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CN-120758725-B - Medium-frequency heat treatment process for thrust wheel

CN120758725BCN 120758725 BCN120758725 BCN 120758725BCN-120758725-B

Abstract

The invention provides an intermediate-frequency heat treatment process for a thrust wheel, which belongs to the technical field of stress relief annealing pretreatment of the thrust wheel, and comprises the steps of grabbing the thrust wheel through a visual positioning manipulator, placing the thrust wheel on a rotary quenching platform, conveying the thrust wheel to a scanning station through a feeding conveying line, rapidly scanning the surface of a workpiece through a high-precision 3D visual system, adaptively grabbing the manipulator, planning a collision-free path by a six-axis cooperative manipulator according to coordinate data provided by the visual system, stably grabbing the thrust wheel with a contact pressure of 15+/-2N by using a pneumatic clamping jaw at the tail end, feeding back in real time by using a built-in force sensor, ensuring nondestructive clamping, realizing deep diathermanous+grain refinement through the gradient cooling coordination effect of variable-power intermediate-frequency heating and PAG+quenching oil, accurately controlling the martensitic transformation rate, improving the surface hardness of the thrust wheel, and reducing the fluctuation of the full-section hardness.

Inventors

  • WANG DAN
  • LI YINLING
  • ZHENG HUIWEN
  • FENG QIANG

Assignees

  • 江苏凯梯爱斯优机械部件有限公司

Dates

Publication Date
20260512
Application Date
20250623

Claims (8)

  1. 1. The medium-frequency heat treatment process for the thrust wheel is characterized by comprising the following steps of: s1, carrying out stress relief annealing pretreatment on the thrust wheel, wherein the thrust wheel is a phi 220mm thrust wheel made of 40CrMnMo material; s2, grabbing the thrust wheel by a visual positioning manipulator, and placing the thrust wheel on a rotary quenching platform, wherein the positioning accuracy is less than or equal to 0.1mm; the step S2 specifically includes the following steps: S21,3D vision scanning and positioning, wherein the supporting wheel is conveyed to a scanning station by a feeding conveying line, a high-precision 3D vision system rapidly scans the surface of a workpiece, the center coordinates and the inclination angles of the supporting wheel are calculated through a point cloud matching algorithm, the optimal grabbing point is determined, and the positioning precision reaches +/-0.05 mm; S22, the manipulator adaptively grabs, the six-axis cooperative manipulator plans a collision-free path according to coordinate data provided by a vision system, stably moves to a grabbing point at 0.3G acceleration, stably grabs a thrust wheel by a contact pressure of 15+/-2N by a tail end pneumatic clamping jaw, and feeds back in real time by a built-in force sensor to ensure nondestructive clamping; s23, high-precision placement and calibration are carried out, a mechanical arm transfers the thrust wheel to a rotary quenching platform, after coarse positioning is carried out through a terminal camera, 8 groups of annular array laser displacement sensors synchronously detect the position of a workpiece, and the system calculates the position deviation in real time and dynamically adjusts the position deviation until the positioning error of the thrust wheel and the platform is less than or equal to 0.1mm, and then vacuum adsorption fixation is triggered; s24, performing closed loop verification and exception handling, wherein a laser sensor rechecks radial runout of the thrust wheel, and enters a quenching process after confirming that the positioning accuracy reaches the standard, and immediately releasing vacuum and re-grabbing if the positioning accuracy is detected to be out of tolerance; s3, performing system setting on the medium-frequency induction heating; s4, carrying out variable-power medium-frequency induction heating on the thrust wheel through an induction coil body; The step S4 specifically includes the following steps: S41, a preheating stage, namely heating the thrust wheel to 480-500 ℃ by adopting an intermediate frequency power supply at the frequency of 1-3kHz and the power density of 0.8-1.2 kW/cm < 2 >, and preserving heat for 18-22S; s42, an austenitizing stage, namely switching to 0.5-1kHz frequency, heating to 865-875 ℃ at a power density of 1.5-2.0 kW/cm <2 >, and preserving heat for 85-95S; S5, carrying out gradient composite cooling on the support wheel after induction heating; S51, spraying an aqueous solution of PAG polymer with the mass fraction of 8-12% to the heated thrust wheel in the first stage, and spraying for 18-22S; s52, spraying rapid quenching oil with the cooling speed of more than or equal to 80 ℃ per second in the second stage, and spraying for 25-30 seconds; s53, introducing compressed air of 0.4-0.6MPa to cool to room temperature in the third stage.
  2. 2. The intermediate frequency heat treatment process of a thrust wheel according to claim 1, wherein in the step S4, a profiling induction coil body is adopted for induction heating, a gap between the induction coil body and the surface of the thrust wheel is 1.5-2.0mm, and a circulating cooling water channel is integrated in a copper pipe of the induction coil body.
  3. 3. The intermediate frequency heat treatment process of the thrust wheel according to claim 1, wherein the heating process in the step S4 is to monitor the temperature in real time by a bicolor infrared thermometer, and when the monitored temperature deviates from a set value of +/-5 ℃, a PID algorithm is triggered to dynamically adjust the power density, and the temperature fluctuation is maintained to be less than or equal to +/-5 ℃.
  4. 4. The intermediate frequency heat treatment process of a thrust wheel according to claim 1, wherein the PAG polymer aqueous solution in the first stage of step S5 contains an antirust agent and an antifoaming agent, and the cooling rate in a high temperature region above 300 ℃ is not less than 120 ℃ per second, and the cooling rate in a low temperature region below 200 ℃ is not more than 20 ℃ per second.
  5. 5. A process for intermediate frequency heat treatment of a thrust wheel as claimed in claim 1, wherein the rotational speed of the rotary quench plate is 10-15 rpm and is maintained throughout the heating and cooling stages.
  6. 6. The intermediate frequency heat treatment process of a thrust wheel according to claim 1, wherein the temperature rise rate of the austenitizing stage in S4 is controlled to be less than or equal to 25 ℃ per second, and the temperature rise rate is automatically reduced when the temperature difference between the surface and the core of the thrust wheel is greater than 50 ℃.
  7. 7. The intermediate frequency heat treatment process of a thrust wheel according to claim 1, wherein the kinematic viscosity of the rapid quenching oil in the second stage of step S5 at 40 ℃ is 12-15 cSt, and the flash point is more than or equal to 180 ℃.
  8. 8. The intermediate frequency heat treatment process of a thrust wheel according to claim 4, wherein the rust inhibitor is 0.15-0.25% by mass of Benzotriazole (BTA), and the defoamer is 0.05-0.10% by mass of Polydimethylsiloxane (PDMS).

Description

Medium-frequency heat treatment process for thrust wheel Technical Field The invention belongs to the technical field of heat treatment of thrust wheels, and particularly relates to an intermediate-frequency heat treatment process of a thrust wheel. Background The thrust wheel is one of four wheels of the chassis of the crawler engineering machinery, and has the main function of supporting the weight of the excavator and the bulldozer and enabling the crawler to advance along the wheels, so that the thrust wheel is required to have stronger strength, hardness and wear resistance. In the prior art, a quenching process is generally adopted, and the hardness of the surface of the thrust wheel is increased by carrying out quenching, tempering and other process treatments on the surface of the thrust wheel. In the quenching process, an induction coil is generally adopted to heat the thrust wheel, and medium-frequency induction heating is adopted to ensure the hardness of the thrust wheel. The traditional roller heat treatment process adopts fixed frequency through medium frequency induction heating, so that the temperature difference between the surface layer and the core part of a workpiece is large, the temperature rise is fast in high-frequency heating, but the hardening layer is shallow, the heavy load working condition requirement cannot be met, and the high-frequency medium frequency sectional heating is adopted, so that the energy consumption is high, the crystal grains are coarsened, in the cooling process after induction heating in quenching, the single water cooling easily generates a steam film to cause uneven hardness, a saline water medium corrodes equipment, the wastewater treatment cost is high, the cooling speed of the saline water is too high below 300 ℃, the deformation rate is increased, the oil cooling efficiency is low, and the hardness is difficult to reach the standard. In view of the problems, the invention provides a medium-frequency heat treatment process for the thrust wheel, 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, ensures the hardening depth and simultaneously remarkably improves the efficiency, and solves the industrial problems of quenching deformation and uneven hardness of the thrust wheel. Disclosure of Invention The invention aims to solve the problems in the prior art and provides a medium-frequency heat treatment process for a thrust wheel. The aim of the invention can be achieved by the following technical scheme: a medium-frequency heat treatment process for a thrust wheel comprises the following steps: s1, carrying out stress relief annealing pretreatment on the thrust wheel; s2, grabbing the thrust wheel by a visual positioning manipulator, and placing the thrust wheel on a rotary quenching platform, wherein the positioning accuracy is less than or equal to 0.1mm; the step S2 specifically includes the following steps: S21,3D vision scanning and positioning, wherein the supporting wheel is conveyed to a scanning station by a feeding conveying line, a high-precision 3D vision system rapidly scans the surface of a workpiece, the center coordinates and the inclination angles of the supporting wheel are calculated through a point cloud matching algorithm, the optimal grabbing point is determined, and the positioning precision reaches +/-0.05 mm; S22, the manipulator adaptively grabs, the six-axis cooperative manipulator plans a collision-free path according to coordinate data provided by a vision system, stably moves to a grabbing point at 0.3G acceleration, stably grabs a thrust wheel by a contact pressure of 15+/-2N by a tail end pneumatic clamping jaw, and feeds back in real time by a built-in force sensor to ensure nondestructive clamping; s23, high-precision placement and calibration are carried out, a mechanical arm transfers the thrust wheel to a rotary quenching platform, after coarse positioning is carried out through a terminal camera, 8 groups of annular array laser displacement sensors synchronously detect the position of a workpiece, and the system calculates the position deviation in real time and dynamically adjusts the position deviation until the positioning error of the thrust wheel and the platform is less than or equal to 0.1mm, and then vacuum adsorption fixation is triggered; s24, performing closed loop verification and exception handling, wherein a laser sensor rechecks radial runout of the thrust wheel, and enters a quenching process after confirming that the positioning accuracy reaches the standard, and immediately releasing vacuum and re-grabbing if the positioning accuracy is detected to be out of tolerance; s3, performing system setting on the medium-frequency induction heating; s4, carrying out variable-power medium-frequency induction heating on the thrust wheel through an induction coil body; The step S4 specifically i