability. The entire process takes ≤4 seconds, and the positioning repeatability reaches 0.07mm. S3, system settings for medium frequency induction heating; S4, performing variable power medium frequency induction heating on the track roller through the induction coil; Wherein, step S4 specifically includes the following steps: S41, preheating stage: use medium frequency power supply at 1-3kHz frequency, 0.8-1.2kW / cm 2 Heat the track rollers to 480-500°C with a power density of 18-22 seconds; S42, austenitizing stage: switch to 0.5-1kHz frequency, 1.5-2.0kW / cm 2 Heat to 865-875℃ with power density and keep warm for 85-95s; S5, performing gradient composite cooling on the track roller after induction heating.

2. A medium frequency heat treatment process for a track roller according to claim 1, characterized in that: The step S5 specifically includes the following steps: S51, in the first stage, a PAG polymer aqueous solution with a mass fraction of 8-12% is sprayed onto the heated supporting roller for 18-22 seconds; S52, in the second stage, spraying rapid quenching oil with a cooling rate of ≥80℃ / s, spraying for 25-30s; S53, the third stage is to introduce 0.4-0.6MPa compressed air to cool to room temperature.

3. The medium frequency heat treatment process for a track roller according to claim 1, characterized in that: In the step S4, the induction heating adopts a contoured induction coil, the gap between the induction coil and the surface of the track wheel is 1.5-2.0 mm, and a circulating cooling water channel is integrated inside the copper tube of the induction coil.

4. The medium frequency heat treatment process for a track roller according to claim 1, characterized in that: In step S4, the temperature of the heating process is monitored in real time by a two-color infrared thermometer. When the monitored temperature deviates from the set value by ±5°C, the PID algorithm is triggered to dynamically adjust the power density to maintain the temperature fluctuation ≤±5°C.

5. The medium frequency heat treatment process for a track roller according to claim 2, characterized in that: The PAG polymer aqueous solution in the first stage of step S5 contains a rust inhibitor and a defoamer, and its cooling rate in the high temperature zone above 300°C is ≥120°C / s, and its cooling rate in the low temperature zone below 200°C is ≤20°C / s.

6. A medium frequency heat treatment process for a track roller according to any one of claim 1, characterized in that: The rotating quenching platform rotates at a speed of 10-15 rpm and keeps rotating throughout the heating and cooling stages.

7. A medium frequency heat treatment process for a track roller according to any one of claim 1, characterized in that: The heating rate in the austenitization stage in S4 is controlled to be ≤25°C / s, and the heating rate is automatically reduced when the temperature difference between the track roller surface and the core is greater than 50°C.

8. A medium frequency heat treatment process for a track roller according to claim 2 or 5, characterized in that: The kinematic viscosity of the second-stage rapid quenching oil in step S5 is 12-15 cSt (40° C.) and the flash point is ≥180° C.

9. A medium frequency heat treatment process for a track roller according to claim 1 or 4, characterized in that: The mass percentage of the PAG polymer aqueous solution is 8%-12%.

10. The medium frequency heat treatment process for a track roller according to claim 4, characterized in that: The rust preventive agent is benzotriazole (BTA) with a mass percentage of 0.15%-0.25%, and the defoaming agent is polydimethylsiloxane (PDMS) with a mass percentage of 0.05%-0.10%.

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