Steel shot heat treatment equipment and quenching process thereof

Abstract

The invention provides steel shot heat treatment equipment and a quenching process thereof, and particularly relates to a steel ball continuous heat treatment device. Comprising a rust removal module, a heating module, a quenching module, a post-treatment module and a cleaning module, the derusting module, the quenching module, the post-treatment module and the cleaning module are communicated through a pipeline, and the heating module is located between the derusting module and the quenching module and correspondingly wraps the outer side wall of the pipeline; two times of heating are adopted, steel shots are pre-cleaned and pre-heated, energy consumption in the heat treatment process is reduced, energy conservation and environmental protection are achieved, energy is saved by 35% compared with a traditional production line, and energy consumption and carbon emission are reduced through high-efficiency energy-saving assemblies such as a high-frequency induction rapid heating channel, an eddy current quenching system and an electromagnetic eddy current drying tower.

Description

Technical Field

[0001] The present invention provides a steel shot heat treatment device and its quenching process, specifically relating to a continuous heat treatment device for steel balls. Background Art

[0002] The heat treatment of steel shots for sandblasting is a key process in the surface treatment industry, and its quality directly affects the sandblasting efficiency and surface treatment effect. The traditional heat treatment process generally has the following technical bottlenecks: 1. The production line adopts a decentralized layout, and materials need to be transferred multiple times in processes such as quenching and tempering. The floor area of the equipment reaches 300 - 500 square meters; 2. The thermal efficiency of the gas heating furnace is less than 40%, and the energy consumption per ton of products is as high as 120 - 150 kW·h; 3. The connection between processes relies on manual transfer, and the average processing cycle is as long as 6 - 8 hours; 4. The temperature fluctuation exceeds ±25°C, resulting in a difference in steel shot hardness of HRC3 - 5, and the qualified rate is only 75 - 82%. The industry urgently needs to solve the problems of energy consumption and quality control through process innovation; in the existing technology, although the induction heating technology disclosed in CN112195334A realizes a rapid temperature rise of 0.8 - 1.2°C / s in strip steel treatment, its toroidal coil structure has uneven heating problems during batch processing of steel shots. The core - surface temperature difference of steel shots with a diameter of 2 - 3 mm reaches 50 - 80°C; although the dual - frequency alternating heating mode (switching between medium - frequency 5 - 10 kHz and high - frequency 50 - 100 kHz) adopted in this patent improves the tissue uniformity of strip steel, it is prone to electromagnetic field interference when applied to spherical workpieces, resulting in 15 - 20% of over - heated or under - heated defective products; the fully continuous production system proposed in CN112143877A achieves a process automation rate of 98% in sheet metal processing, but its linear layout (length exceeding 150 meters) faces two major challenges in steel shot processing: one is the positioning deviation caused by the rolling of the shot body, which affects the quenching uniformity, and the other is the thickening of the surface oxidation (up to 20 - 30 μm) caused by continuous transmission; although the laser temperature measurement accuracy of ±10°C of this system is better than that of traditional equipment, it cannot meet the process requirements of ±5°C for steel shots, resulting in a fluctuation of the martensite conversion rate of 12 - 15%; the current steel shot heat treatment technology has significant defects: firstly, the layout of the production line does not consider the fluidity characteristics of the shot body, and 8 - 12% mechanical damage occurs during the material transmission process; secondly, the heat treatment energy consumption accounts for more than 40% of the production cost, and the waste heat recovery rate is less than 15%; thirdly, the automated control system lacks three - dimensional temperature field monitoring, and the control deviation of key process parameters (austenitizing time, cooling rate, etc.) exceeds 20% of the process requirements; fourthly, there are air - flow dead corners in the traditional roller - hearth furnace, resulting in 3 - 5% of steel shots having quenching soft spots (hardness lower than HRC50), seriously affecting the sandblasting life (reducing by 30 - 40%). Summary of the Invention

[0003] The present invention provides a steel shot heat treatment device and its quenching process, and provides a steel shot heat treatment device.

[0004] A steel shot heat treatment device, comprising: a rust removal module, a heating module, a quenching module, a post-treatment module, and a cleaning module; the rust removal module, the quenching module, the post-treatment module, and the cleaning module are connected through pipelines, the heating module is located between the rust removal module and the quenching module, and is correspondingly wrapped around the outer side wall of the pipeline; The rust removal module uses a spiral lifting structure to transport and lift the steel shot, and a vibration structure is provided on the side wall to vibrate the steel shot for rust removal; The heating module uses a high-frequency heating coil, and the steel shot passes through the coil axis in sequence, The main body of the quenching module is a bath tank for rapid cooling of the quenching medium; The steel shot is batch-processed through the rust removal module for surface rust removal, heating, quenching, post-treatment, and cleaning to achieve heat treatment operations.

[0005] Preferably, the heating module is provided with two-stage heating. The first stage heats the steel shot to 500°C ± 10°C and holds for 10 minutes; the second-stage heating continuously heats the steel shot to 845°C ± 5°C and holds for 25 minutes in a controllable carbon potential atmosphere; the post-treatment module is used for separating and peeling off the oxide scale formed on the surface of the steel shot after quenching. The post-treatment module includes a material transportation structure, a vibration structure, an air extraction structure for adsorbing the oxide scale, and a ventilation system.

[0006] Preferably, the rust removal module is vibration rust removal, including a base, a blanking pipe vertically suspended at the center of the base, a hopper is provided at the top of the blanking pipe, a spiral lifting structure is provided on the base, the spiral lifting structure is located outside the blanking pipe, the steel shot rises through the spiral lifting structure, an electric drive rotary disk is embedded in the base, and replaceable sandpaper is attached to the surface of the rotary disk for polishing the surface of the steel shot. A guiding structure is provided at the upper end of the spiral lifting structure, and the guiding structure is connected to the heating module and forms continuous transportation of the steel shot.

[0007] Preferably, the outlet end of the heating module is connected to the inlet end of the quenching module. A flowing quenching medium is provided in the quenching module, and an outlet is provided at the bottom of the quenching module and is connected to the post-treatment module for oxide scale separation.

[0008] Preferably, the quenching module includes a lower tank body. The main body of the lower tank body is tubular, including a flat pipe at the large end, a round pipe at the small end, and a reducing pipe connecting the large and small ends. The large end corresponds to the heating module. The quenching tank is embedded in the large end of the lower tank body and is sealed with the lower tank body. Two groups of channels are reserved between the quenching tank and the lower tank body for the circulation of the steel shot; A lifting support plate is provided in the quenching tank. The lifting support plate can be lifted and lowered in the quenching tank, and the edge is slidably attached to the inner wall of the quenching tank; The side wall of the quenching tank is provided with a quenching medium pipe, which penetrates through the lower tank body. There are two sets of the quenching medium pipes, which are respectively used for the inlet and outlet of the quenching medium. An external bath tank is arranged outside the quenching tank. The edge of the external bath tank is hermetically attached to the inner wall of the lower tank body, and a cavity is formed on the outer side wall of the quenching tank. There are two sets of flow guiding plates arranged on the external bath tank, which correspond to the quenching tank. There are two sets of water bath pipes arranged on the external bath tank. The water bath pipes correspond to the flow guiding plates one by one and penetrate through the lower tank body. The water bath pipes are used for the circulation of the cooling medium.

[0009] Preferably, a lifting lead screw is arranged at the bottom of the external bath tank. The lifting lead screw penetrates through the quenching tank and is connected to the bottom of the lifting support plate. A flow dividing cover is arranged on the inner side wall of the quenching tank. The flow dividing cover correspondingly covers the quenching medium pipe to carry out the flow dividing and diffusion of the circulation. Preferably, a buffer pad is arranged on the inner side wall of the reduced-diameter pipe of the lower tank body to buffer the falling of the steel shots.

[0010] The heat treatment process corresponding to the equipment includes the following steps: Surface pretreatment: Send the steel shots into the spiral vibration rust removal module, and process them for 90 - 120 seconds under the conditions of a vibration frequency of 20 - 25 Hz and an amplitude of 3 - 5 mm. Remove the surface rust by using a mixture medium of nylon bristles and grit, and use an electromagnetic separator to realize the recovery of the grit, with a recovery rate ≥ 99.5%; Gradient heating: a. Preheating section: Use a longitudinal induction coil (frequency 10 kHz, power 80 - 120 kW) to heat the steel shots to 480 - 520 °C, keep them warm for 8 - 12 minutes, and control the carbon potential Cp = 0.35 - 0.45%; b. Austenitizing section: Continuously heat the steel shots to 840 - 850 °C through a transverse induction coil (frequency 1 - 2 kHz, power 180 - 220 kW), keep them warm for 20 - 30 minutes, and complete austenitization under a protective atmosphere of CO / CO2 = 1.1 - 1.3, with an austenitization rate ≥ 97%; Rapid quenching: Send the heated steel shots into the eddy current quenching system, and rapidly cool them to 280 ± 10 °C at a cooling rate ≥ 150 °C / s in a polymer solution with a concentration of 12 ± 0.5%, and then continue to cool to 50 - 70 °C; Scale peeling: Carry out shot peening treatment on the quenched steel shots through a centrifugal sandblasting unit. The diameter of the glass beads is 0.3 - 0.7 mm, the spraying pressure is 0.5 - 0.7 MPa, the coverage rate ≥ 200%, and use a negative pressure recovery system to filter the scale debris, with a residue rate ≤ 0.03%; Eddy current drying: Under the conditions of an alternating magnetic field intensity of 2500 - 3500 A / m and a frequency of 45 - 55 Hz, evaporate the residual moisture on the surface of the steel shots to ≤ 0.01% (mass fraction), and the drying time is 40 - 60 seconds.

[0011] In Step 2: The heating rates of the preheating section and the austenitizing section are 50 - 60 °C / s and 80 - 100 °C / s respectively. During the heating process, the oxygen content under nitrogen protection is ≤ 50 ppm, and the surface temperature difference ΔT of the steel shot is monitored in real time by a 32 - point infrared thermal imager array and ≤ 15 °C; In Step 3: The viscosity of the polymer solution is 28 - 38 cP (at 40 °C), the medium flow rate in the quenching tank is 700 - 900 L / min, the medium temperature fluctuation is controlled by a plate heat exchanger ≤ ±2 °C, and the lifting pallet of the quenching tank is adjusted to lift and lower at a speed of 0.5 - 2 mm / s to adjust the residence time of the steel shot; In Step 4: The projection angle of the glass beads for shot peening is 30 - 60°, the aperture of the honeycomb deflector is 3 - 8 mm, the air volume of the negative pressure system is 1000 - 1500 m 3 / h, and a 0.3 - 0.5 μm precision filter is configured; In Step 5: The alternating magnetic field is generated by an electromagnetic eddy current drying tower. The steel shot is dried within a 5 - 8 - meter ramp (with a slope of 8 - 12°), and the magnetic field power is adjusted in real time through an infrared temperature measuring device (with an accuracy of ±1 °C) to ensure that the surface temperature of the steel shot is maintained at 150 - 180 °C.

[0012] Preferably, it further includes: continuously conveying the steel shot on a magnetic levitation conveyor belt (with a gap of 0.8 - 1.2 mm and a temperature resistance ≥ 1200 °C), the conveying speed is adjustable at 0.5 - 5 m / min, and the single - section height difference between modules and the cumulative total height difference are dynamically controlled by a laser rangefinder ≤ 50 mm and ≤ 200 mm respectively; When it is detected that the temperature in the heating section > 920 °C lasts for 2 seconds, the emergency water cooling system (with a flow rate ≥ 200 L / min) is automatically triggered; when the conductivity of the quenching medium > 200 μS / cm, the standby medium tank is switched and the replacement is completed within 3 seconds; The final performance of the steel shot meets: - The surface hardness is 62 - 64 HRC, and the core hardness is 55 - 57 HRC (ASTM E384 standard); - The roundness is ≤ 0.01 mm (DIN 5401 standard); - The residual compressive stress is 450 - 550 MPa (measured by the XRD method); - There is no red rust after 72 - hour salt spray test (ASTM B117 standard).

[0013] A steel shot heat treatment equipment and its quenching process of the present invention are energy - saving and environment - friendly, saving 35% energy compared with the traditional production line. Through high - efficiency energy - saving components such as a high - frequency induction rapid - heating channel, an eddy current quenching system, and an electromagnetic eddy current drying tower, the energy consumption is reduced and the carbon emission is decreased. Description of the Drawings

[0014] Figure 1Schematic diagram of the process of a steel shot heat treatment equipment according to the present invention.

[0015] Figure 2 Three-dimensional structure diagram of the quenching module of the present invention.

[0016] Figure 3 Exploded three-dimensional view of the quenching module of the present invention.

[0017] Figure 4 Schematic structure diagram of the quenching module of the present invention.

[0018] Figure 5 Process flow chart of the heat treatment of the present invention.

[0019] Figure 6 Schematic illustration of the heating step of the present invention.

[0020] Figure 7 Schematic structure diagram of the quenching process of the present invention.

[0021] Figure 8 Schematic illustration of the detection process of the present invention.

[0022] In the drawings:

[0023] 1. Lower tank body; 2. Lifting support plate; 3. Quenching tank; 4. Deflector plate; 5. Outer bath; 6. Lifting lead screw; 7. Quenching medium pipe; 8. Shunt cover; 9. Buffer pad; 10. Water bath pipe. Detailed implementation mode

[0024] The present invention will be further described below with reference to the accompanying drawings.

[0025] Example 1:

[0026] A steel shot heat treatment equipment includes: a rust removal module, a heating module, a quenching module, a post-treatment module, and a cleaning module; the rust removal module, the quenching module, the post-treatment module, and the cleaning module are connected through pipelines, and the heating module is located between the rust removal module and the quenching module and is correspondingly wrapped around the outer wall of the pipeline; Rust removal module: Adopt a spiral lifting structure (lifting angle 30 - 45°) in cooperation with a vibration structure (frequency 20 - 25 Hz, amplitude 3 - 5 mm); The heating module is configured with a high-frequency heating coil array (operating frequency 10 - 20 kHz), and the steel shots continuously pass along the central axis of the coil; The main body of the quenching module is a bath structure, with a flowing quenching medium (flow rate 700 - 900 L / min) inside; The post-treatment module integrates a vibration structure (acceleration 5 - 8 g), a gas extraction system (negative pressure value -15 ~ -20 kPa), and a ventilation system; The first heating stage: Heat the steel shots to 500°C ± 10°C and hold for 10 min (longitudinal induction coil, frequency 10 kHz, power 80 - 120 kW); The second heating stage: Continuously heat to 845°C ± 5°C and hold for 25 min (transverse induction coil, frequency 1 - 2 kHz, power 180 - 220 kW); Controlled carbon potential atmosphere (CO / CO2 = 1.1 - 1.3, oxygen content ≤ 50 ppm); The base is built - in an electric - driven rotary disk (rotation speed 30 - 50 rpm), and the surface is attached with replaceable sandpaper (grit size 80 - 120 mesh); At the top of the vertical feeding pipe (diameter Φ200 mm), there is a hopper (volume 500 L); A spiral lifting structure (pitch 150 mm, lifting speed 0.5 - 2 m / min) surrounds the outer circumference of the feeding pipe; The sandpaper wear detection interval is ≥ 200 hours; The recovery efficiency of the electromagnetic separator is ≥ 99.5%; The lower tank body 1 is a tubular structure including a large - end flat pipe (cross - section 400×200 mm), a small - end round pipe (Φ150 mm), and a reducing pipe (cone angle 15°). A buffer pad 9 (silicone material, thickness 20 mm, Shore hardness 60 HA) is arranged on the inner wall of the reducing pipe; The quenching tank 3 and the lifting support plate 2 (Z - type guide groove, sealing gap ≤ 0.1 mm) are connected to the lifting lead screw 6 (lead 10 mm, positioning accuracy ± 0.05 mm). The flow - dividing cover 8 (hole diameter Φ3 mm, opening ratio 40%) covers the quenching medium pipe 7 (inlet and outlet pipe diameter Φ50 mm); The outer bath 5, the double - deflector plates 4 (tilt angle 45°, spacing 80 mm) and the water bath pipe 10 (flow control accuracy ± 5%) form a turbulent flow cooling; A 5 - 8 mm cavity is formed between the outer bath 5 and the quenching tank 3; Step 1: Surface pretreatment - Vibration derusting: 20 - 25 Hz / 3 - 5 mm amplitude, process for 90 - 120 seconds; - Grit recycling: The electromagnetic separator (magnetic field strength 0.8 T) is recycled; Step 2: Gradient heating - Pre - heating stage: 480 - 520°C × 8 - 12 min (heating rate 50 - 60°C / s); - Austenitizing stage: 840 - 850°C × 20 - 30 min (heating rate 80 - 100°C / s); Step 3: Rapid quenching - A 12 ± 0.5% polymer solution (viscosity 28 - 38 cP / 40°C), cooling rate ≥ 150°C / s; - Final cooling temperature 50 - 70°C (medium temperature difference ± 2°C); Step 4: Scale peeling - Glass bead shot peening: diameter 0.3 - 0.7 mm, pressure 0.5 - 0.7 MPa, coverage rate ≥ 200%; - Negative pressure recovery: air volume 1000 - 1500 m³ / h, 0.3 - 0.5 μm filter; Step 5: Eddy current drying - Alternating magnetic field: 2500 - 3500 A / m, 45 - 55 Hz; - Ramp drying: length 5 - 8 m, slope 8 - 12°, surface temperature 150 - 180 °C (infrared temperature measurement ±1 °C); Performance guarantee

[0027] Example 2:

[0028] This example provides a steel shot heat treatment device, adopting a five - layer vertical compact layout (total height 3.2 m × length 2.5 m × width 1.8 m), including the following core modules: Spiral vibration rust removal module: The vibrating disk (diameter 500 mm, vibration frequency 20 Hz, amplitude 5 mm) is embedded with a mixed medium of nylon bristles and fine grit, and the electromagnetic separator at the bottom (magnetic field intensity 0.8 T) realizes grit recovery, with a loss rate ≤0.5%. The processing capacity of the spiral lifting structure is 800 kg / h, and the lifting angle is 30°.

[0029] High - frequency induction rapid heating channel: The U - shaped ceramic guide rail (bending angle 120°, wall thickness 15 mm) is built - in with 10 groups of micro - induction coils (frequency 20 kHz, power 200 kW), and a nitrogen protection system (purity ≥99.99%, oxygen sensor controls O2 < 50 ppm). The steel shot is heated to 900 ± 15 °C within 10 seconds, and the heating rate ≥90 °C / s.

[0030] Eddy current quenching system: Conical quenching tank (inner diameter 600 mm / outer diameter 800 mm, material SUS316L), high - speed eddy current generator (rotation speed 10000 rpm) drives 12 ± 0.5% polymer solution (viscosity 30 - 35 cP, 40 °C), and the plate heat exchanger controls the medium temperature difference ±2 °C. The steel shot is cooled to below 80 °C within 3 seconds.

[0031] Centrifugal sandblasting and peeling unit: Glass bead shot peening chamber (diameter 1000 mm, spraying pressure 0.6 MPa, glass bead diameter 0.5 mm), 304 stainless steel honeycomb deflector (aperture 5 mm, porosity 60%), negative pressure recovery system (filter accuracy 0.3 μm, air volume 1200 m 3 / h).

[0032] Electromagnetic eddy current drying tower: Alternating magnetic field generator (frequency 50 Hz, power 30 kW), ramp - type drying channel (length 5 m, slope 10°, surface roughness Ra ≤0.8 μm), infrared temperature measurement device (accuracy ±1 °C, response time 0.1 s).

[0033] Transfer and support system: Magnetic levitation conveyor belt (temperature resistant up to 1200°C, gap 0.8 - 1.2 mm, speed 0.5 - 5 m / min), cumulative drop between modules < 200 mm (single - paragraph drop ≤ 50 mm), quick - disassembly maintenance channel (width 600 mm, load - bearing 300 kg / m 2 ).

[0034] The five - layer vertical layout realizes a floor area of 5.76 m 2 (60% less than traditional equipment), and the magnetic levitation conveyor belt has a high - temperature - resistant design (continuous operation at 1200°C > 5000 h).

[0035] Example 3:

[0036] Heating process and structure: 1. Pre - heating section: Longitudinal induction coil (frequency 10 kHz, power 100 kW), steel shot heated to 500 ± 10°C, heat preservation for 10 min, carbon potential control Cp = 0.4%; 2. Austenitizing section: Transverse induction coil (frequency 1 kHz, power 200 kW), heated to 845 ± 5°C, heat preservation for 25 min, protected by CO / CO2 = 1.2 atmosphere; The two - stage heating process reduces energy consumption by 15% (compared with conventional single - stage heating), and the cooling rate of the eddy current quenching system reaches 280°C / s (2.5 times the critical cooling rate); Specific structure of the quenching module: 1. Lower tank body assembly: The large - end flat tube (cross - section size 400×200 mm) transitions to the small - end round tube (Φ150 mm) through a reducing pipe (cone angle 15°), with a buffer pad (silicone material, thickness 20 mm, Shore hardness 60 HA).

[0037] 2. Quenching tank functional unit: Lifting pallet (stroke ±150 mm, Z - type guide groove structure, sealing gap ≤ 0.1 mm), shunt cover (hole diameter Φ3 mm, hole opening rate 40%) evenly distributes the quenching medium, and double - flow guide plates (tilt angle 45°, spacing 80 mm) form turbulence with the outer bath; 3. Cooling control system: Water bath pipe (Φ50 mm, flow control accuracy ±5%), lifting lead screw (lead 10 mm, accuracy IT5 level, axial stiffness 500 N / μm).

[0038] Process indicators: Critical cooling rate ≥ 150°C / s (in the 900°C → 280°C stage), final cooling temperature 60 ± 5°C, ovality change ≤ 0.008 mm.

[0039] Example 4:

[0040] Temperature field monitoring, 32-point infrared thermal imager array (temperature measurement range 0 - 1200 °C, accuracy ±1 °C), temperature difference ΔT in the heating section ≤15 °C, temperature difference of the quenching medium ±2 °C; 32-point real-time feedback regulation of the temperature field (PID parameter self-tuning), closed-loop control of the medium concentration (volatility < ±0.3%). Medium management, on-line detection of the polymer solution concentration (conductivity method, accuracy ±0.1%), automatic liquid replenishment system (response time < 5 s, flow rate error ±0.5 L / min). Deformation suppression system, magnetic levitation gap laser ranging (resolution 0.01 mm, sampling rate 1 kHz), dynamic weighing and rejection system (accuracy ±0.002 g, processing speed 1200 pcs / min).

[0041] Abnormal handling mechanism

[0042] Example 5:

[0043] Process steps and parameters 1. Surface pretreatment, vibration rust removal (20 Hz, amplitude 5 mm, time 90 - 120 s), automatic recovery rate of grit ≥99.5%. 2. Gradient heating, preheating section: 500 ± 10 °C × 10 min, grain size refined to ASTM 8 - 9 levels, austenitizing section: 845 ± 5 °C × 25 min, austenitization rate ≥98%. 3. Rapid quenching, cooling with polymer solution (20 - 80 °C, flow rate 800 L / min), martensite transformation completed within 3 seconds (Ms point 280 °C). 4. Scale peeling, glass bead impact (speed 60 m / s, coverage rate 200%), negative pressure recovery efficiency ≥99.8%. 5. Eddy current drying, alternating magnetic field (frequency 50 Hz, magnetic field strength 3000 A / m), surface moisture residue ≤0.01% (mass fraction). Process effects Hardness uniformity HRC ±1.0 Residual compressive stress 450 - 550 MPa (measured by XRD method) Salt spray test for 72 h without red rust (ASTM B117 standard).

[0044] The above describes the present invention and its implementation manners. Such description is not restrictive. What is shown in the drawings is only one of the implementation manners of the present invention, and the actual structure is not limited thereto. In general, if those of ordinary skill in the art are inspired by it and, without departing from the gist of the present invention, creatively design structural manners and embodiments similar to the technical solution, they shall fall within the protection scope of the present invention.

Claims

1. A steel shot heat treatment equipment, comprising: Rust removal module, heating module, quenching module, post-processing module, cleaning module; characterized in that the rust removal module, quenching module, post-processing module, and cleaning module are connected through pipelines, and the heating module is located between the rust removal module and the quenching module, and is correspondingly wrapped on the outer wall of the pipeline; The rust removal module adopts a spiral lifting structure to transport and lift the steel shot, and a vibration structure is set on the side wall to vibrate and remove rust from the steel shot; The heating module uses a high-frequency heating coil, and the steel shot passes through the central axis of the coil in turn. The main body of the quenching module is a bath setting to quickly cool the quenching medium; Steel shots are batched through the rust removal module for surface rust removal, heating, quenching, post-treatment and cleaning to achieve heat treatment operations.

2. The steel shot heat treatment equipment according to claim 1, characterized in that: The heating module is provided with two-stage heating, the first stage heats the steel shot to 500°C±10°C and keeps warm for 10 minutes; the second stage heats the steel shot continuously to 845°C±5°C and keeps warm for 25 minutes, and the carbon potential atmosphere is controllable; the post-processing module is used to separate and peel off the oxide scale formed on the surface of the steel shot after quenching, and the post-processing module includes a material transportation structure, a vibration structure, an exhaust structure for oxide scale adsorption, and a ventilation system.

3. The steel shot heat treatment equipment according to claim 1, characterized in that: The rust removal module is a vibration rust removal module, including a base, a drop tube vertically suspended at the center of the base, a hopper is arranged on the top of the drop tube, a spiral lifting structure is arranged on the base, the spiral lifting structure is arranged on the outer periphery of the drop tube, the steel shot rises through the spiral lifting structure, an electric drive turntable is embedded in the base, and replaceable sandpaper is attached to the surface of the turntable for grinding the surface of the steel shot, an export structure is arranged on the upper end of the spiral lifting structure, and the structure is connected to the heating module to form a continuous conveying of the steel shot.

4. The steel shot heat treatment equipment according to claim 3, characterized in that: The outlet end of the heating module is connected to the inlet end of the quenching module. A flowing quenching medium is arranged in the quenching module. A discharge port is arranged at the bottom of the quenching module and is connected to the post-processing module for oxide scale separation.

5. The steel shot heat treatment equipment according to claim 4, characterized in that: The quenching module comprises a lower tank body (1), the main body of the lower tank body (1) is tubular, comprising a flat tube at a large end, a round tube at a small end, and a reducer connecting the large and small ends, the large end corresponding to the heating module, the quenching tank (3) is embedded in the large end of the lower tank body (1), and is sealed between the lower tank body (1), and the quenching tank (3) and the lower tank body (1) directly reserve two sets of channels for the circulation of steel shots; A lifting support plate (2) is arranged in the quenching tank (3), and the lifting support plate (2) can be raised and lowered into the quenching tank (3), and the edge of the lifting support plate (2) is slidably fitted to the inner wall of the quenching tank (3); A quenching medium pipe (7) is provided on the side wall of the quenching tank (3) and penetrates the lower tank body (1); two groups of the quenching medium pipes (7) are provided, one for the entry and the other for the exit of the quenching medium; An outer bath tank (5) is arranged outside the quenching tank (3), the edge of the outer bath tank (5) is sealed and fitted with the inner wall of the lower tank body (1), and a cavity is formed on the outer wall of the quenching tank (3), two groups of guide plates (4) are arranged on the outer bath tank (5), the guide plates (4) and the quenching tank (3) correspond to each other, and two groups of water bath pipes (10) are arranged on the outer bath tank (5), the water bath pipes (10) and the guide plates (4) correspond to each other one by one and pass through the lower tank body (1), and the water bath pipes (10) are used for the circulation of cooling medium.

6. The steel shot heat treatment equipment according to claim 5, characterized in that: A lifting screw (6) is provided at the bottom of the outer bath (5), the lifting screw (6) passes through the quenching tank (3) and is connected to the bottom of the lifting support plate (2), and a diverter cover (8) is provided on the inner wall of the quenching tank (3), and the diverter cover (8) is correspondingly covered on the quenching medium pipe (7) to perform flow diversion and diffusion.

7. The steel shot heat treatment equipment according to claim 6, characterized in that: A buffer pad (9) is provided on the inner side wall of the reducer tube of the lower tank body (1) to buffer the falling of the steel shot.

8. The steel shot heat treatment equipment according to claim 7, characterized in that: The heat treatment process corresponding to the equipment includes the following steps: (1) Surface pretreatment: The steel shot is fed into the spiral vibration rust removal module and treated for 90-120 seconds at a vibration frequency of 20-25 Hz and an amplitude of 3-5 mm. The surface rust is removed by a mixed medium of nylon bristles and grit, and the grit is recovered by an electromagnetic separator with a recovery rate of ≥99.5%; (2) Gradient heating: a. Preheating section: Use longitudinal induction coil (frequency 10kHz, power 80-120kW) to heat the steel shot to 480-520℃, keep warm for 8-12 minutes, and control the carbon potential Cp=0.35-0.45%; b. Austenitizing stage: The steel shot is continuously heated to 840-850℃ by a transverse induction coil (frequency 1-2kHz, power 180-220kW), kept warm for 20-30 minutes, and austenitizing is completed in a protective atmosphere of CO / CO2=1.1-1.3, and the austenitizing rate is ≥97%; (3) Rapid quenching: The heated steel shot is sent into the eddy current quenching system and rapidly cooled to 280±10℃ at a cooling rate of ≥150℃ / s in a 12±0.5% concentration polymer solution, and then continued to cool to 50-70℃; (4) Oxide scale peeling: The quenched steel shot is shot peened by a centrifugal sand blasting unit, with a glass bead diameter of 0.3-0.7 mm, a spray pressure of 0.5-0.7 MPa, a coverage rate of ≥ 200%, and a negative pressure recovery system is used to filter the oxide scale debris, with a residual rate of ≤ 0.03%; (5) Eddy current drying: Under the conditions of alternating magnetic field strength of 2500-3500A / m and frequency of 45-55Hz, the residual moisture on the surface of the steel shot is evaporated to ≤0.01% (mass fraction), and the drying time is 40-60 seconds.

9. The method according to claim 8, characterized in that In the step of lifting the support plate (2), the heating rates of the preheating section and the austenitizing section are 50-60°C / s and 80-100°C / s respectively, the nitrogen protection oxygen content during the heating process is ≤50ppm, and the surface temperature difference of the steel shot ΔT is ≤15°C in real time monitored by a 32-point infrared thermal imager array; In step (3), the viscosity of the polymer solution is 28-38 cP (40°C), the medium flow rate in the quenching tank is 700-900 L / min, the medium temperature fluctuation is controlled by a plate heat exchanger to be ≤±2°C, and the lifting plate of the quenching tank is raised and lowered at a speed of 0.5-2 mm / s to adjust the residence time of the steel shot; In step (4): the projection angle of the shot peening glass beads is 30-60°, the aperture of the honeycomb guide plate is 3-8mm, and the air volume of the negative pressure system is 1000-1500m 3 / h, and equipped with 0.3-0.5μm precision filter; In step (5): the alternating magnetic field is generated by an electromagnetic eddy current drying tower, and the steel shot is dried in a 5-8 meter ramp (slope 8-12°), and the magnetic field power is adjusted by real-time feedback through an infrared temperature measuring device (accuracy ±1°C) to ensure that the surface temperature of the steel shot is maintained at 150-180°C.

10. The method according to claim 9, characterized in that: Also includes: Steel shot is continuously transported on a magnetic suspension conveyor belt (gap 0.8-1.2mm, temperature resistance ≥1200℃), with an adjustable conveying speed of 0.5-5m / min, and the single-step drop between modules is dynamically controlled by a laser rangefinder to be ≤50mm and the cumulative total drop ≤200mm; When the temperature of the heating section is detected to be greater than 920℃ for 2 seconds, the emergency water cooling system (flow rate ≥ 200L / min) is automatically triggered; when the conductivity of the quenching medium is greater than 200μS / cm, the standby medium tank is switched and the replacement is completed within 3 seconds; The final steel shot performance meets: -Surface hardness 62-64HRC, core hardness 55-57HRC (ASTME384 standard); - Ovality ≤ 0.01mm (DIN5401 standard); - Residual compressive stress 450-550MPa (determined by XRD method); - No red rust after 72 hours of salt spray test (ASTM B117 standard).

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