Double-rib induction quenching process for steel track shoe

Abstract

The invention discloses a double-rib induction quenching process for a steel track shoe, which comprises the following steps: mounting a positioning device on a machine tool worktable, and sleeving two pin shaft holes of the machined track shoe into a round pin shaft and a prismatic pin to fix the track shoe, so that the surface of the track, which is provided with a landing rib, is vertically arranged; connecting the intermediate-frequency inductor with a moving part of the machine tool so that the intermediate-frequency inductor can move; adjusting the angle of the base to enable the landing rib plane of the track shoe to be parallel to the working surface of the magnetizer of the intermediate-frequency inductor, and adjusting the gap between the landing rib of the track shoe and the magnetizer of the intermediate-frequency inductor; before each section of the landing rib is heated, a water sprayer is started to spray and heat each section of the landing rib, and a medium-frequency inductor is lifted to spray the section of the landing rib; and the track shoe is subjected to tempering treatment. The method is easy to operate and high in machining efficiency, the production cost can be reduced, thermal diffusion during heating of the landing rib can be reduced, thermal deformation of a transition zone between the landing rib and a base body and a pin shaft hole can be reduced, and the depth consistency of a hardening layer is good.

Description

Technical Field

[0001] The invention belongs to the technical field of induction heat treatment technology, and in particular relates to a double-rib induction quenching process for a steel track shoe. Background Art

[0002] The crawler walking mechanism has significant advantages such as low ground contact pressure, good adhesion performance, high traction efficiency, simple structure and convenient control. The crawler transmits the traction, adhesion and braking force of the ground to the vehicle body, providing a continuous rolling track for the road wheels, greatly improving the maneuverability and passability of the vehicle on soft and rugged ground. The track shoe is a key component for the operating machinery to contact the ground. It plays a role in transmitting the interaction force and torque between the machinery and the ground. Its structural form directly affects the traction capacity. The track shoe is in direct contact with the road surface during operation, bearing the weight of the entire machine, traction and friction with the road surface, and is subjected to complex stresses such as impact, stretching, extrusion and bending. It is very easy to cause excessive wear, deformation and failure during use. Therefore, the substrate of the track shoe is required to have good strength and toughness, and the ground ribs are required to have high wear resistance.

[0003] The commonly used materials for cast track plates are high manganese steels such as ZGMn13. Through water toughening treatment, high manganese steel can obtain a single austenite structure, and its surface structure is easy to undergo phase transformation to form martensite under strong impact or extrusion force, so that high manganese steel has good core plastic toughness, low crack extension and surface wear resistance. The commonly used materials for forged track plates are medium and low carbon alloy steels such as 20CrMnSiNi2A, 30SiMnMoVTi, 42CrMoA, etc. The strengthening method of low carbon alloy steel track plates such as 20CrMnSiNi2A is overall quenching + low temperature tempering, and the strengthening method of medium carbon alloy steel track plates such as 30SiMnMoVTi, 42CrMoA is overall quenching + medium and high temperature tempering + local induction heat treatment. Low-carbon alloy steel track shoes have a low carbon content and a hardness of about 45HRC after quenching and low-temperature tempering. They have poor wear resistance on gravel roads and are not suitable for harsh road conditions. Medium-carbon alloy steel track shoes can be made into a medium hardness range with good strength and toughness through the adjustment of the heat treatment system. The ground reinforcement has high wear resistance, making them the best choice for heavy loads and harsh road conditions.

[0004] For medium-carbon alloy steel track plates used in heavy loads and harsh road conditions, the ground bars are usually designed with a staggered distribution structure of long and short arc bars to improve the grip effect. At the same time, in order to increase the service life and quality stability of the track plates, the depth of the ground bar hardening layer must be controlled within a reasonable range. A certain type of 42CrMo(Nb)A steel track plate requires a ground bar hardening layer depth of 8~10mm and a hardness of ≥55HRC. To achieve this requirement, a single bar scanning induction quenching method is usually used. This method can better ensure the hardening layer depth, but the production efficiency is low. Due to the inconsistent shape and structure of the ground bars, it is difficult to achieve the above technical requirements with double bar induction quenching. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a double-rib induction quenching process for steel track plates, which is simple to operate, has high processing efficiency, can reduce production costs, is beneficial to reducing heat diffusion when heating the ground bars, can reduce the thermal deformation of the transition zone between the ground bars and the substrate and the pin shaft hole, and has good consistency in the depth of the hardened layer.

[0006] The technical solution adopted by the present invention is: A double-reinforcement induction quenching process for a steel track shoe, which is implemented by a double-reinforcement induction quenching device for a steel track shoe, and the double-reinforcement induction quenching device for a steel track shoe comprises an intermediate frequency sensor and a positioning device; the intermediate frequency sensor comprises a water sprayer, an induction coil, a magnetizer, a fixed plate, a guide plate, an insulating plate, an insulating gasket, an insulating sleeve, a circulating water interface, and a spray water interface; the induction coil and the circulating water interface are fixed on the guide plate; an insulating plate is fixedly installed in the middle gap of the guide plate; the magnetizer is installed on the induction coil; a fixing bolt A is welded on the induction coil, and the fixing plate is fixed by the fixing bolt A and the nut A; a spray water interface is provided on the side wall of the water sprayer; two circulating water interfaces are connected to the cavity of the induction coil, which are used to cool the induction coil by circulating water; the water sprayer is fixedly installed on the fixing plate; the positioning device is arranged close to the induction coil of the intermediate frequency sensor, and is used to position the steel track shoe; The following steps are involved: Step 1: Install the positioning device on the workbench of the machine tool, insert the round pin and the prismatic pin into the two pin holes of the machined track shoe to fix it, so that the surface of the track with the ground ribs is set vertically; connect the intermediate frequency sensor to the moving part of the machine tool so that the intermediate frequency sensor can move, and make the water spraying surface of the sprinkler of the intermediate frequency sensor face the surface of the track with the ground ribs; and make the magnetizer and the sprinkler completely cover the width of the ground ribs; Step 2: Adjust the angle of the base so that the ground rib plane of the track shoe is parallel to the working surface of the intermediate frequency sensor magnetizer, and adjust the gap between the ground rib surface of the track shoe and the intermediate frequency sensor magnetizer to 4±0.3mm; Step 3: Divide the track plate ribs into n sections; when the track plate is a 4-rib track plate, n=2; when the track plate is an 8-rib track plate, n=4; and name the sections of the track plate ribs from bottom to top as the first section of ribs, the second section of ribs, the third section of ribs and the fourth section of ribs; start the sprinkler to spray, and raise the position of the intermediate frequency sensor until the sprinkler can spray the pin shaft hole above the track plate, the middle section pin shaft hole for the one-piece track plate, and the top position for the single track plate; after staying for 1 second, move to the bottom of the track plate at a uniform speed, so that the surface of the track plate ribs and the pin shaft hole are both in a wet state; Step 4: Start heating from the bottom of the ground bar, heat it for a few seconds, and then scan and heat it upwards. After the first section of the ground bar is completely heated, stop heating and raise the medium-frequency sensor so that the sprinkler spray can completely cover the heated ground bar; Step 5: Lift the medium frequency sensor to spray the second section of the grounding bar; move the medium frequency sensor until the lowest magnetic conductor is higher than the upper end of the first section of the grounding bar, fix it for a few seconds and then scan and heat it upwards. After the second section of the grounding bar is fully heated, stop heating and lift the medium frequency sensor so that the spray liquid of the sprinkler can completely cover the heated grounding bar; Step 6: If the track shoe is a 4-rib track shoe, all induction hardening processes have been completed; if the track shoe is an 8-rib track shoe, proceed to the next step; Step 7: Lift the medium frequency sensor to spray the third section of the grounding bar; move the medium frequency sensor until the lowest magnetic conductor is higher than the upper end of the second section of the grounding bar, fix it for a few seconds and then scan and heat it upwards. After the third section of the grounding bar is fully heated, stop heating and lift the medium frequency sensor so that the spray liquid of the sprinkler can completely cover the heated grounding bar; Step 8: Lift the medium frequency sensor to spray the fourth section of the grounding bar; move the medium frequency sensor until the lowest magnetic conductor is higher than the upper end of the third section of the grounding bar, fix it for a few seconds and then scan and heat it upwards. After the fourth section of the grounding bar is fully heated, stop heating and lift the medium frequency sensor so that the spray liquid of the sprinkler can completely cover the heated grounding bar; Step 9: Temper the track plate within 4 hours, the tempering temperature is 150±10℃, the insulation time is 120~180min, air cooling or furnace cooling.

[0007] Furthermore, the heating power of the medium frequency inductor is 55~60KW, and the induction frequency is 8000HZ.

[0008] Furthermore, in step 1, before the track shoe is clamped, the grounding ribs of the track shoe are milled flat before quenching, and the distance between the surface and the magnetizer is consistent during induction quenching.

[0009] Furthermore, in step one, the track shoe is tempered before clamping, and the hardness of the track shoe is 30-40HRC.

[0010] Furthermore, the cooling medium in the sprinkler is a 5-7% PAG aqueous solution, and the spray flow rate of the PAG aqueous solution is 18 L / min.

[0011] Furthermore, a heater and a refrigerator are provided in the sprinkler, and the temperature of the PAG aqueous solution is controlled at 35-40°C.

[0012] Furthermore, the positioning device includes a base, a round pin and a prismatic pin; the round pin and the prismatic pin are fixed to the base by hexagon socket bolts; the round pin and the prismatic pin are arranged perpendicular to the base.

[0013] Furthermore, the insulating plate is made of polytetrafluoroethylene, and the insulating plate is fixedly installed in the middle gap of the flow plate by fixing bolts C and fixing nuts C; an insulating sleeve is sleeved on the outside of the fixing bolt C, and an insulating gasket is respectively provided between the bolt head of the fixing bolt C and the insulating plate and between the fixing nut C and the insulating plate; the material of the insulating sleeve and the insulating gasket is bakelite.

[0014] Furthermore, the material of the sprinkler, induction coil and guide plate is T2 copper, the material of the circulating water interface and the spray water interface (13) is H62 brass; the material of the base, round pin and prismatic pin are all 3Cr13, with a hardness of 47~52HRC.

[0015] Furthermore, the magnetizer is Fluxtrol 50 type high-density ferrite, the size of a single piece is 42×24mm, and a 16mm groove is processed in the middle. Two pieces are in a group, and three groups of magnetizers are evenly buckled with the induction coil, and the lateral spacing of the magnetizers is 40.5~41mm; a 42×15mm recessed section is provided in the middle of the induction coil, and the middle group of magnetizers is buckled to the recessed section of the induction coil, and the horizontal height of the magnetizer in the recessed section is 15mm lower than that of the magnetizers on both sides; the sprinkler is provided with water spray holes with a lateral spacing and a longitudinal spacing of 5mm and a diameter of Φ1.5mm. The angle of the water spray holes is 30° downward from the vertical horizontal plane. The water spray holes of the sprinkler are distributed in 3 areas, which are located directly below the three groups of magnetizers respectively, and the water spray holes in a single area are arranged in 10 rows×10 columns.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention has good versatility and can be used for induction hardening of one-piece 8-rib track shoes and split 4-rib track shoes.

[0017] 2. The present invention ensures that the depth of the hardened layer of the grounding bar after quenching is consistent and can be stably controlled within the range of 8-9 mm or 9-10 mm.

[0018] 3. The cooling medium of the present invention has an appropriate concentration and controllable temperature, and no cracks will be generated when the workpiece is cooled; when the PAG aqueous solution contacts the parts, a layer of polymer will be covered on the surface thereof, and there will be no bubble precipitation and bursting process of the pure water medium, thus avoiding the formation of quenching soft spots.

[0019] 4. The present invention performs an air spray on the track plate before each induction heating to keep its outer surface and the pin shaft hole moist, which is beneficial to reduce the heat diffusion when heating the ground bar, and can reduce the thermal deformation of the transition zone between the ground bar and the substrate and the pin shaft hole.

[0020] 5. When the double-rib induction quenching process of the present invention is used to treat an 8-rib track shoe, it takes about 2 minutes to 30 seconds, while the existing single-rib induction quenching process of the present invention takes about 5 minutes to treat an 8-rib track shoe. The processing efficiency of a single process is improved by 100% and the production cost is reduced by 10%.

[0021] 6. The present invention realizes rapid heating and rapid cooling of the ground bar, and the grains are significantly refined. The grains after quenching are more than 3 levels finer than those before quenching, which significantly improves the toughness and impact resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The figure is a front view of the double-rib induction quenching device for steel track shoes used in the present invention.

[0023] Figure 2 The figure is a top view of the double-rib induction quenching device for steel track shoes used in the present invention.

[0024] Figure 3 The figure is a front view of the intermediate frequency inductor of the double-rib induction hardening device for steel track shoes used in the present invention.

[0025] Figure 4 The figure is a top view of the medium frequency inductor of the double-rib induction hardening device for steel track shoes used in the present invention.

[0026] Figure 5 The figure is a top view of the positioning device of the double-rib induction quenching device for steel track shoes adopted by the present invention.

[0027] Figure 6 This is a structural diagram of the track shoe in Example 1 of the present invention.

[0028] Figure 7 This is a structural diagram of the track shoe in Example 2 of the present invention.

[0029] Figure 8 This is a crystal phase diagram of the track shoe ribs before induction quenching in Example 2 of the present invention.

[0030] Fig. 9 This is a crystal phase diagram of the track shoe ribs after induction quenching in Example 2 of the present invention.

[0031] In the figure: 1. guide plate; 2. induction coil; 3. magnetic conductor; 4. sprinkler; 5. fixing plate; 6. circulating water interface; 7. fixing bolt C; 8. nut C; 9. fixing bolt B; 10. nut B; 11. fixing bolt A; 12. nut A; 13. spray water interface; 14. insulating gasket; 15. insulating sleeve; 16. insulating plate; 17. base; 18. round pin; 19. prismatic pin; 20. hexagon socket bolt. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0033] like Figure 1-5 As shown, the double-rib induction quenching device for steel track shoes used in the present invention includes a medium frequency sensor I and a positioning device II; the medium frequency sensor I includes a water sprinkler 4, an induction coil 2, a magnetic conductor 3, a fixing plate 5, a guide plate 1, an insulating plate 16, an insulating gasket 14, an insulating sleeve 15, a circulating water interface 6, and a spray water interface 13. The materials of the water sprinkler 4, the induction coil 2 and the guide plate 1 are T2 copper, and the materials of the circulating water interface 6 and the spray water interface 13 are H62 brass.

[0034] The induction coil 2 and the circulating water interface 6 are fixed on the guide plate 1. An insulating plate 16 is fixed in the middle gap of the guide plate 1; the insulating plate 16 is made of polytetrafluoroethylene. The insulating plate 16 is fixed in the middle gap of the guide plate 1 by fixing bolts C7 and fixing nuts C8; an insulating sleeve 15 is sleeved on the outside of the fixing bolt C7, and an insulating gasket 14 is respectively arranged between the bolt head of the fixing bolt C7 and the insulating plate 16 and between the fixing nut C8 and the insulating plate 16; the insulating sleeve 15 and the insulating gasket 14 are made of bakelite.

[0035] The magnetizer 3 is Fluxtrol 50 type high-density ferrite, the size of a single piece is 42×24mm, with a 16mm groove processed in the middle, 2 pieces in a group, and the 2 pieces in each group are arranged up and down. Three groups of magnetizers 3 are evenly clamped to the induction coil 2 and fixed by gluing. The effective working size of a single area is 42×52mm, and the lateral spacing of the magnetizers 3 is 40.5~41mm. A 42×15mm recessed section is provided in the middle of the induction coil 2. The middle group of magnetizers 3 is clamped to the recessed section of the induction coil 2, and the horizontal height of the magnetizers 3 in the recessed section is 15mm lower than the magnetizers 3 on both sides.

[0036] The fixing bolt A11 is welded on the induction coil 2, and the fixing plate 5 is limited and fixed by the fixing bolt A11 and the nut A12. A spray water interface 13 is provided on the side wall of the sprinkler 4. A heater and a cooler are provided in the sprinkler 4 to control the temperature of the spray liquid. Two circulating water interfaces 6 are connected to the cavity of the induction coil 2, which are used to cool the induction coil 2 by circulating water. The sprinkler 4 is fixedly mounted on the fixing plate 5 by fixing bolts B9 and nuts B10. The sprinkler 4 is provided with water spray holes with a horizontal spacing and a vertical spacing of 5 mm and a diameter of Φ1.5 mm. The angle of the water spray hole is 30° downward from the vertical horizontal plane. The water spray holes of the sprinkler 4 are distributed in 3 areas, which are respectively located directly below the three groups of magnetizers 3. The water spray holes in a single area are arranged in 10 rows × 10 columns.

[0037] The positioning device II is arranged near the induction coil 2 of the medium frequency inductor and is used to position the steel track shoe. The positioning device comprises a base 17, a round pin 18 and a prismatic pin 19; the round pin 18 and the prismatic pin 19 are fixed to the base 17 by hexagon socket bolts 20; the round pin 18 and the prismatic pin 19 are arranged perpendicular to the base 17. The base 17, the round pin 18 and the prismatic pin 19 are all made of 3Cr13 with a hardness of 47~52HRC. Example

[0038] The present invention is used for 42CrMoNbA steel one-piece 8-rib track plate (its structure is as follows Figure 6 When quenching the ground reinforcement (as shown in the figure), the specific operations are as follows: Step 1: Install the positioning device on the machine tool workbench, insert the round pin and the prismatic pin into the two pin holes of the machined 42CrMoNbA steel one-piece track shoe to fix it. Before fixing, the track shoe is quenched and tempered before clamping, and the hardness of the track shoe is 30~40HRC. The ground ribs of the track shoe have been milled flat before quenching, and the surface is at the same distance from the magnetizer during induction quenching.

[0039] When the track shoe is fixed, the surface of the track with the ground ribs is set vertically; the medium frequency sensor is connected to the moving parts of the machine tool so that the medium frequency sensor can move, and the magnetizer 3 of the medium frequency sensor is facing the surface of the track with the ground ribs; and the magnetizer and the water sprayer can completely cover the width of the ground ribs.

[0040] Step 2: Adjust the base angle so that the track shoe rib plane is parallel to the working surface of the intermediate frequency sensor magnet, adjust the gap between the track shoe rib surface and the intermediate frequency sensor magnet to 4±0.3mm, and set the heating power of the intermediate frequency sensor to 58KW. This step is only for the first piece of the same machining batch, and there is no need to perform this step later.

[0041] Step 3: Divide the track plate grounding bar into 4 sections; when dividing the sections, divide the two grounding bars that can be processed at the same time into a group, and divide the bottom end to the top end of the group into a section. And name the track plate grounding bar sections from bottom to top as the first grounding bar, the second grounding bar, the third grounding bar and the fourth grounding bar; turn on the sprinkler 4 to spray, raise the medium frequency sensor position to the sprinkler to spray the pin shaft hole in the middle section of the track plate, stay for 1 second, and then move to the bottom of the track plate at a constant speed, so that the surface of the track plate grounding bar and the pin shaft hole are both in a wet state.

[0042] Step 4: Start heating from the bottom of the ground rib. The starting heating position of the medium frequency sensor is the bottom surface of the magnet below a group of magnets in the concave section. After fixed heating for 4 seconds, scan and heat upward at a speed of 330mm / min. After the first section of ribs is fully heated, stop heating immediately and quickly raise the medium frequency sensor 35mm so that the spray liquid can completely cover the heated ground ribs on both sides. The spraying time is 8S.

[0043] Step 5: Lift the intermediate frequency sensor to a position 40mm above the second section of the grounding bar to be heated, spray the second section of the grounding bar to be heated, so that the surface of the grounding bar and the pin shaft hole are in a wet state, stay for 1 second and then move downward at a uniform speed until the lowest magnet is 15mm higher than the upper end of the first section of the grounding bar (that is, the lower magnet in a group of magnets 3 in the recessed section is 15mm higher than the upper end of the first section of the grounding bar, so that the magnet does not sense the first section of the grounding bar), fix heating for 4 seconds, scan upward at a speed of 330mm / min for heating, stop heating immediately after the second section of the grounding bar is fully heated, and quickly lift the intermediate frequency sensor 35mm so that the spray liquid can completely cover the heated grounding bar. The spraying time is 8S.

[0044] Step 6: Raise the intermediate frequency sensor to the position where the sprinkler can spray the pin shaft hole at the upper end of the track shoe. After staying for 1 second, move the intermediate frequency sensor to the bottom of the track shoe at a uniform speed so that the surface of the track shoe's ground ribs and the pin shaft hole are both in a wet state.

[0045] Step 7: Move the medium frequency sensor until the lowest magnetic conductor is 15mm higher than the upper end of the second section of the ground rib. After fixed heating for 4 seconds, scan and heat upward at a speed of 330mm / min. After the third section of the ground rib is fully heated, stop heating immediately and quickly raise the medium frequency sensor 35mm so that the spray liquid can completely cover the heated ground ribs on both sides. The spray time is 8S.

[0046] Step 8: Lift the intermediate frequency sensor to a position 40mm above the fourth section of the grounding bar to be heated, spray the fourth section of the grounding bar to be heated, so that the surface of the grounding bar and the pin shaft hole are in a wet state. After staying for 1 second, move downward at a uniform speed until the lowest magnetic conductor is 15mm higher than the upper end of the third section of the grounding bar (the magnetic conductor does not sense the third section of the grounding bar). After fixed heating for 4 seconds, scan and heat upward at a speed of 330mm / min. After the fourth section of the grounding bar is fully heated, stop heating immediately and quickly lift the intermediate frequency sensor 35mm so that the spray liquid can completely cover the heated grounding bars on both sides. The spraying time is 30S.

[0047] Step 9: Transfer the induction hardened track shoe to a box or pit resistance furnace for tempering within 4 hours. The tempering temperature is 150±10℃, the holding time is 120~180min, and the air cooling or furnace cooling is adopted. Example

[0048] The present invention is used for 42CrMoA steel single 4-rib track plate (its structure is as follows Figure 7 When quenching the ground reinforcement (as shown in the figure), the specific operations are as follows: Step 1: Install the positioning device on the machine tool workbench, insert the round pin and the prismatic pin into the two pin holes of the machined 42CrMoA steel single track shoe A or single track shoe B to fix it. Before fixing, the track shoe is quenched and tempered before clamping, and the hardness of the track shoe is 30~40HRC. The ground ribs of the track shoe have been milled flat before quenching, and the surface is at the same distance from the magnetizer during induction quenching.

[0049] When the track shoe is fixed, the surface of the track with the ground ribs is set vertically; the medium frequency sensor is connected to the moving parts of the machine tool so that the medium frequency sensor can move, and the magnetizer 3 of the medium frequency sensor is facing the surface of the track with the ground ribs; and the magnetizer and the water sprayer can completely cover the width of the ground ribs.

[0050] Step 2: Adjust the base angle so that the track shoe rib plane and the intermediate frequency sensor magnet working surface are parallel, adjust the gap between the track shoe rib surface and the intermediate frequency sensor magnet to 4±0.3mm, and set the intermediate frequency sensor heating power to 58KW. This step is only for the first piece in the same machining batch, and there is no need to perform this step later.

[0051] Step 3: Divide the track plate grounding bar into 2 sections; and name the sections of the track plate grounding bar as the first section and the second section from bottom to top; start the sprinkler 4 to spray, raise the position of the medium frequency sensor until the sprinkler can spray the pin shaft hole on the upper end surface of the track plate, stay for 1 second and then move to the bottom of the track plate at a uniform speed, so that the surface of the track plate grounding bar and the pin shaft hole are both in a wet state.

[0052] Step 4: Start heating from the bottom of the ground bar. After fixed heating for 4 seconds, scan and heat upward at a speed of 330mm / min. After the first section of ground bars are fully heated, stop heating immediately and quickly raise the medium frequency sensor 35mm so that the spray liquid can completely cover the heated ground bars. The spray time is 8S.

[0053] Step 5: Lift the medium frequency sensor to a position 40mm above the second section of the ground bar to be heated, and spray the second section of the ground bar to be heated; make the surface of the ground bar and the pin shaft hole wet, stay for 1 second, and then move the medium frequency sensor downward at a uniform speed until the lowest magnetic conductor exceeds the upper end of the second section of the ground bar by 15mm (the magnetic conductor does not sense the first section of the ground bar). After fixed heating for 4 seconds, scan and heat upward at a speed of 330mm / min. After the second section of the ground bar is fully heated, stop heating immediately and quickly lift the medium frequency sensor 35mm so that the spray liquid can completely cover the heated ground bar. The spraying time is 30S.

[0054] Step 6: Transfer the induction hardened track shoe to a box or pit resistance furnace for tempering within 4 hours. The tempering temperature is 150±10℃, the holding time is 120~180min, and the air cooling or furnace cooling is used. Figure 8 , 9 As shown, the grains after quenching are obviously finer than those before quenching.

Claims

1. A double-rib induction quenching process for a steel track shoe, which is implemented by using a double-rib induction quenching device for a steel track shoe, the double-rib induction quenching device for a steel track shoe comprising a medium frequency sensor and a positioning device; the medium frequency sensor comprising a water sprayer (4), an induction coil (2), a magnetic conductor (3), a fixing plate (5), a guide plate (1), an insulating plate (16), an insulating gasket (14), an insulating sleeve (15), a circulating water interface (6), and a spray water interface (13); the induction coil (2) and the circulating water interface (6) are fixed on the guide plate (1); a fixing device is arranged in a middle gap of the guide plate (1) An insulating plate (16) is provided; the magnetic conductor (3) is mounted on the induction coil (2); a fixing bolt A (11) is welded to the induction coil (2), and the fixing plate (5) is fixed by the fixing bolt A (11) and the nut A (12); a spray water interface (13) is provided on the side wall of the sprinkler (4); two circulating water interfaces (6) are connected to the cavity of the induction coil (2) and are used to pass circulating water in the induction coil (2) for cooling; the sprinkler (4) is fixedly mounted on the fixing plate (5); a positioning device is provided near the induction coil (2) of the medium frequency sensor and is used to position the steel track shoe; The following steps are involved: Step 1: Install the positioning device on the workbench of the machine tool, insert the round pin and the prismatic pin into the two pin holes of the machined track shoe to fix it, so that the surface of the track with the ground ribs is arranged vertically; connect the intermediate frequency sensor to the moving part of the machine tool so that the intermediate frequency sensor can move, and make the water spraying surface of the water sprayer (4) of the intermediate frequency sensor face the surface of the track with the ground ribs; and make the magnetizer and the water sprayer completely cover the width of the ground ribs; Step 2: Adjust the angle of the base so that the ground rib plane of the track shoe is parallel to the working surface of the intermediate frequency sensor magnetizer, and adjust the gap between the ground rib surface of the track shoe and the intermediate frequency sensor magnetizer to 4±0.3mm; Step 3: Divide the track plate ribs into n sections; when the track plate is a 4-rib track plate, n=2; when the track plate is an 8-rib track plate, n=4; and name the sections of the track plate ribs from bottom to top as the first section of ribs, the second section of ribs, the third section of ribs, and the fourth section of ribs; start the water sprayer (4) to spray, and raise the position of the intermediate frequency sensor until the water sprayer (4) can spray the pin shaft hole above the track plate, the middle section pin shaft hole of the one-piece track plate, and the top position of the single track plate; after staying for 1 second, move at a constant speed to the bottom of the track plate, so that the surface of the track plate ribs and the pin shaft hole are both in a wet state; Step 4: Start heating from the bottom of the ground bar, heat it for a few seconds, and then scan and heat it upwards. After the first section of the ground bar is completely heated, stop heating and raise the medium frequency sensor so that the spray liquid from the sprinkler (4) can completely cover the heated ground bar; Step 5: Lift the medium frequency sensor to spray the second section of the grounding bar; move the medium frequency sensor until the lowest magnetic conductor is higher than the upper end of the first section of the grounding bar, fix it for a few seconds and then scan and heat it upwards. After the second section of the grounding bar is fully heated, stop heating and lift the medium frequency sensor so that the spray liquid of the sprinkler can completely cover the heated grounding bar; Step 6: If the track shoe is a 4-rib track shoe, all induction hardening processes have been completed; if the track shoe is an 8-rib track shoe, proceed to the next step; Step 7: lift the medium frequency sensor to spray the third section of the grounding bar; move the medium frequency sensor until the lowest magnetic conductor is higher than the upper end of the second section of the grounding bar, fix it for heating for a few seconds and then scan it upwards to heat it. After the third section of the grounding bar is completely heated, stop heating and lift the medium frequency sensor so that the spray liquid of the sprinkler (4) can completely cover the heated grounding bar; Step 8: lift the medium frequency sensor to spray the fourth section of the grounding bar; move the medium frequency sensor until the lowest magnetic conductor is higher than the upper end of the third section of the grounding bar, fix it for heating for a few seconds and then scan it upwards to heat it. After the fourth section of the grounding bar is completely heated, stop heating and lift the medium frequency sensor so that the spray liquid of the sprinkler (4) can completely cover the heated grounding bar; Step 9: Temper the track plate within 4 hours, the tempering temperature is 150±10℃, the insulation time is 120~180min, air cooling or furnace cooling.

2. The double-reinforcement induction hardening process for steel track shoes according to claim 1, characterized in that: The heating power of the medium frequency sensor is 55~60KW, and the induction frequency is 8000HZ.

3. According to the double-rib induction quenching process for steel track shoes as described in claim 1, in step 1, before the track shoes are clamped, the ground ribs of the track shoes are milled flat before quenching, and the distance between their surfaces and the magnetizer is consistent during induction quenching.

4. According to the double-reinforcement induction quenching process for steel track shoes as claimed in claim 1, in step 1, the track shoes are subjected to tempering treatment before clamping, and the hardness of the track shoes is 30-40HRC.

5. The double-reinforcement induction hardening process for steel track shoes according to claim 1, characterized in that: The cooling medium in the sprinkler (4) is a 5-7% PAG aqueous solution, and the spraying flow rate of the PAG aqueous solution is 18 L / min.

6. The double-reinforcement induction hardening process for steel track shoes according to claim 1, characterized in that: A heater and a refrigerator are provided in the water sprayer (4), and the temperature of the PAG aqueous solution is controlled at 35-40°C.

7. The double-reinforcement induction hardening process for steel track shoes according to claim 1, characterized in that: The positioning device comprises a base (17), a round pin shaft (18) and a prismatic pin shaft (19); the round pin shaft (18) and the prismatic pin shaft (19) are fixed to the base (17) by means of a hexagon socket bolt (20); the round pin shaft (18) and the prismatic pin shaft (19) are arranged perpendicular to the base (17).

8. The double-reinforcement induction hardening process for steel track shoes according to claim 1, characterized in that: The insulating plate (16) is made of polytetrafluoroethylene and is fixedly mounted in the middle gap of the flow plate (1) by means of a fixing bolt C (7) and a fixing nut C (8); an insulating sleeve (15) is sleeved on the outer side of the fixing bolt C (7); an insulating gasket (14) is respectively arranged between the bolt head of the fixing bolt C (7) and the insulating plate (16) and between the fixing nut C (8) and the insulating plate (16); the insulating sleeve (15) and the insulating gasket (14) are made of bakelite.

9. The double-reinforcement induction hardening process for steel track shoes according to claim 7, characterized in that: The material of the sprinkler (4), the induction coil (2) and the guide plate (1) is T2 copper, and the material of the circulating water interface (6) and the spray water interface (13) is H62 brass; the material of the base (17), the round pin (18) and the prismatic pin (19) are all 3Cr13, with a hardness of 47-52HRC.

10. The double-reinforcement induction hardening process for steel track shoes according to claim 9, characterized in that: The magnetizer (3) is a Fluxtrol 50 type high-density ferrite, the size of a single piece is 42×24 mm, and a 16 mm groove is processed in the middle. Two pieces are grouped together. Three groups of magnetizers (3) are evenly buckled with the induction coil (2), and the lateral spacing of the magnetizers (3) is 40.5-41 mm. A 42×15 mm concave section is provided in the middle of the induction coil (2). The middle group of magnetizers (3) is buckled to the concave section of the induction coil (2), and the horizontal height of the magnetizers (3) in the concave section is 15 mm lower than that of the magnetizers (3) on both sides. The sprinkler (4) is provided with water spray holes with a lateral spacing and a longitudinal spacing of 5 mm and a diameter of Φ1.5 mm. The angle of the water spray holes is 30° downward from the vertical horizontal plane. The water spray holes of the sprinkler (4) are distributed in three areas, respectively located directly below the three groups of magnetizers (3). The water spray holes in a single area are arranged in 10 rows×10 columns.

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