Induction heating device for thin plate annular part with large radius-thickness ratio and heating method of induction heating device

Abstract

The invention relates to the technical field of heat treatment, and particularly discloses an induction heating device and a heating method of a thin plate annular part with a large radius-thickness ratio, the induction heating device comprises a high-frequency inductor and a positioning seat, the high-frequency inductor comprises a fixing plate, a flow guide plate and an induction coil, and the induction coil is provided with a magnetizer; a circulating water receiving opening is formed between the induction coil and the flow guide plate, the positioning seat comprises a base and a heat insulation plate, the annular thin plate workpiece is arranged on the heat insulation plate, the induction coil, the heat insulation plate and the annular thin plate workpiece are concentric, the induction coil is of a split structure, the heat insulation plate is made of composite light ceramic, and clamping grooves are evenly formed in the heat insulation plate. The inner diameter of the clamping groove is smaller than that of the annular thin plate workpiece. According to the scheme, the quality of the parts can be improved, deformation in the machining process is reduced, the machining precision is improved, the product rejection rate is reduced, the production cost is saved, meanwhile, the heating process and the cooling process of each part are consistent, and the hardness uniformity after heat treatment is good.

Description

Technical Field

[0001] The invention relates to the technical field of heat treatment, and in particular provides an induction heating device for a thin plate annular part with a large diameter-to-thickness ratio and a heating method thereof. Background Art

[0002] Thin plate annular parts are parts with thin walls and high-to-diameter ratio. These parts have the characteristics of light weight, less material, compact structure and good corrosion resistance. They are widely used in shipbuilding, aerospace, automobile industry, electronic communications, household appliances, metal fixtures and many other fields.

[0003] Thin-plate annular parts such as disc springs, diaphragm springs, external toothed steel sheets, etc. are mostly made of spring steels such as 65Mn, 50CrVA, 60Si 2MnA, etc., with a thickness of 2 to 5mm and an outer diameter of Φ200 to Φ400mm. Since the parts are relatively large in diameter and thickness and need to be disc-shaped, they usually need to be supplemented by pressure quenching (referred to as pressure quenching), hot leveling / shaping, machining, etc. to meet the corresponding technical requirements. In terms of heating, in order to avoid serious decarburization and warping during the heating process, the furnace is often loaded in a single-layer flat manner, and a roller furnace with atmosphere protection function and zone speed control is used for heating.

[0004] Roller furnace is a continuous operation production furnace type, which is mature and has obvious advantages in the fields of diaphragm springs, garden saw blades, etc. However, for the small batch intermittent production mode of the special equipment industry, the equipment needs to be frequently closed and opened. If thin plate annular workpiece parts are heated by roller furnace, the time from the start-up of the equipment to the heating can be as long as 8 to 10 hours, which will cause huge energy waste and cause the risk of delaying production progress.

[0005] Induction heat treatment equipment is very convenient to start and stop and has a short heating time. It is an ideal equipment for the overall heating of thin-plate annular parts and is suitable for small-batch intermittent production mode. For thin-plate annular parts with a diameter-to-thickness ratio of 50 to 100 (a conventional diameter-to-thickness ratio for thin-plate annular parts), a thickness of more than 3mm, and a weight of ≥1kg, there are a small number of application cases for induction overall heating technology; while for thin-plate annular parts with a diameter-to-thickness ratio greater than 100 (a large diameter-to-thickness ratio for thin-plate annular parts), a thickness of less than 3mm, and a weight of less than 1kg, there are still many difficulties and problems in the application of induction overall heating technology, which are mainly reflected in: the parts are light in weight and poor in rigidity, there is a relatively strong magnetic field during induction heating, and when the steel sheet is in an unbalanced state in the magnetic field, the parts will produce serious warping and deformation and there is a risk of "sparking (the part contacts the sensor after warping)".

[0006] Therefore, designing an induction heating device and a heating method for thin-plate annular parts with a large diameter-to-thickness ratio to avoid the occurrence of the above-mentioned problems, reduce the heat loss of the parts during the heating process and improve the heating stability is an issue that needs to be urgently addressed. Summary of the invention

[0007] In order to solve the above problems, the present invention provides an induction heating device for a thin plate annular part with a large diameter-to-thickness ratio and a heating method thereof.

[0008] The present invention provides an induction heating device for a thin-plate annular part with a large diameter-to-thickness ratio. The induction heating device comprises a high-frequency inductor and a positioning seat located below the high-frequency inductor; the high-frequency inductor comprises a fixed plate, a guide plate connected to the side of the fixed plate, and an induction coil connected to the bottom of the fixed plate, a magnetic conductor is arranged on the induction coil, and a circulating water inlet is included between the induction coil and the guide plate; the positioning seat comprises a base and a heat insulation plate connected to the base, the thin-plate annular workpiece is placed on the heat insulation plate, and the induction coil, the heat insulation plate and the thin-plate annular workpiece are concentric.

[0009] Furthermore, the induction coil is a split structure, specifically including symmetrically arranged induction coil one and induction coil two, both of which include a flat section and an S-shaped bending section, and the magnetic conductor is installed on the flat section of the magnetic conductor; the inner diameter of the induction coil scanning track is larger than the inner diameter of the thin plate annular workpiece, and the outer diameter of the scanning track is larger than the outer diameter of the thin plate annular workpiece; the scanning track of the magnetic conductor part corresponds to the non-tooth position of the thin plate annular workpiece.

[0010] Furthermore, the material of the induction coil and the guide plate is red copper, the material of the fixing plate is epoxy resin, the material of the magnetic conductor is high-density ferrite, and the material of the circulating water interface is brass.

[0011] Furthermore, a connecting groove is provided at the upper end of the base, a positioning pin is provided in the connecting groove, and the heat insulation board is connected to the base through the positioning pin; the base and the positioning pin are made of stainless steel.

[0012] Furthermore, the material of the heat insulation board is composite lightweight ceramic, specifically, the heat insulation board is formed by high temperature sintering of kaolin ceramic fiber filaments, cordierite powder, high purity magnesium oxide powder, aluminum oxide powder, and high temperature adhesive.

[0013] Furthermore, at least three clamping grooves are evenly arranged on the insulation board, and the inner diameter of the clamping groove is smaller than the inner diameter of the thin plate annular workpiece; the verticality, parallelism and coaxiality of the insulation board are all controlled within 0.1 mm.

[0014] Furthermore, a positioning boss is provided on the heat insulation plate, the outer diameter of the positioning boss is smaller than the inner diameter of the thin plate annular workpiece, and the gap between the positioning boss and the inner end surface of the thin plate annular workpiece is 0.1±0.05mm.

[0015] An induction heating method for a thin plate annular part with a large diameter-to-thickness ratio, using the above-mentioned induction heating device for induction heating, comprises the following steps:

[0016] S1: Install the high-frequency sensor and the positioning seat, place the thin plate annular workpiece on the heat insulation board, insert the inner hole of the thin plate annular workpiece into the positioning boss, and align the material clamping part with the clamping groove of the heat insulation board;

[0017] S2: Adjust the position of the high-frequency inductor so that the distance between the bottom plane of the induction coil and the thin plate annular workpiece is 10±1mm, and the center of the induction coil coincides with the center of the thin plate annular workpiece;

[0018] S3: Start the driving member of the positioning seat, so that the positioning seat rotates at a fixed speed without relative motion;

[0019] S4: Turn on heating, which specifically includes the following sub-steps:

[0020] S41: transferring heat from a higher temperature portion of the thin plate annular workpiece to a lower temperature portion, in which state the thin plate annular workpiece keeps rotating at a uniform speed on the positioning seat, and the surface of the thin plate annular workpiece keeps a metallic color;

[0021] S42: After uniform heating, heating is started again to make the temperature of each part of the thin plate annular workpiece exceed the austenitizing temperature of the material by more than 50°C;

[0022] S43: reduce the power and continue heating, so that the heat of the high temperature part of the thin plate annular workpiece is transferred to the low temperature part;

[0023] S5: Stop the heating and rotation of the equipment, remove the heated thin plate annular workpiece from the clamping groove 0 of the positioning seat, and transfer to the press quenching process;

[0024] Step S1 and step S2 are limited to the first thin plate annular workpiece in the same state batch, and subsequent thin plate annular workpieces in the same state batch do not need to perform steps S1 and S2.

[0025] Further, in S41, the heating is first performed at a power of 30 to 35 kW for 3 to 5 seconds, and then the heating is stopped for 5 to 7 seconds, so that the heat of the higher temperature part of the part is transferred to the lower temperature part;

[0026] In S43, the power is reduced to 15 to 20KW and heated for 3 to 5 seconds, so that the heat from the higher temperature part is transferred to the lower temperature part.

[0027] Furthermore, in S42, heating is performed at a power of 28 to 33 kW for 23 to 27 seconds, so that the temperature of each part of the part exceeds the austenitizing temperature of the material by more than 50°C. A portable temperature measuring gun or a colorimetric card is used to judge the temperature.

[0028] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0029] 1. The induction heating device of the present invention can improve the quality of parts, reduce deformation during processing, improve processing accuracy, increase the first-time qualified rate of parts forming, reduce product scrap rate, and save production costs.

[0030] 2. The composite lightweight ceramic insulation board of the present invention is a high-quality refractory material with the characteristics of low thermal expansion, low heat loss, good dimensional stability, etc. It can greatly reduce the heat loss of parts during the heating process. At the same time, no foreign matter will adhere to the parts when taking out the material, thereby affecting the press quenching effect.

[0031] 3. The dual rigidity design of the split induction coil and the epoxy resin plate fixation in the present invention prevents the high-frequency inductor from shaking due to magnetic force during heating, and can indirectly keep the parts in a balanced state in the magnetic field.

[0032] 4. The heating and cooling processes of each part in the present invention are consistent, and the hardness uniformity after heat treatment is good. The hardness uniformity of a single piece is within 1HRC, and the hardness uniformity of a batch is within 3HRC, which is better than the effect of a controlled atmosphere multi-purpose furnace / vacuum furnace with a single piece of 3HRC and a batch of 5HRC.

[0033] 5. In the process of high-frequency induction heating and press quenching, the thin-plate annular parts are rapidly heated and rapidly cooled, and the grains can be significantly refined. The grains after quenching are more than 3 levels finer than those before quenching, and the fatigue life can be increased by more than 50%.

[0034] 6. Under the small batch intermittent production mode, the heating technology and quenching processing time of the present invention are equivalent to those of the roller furnace production line (about 1.5 min / piece), and the production cost is about 20% of that of the roller furnace production line (induction heating of 100 pieces consumes about 30 KW of electricity and no gas; roller furnace heating of 100 pieces consumes about 75 KW of electricity and consumes propane gas). BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a schematic structural diagram of an induction heating device provided according to an embodiment of the present invention;

[0036] Figure 2 is a schematic structural diagram of a positioning seat provided according to an embodiment of the present invention;

[0037] Figure 3 is a schematic diagram of the structure of a high-frequency sensor provided according to an embodiment of the present invention;

[0038] Figure 4 is a schematic diagram of the structure of an induction coil provided according to an embodiment of the present invention;

[0039] Figure 5is a schematic structural diagram of a heat insulation board provided according to an embodiment of the present invention;

[0040] Figure 6 Schematic diagram of the structure of a thin plate annular workpiece provided according to an embodiment of the present invention.

[0041] The accompanying drawings include: guide plate 1, fixing plate 2, induction coil 3, magnetic conductor 4, circulating water interface 5, base 6, heat insulation board 7, positioning pin 8, high-frequency sensor 9, positioning seat 10, induction coil one 11, induction coil two 12, flat section 13, bending section 14, connecting groove 15, clamping groove 16, positioning boss 17. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the following Figure 1-6 It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0043] An induction heating device for a thin plate annular part with a large diameter-to-thickness ratio, the induction heating device comprising a high-frequency inductor 9 and a positioning seat 10 located below the high-frequency inductor 9, the high-frequency inductor 9 comprising a fixed plate 2, a guide plate 1 connected to the side of the fixed plate 2, an induction coil 3 connected to the bottom of the fixed plate 2, a magnetic conductor 4 is arranged on the induction coil 3, a circulating water inlet is included between the induction coil 3 and the guide plate 1, the positioning seat 10 comprises a base 6 and a heat insulation plate 7 connected to the base 6, the thin plate annular workpiece is placed on the heat insulation plate 7, the thin plate annular workpiece is as shown in FIG. Figure 6 As shown, M is the inner hole of the thin plate annular workpiece, N is the tooth portion of the thin plate annular workpiece, and the induction coil 3, the heat insulation plate 7 and the thin plate annular workpiece are concentric.

[0044] like Figure 3 , Figure 4 As shown, the induction coil 3 is a split structure, specifically including a symmetrically arranged induction coil 1 11 and an induction coil 2 12, both of which include a flat section 13 and an S-shaped bending section 14, and the magnetic conductor 4 is installed on the flat section 13 of the magnetic conductor 4. Figure 4 The magnetic flux lines are shown at S in the middle. The inner diameter of the scanning track of the induction coil 3 is larger than the inner diameter of the thin plate annular workpiece, and the outer diameter of the scanning track is larger than the outer diameter of the thin plate annular workpiece. The scanning track of the magnetic conductor 4 corresponds to the non-tooth position of the thin plate annular workpiece. A connecting groove 15 is opened at the upper end of the base 6. A positioning pin 8 is provided in the connecting groove 15, and the heat insulation board 7 is connected to the base 6 through the positioning pin 8.

[0045] The material of the induction coil 3 and the guide plate 1 is T2 copper, the material of the fixing plate 2 is epoxy resin, the material of the magnetic conductor 4 is Fluxtrol 559H high-density ferrite, the material of the circulating water interface 5 is H62 brass, the material of the base 6 and the positioning pin 8 is SUS304 stainless steel, and the material of the heat insulation board 7 is composite lightweight ceramic. Specifically, the heat insulation board 7 is formed by high-temperature sintering of kaolin ceramic fiber silk, cordierite powder, high-purity magnesium oxide powder, aluminum oxide powder, and high-temperature adhesive. The composite lightweight ceramic heat insulation board 7 is a high-quality refractory material that can greatly reduce the heat loss of parts during heating. The dual rigidity design of the split induction coil 3 and the epoxy resin fixing plate 2 can prevent the high-frequency sensor 9 from shaking due to magnetic force during heating, and can indirectly make the parts in a balanced state in the magnetic field.

[0046] At least three clamping grooves 16 are evenly arranged on the heat insulation board 7. Figure 5 As shown, the heat insulation board 7 in this embodiment is provided with three clamping grooves 16, the inner diameter of the clamping groove 16 is smaller than the inner diameter of the thin plate annular workpiece, the verticality, parallelism and coaxiality of the heat insulation board 7 are all controlled within 0.1mm, and the heat insulation board 7 is provided with a positioning boss 17, the outer diameter of the positioning boss 17 is smaller than the inner diameter of the thin plate annular workpiece, the gap between the positioning boss 17 and the inner end face of the thin plate annular workpiece is 0.1±0.05mm, and the inner diameter of the clamping groove 16 is 10 to 12mm smaller than the inner diameter of the thin plate annular workpiece.

[0047] An induction heating method for a thin plate annular part with a large diameter-to-thickness ratio, using the above-mentioned induction heating device for induction heating, comprises the following steps:

[0048] S1: Install the high-frequency sensor 9 and the positioning seat 10, place the thin plate annular workpiece on the insulation board 7, insert the inner hole of the thin plate annular workpiece into the positioning boss 17, and align the material clamping part with the clamping groove 16 of the insulation board 7.

[0049] S2: Adjust the position of the high-frequency inductor 9 so that the distance between the bottom plane of the induction coil 3 and the thin plate annular workpiece is 10±1 mm, and the center of the induction coil 3 coincides with the center of the thin plate annular workpiece.

[0050] S3: Start the driving member of the positioning seat 10 to make the positioning seat 10 rotate at a fixed speed without relative motion.

[0051] S4: Turn on heating, which specifically includes the following sub-steps:

[0052] S41: Transfer the heat from the higher temperature part of the thin plate annular workpiece to the lower temperature part. In this state, the thin plate annular workpiece keeps rotating at a uniform speed on the positioning seat 10, and the surface of the thin plate annular workpiece keeps a metallic color. In this step, first heat at a power of 30 to 35KW for 3 to 5 seconds, and then stop heating for 5 to 7 seconds, so that the heat from the higher temperature part of the part is transferred to the lower temperature part.

[0053] S42: After uniform heating, heating is turned on again to make the temperature of each part of the thin plate annular workpiece exceed the austenitizing temperature of the material by more than 50°C. In this step, heating is performed at a power of 28 to 33KW for 23 to 27 seconds to make the temperature of each part of the part exceed the austenitizing temperature of the material by more than 50°C. A portable temperature measuring gun or a colorimetric card is used here to judge the temperature.

[0054] S43: Reduce the power and continue heating to transfer the heat from the higher temperature part of the thin plate annular workpiece to the lower temperature part. In this step, reduce the power to 15 to 20KW and heat for 3 to 5 seconds to transfer the heat from the higher temperature part to the lower temperature part.

[0055] S5: Stop the heating and rotation of the equipment, remove the heated thin plate annular workpiece from the clamping groove 160 of the positioning seat 10, and enter the press quenching process.

[0056] Step S1 and step S2 are limited to the first thin plate annular workpiece in the same state batch, and subsequent thin plate annular workpieces in the same state batch do not need to perform steps S1 and S2.

[0057] The wall thickness of the thin plate annular workpiece manufactured in this embodiment is about 2 mm, and the weight is less than 0.5 kg.

[0058] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. Those skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. An induction heating device for thin plate annular parts with large diameter-to-thickness ratio, characterized in that: The induction heating device comprises a high-frequency inductor (9) and a positioning seat (10) located below the high-frequency inductor (9); the high-frequency inductor (9) comprises a fixing plate (2), a guide plate (1) connected to the side of the fixing plate (2), and an induction coil (3) connected to the bottom of the fixing plate (2); a magnetic conductor (4) is arranged on the induction coil (3); a circulating water inlet is provided between the induction coil (3) and the guide plate (1); the positioning seat (10) comprises a base (6) and a heat insulation plate (7) connected to the base (6); a thin plate annular workpiece is placed on the heat insulation plate (7); the induction coil (3), the heat insulation plate (7) and the thin plate annular workpiece are concentric.

2. The induction heating device for thin plate annular parts with large diameter-to-thickness ratio according to claim 1 is characterized in that: The induction coil (3) is a split structure, specifically comprising an induction coil 1 (11) and an induction coil 2 (12) symmetrically arranged, the induction coil 1 (11) and the induction coil 2 (12) both comprising a flat section (13) and an S-shaped bending section (14), the magnetic conductor (4) being mounted on the flat section (13) of the magnetic conductor (4); the inner diameter of the scanning track of the induction coil (3) is greater than the inner diameter of the thin plate annular workpiece, and the outer diameter of the scanning track is greater than the outer diameter of the thin plate annular workpiece; the scanning track of the magnetic conductor (4) corresponds to the non-tooth portion of the thin plate annular workpiece.

3. The induction heating device for thin plate annular parts with large diameter-to-thickness ratio according to claim 1 is characterized in that: The induction coil (3) and the guide plate (1) are made of red copper, the fixing plate (2) is made of epoxy resin, the magnetic conductor (4) is made of high-density ferrite, and the circulating water interface (5) is made of brass.

4. The induction heating device for thin plate annular parts with large diameter-to-thickness ratio according to claim 1 is characterized in that: The upper end of the base (6) is provided with a connection groove (15), a positioning pin (8) is provided in the connection groove (15), and the heat insulation board (7) is connected to the base (6) through the positioning pin (8); the base (6) and the positioning pin (8) are made of stainless steel.

5. The induction heating device for thin plate annular parts with large diameter-to-thickness ratio according to claim 1 is characterized in that: The material of the heat insulation board (7) is composite lightweight ceramics. Specifically, the heat insulation board (7) is formed by high-temperature sintering of kaolin ceramic fiber filaments, cordierite powder, high-purity magnesium oxide powder, aluminum oxide powder, and a high-temperature adhesive.

6. The induction heating device for thin plate annular parts with large diameter-to-thickness ratio according to claim 1 is characterized in that: At least three clamping grooves (16) are evenly arranged on the heat insulation plate (7), and the inner diameter of the clamping groove (16) is smaller than the inner diameter of the thin plate annular workpiece; the verticality, parallelism and coaxiality of the heat insulation plate (7) are all controlled within 0.1 mm.

7. The induction heating device for thin plate annular parts with large diameter-to-thickness ratio according to claim 1 is characterized in that: The heat insulation plate (7) is provided with a positioning boss (17), the outer diameter of the positioning boss (17) is smaller than the inner diameter of the thin plate annular workpiece, and the gap between the positioning boss (17) and the inner end surface of the thin plate annular workpiece is 0.1±0.05 mm.

8. An induction heating method for thin plate annular parts with a large diameter-to-thickness ratio, using the induction heating device according to any one of claims 1 to 8 for induction heating, characterized in that: The steps include: S1: Install the high-frequency sensor (9) and the positioning seat (10), place the thin plate annular workpiece on the heat insulation board (7), insert the inner hole of the thin plate annular workpiece into the positioning boss (17), and align the material clamping part with the clamping groove (16) of the heat insulation board (7); S2: adjusting the position of the high-frequency inductor (9) so that the distance between the bottom plane of the induction coil (3) and the thin plate annular workpiece is 10±1 mm, and the center of the induction coil (3) coincides with the center of the thin plate annular workpiece; S3: starting the driving member of the positioning seat (10) so that the positioning seat (10) rotates at a fixed speed without any relative movement; S4: Turn on heating, which specifically includes the following sub-steps: S41: transferring heat from a higher temperature portion of the thin plate annular workpiece to a lower temperature portion, in which state the thin plate annular workpiece keeps rotating at a uniform speed on the positioning seat (10), and the surface of the thin plate annular workpiece keeps a metallic color; S42: After uniform heating, heating is started again to make the temperature of each part of the thin plate annular workpiece exceed the austenitizing temperature of the material by more than 50°C; S43: reduce the power and continue heating, so that the heat of the high temperature part of the thin plate annular workpiece is transferred to the low temperature part; S5: Stop heating and rotating the equipment, remove the heated thin plate annular workpiece from the clamping groove (16) 0 of the positioning seat (10), and enter the press quenching process; Step S1 and step S2 are limited to the first thin plate annular workpiece in the same state batch, and subsequent thin plate annular workpieces in the same state batch do not need to perform steps S1 and S2.

9. The induction heating method for thin plate annular parts with large diameter-to-thickness ratio according to claim 8, characterized in that: In S41, the heating is first performed at a power of 30 to 35 kW for 3 to 5 seconds, and then the heating is stopped for 5 to 7 seconds, so that the heat from the higher temperature part of the part is transferred to the lower temperature part; In S43, the power is reduced to 15 to 20 kW and the heating is performed for 3 to 5 seconds, so that the heat from the higher temperature part is transferred to the lower temperature part.

10. The induction heating method for thin plate annular parts with large diameter-to-thickness ratio according to claim 8, characterized in that: In S42, heating is performed at a power of 28 to 33 kW for 23 to 27 seconds, so that the temperature of each part of the part exceeds the austenitizing temperature of the material by more than 50°C. A portable temperature gun or a colorimetric card is used to determine the temperature.

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