Electromagnetic valve seat machining method based on electric upsetting

Abstract

The electromagnetic valve seat machining method based on electric heating upsetting comprises the following steps that firstly, a cylindrical bar is selected, electric heating upsetting is adopted to conduct staged machining on the cylindrical bar in a staged mode, an intermediate structural part is obtained, the intermediate structural part comprises a rod part, a garlic-shaped protruding part is arranged at one end of the rod part, and the size of the protruding part is larger than that of the rod part; 2, the heated middle structural part is placed in a die to be forged and formed, a blank is obtained, the protruding part comprises a counter bore, and the counter bore is located in the extending direction of the rod part; 3, the blank is subjected to magnetic property annealing, and magnetic property annealing is conducted; and 4, the blank is subjected to turning finish machining, and a finished electromagnetic valve seat is obtained. According to the method, blank materials can be utilized to a great extent, consumables are reduced, the allowance is small, and therefore compared with a traditional machining mode, the machining time is shorter, the material utilization rate is high, and better microstructure streamlines and compact grain size are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of parts processing, in particular to a method for processing a solenoid valve seat based on electric heating upsetting. Background Art

[0002] Most of the materials of the solenoid valve seat are 00Cr18Si2Mo2 electromagnetic steel. The existing processing method for forming the solenoid valve seat is mainly to turn a cylindrical bar with a diameter of φ30mm (millimeter), a length of 29mm and a material of 00Cr18Si2Mo2 electromagnetic steel. The existing processing method mainly includes two steps, first turning the cylindrical bar to obtain a rough blank, and then fine machining the rough blank to obtain the final solenoid valve product.

[0003] The existing processing methods of solenoid valve seats mainly have the following deficiencies and defects:

[0004] 1. In order to obtain cylindrical bars with a diameter of φ30mm and ensure that the microscopic grain size of the cylinder is about 8-9 (average 10um), it is necessary to use casting billets with a diameter of φ100-120mm for forging, and then hot-draw them after forging, and finally grind them to the required cylindrical bars with a diameter of φ30mm. The larger the diameter of the casting billet, the larger the tonnage of the smelting equipment and forging equipment required, and at the same time it will also cause a higher scrap rate of materials.

[0005] 2. A cylindrical bar with a diameter of φ30mm (millimeter) and a length of 29mm weighs about 160g (grams), and the weight of the resulting blank is about 56g. That is, the material loss of the blank obtained by turning the cylindrical bar before and after processing is about 100g, and the material utilization rate is low.

[0006] 3. Since there is a lot of excess material from raw materials to cylindrical bars and then to blanks, the processing time is also long. At a feed speed of 20m / min, i.e. 0.3m / s, a rough turning feed of 0.2-0.3mm / r, a fine turning feed of 0.15mm / r, a processing volume of 8mm per side, and 266 processing steps, it takes about 130-150 seconds to process.

[0007] 4. In the process of directly turning the cylindrical bar into a blank, there are discontinuous microstructural streamlines in the blank, which will lead to a tendency of strengthening cracking at the corner position of the blank. Summary of the invention

[0008] In view of the deficiencies in the prior art, an object of the present invention is to provide a method for machining a solenoid valve seat based on electric hot upsetting, which can solve the problems described in the background technology.

[0009] The technical solution for achieving the purpose of the present invention is: a method for processing a solenoid valve seat based on electric heating upsetting, comprising the following steps:

[0010] Step 1: Select a cylindrical bar stock, and use an electric hot forging to process the cylindrical bar stock in stages to obtain an intermediate structural part, wherein the intermediate structural part includes a rod portion, and a garlic-shaped protrusion is provided at one end of the rod portion, and the size of the protrusion is larger than the rod portion;

[0011] Step 2: placing the heated intermediate structural member into a die and performing forging to obtain a blank, wherein the protruding portion includes a countersunk hole, and the countersunk hole is located in the extension direction of the rod portion;

[0012] Step 3: annealing the blank for magnetic properties; annealing the blank for magnetic properties;

[0013] Step 4: Finish turning the blank to obtain the finished solenoid valve seat.

[0014] Furthermore, in step 1, a cylindrical bar with a diameter of 11.7 mm and a length of 260 mm is selected.

[0015] Furthermore, in step 1, the cylindrical bar is processed by electric hot upsetting to obtain an intermediate structural part, and its specific implementation process includes the following steps:

[0016] Taking advantage of the high resistance of the cylindrical bar itself, the cylindrical bar is electrically heated and the heating temperature is maintained at 900℃-1120℃. During the heating process, a deformation force is applied to the cylindrical bar so that one end of the cylindrical bar forms a garlic shape, thereby obtaining an intermediate structural part.

[0017] Furthermore, the forging process specifically comprises the following steps:

[0018] Step 41: Electric upsetting preheating stage: the cylindrical bar is powered on for preheating, and the anvil of the electric upsetting device is preheated by heat radiation from the cylindrical bar. In this stage, the upsetting cylinder pressure of the electric upsetting device is set to 5-10 kN, the displacement is 0 mm, and the current is 2000-5000 A. The preheating temperature of the heating zone where the cylindrical bar portion between the electrode and the anvil of the electric upsetting device is located reaches 200-500°C and is maintained for 2-5 seconds. The anvil is preheated synchronously by heat conduction, and the heating zone where the cylindrical bar portion between the electrode and the anvil of the electric upsetting device is located is the bar heating zone.

[0019] Step 42: Entering the initial electric heating upsetting stage, i.e., initial deformation, the cylindrical bar is initially preformed by reaching the deformation temperature through the bar heating zone, and the displacement and pressure of the upsetting cylinder and the retreat of the anvil;

[0020] In the initial electric heating upsetting stage, the heating current and pressure are equivalent to those in the preheating stage, or the difference is within the preset threshold range, and the upsetting cylinder performs two linear displacements in the direction of the anvil in sequence, the total displacement of the two linear displacements is [50, 70] mm, and the displacement of the first linear displacement is less than the displacement of the second linear displacement; the initial electric heating upsetting stage includes two different upsetting pressures, the upsetting pressure in the first section is [11, 15] kN, and the upsetting pressure in the second section is [13, 17] kN; and two different upsetting currents, the first upsetting current is [2700, 3100] A, and the second upsetting current is [2500, 3100] A. The upsetting current is [2900, 3300] A, so as to gradually raise the temperature of the heating zone of the bar to 900-1120℃ to reach the temperature range required for deformation; and by gradually increasing the pressure, the deformation part of the cylindrical bar gradually accelerates the metal aggregation to form a micro-drum shape. As the cylindrical bar begins to upset, the anvil also begins to synchronously accompany the cylindrical bar to upset and retreat at the same time, and during the retreat operation of the anvil, 3-4 displacements are set, and each retreat displacement executes a different retreat speed, so that the garlic-shaped protrusion formed by the cylindrical bar after upsetting is smooth, and the smoothness is sufficient to meet the needs,

[0021] If it is set to 4 displacements, the retraction speed of the anvil decreases gradually, and the retraction speeds corresponding to the 4 displacements are 1.3mm / s, 1.1mm / s, 0.8mm / s, and 0.6mm / s, respectively. During the 4 displacements of the anvil, the height of the raised part of the intermediate structure is 44mm according to the preset height, and the 4 displacement distances are: [5, 15]mm, [15, 25]mm, [25, 35]mm, [35, 45]mm, respectively.

[0022] Step 43: Entering the middle upsetting stage, i.e., rapid deformation, by increasing the pressure and current of the upsetting cylinder, the cylindrical bar in the slightly drum-shaped state located in the bar heating zone is rapidly deformed into a drum-shaped state;

[0023] In the middle upsetting stage, the intermediate structural part is sequentially subjected to three linear displacements, the total displacement of the three linear displacements is [100, 140] mm, and the displacement of the first linear displacement is less than the displacement of the second linear displacement and less than the displacement of the third linear displacement; the heating current in the middle upsetting stage is greater than the heating current in the electric upsetting preheating stage, and 3-5 stages of displacement are set accordingly, the heating current increases stage by stage, and the heating current increment in each stage is 150-250A, the forging pressure in the middle upsetting stage is greater than the forging pressure in the initial electric heating upsetting stage, and the forging pressure in 3-5 stages is set accordingly, and is also increased by 0.5-5kN stage by stage, so that the deformation resistance of the cylindrical bar material gradually increases during the rapid deformation process;

[0024] Step 44: Entering the final upsetting stage, by increasing the upsetting cylinder pressure and current, and gradually slowing down or stopping the anvil retraction speed, the intermediate structure continues to gather and gradually shape;

[0025] In the final upsetting stage, the displacement of the anvil back is 40-60mm. By adjusting the upsetting displacement, it is ensured that the intermediate structure is placed in the die for forging to meet the blank size requirements; the corresponding current and upsetting pressure are greater than those in the middle upsetting stage, the current increases by 150-250A, and the forging pressure also increases by 0.5-5kN;

[0026] Step 45: Enter the necking stage, so that the cylindrical bar in the heating zone of the bar is gradually deformed into a garlic shape with a smooth transition from the cylindrical bar, so that the blank head and the rod can be easily forged into place during the segmentation stage.

[0027] During the necking stage, the displacement of the upsetting cylinder is 5-15mm, the upsetting cylinder pressure in the middle upsetting stage is > the upsetting cylinder pressure in the necking stage > the upsetting cylinder pressure in the initial electric heating upsetting stage, the upsetting current in the middle upsetting stage is > the upsetting current in the necking stage > the upsetting current in the initial electric heating upsetting stage, and the anvil is restarted to retract, with a retraction speed of 1.5-6mm / s, a retraction distance of 5-10mm, and the necking is maintained for 2-6 seconds.

[0028] Furthermore, the magnetic property annealing has an annealing temperature of 850-980°C, an annealing holding time of 2 hours, and water cooling after being taken out of the furnace.

[0029] The beneficial effects of the present invention are as follows: the present invention can utilize the blank material to a large extent, reduce consumables, have less excess, and therefore, the processing time is shorter than that of traditional processing methods, the material utilization rate is high, and it has better microstructure streamlines and dense grain size. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the process of the present invention;

[0031] Figure 2 It is a structural schematic diagram of the intermediate structural member;

[0032] Figure 3 This is a structural diagram of the finished solenoid valve seat;

[0033] In the figure, 1 is the rod, 2 is the protrusion, and 3 is the countersunk hole. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0035] like Figure 1-Figure 3 As shown, a method for processing a solenoid valve seat based on electric heating upsetting includes the following steps:

[0036] Step 1: Select a cylindrical bar with a diameter of 11.7 mm (millimeter) and a length of 260 mm, and use an electric hot forging to process the cylindrical bar to obtain an intermediate structural part, wherein the intermediate structural part includes a rod portion 1, and one end of the rod portion 1 includes a protrusion 2 that is larger than the rod portion 1 and is in the shape of a garlic.

[0037] In an optional embodiment, the cylindrical bar is processed by electric hot upsetting to obtain an intermediate structure, and its specific implementation process includes the following steps:

[0038] Taking advantage of the high electrical resistance of the cylindrical bar itself, the cylindrical bar is electrically heated, and the temperature formed by heating is maintained at 800℃-1020℃. During the heating process, a deformation force is applied to the cylindrical bar, so that one end of the cylindrical bar forms a spherical head shape (also called a garlic head shape), thereby obtaining an intermediate structural part.

[0039] Step 2: Place the heated intermediate structure into a die and perform forging in stages to obtain a blank. The blank includes a protrusion 2 and a rod 1. The protrusion 2 includes a countersunk hole 3. The size of the protrusion 2 is larger than that of the rod 1. The countersunk hole 3 is located in the extension direction of the rod 1.

[0040] refer to Figure 2 , Figure 2 Schematic diagram of the structure of the intermediate structural member. One end of the intermediate structural member is forged to obtain a ball head shape, the middle part of the ball head shape is forged to obtain a countersunk hole 3, and the other parts of the intermediate structural member constitute the rod part 1.

[0041] In an optional embodiment, the forging is performed in stages, which specifically includes the following steps:

[0042] Step 41: Electric upsetting preheating stage: the cylindrical bar is powered on for preheating, and the anvil of the electric upsetting device is preheated by heat radiation from the cylindrical bar; in this stage, the upsetting cylinder pressure of the electric upsetting device is set to 5-10kN, the displacement is 0mm, and the current is 2000-5000A; the preheating temperature of the heating zone where the cylindrical bar portion between the electrode and the anvil of the electric upsetting device is located reaches 200-500℃ and is maintained for 5-10s, that is, the preheating temperature of the heater where the cylindrical bar portion is located needs to be maintained for 5-10s to reach 200-500℃; the anvil is preheated synchronously by heat conduction, and the heating zone where the cylindrical bar portion between the electrode and the anvil of the electric upsetting device is located is the bar heating zone;

[0043] Step 42: Entering the initial electric heating upsetting stage, i.e., initial deformation, the cylindrical bar is initially preformed by reaching the deformation temperature through the bar heating zone, and the displacement and pressure of the upsetting cylinder and the retreat of the anvil;

[0044] In the initial electric heating upsetting stage, the heating current and pressure are the same as those in the preheating stage, or the difference is within the preset threshold value range, the upsetting cylinder performs two linear displacements in the direction of the anvil in sequence, the total displacement of the two linear displacements is 50-70mm (including the end value), and the displacement of the first linear displacement is less than the displacement of the second linear displacement; the initial electric heating upsetting stage includes two different upsetting pressures, the upsetting pressure of the first stage is 11-15kN (including the end value), and the upsetting pressure of the second stage is 13-17kN (inclusive of end values), and the upsetting currents in the two displacement processes are different, the upsetting current in the first displacement process is 2700-3100A (inclusive of end values), and the upsetting current in the second displacement process is 2900-3300A (inclusive of end values), so as to gradually heat the heating zone of the bar to 900-1120℃, thereby reaching the temperature range required for deformation; and by gradually increasing the pressure, the deformation part of the cylindrical bar gradually accelerates the metal aggregation to form a micro-drum shape. As the cylindrical bar begins to be upset, the anvil also begins to synchronously accompany the cylindrical bar to upset and retreat at the same time. And during the anvil retreat operation, 3-4 displacements are set, and each retreat displacement executes a different retreat speed, so that the garlic-shaped protrusion formed by the cylindrical bar after upsetting is smooth, and the smoothness is sufficient to meet the needs. If the displacement is set to 4 stages, the retraction speed of the anvil changes from fast to slow (that is, it decreases gradually), and the retraction speeds corresponding to the 4 stages are 1.3mm / s, 1.1mm / s, 0.8mm / s, and 0.6mm / s. During the 4 stages of the anvil's retraction, the height of the raised part of the intermediate structure is 44mm according to the preset height, and the 4 stages of displacement are: [5, 15]mm, [15, 25]mm, [25, 35]mm, and [35, 45]mm.

[0045] Step 43: Entering the middle upsetting stage, i.e., rapid deformation, by increasing the pressure and displacement of the upsetting cylinder, the cylindrical bar in the bar heating zone with a slightly drum shape is rapidly deformed into a drum shape;

[0046] In the middle upsetting stage, the intermediate structure is sequentially subjected to three to five linear displacements, the total displacement of the three linear displacements is 100-140mm (including the end value), and the displacement of the first linear displacement is less than the displacement of the second linear displacement and less than the displacement of the third linear displacement. The heating current of the cylindrical bar in the middle upsetting stage is greater than the heating current of the cylindrical bar in the electric upsetting preheating stage, and the current corresponding to each stage is gradually increased, and the current increment of each stage is 150-250A (including the end value), so that during the rapid deformation process of the middle upsetting stage, the current can ensure that the temperature of the heating zone of the bar is always maintained within the deformation temperature range. The forging pressure in the middle upsetting stage is greater than the forging pressure in the initial electric heating upsetting stage, and the middle upsetting stage is set to include 3-5 different forging pressures. The forging pressure in each stage increases step by step. Starting from the first stage, the forging pressure in each stage increases by 0.5-5kN, so that during the rapid deformation process, the deformation resistance of the cylindrical bar material increases gradually, and the pressure of the upsetting cylinder is gradually increased synchronously to ensure that the deformation meets the requirements;

[0047] Step 44: Entering the final upsetting stage, the pressure and current of the upsetting cylinder are increased, and the anvil retraction speed is gradually slowed down or stopped, so that the intermediate structure continues to gather and gradually shape.

[0048] In the final upsetting stage, the anvil's retraction displacement is 50±10mm. By adjusting the upsetting displacement, it is ensured that the intermediate structure is placed in the die for forging to meet the blank size requirements; the corresponding current and upsetting pressure are larger than those in the middle upsetting stage, and the current increases by 200A±50A; the forging pressure also increases by 0.5-5kN.

[0049] Step 45: Enter the necking stage, so that the cylindrical rod in the rod heating zone is gradually deformed into a transitionally smooth garlic shape.

[0050] In the necking stage, the displacement of the upsetting cylinder is 5-15mm, the upsetting cylinder pressure in the middle upsetting stage is > the upsetting cylinder pressure in the necking stage > the upsetting cylinder pressure in the initial electric heating upsetting stage, and similarly, the upsetting current in the middle upsetting stage is > the upsetting current in the necking stage > the upsetting current in the initial electric heating upsetting stage. At the same time, restart the anvil back, and back quickly, with a back speed of 1.5-6mm / s, a back distance of 5-10mm, and necking is maintained for 2-6 seconds.

[0051] In step 45, that is, in the necking stage, since the upsetting cylinder stops moving, that is, the cylindrical bar is no longer fed to the bar heating zone, and the anvil continues to retreat, the drum shape is elongated, so that under the condition of ensuring the pressure of the upsetting cylinder, the first position to be elongated is the drum-shaped part close to the electrode position, thus forming a garlic shape.

[0052] Step 3: Magnetic annealing is performed on the blank. The magnetic annealing is performed in stages.

[0053] Step 4: Finish turning the blank to obtain the finished solenoid valve seat.

[0054] refer to Figure 3 , Figure 3 The schematic diagram of the finished product of the solenoid valve seat is shown in Figure 1. Through the above steps, the diameter of the blank rod 1 can be ensured to be close to the required φ11.3, and the garlic-shaped protrusion 2 can be forged by electric hot forging to obtain a countersunk hole 3 with an outer diameter of φ28.7 and an inner diameter of φ19.7. The blank material can be used to a large extent, consumables can be reduced, and the excess is small. Therefore, the processing time is shorter than that of the traditional processing method.

[0055] The present invention can utilize the blank material to a great extent, reduce consumables, and have less excess. Therefore, the processing time is shorter than that of the traditional processing method, the material utilization rate is high, and it has better microstructure streamlines and dense grain size.

[0056] The embodiment disclosed in this specification is only an example of a unilateral feature of the present invention, and the protection scope of the present invention is not limited to this embodiment, and any other functionally equivalent embodiments fall within the protection scope of the present invention. For those skilled in the art, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all of these changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. A method for processing a solenoid valve seat based on electric heating upsetting, characterized in that: The steps include: Step 1: Select a cylindrical bar stock, and use an electric hot forging to process the cylindrical bar stock in stages to obtain an intermediate structural part, wherein the intermediate structural part includes a rod portion, and a garlic-shaped protrusion is provided at one end of the rod portion, and the size of the protrusion is larger than the rod portion; Step 2: placing the heated intermediate structural member into a die and performing forging to obtain a blank, wherein the protruding portion includes a countersunk hole, and the countersunk hole is located in the extension direction of the rod portion; Step 3: annealing the blank for magnetic properties; annealing the blank for magnetic properties; Step 4: Finish turning the blank to obtain the finished solenoid valve seat.

2. The electromagnetic valve seat processing method based on electric heating upsetting according to claim 1 is characterized in that: In step 1, a cylindrical bar with a diameter of 11.7 mm and a length of 260 mm is selected.

3. The electromagnetic valve seat processing method based on electric heating upsetting according to claim 2 is characterized in that: In step 1, the cylindrical bar is processed by electric hot upsetting to obtain an intermediate structural part, and its specific implementation process includes the following steps: Taking advantage of the high resistance of the cylindrical bar itself, the cylindrical bar is electrically heated and the heating temperature is maintained at 900℃-1120℃. During the heating process, a deformation force is applied to the cylindrical bar so that one end of the cylindrical bar forms a garlic shape, thereby obtaining an intermediate structural part.

4. The electromagnetic valve seat processing method based on electric heating upsetting according to claim 3 is characterized in that: The forging process specifically comprises the following steps: Step 41: Electric upsetting preheating stage: the cylindrical bar is powered on for preheating, and the anvil of the electric upsetting device is preheated by heat radiation from the cylindrical bar. In this stage, the upsetting cylinder pressure of the electric upsetting device is set to 5-10 kN, the displacement is 0 mm, and the current is 2000-5000 A. The preheating temperature of the heating zone where the cylindrical bar portion between the electrode and the anvil of the electric upsetting device is located reaches 200-500°C and is maintained for 2-5 seconds. The anvil is preheated synchronously by heat conduction, and the heating zone where the cylindrical bar portion between the electrode and the anvil of the electric upsetting device is located is the bar heating zone. Step 42: Entering the initial electric heating upsetting stage, i.e., initial deformation, the cylindrical bar is initially preformed by reaching the deformation temperature through the bar heating zone, and the displacement and pressure of the upsetting cylinder and the retreat of the anvil; In the initial electric heating upsetting stage, the heating current and pressure are equivalent to those in the preheating stage, or the difference is within the preset threshold range, and the upsetting cylinder performs two linear displacements in the direction of the anvil in sequence, the total displacement of the two linear displacements is [50, 70] mm, and the displacement of the first linear displacement is less than the displacement of the second linear displacement; the initial electric heating upsetting stage includes two different upsetting pressures, the upsetting pressure in the first section is [11, 15] kN, and the upsetting pressure in the second section is [13, 17] kN; and two different upsetting currents, the first upsetting current is [2700, 3100] A, and the second upsetting current is [2500, 3100] A. The upsetting current is [2900, 3300] A, so as to gradually raise the temperature of the heating zone of the bar to 900-1120℃ to reach the temperature range required for deformation; and by gradually increasing the pressure, the deformation part of the cylindrical bar gradually accelerates the metal aggregation to form a micro-drum shape. As the cylindrical bar begins to upset, the anvil also begins to synchronously accompany the cylindrical bar to upset and retreat at the same time, and during the retreat operation of the anvil, 3-4 displacements are set, and each retreat displacement executes a different retreat speed, so that the garlic-shaped protrusion formed by the cylindrical bar after upsetting is smooth, and the smoothness is sufficient to meet the needs, If it is set to 4 displacements, the retraction speed of the anvil decreases gradually, and the retraction speeds corresponding to the 4 displacements are 1.3mm / s, 1.1mm / s, 0.8mm / s, and 0.6mm / s, respectively. During the 4 displacements of the anvil, the height of the raised part of the intermediate structure is 44mm according to the preset height, and the 4 displacement distances are: [5, 15]mm, [15, 25]mm, [25, 35]mm, [35, 45]mm, respectively. Step 43: Entering the middle upsetting stage, i.e., rapid deformation, by increasing the pressure and current of the upsetting cylinder, the cylindrical bar in the bar heating zone with a slightly drum shape is rapidly deformed into a drum shape; In the middle upsetting stage, the intermediate structural part is sequentially subjected to three linear displacements, the total displacement of the three linear displacements is [100, 140] mm, and the displacement of the first linear displacement is less than the displacement of the second linear displacement and less than the displacement of the third linear displacement; the heating current in the middle upsetting stage is greater than the heating current in the electric upsetting preheating stage, and 3-5 stages of displacement are set accordingly, the heating current increases stage by stage, and the heating current increment in each stage is 150-250A, the forging pressure in the middle upsetting stage is greater than the forging pressure in the initial electric heating upsetting stage, and the forging pressure in 3-5 stages is set accordingly, and is also increased by 0.5-5kN stage by stage, so that the deformation resistance of the cylindrical bar material gradually increases during the rapid deformation process; Step 44: Entering the final upsetting stage, by increasing the upsetting cylinder pressure and current, and gradually slowing down or stopping the anvil retraction speed, the intermediate structure continues to gather and gradually shape; In the final upsetting stage, the displacement of the anvil back is 40-60mm. By adjusting the upsetting displacement, it is ensured that the intermediate structure is placed in the die for forging to meet the blank size requirements; the corresponding current and upsetting pressure are greater than those in the middle upsetting stage, the current increases by 150-250A, and the forging pressure also increases by 0.5-5kN; Step 45: Enter the necking stage, so that the cylindrical bar in the heating zone of the bar is gradually deformed into a garlic shape with a smooth transition from the cylindrical bar, so that the blank head and the rod can be easily forged into place during the segmentation stage. During the necking stage, the displacement of the upsetting cylinder is 5-15mm, the upsetting cylinder pressure in the middle upsetting stage is > the upsetting cylinder pressure in the necking stage > the upsetting cylinder pressure in the initial electric heating upsetting stage, the upsetting current in the middle upsetting stage is > the upsetting current in the necking stage > the upsetting current in the initial electric heating upsetting stage, and the anvil is restarted to retract, with a retraction speed of 1.5-6mm / s, a retraction distance of 5-10mm, and the necking is maintained for 2-6 seconds.

5. The electromagnetic valve seat processing method based on electric heating upsetting according to claim 4 is characterized in that: The magnetic property annealing has an annealing temperature of 850-980°C, an annealing holding time of 2 hours, and water cooling after being taken out of the furnace.

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