Dovetail guide quenching inductor and heat treatment method

Abstract

This invention relates to the field of induction heat treatment for guide rails, specifically to a quenching inductor and heat treatment method for dovetail guide rails. The quenching inductor includes an induction coil with two parallel conductors. Each conductor has a Z-shaped portion adapted to the shape and size of the dovetail guide rail. The upper side of the Z-shaped portion is parallel to the upper surface of the guide rail, and the angle at the lower corner is less than 2° of the guide rail wedge angle. A magnetic conductor is installed at the lower corner of the Z-shaped portion. The dovetail guide rail heat-treated using this invention exhibits a uniform quenching layer and stable product quality.

Description

Technical Field

[0001] This invention relates to the field of induction heat treatment of guide rails, and specifically to a dovetail guide rail quenching inductor and heat treatment method. Background Technology

[0002] Among the core moving components of machine tools, dovetail guideways are widely used in the feeding and positioning systems of various high-precision machine tools due to their advantages such as high guiding accuracy, strong load-bearing capacity, and compact structure. The uniformity and hardness level of the surface hardened layer directly determine the wear resistance, contact stiffness, and long-term motion accuracy of the guideway, which are key factors affecting the service life and machining stability of the entire machine tool.

[0003] The upper side of the dovetail guide is inverted trapezoidal, with concave structures on both sides. The angle at the concave point is called the wedge angle. Due to the geometry of the dovetail guide, the closer the traditional inductor and heat treatment methods are to the wedge angle during the machining of the dovetail guide, the better the heat dissipation conditions and the more the magnetic lines of force are scattered. This results in a slower temperature rise at the wedge angle and a sharp decrease in heating efficiency. This phenomenon is more severe closer to the root of the dovetail guide wedge angle, resulting in poor hardening layer distribution, low hardness, and often poor quenching effect. This not only affects the wear resistance of the dovetail guide but can even seriously affect the overall accuracy of the machine tool. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a quenching inductor and heat treatment method for improving the uniformity of the quenched layer of dovetail guide rails.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: This invention provides a dovetail guide rail quenching inductor, including an inductor coil. The inductor coil has two parallel conductors, and the conductors have a Z-shaped portion adapted to the shape and size of the dovetail guide rail. The upper side of the Z-shaped portion is parallel to the upper end face of the guide rail, and the angle at the lower corner is less than the wedge angle of the guide rail by 2°. A magnetic conductor is installed at the lower corner of the Z-shaped portion.

[0006] This structural design allows the sensing surface of the invention to be close to the wedge-shaped surface of the guide rail during use, effectively reducing the dissipation of magnetic lines of force and improving the heating efficiency of the inductor. In particular, the angle of the Z-shaped lower corner is 2° smaller than the angle of the dovetail guide rail wedge, meaning the distance between the conductor and the sensing surface of the wedge gradually decreases from the outside in. Combined with the effect of the magnetic conductor, this more precisely alters the magnetic field distribution, increases the current density at the root of the wedge, and enhances the heating effect at the wedge-shaped surface of the guide rail.

[0007] Moreover, the present invention is equipped with two parallel conductors, which can preheat one and reheat the other, not only improving heating efficiency, but also resulting in low deformation and a deep hardened layer, thus meeting the wear resistance requirements of the guide rail.

[0008] The induction coil is connected to water pipes at both ends, and a water spray hole is opened on the outer side of a conductor. The water flowing inside the induction coil can both cool the inductor and provide quenching cooling water.

[0009] Furthermore, the magnetic conductor is composed of phosphated silicon steel sheets, each with a thickness of 0.2~0.3mm. Silicon steel sheets are typical soft magnetic alloy materials with extremely high permeability, enabling efficient directional conversion of electrical energy into magnetic field energy. They also possess extremely low coercivity, allowing for easy and reversible magnetization and demagnetization processes, significantly reducing hysteresis losses. Combining the advantages of small size and high efficiency, they effectively improve equipment output power and operating efficiency, reduce unnecessary power consumption and temperature rise, and exhibit excellent durability and stability over long-term operation. The phosphated silicon steel sheets ensure electrical insulation between the sheets. Each sheet, 0.2~0.3mm thick, can be stacked and designed to conform to the complex shape of the workpiece, making them particularly advantageous for use on the wedge-angle sensing surface of dovetail guideways.

[0010] Furthermore, fixing plates are connected to the upper ends of both sides of the conductor, and the fixing plates are connected to the bakelite insulating board by copper screws. The fixing plates provide support for both sides of the induction coil, which helps to maintain the stability of the induction coil, especially ensuring the gap between the induction coil and the guide rail, and ensuring the uniformity of the guide rail structure by performing uniform heat treatment on the guide rail.

[0011] Furthermore, the conductive plate and the fixing plate are 5mm thick pure copper plates. Furthermore, the induction coil is made of a square tube of pure copper, with a thickness of 1.5~2.0mm. Pure copper has extremely high electrical and thermal conductivity, which can minimize Joule heat loss under high-frequency skin effect and support efficient water cooling, ensuring that energy is accurately converted into the workpiece magnetic field rather than the coil self-heating.

[0012] Furthermore, a mica fixing block is provided on the magnetic conductor, and the mica fixing block is bonded between the magnetic conductor and the induction coil with epoxy resin. The mica fixing block is insulating and heat-resistant, and serves to fix the silicon steel sheet magnetic conductor.

[0013] Furthermore, the diameter of the water spray holes is 1.5~1.8mm, the center distance is 2.5mm, and the spray direction forms a 45° angle with the surface of the dovetail guide rail. This arrangement of the water spray holes enables the coolant to be sprayed evenly onto the induction-heated guide rail, achieving a good continuous quenching effect.

[0014] For dovetail guide rails made of HT250 material, this invention provides a heat treatment method using the aforementioned quenching inductor, comprising the following steps: placing the quenching inductor above the dovetail guide rail with a gap of 2-3 mm; continuous induction heating and quenching; wherein the inductor has a voltage of 750V, a frequency of 8kHz, a power of 180kW, a relative movement speed of the inductor coil to the guide rail of 180mm / min, and a cooling water pressure of 0.5MPa. Using the above-mentioned preferred process conditions, it is possible to ensure that the quenching hardness of the dovetail guide rail reaches HRC50 or higher, the quenching depth reaches 3-4 mm, the hardened layer is uniform, and the product quality is stable.

[0015] Furthermore, the present invention also includes an air blowing device, which is disposed on the side of the induction coil away from the water spray hole and arranged with the airflow direction toward the gap between the induction coil and the guide rail. Since both conductors of the present invention are equipped with magnetic conductors, and the temperature at the preheating point is also very high, if the coolant splashes forward onto the preheating point, it will affect the quenching hardness or the uniformity of the quenched structure. Therefore, by introducing compressed gas into the air blowing device to blow backward, the coolant can be prevented from splashing forward, ensuring the uniformity of induction heating and quenching. When an inert gas is introduced, it can also protect the guide rail surface from reacting with oxygen in the air, avoiding oxidation and decarburization of the material, and maintaining the stability of the chemical properties of the guide rail surface material.

[0016] This invention provides a heat treatment method utilizing the aforementioned quenching inductor, comprising the steps of: placing the quenching inductor above a dovetail guide rail with a gap of 1-4 mm; activating an air blowing device; and continuously induction heating and quenching. The inductor power supply has a voltage of 650-850V, a frequency of 6-10kHz, and a power of 150-200kW. The moving speed of the inductor coil relative to the guide rail is 150-200mm / min, and the cooling water pressure used for quenching is 0.4-0.6MPa. Using this heat treatment method, induction heating and quenching are performed simultaneously and continuously, resulting in high heat treatment efficiency. In particular, it increases the quenching temperature at the wedge angle of the dovetail guide rail, leading to more uniform heating of the guide rail and the absence of an oxide layer, thus significantly improving product quality.

[0017] The beneficial effects of this invention are: 1. The conductor is Z-shaped to match the shape of the dovetail guide rail. The angle of the lower corner of the Z-shape is 2° smaller than the wedge angle of the dovetail guide rail. This special design of shape and angle, combined with the effect of the magnetic conductor, improves the magnetic field distribution, increases the current density at the root of the wedge angle, and ensures uniform heating of the guide rail surface. Two parallel conductors allow for preheating of one and reheating of the other, improving heating efficiency and resulting in low deformation and a deep hardened layer, meeting the wear resistance requirements of the guide rail.

[0018] 2. The fixing plate of the present invention provides stable support for the induction coil, which helps to maintain the smooth operation of the induction coil, ensures that the gap between the induction coil and the guide rail remains unchanged during the induction heating process, and ensures that the guide rail receives uniform heat treatment and the uniformity of the guide rail structure.

[0019] 3. The process conditions adopted for dovetail guide rails made of HT250 material are as follows: preheating and reheating are carried out continuously, as are induction heating and quenching. The heat treatment efficiency is high, which can ensure that the quenching hardness of the dovetail guide rail reaches HRC50 or above, the quenching depth reaches 3~4mm, the hardened layer is uniform, the process is controllable, and the product quality is stable.

[0020] 4. Since both conductors of this invention are equipped with magnetic conductors, and the preheating temperature is also very high, if the coolant splashes forward onto the preheating area, it will affect the quenching hardness or the uniformity of the quenched structure. Therefore, by introducing compressed gas into the blowing device to blow backward, the coolant can be prevented from splashing forward, ensuring the uniformity of induction heating and quenching effects. When inert gas is introduced, it can also protect the guide rail surface from reacting with oxygen in the air, avoiding oxidation and decarburization of the material, and maintaining the stability of the chemical properties of the guide rail surface material. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 yes Figure 1 A top-view structural diagram, excluding the bakelite insulation board and mica fixing block; Figure 3 yes Figure 2 A schematic diagram of the structure at point AA; Figure 4 This is a schematic diagram showing the location of the air blowing device; In the diagram: 1. Dovetail rail; 2. Induction coil; 20. Conductor; 21. Water spray hole; 3. Magnetic conductor; 4. Conductive plate; 5. Fixing plate; 6. Bakelite insulation board; 7. Fastening screw; 8. Mica fixing block; 9. Water pipe; 10. Air blowing device; α. Angle of the lower corner; β. Angle of the wedge angle. Detailed Implementation

[0022] The principles and features of the present invention are described below with reference to the accompanying drawings. The embodiments described are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0023] Example 1: like Figures 1 to 3As shown, this embodiment is a dovetail guide rail 1 quenching inductor, which includes an inductor coil 2 connected to a conductive plate 4. The inductor coil 2 is made of a square tube of pure copper with a thickness of 1.5~2.0mm. The inductor coil 2 is generally U-shaped and has two parallel conductors 20. Since the left and right sides of the dovetail guide rail 1 are concave to form wedge angles, this embodiment designs the conductors 20 to have a Z-shaped portion that matches the shape and size of the dovetail guide rail 1. Furthermore, the upper side of the Z-shaped portion is designed to be parallel to the upper end face of the guide rail, and the angle at the lower corner is less than the wedge angle of the guide rail by 2°, for example... Figure 1 The α value is 53° and the β value is 55°.

[0024] In this way, the distance between conductor 20 and the sensing surface of the wedge angle gradually decreases from the outside to the inside, and conductor 20 is closer to the root of the wedge angle. Combined with the magnetic conductor 3 installed at the lower corner of the Z-shaped part of conductor 20, the magnetic field distribution is changed more precisely, the current density at the root of the wedge angle is increased, and the heating effect on the wedge angle of the guide rail is enhanced.

[0025] The present invention provides as follows Figure 2 The two parallel conductors 20 shown enable one to preheat and the other to reheat, which not only improves heating efficiency but also results in low deformation and a deep hardened layer, meeting the wear resistance requirements of the guide rail. In this embodiment, the guide rail is simultaneously induction heated and quenched; therefore, water pipes 9 are connected to both ends of the induction coil 2, such as... Figure 3 As shown, a water spray hole 21 is opened on the outside of the conductor 20 used for reheating. Cooling water is introduced into the induction coil 2 and sprayed out from the water spray hole 21 to quench the high-temperature track. The water flowing inside the induction coil 2 can both cool the inductor and provide cooling water for quenching. In use, preheating, reheating, and quenching are carried out simultaneously and continuously, resulting in high heat treatment efficiency.

[0026] Specifically, in this example, the diameter of the water spray holes 21 is 1.5~1.8mm, the center distance is 2.5mm, and the water spray direction forms a 45° angle with the surface of the dovetail guide rail 1. Those skilled in the art can select appropriate water pressure and temperature, such as 0.5Mpa water pressure and 20~40℃ water temperature, to obtain a suitable cooling rate and achieve the expected quenching effect.

[0027] In this preferred embodiment, the magnetic conductor 3 is a phosphated silicon steel sheet magnetic conductor 3, with a single sheet thickness of 0.2~0.3mm. The silicon steel sheet magnetic conductor 3 is a typical soft magnetic alloy material with extremely high permeability, enabling efficient directional conversion of electrical energy into magnetic field energy. It also possesses extremely low coercivity, making magnetization and demagnetization processes easily reversible and significantly reducing hysteresis losses. Furthermore, it boasts significant advantages in small size and high efficiency, effectively improving equipment output power and operating efficiency, reducing unnecessary power consumption and temperature rise, and exhibiting excellent durability and stability over long-term operation. The phosphated silicon steel sheet magnetic conductor 3 ensures electrical insulation between sheets. Each sheet is 0.2~0.3mm thick and can be stacked for use. It can be designed to conform to the complex shape of the workpiece, and is particularly advantageous for use on dovetail wedge-shaped sensing surfaces. Further, a mica fixing block 8 is provided on the magnetic conductor 3, which is bonded between the magnetic conductor 3 and the induction coil 2 using epoxy resin. The mica fixing block 8 is insulated and heat resistant, and serves to fix the silicon steel sheet magnetic conductor 3.

[0028] To maintain the stability of the induction coil 2, fixing plates 5 are further connected to the upper ends of both sides of the conductor 20. The fixing plates 5 are connected to the bakelite insulating board 6 by copper screws. The fixing plates 5 provide support for both sides of the induction coil 2, ensure the gap between the induction coil 2 and the guide rail, and perform uniform heat treatment on the guide rail to ensure the uniformity of the guide rail structure. In this embodiment, the conductive plate 4 and the fixing plate 5 are 5mm thick pure copper plates.

[0029] The method of using the quenching inductor in this embodiment includes the following steps: placing the quenching inductor above the dovetail guide rail 1, with a gap of 1-4 mm; continuously induction heating and quenching; the voltage of the inductor power supply is 650-850V, the frequency is 6-10kHz, and the power is 150-200kW; the moving speed of the induction coil 2 relative to the guide rail is 150-200mm / min; and the cooling water pressure used for quenching is 0.4-0.6MPa. Those skilled in the art can select specific process parameters according to the specific specifications of the dovetail guide rail 1 and product quality standards.

[0030] For the dovetail guide rail 1 made of HT250 material, this embodiment provides a specific heat treatment method as follows: 1. Position the dovetail guide rail 1 workpiece on the operating table; 2. Place the quenching inductor above the dovetail guide rail 1. The upper side of the Z-shaped part is parallel to the upper end face of the guide rail and the gap is 2mm. The angle between the conductor 20 at the lower corner and the adjacent sensing surface is 1°, and the vertical distance between the top of the lower corner and the sensing surface is 2mm. 3. Supply cooling water, turn on the power supply of induction coil 2, and begin continuous induction heating and quenching of the workpiece. The voltage of the inductor is 750V, the frequency is 8KHZ, the power is 180KW, the moving speed of induction coil 2 relative to the guide rail is 180mm / min, the cooling water pressure used for quenching is 0.5Mpa, and the water temperature is 30℃.

[0031] Using this heat treatment method, induction heating and quenching are carried out simultaneously and continuously, resulting in high heat treatment efficiency. In particular, this invention increases the quenching temperature at the wedge angle of the dovetail guide rail, resulting in more uniform heating of the guide rail, a more uniform hardened layer, and stable product quality.

[0032] Example 2: The aforementioned dovetail guide rail 1, made of HT250 material, is subjected to heat treatment. The difference between this embodiment and Embodiment 1 is that, during heat treatment, the upper side of the Z-shaped part is parallel to the upper end surface of the guide rail with a gap of 3mm, and the vertical distance between the top of the lower corner and the sensing surface is 3mm.

[0033] Comparative example: The aforementioned dovetail guide rail 1, made of HT250 material, was heat-treated. The difference between this comparative example and Example 1 lies in the structure of the Z-shaped portion of the induction coil 2. In this comparative example, the Z-shaped portion is completely parallel to the surface of the dovetail guide rail 1, and the gap between the Z-shaped portion and the guide rail surface is 2mm during use.

[0034] Example 3: like Figure 4 As shown, this embodiment, based on embodiment 1, includes an air blowing device 10. The air blowing device 10 is positioned on the side of the induction coil 2 away from the water spray hole 21 and is arranged such that the airflow direction is toward the gap between the induction coil 2 and the dovetail guide rail 1.

[0035] Since both conductors 20 of this invention are equipped with magnetic conductors 3, and the temperature at the preheating point is also very high, if the coolant splashes forward onto the preheating point, it will affect the quenching hardness or the uniformity of the quenched structure. Therefore, by introducing compressed gas into the air blowing device 10 to blow backward, the coolant can be prevented from splashing forward, ensuring the uniformity of induction heating and quenching. When inert gas is introduced, it can also protect the guide rail surface from reacting with oxygen in the air, avoiding oxidation and decarburization of the material, and maintaining the stability of the chemical properties of the guide rail surface.

[0036] Optionally, the air blowing device 10 is generally L-shaped to match the shape of the wedge angle of the dovetail guide rail 1. The main body of the air blowing device is an air knife, the air blowing slit gap is 0.05~0.1mm, and the air inlet pressure is 0.4~0.7Mpa.

[0037] The blowing device 10 can be installed on the support structure of the induction coil to achieve synchronous movement with the induction coil 2, ensuring stable blowing throughout the entire heat treatment process.

[0038] This embodiment further provides a specific heat treatment implementation method. The difference between this method and Embodiment 1 is that the blowing device 10 is started before continuous induction heating and quenching. Nitrogen gas is introduced into the blowing device 10, the blowing slit gap is 0.1 mm, and the gas supply pressure is 0.5 MPa.

[0039] Performance testing: The testing items and standards are as follows: Surface hardness testing, performed in accordance with GB / T230.1-2018; Effective hardened layer depth testing, performed in accordance with GB / T 5617-2005; Hardness uniformity testing, performed in accordance with GB / T 17394.1-2014; The test results are shown in Table 1.

[0040]

[0041] The test results show that the dovetail guide rail 1 heat-treated by the present invention has a uniform quenching layer and stable product quality.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are within the scope of protection of the claims of the present invention.

Claims

1. A dovetail guide rail quenching inductor, characterized in that, The induction coil (2) has two parallel conductors (20). The conductors (20) have a Z-shaped part that matches the shape and size of the dovetail guide rail (1). The upper side of the Z-shaped part is parallel to the upper end face of the guide rail, and the angle at the lower corner is less than the wedge angle of the guide rail by 2°. A magnetic conductor (3) is installed at the lower corner of the Z-shaped part. The two ends of the induction coil (2) are connected to water pipes (9), and a water spray hole (21) is opened on the outer side of one conductor (20).

2. The dovetail guide rail quenching inductor according to claim 1, characterized in that, The magnetic conductor (3) is composed of silicon steel sheet magnetic conductors (3) that have been phosphated, and the thickness of a single magnetic conductor (3) is 0.2~0.3mm.

3. The dovetail guide rail quenching inductor according to claim 2, characterized in that, The upper ends of both sides of the conductor (20) are respectively connected to fixing plates (5), and the fixing plates (5) are connected to the bakelite insulating board (6) by copper screws.

4. A dovetail guide rail quenching inductor according to claim 3, characterized in that, The conductive plate (4) and the fixing plate (5) are 5mm thick pure copper plates.

5. A dovetail guide rail quenching inductor according to claim 1, characterized in that, The induction coil (2) is made of a square tube of pure copper with a thickness of 1.5~2.0mm.

6. The dovetail guide rail quenching inductor according to claim 1, characterized in that, A mica fixing block (8) is provided on the magnetic conductor (3), and the mica fixing block (8) is bonded between the magnetic conductor (3) and the induction coil (2) by epoxy resin.

7. A dovetail guide rail quenching inductor according to claim 1, characterized in that, The diameter of the water spray hole (21) is 1.5~1.8mm, the center distance is 2.5mm, and the water spray direction is at a 45° angle to the surface of the dovetail guide rail (1).

8. A dovetail guide rail quenching inductor according to claim 1, characterized in that, It also includes an air blowing device (10), which is located on the side of the induction coil (2) away from the water spray hole (21) and arranged with the airflow direction toward the gap between the induction coil (2) and the dovetail guide rail (1).

9. A heat treatment method, employing the quenching inductor according to any one of claims 1 to 7, characterized in that, Including the following steps: Place the quenching inductor above the dovetail guide rail, with a gap of 2-3 mm between them; Continuous induction heating and quenching are performed. The voltage of the inductor is 750V, the frequency is 8KHZ, the power is 180KW, the moving speed of the induction coil relative to the guide rail is 180mm / min, and the cooling water pressure used for quenching is 0.5Mpa.

10. A heat treatment method using the quenching inductor as described in claim 8, characterized in that, Including the following steps: Place the quenching inductor above the dovetail guide rail, with a gap of 1~4mm between them; Start the air blowing device; Continuous induction heating and quenching are performed. The voltage of the inductor power supply is 650~850V, the frequency is 6~10KHZ, the power is 150~200KW, the moving speed of the induction coil relative to the guide rail is 150~200mm / min, and the cooling water pressure used for quenching is 0.4~0.6Mpa.

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