CN118186184A - Induction heat treatment device, quenching system and induction heat treatment method - Google Patents

Abstract

The present disclosure relates to an induction heat treatment apparatus, a quenching system, and an induction heat treatment method, wherein the induction heat treatment apparatus is used for induction heating a workpiece (101), the induction heat treatment apparatus includes an inductor assembly (1), the inductor assembly (1) is configured to surround the workpiece (101) and relatively move with the workpiece (101) along a preset path to perform scanning, and the inductor assembly (1) includes: a first induction frame (11) connected to a power source; the second induction frame (12) is arranged at intervals along the first direction (x) with the first induction frame (11), and the second induction frame (12) is electrically connected with the first induction frame (11); and a third induction frame (13), the third induction frame (13) being connected in parallel with the second induction frame (12); wherein the current directions in the first induction frame (11), the second induction frame (12) and the third induction frame (13) are the same.

Description

Induction heat treatment device, quenching system and induction heat treatment method

Technical Field

The disclosure relates to the technical field of heat treatment, in particular to an induction heat treatment device, a quenching system and an induction heat treatment method.

Background

The induction heat treatment is an efficient and energy-saving heat treatment process, and in order to improve the wear resistance of the surface of a workpiece, induction quenching treatment is needed to be carried out on the surface of the workpiece, and the wear resistance and the service performance of the surface of the workpiece are improved by obtaining a hardening layer and surface hardness which meet technical requirements. The inductor is connected with the high-frequency power supply and the medium-frequency power supply through the transformer, is an important component for electromagnetic induction heating of the workpiece, has higher manufacturability requirement, and directly influences the induction heat treatment efficiency and the product quality due to the structural design advantages and disadvantages.

When the inductor is heated to the end position of the workpiece, the electromagnetic field is distorted, the end face cuts alternating magnetic induction lines, the temperature rising speed of the end chamfer position is high, the end is difficult to uniformly heat, the problem that the depth of a hardening layer of the end hardening layer is uneven such as deep or shallow is often caused, and the phenomenon is also called a sharp angle effect.

Disclosure of Invention

The embodiment of the disclosure provides an induction heat treatment device, a quenching system and an induction heat treatment method, which can improve the uniformity of induction heat treatment.

According to a first aspect of the present disclosure, there is provided an induction heat treatment apparatus for induction heating a workpiece, the induction heat treatment apparatus comprising an inductor assembly configured to surround the workpiece and relatively move with the workpiece along a preset path to perform scanning, the inductor assembly comprising:

The first induction frame is connected to a power supply;

The second induction frame is arranged at intervals along the first direction with the first induction frame and is arranged at the first side of the first induction frame, and the second induction frame is electrically connected with the first induction frame; and

The third induction frames are arranged on the second side face of the first induction frame at intervals along the first direction, are electrically connected to the first induction frame, and are connected with the second induction frame in parallel;

The current directions in the first induction frame, the second induction frame and the third induction frame are the same.

In some embodiments, the first sensing frame, the second sensing frame, and the third sensing frame are all perpendicular to the first direction.

In some embodiments, the central axes of the first, second, and third sensing frames coincide.

In some embodiments, the induction heat treatment apparatus further comprises:

The first connecting beam is used for connecting the first induction frame to a power supply, and extends along a second direction which is perpendicular to the first direction; and

And the second connecting beam is used for connecting the second induction frame and the third induction frame to a power supply, at least part of the length section of the second connecting beam extends along the second direction, the second connecting beam and the first connecting beam are arranged at intervals along the third direction, and the third direction is perpendicular to the first direction and the second direction.

In some embodiments, the first sensing frame, the second sensing frame, the third sensing frame, the first connecting beam and the second connecting beam are hollow structures, and the induction heat treatment apparatus further comprises:

Two cooling water joints are respectively arranged at one ends of the first connecting beam and the second connecting beam, which are respectively far away from the inductor assembly, wherein one cooling water joint is used for flowing in cooling water, and the other cooling water joint is used for flowing out cooling water.

In some embodiments, the induction heat treatment apparatus further comprises:

The bottom plate is perpendicular to the second direction, is connected to one end, far away from the inductor assembly, of the first connecting beam and the second connecting beam, and is connected to a power supply; and

And the insulating plate is connected to the bottom plate and perpendicular to the third direction, and is arranged between the first connecting beam and the second connecting beam.

In some embodiments, the inductor assembly further comprises:

the first connecting section extends along the second direction and is connected to the first induction frame, and the first connecting section and the first connecting beam are arranged at intervals along the third direction;

The two second connecting sections extend along the second direction, are connected to the second induction frame and are arranged at intervals along the third direction; and

The two third connecting sections extend along the second direction, the two third connecting sections are connected to the third induction frame, and the two third connecting sections are arranged at intervals along the third direction.

In some embodiments, the inductor assembly further comprises:

A first transition section connected between the first connection section and a second connection section adjacent to the first connection beam, the first transition section extending in a first direction; and/or

The second transition section is connected between the first connecting section and the third connecting section close to the first connecting beam and extends along the first direction; and/or

The third transition section is connected between the second connecting section and the second connecting section far away from the first connecting beam and extends along the first direction; and/or

And the fourth transition section is connected between the third connecting section and the second connecting section far away from the first connecting beam and extends along the first direction.

In some embodiments, the inductor assembly further comprises:

And the magnetizer is arranged on at least one of the first induction frame, the second induction frame and the third induction frame.

In some embodiments, the magnetic conductor comprises a plurality of silicon steel sheets, the plurality of silicon steel sheets are adjacently arranged along the circumferential direction of the inductor assembly, and the notch of the silicon steel sheets is positioned on one side of the inductor assembly facing the workpiece.

In some embodiments, the thickness of the sheet of silicon steel is adapted to the depth of the hardened layer and/or the frequency of induction heating.

In some embodiments of the present invention, in some embodiments,

The first distance between the first induction frame and the second induction frame is adapted to the depth of the hardening layer of the end part of the workpiece; and/or

The second distance between the first and third sensing frames is adapted to the depth of hardened layer at the end of the workpiece.

In some embodiments, the first distance is equal to the second distance.

In some embodiments, the first sensing frame, the second sensing frame, and the third sensing frame are all annular.

According to a second aspect of the present disclosure, there is provided a quenching system comprising:

The induction heat treatment apparatus of the above embodiment; and

And the water spraying device is used for spraying cooling water to the induction-heated workpiece.

According to a third aspect of the present disclosure, there is provided an induction heating method of an induction heat treatment apparatus based on the above embodiment, comprising:

rotating the workpiece around a preset central line;

Moving the sensor assembly to a first end of the workpiece;

moving the sensor assembly along a predetermined path to be flush with the first end of the workpiece;

the sensor assembly is moved along a predetermined path away from the second end of the workpiece.

In some embodiments, during movement of the sensor assembly, the second sensor frame is flush with the workpiece before the first sensor frame, moving the sensor assembly along the predetermined path to be flush with the first end of the workpiece comprises:

During the process that the second induction frame is flush with the first end of the workpiece, the inductor component does not heat the workpiece;

In the process that the first induction frame is flush with the first end of the workpiece, only the first induction frame heats the workpiece;

In the process that the third induction frame is flush with the first end of the workpiece, the first induction frame is used for heating the workpiece, the heating power of the second induction frame and the heating power of the third induction frame are gradually increased, and the maximum heating power of the second induction frame and the maximum heating power of the third induction frame are smaller than the heating power of the first induction frame.

In some embodiments, moving the sensor assembly along the predetermined path away from the second end of the workpiece during movement of the sensor assembly, the second sensor frame being moved away from the workpiece before the first sensor frame comprises:

gradually reducing the heating power of the third induction frame during the process that the second induction frame leaves the second end of the workpiece;

After the second induction frame leaves the second end of the workpiece, only the first induction frame heats the workpiece;

after the first sensing frame is moved away from the second end of the workpiece, the sensor assembly is stopped from heating.

Based on the technical scheme, the induction heat treatment device disclosed by the embodiment of the disclosure is provided with the second induction frame and the third induction frame in parallel, so that the heating power of the inductor assembly can be automatically reduced in the moving process of the end part of the workpiece, the over-fast temperature rise of the end part caused by the sharp angle effect is further compensated, the uniformity of induction heat treatment is improved, and the depth of the end part hardening layer of the workpiece is uniform and consistent with that of the main body part hardening layer; the inductor assembly can realize the uniform heating effect on the workpiece through single scanning, and the efficiency of induction heat treatment can be improved without reciprocating adjustment.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate and explain the present disclosure, and together with the description serve to explain the present disclosure. In the drawings:

fig. 1 is a schematic structural view of some embodiments of an induction heat treatment apparatus of the present disclosure.

Fig. 2 is a side view of some embodiments of an induction heat treatment apparatus of the present disclosure.

Fig. 3 is a schematic structural view of some embodiments of the inductor assembly of the present disclosure for induction heating of a workpiece.

Fig. 4a-g are schematic diagrams of workpiece surface heating power density profiles at various stages in a scanning induction heating process of an inductor assembly of the present disclosure.

Description of the reference numerals

1. An inductor assembly; 2. a first connecting beam; 3. a second connection beam; 4. a cooling water joint; 5. a bottom plate; 6. an insulating plate; 7. a fixing member; 11. a first sensing frame; 111. a first connection section; 12. a second induction frame; 122. a second connection section; 13. a third sensing frame; 133. a third connecting section; 110. a first transition section; 120. a second transition section; 130. a third transition section; 140. a fourth transition section; 101. a workpiece; x, a first direction; y, the second direction; z, third direction.

Detailed Description

The present disclosure is described in detail below. In the following paragraphs, the different aspects of the embodiments are defined in more detail. Aspects so defined may be combined with any other aspect or aspects unless explicitly stated to be non-combinable. In particular, any feature or features may be combined with one or more other features may be desired and advantageous.

The terms "first," "second," and the like in this disclosure are merely for convenience of description to distinguish between different constituent components having the same name, and do not denote a sequential or primary or secondary relationship.

In the description of the present disclosure, it should be understood that the terms "upper," "lower," "inner" or "outer," etc. indicate orientations or positional relationships that are defined based on the sensor assembly, the sensing frame, the workpiece, etc. are merely used for convenience in describing the present disclosure, and do not indicate or imply that the devices being referred to must have a particular orientation, be configured and operated in a particular orientation, and thus should not be construed as limiting the scope of the present disclosure.

The inventor finds that in the research process, in order to control the fluctuation problem of the end hardening layer, aiming at the product with shallower requirements on the hardening layer, the influence of an alternating magnetic field on the end is reduced by a single-coil inductor structure or a shielding magnetizer and other modes in the industry, and the problem of nonuniform end hardening layer is relieved; for products with deeper requirements on the hardening layer, a sensor structure with a plurality of effective rings is generally adopted, and the uneven heating of the end part is compensated by adjusting the heating position, controlling the heating residence time of the end part and other heat treatment modes. The end tip effect inherent in induction heating cannot be avoided by the above measures, and the improvement effect on the problem of uneven heating is not ideal, for example, the end heating is possibly insufficient due to manual intervention. Particularly, the workpiece with the groove structure near the end part is more likely to generate local stress concentration problem because of uneven end part hardening layer, so that cracking is generated along the groove direction.

To solve the problem of uneven end heating caused by the sharp angle effect, first, the present disclosure proposes an induction heat treatment apparatus for induction heating a workpiece 101, as shown in fig. 1 to 4g, the induction heat treatment apparatus including an inductor assembly 1, the inductor assembly 1 being configured to surround the workpiece 101 and relatively move with the workpiece 101 along a preset path to scan, the inductor assembly 1 including:

a first induction frame 11 connected to a power source;

the second induction frame 12 is arranged at intervals along the first direction x with the first induction frame 11 and is arranged at the first side of the first induction frame 11, and the second induction frame 12 is electrically connected with the first induction frame 11; and

The third induction frames 13 are arranged on the second side surface of the first induction frame 11 at intervals along the first direction x, the third induction frames 13 are electrically connected to the first induction frame 11, and the third induction frames 13 are connected with the second induction frame 12 in parallel;

Wherein the current directions in the first sensing frame 11, the second sensing frame 12 and the third sensing frame 13 are the same.

Specifically, the second sensing frame 12 and the third sensing frame 13 are connected in parallel and then connected in series to the first sensing frame 11. Specifically, the first induction frame 11 is divided into upper and lower winding loops after being wound one turn. Specifically, the power supply supplies alternating current, and the current is returned to the power supply through the upper and lower second sensing frames 12 and 13 after passing through the middle first sensing frame 11, or the current is returned to the power supply through the middle first sensing frame 11 after passing through the upper and lower second sensing frames 12 and 13. Specifically, the third sensing frame 13 is spaced from the first sensing frame 11 along the first direction x and is disposed at the second side of the first sensing frame 11.

Specifically, during induction heating, the workpiece 101 rotates along a preset center line, the inductor assembly 1 does not rotate, and the inductor assembly 1 moves along a preset path, so that the inductor assembly 1 and the workpiece 101 relatively move, and uniform heating of the entire surface of the workpiece 101 by the inductor assembly 1 is realized.

Specifically, when the inductor assembly 1 is heated to the end position of the workpiece 101, the second or third induction frames 12, 13 are exposed to the end surface, wherein the resistance in one exposed induction frame is the smallest, and the current preferentially passes through the induction frame, so that no current passes through the other unexposed induction frame, and the eddy current depth at the workpiece level with the unexposed inductor assembly 1 is reduced, thereby reducing the overall induction heating power when the inductor assembly 1 is heated to the end of the workpiece 101.

Specifically, when the inductor assembly 1 is heated to the end position of the workpiece 101, the end surface area heating profile, and thus the end induction heat treatment hardened layer profile shape, can be controlled due to the difference in current carrying density of the three induction frame conductive portions. Specifically, the induction-heated workpiece 101 is rapidly cooled to form a hardened layer.

Specifically, when the inductor assembly 1 is heated to the non-end position of the workpiece 101, if the resistances of the second induction frame 12 and the third induction frame 13 are the same, the three induction frames all wrap the workpiece 101, the middle first induction frame 11 is the main magnetic field generating area, the induction heating power is the highest, and the current value of the upper and lower side branch induction frames is 1/2 of that of the first induction frame. Specifically, the effective wrapping area of the upper, middle and lower three induction frames is increased compared with that of a conventional inductor structure, so that the surface temperature of the workpiece 101 is controlled, and an overheat metallographic structure caused by high heating temperature is not easy to occur.

Specifically, the induction heat treatment device adopts a plurality of induction frames to surround the workpiece 101, so that the inductor assembly 1 can cover all parts of the workpiece 101 in the heating process, the end overheating phenomenon possibly caused by the traditional inductor is reduced, particularly in the complex outline or edge area of the workpiece, the uniformity of heat treatment can be greatly improved, and the consistency of the depth of a hardening layer at the end part of the workpiece is improved.

Specifically, the inductor assembly 1 can adapt to workpieces of different sizes and shapes by moving along a preset path, and can accurately control the heating area and the vortex depth by adjusting the moving path and the speed, so that diversified heat treatment requirements are met, and the universality and the flexibility of the equipment are improved.

Specifically, the current directions of the three induction frames are consistent, so that the distribution of an electromagnetic field can be optimized, the energy loss is reduced, and the electromagnetic induction heating efficiency is enhanced.

Alternatively, the induction heat treatment device is suitable for workpieces 101 with the whole surfaces of shafts, planes, inner holes or special-shaped thin walls and the like needing induction treatment. Alternatively, the preset path may be a straight line, a curve, or the like. Alternatively, the second sensing frame 12 may be flush with the workpiece 101 before the first sensing frame 11, or the third sensing frame 13 may be flush with the workpiece 101 before the first sensing frame 11.

Alternatively, one or more of the first, second and third sensing frames 11, 12 and 13 may be provided. Alternatively, the resistances of the first, second and third sensing frames 11, 12 and 13 may be the same or different. Alternatively, the first, second and third induction frames 11, 12 and 13 may each be made of rectangular copper pipe welded, such as hollow copper pipe, etc., and the induction frames may also include one or more coils. Alternatively, the first, second and third sensing frames 11, 12 and 13 may have a ring shape, a rectangular shape or other regular polygonal shapes.

Alternatively, the planes of the three sensing frames may be parallel or may form a certain included angle, and the planes of the three sensing frames may be perpendicular to the first direction x or may form a certain included angle with the first direction x. Alternatively, the central axes of the three sensing frames may or may not coincide.

The induction heat treatment device of the embodiment is arranged in parallel through the second induction frame 12 and the third induction frame 13, so that the heating power of the inductor assembly 1 can be automatically reduced in the moving process of the end part of the workpiece 101, the over-fast temperature rise of the end part caused by the sharp angle effect is further compensated, the uniformity of induction heat treatment is improved, and the depth of the end part hardening layer of the workpiece 101 is uniform and consistent with the depth of the main part hardening layer; the inductor assembly 1 can realize uniform heating effect on the workpiece 101 by single scanning, and the efficiency of induction heat treatment can be improved without reciprocating adjustment.

In some embodiments, the working principle of the inductor assembly 1 is further elucidated in connection with fig. 4a to 4g, in which the black areas represent the eddy current depth or the heating power density, and the thin solid lines represent the depth of the hardened layer. Specifically, the second sensing frame 12, the first sensing frame 11, and the third sensing frame 13 of this embodiment are arranged from top to bottom, the sensor assembly 1 moves from bottom to top, the workpiece 101 rotates around the preset center line, and the resistance values of the second sensing frame 12 and the third sensing frame 13 are equal.

In the first stage, as shown in fig. 4a, during the movement of the inductor assembly 1, the second inductor frame 12 is gradually flush with the first end of the workpiece 101, the first inductor frame 11 and the third inductor frame 13 are located outside the end face of the workpiece 101, no workpiece is located in the third inductor frame 13, so that the resistance in the third inductor frame 13 is zero, the current passes through the first inductor frame 11 and then directly returns to the power supply through the third inductor frame 13, so that no current flows in the second inductor frame 12 and does not heat the workpiece 101, and therefore, during the process that the second inductor frame 12 is gradually flush with the first end of the workpiece 101, the inductor assembly 1 does not heat the workpiece 101.

In the second stage, as shown in fig. a to 4b, in the process that the first induction frame 11 is flush with the first end of the workpiece 101, the third induction frame 13 is located at the outer side of the end face of the workpiece 101, no workpiece 101 is located in the third induction frame 13, so that the resistance in the third induction frame 13 is zero, the current passes through the first induction frame 11 and directly returns to the power supply through the third induction frame 13, so that no current flows in the second induction frame 12, the workpiece 101 is not heated, and at this time, the workpiece 101 is located in the first induction frame 11, so that only the flush part of the first induction frame 11 heats the workpiece 101.

In a third phase, as shown in fig. 4b to 4c, during the process of the third induction frame 13 being flush with the first end of the workpiece 101, the third induction frame 13 passes the end surface of the workpiece 101 until completely surrounding the end of the workpiece 101, during which the current of the second induction frame 12 and the third induction frame 13 gradually increases from zero to half of the first induction frame 11, and the heating power of the second induction frame 12 and the third induction frame 13 gradually increases from zero to about one fourth of the first induction frame 11.

In the fourth stage, as shown in fig. 4c to 4e, the inductor assembly 1 is entirely flush with the workpiece 101, the three induction frames all wrap the workpiece 101, the current intensity in the first induction frame 11 is the largest, which is the main magnetic field generating area, the induction heating power is the highest, the current intensity in the second induction frame 12 and the third induction frame 13 is half of the first induction frame 11, the heating power is about one fourth of the first induction frame 11, and the inductor assembly 1 provides the maximum induction heating power in the fourth stage.

In the fifth stage, as shown in fig. 4e to 4f, during the process of the second induction frame 12 leaving the second end of the workpiece 101, the resistance of the second induction frame 12 gradually decreases to zero, the heating power of the second induction frame 12 and the third induction frame 13 gradually decreases to zero, and the first induction frame 11 has not yet left the second end of the workpiece 101, so the first induction frame 11 is heated normally.

In the sixth stage, as shown in fig. 4f to 4g, after the second induction frame 12 leaves the second end of the workpiece 101, the second induction frame 12 is located outside the end face of the workpiece 101, and no workpiece 101 is located in the second induction frame 12, so that the resistance in the second induction frame 12 is zero, and the current passes through the first induction frame 11 and returns to the power supply through the second induction frame 12 directly, so that no current flows in the third induction frame 13, the workpiece 101 is not heated, and only the flush part of the first induction frame 11 heats the workpiece 101.

In the seventh stage, as shown in fig. 4g, after the first induction frame 11 leaves the second end of the workpiece 101, the third induction frame 13 is gradually separated from the workpiece 101 from being level with the workpiece 101, at this time, the first induction frame 11 and the second induction frame 12 are located outside the end face of the workpiece 101, no workpiece is located in the second induction frame 12, so the resistance in the second induction frame 12 is zero, and the current passes through the first induction frame 11 and returns to the power supply through the second induction frame 12 directly, so no current flows in the third induction frame 13 and does not heat the workpiece 101, and therefore, after the first induction frame 11 leaves the second end of the workpiece 101, the inductor assembly 1 stops heating the workpiece 101.

In this embodiment, the heating power of the inductor assembly 1 in the first stage to the third stage to the first end of the workpiece 101 is gradually increased, the inductor assembly 1 in the fourth stage heats the non-end region of the workpiece, the heating power is kept unchanged, the heating power of the inductor assembly 1 in the fifth stage to the seventh stage to the second end of the workpiece 101 is gradually reduced, and the low heating power of the inductor assembly 1 in the first end and the second end of the workpiece 101 can compensate for the rapid temperature rise of the end portion caused by the sharp angle effect, so that the depth of the end portion hardening layer of the workpiece 101 is uniform with the depth of the main body portion hardening layer.

In some embodiments, as shown in fig. 1 to 4g, the planes of the first sensing frame 11, the second sensing frame 12 and the third sensing frame 13 are all perpendicular to the first direction x.

Specifically, the planes of the three induction frames are perpendicular to the first direction x, so that each position of the workpiece 101 can enter the inductor assembly 1 in a tangential direction all the time. Alternatively, the central axes of the first, second and third sensing frames 11, 12 and 13 may or may not coincide.

The planes of the three induction frames are perpendicular to the first direction x, so that the heating uniformity of the inductor assembly 1 can be improved; the alternating magnetic fields in the induction frame can be cut along the same direction all the time by the workpiece 101, the uniform heat treatment effect of the whole workpiece 101 is ensured, and the quality and the efficiency of heat treatment are improved.

In some embodiments, as shown in fig. 1-4 g, the central axes of the first sensing frame 11, the second sensing frame 12, and the third sensing frame 13 coincide.

Specifically, the first direction x is the axial direction of the inductor assembly 1.

The central axes of the three induction frames are coincident, so that the heating uniformity of the inductor assembly 1 can be further improved; the alternating magnetic fields in the induction frame can be cut by the workpiece 101 along the same direction all the time, and the workpiece 101 is always positioned in the geometric center of the inductor assembly 1, so that the uniformity and the efficiency of heat treatment can be improved.

In some embodiments, as shown in fig. 1 and 2, the induction heat treatment apparatus further comprises:

a first connection beam 2 for connecting the first sensing frame 11 to a power source, the first connection beam 2 extending along a second direction y, the second direction y being perpendicular to the first direction x; and

And a second connection beam 3 for connecting the second sensing frame 12 and the third sensing frame 13 to a power source, at least a portion of the length of the second connection beam 3 extending in a second direction y, the second connection beam 3 and the first connection beam 2 being spaced apart in a third direction z, the third direction z being perpendicular to the first direction x and the second direction y.

Specifically, the inductor assembly 1 is connected to the power supply through the first connecting beam 2 and the second connecting beam 3, so that electric wiring can be simplified, current distribution is safer and more orderly, and meanwhile disassembly, maintenance and troubleshooting of the induction frame are facilitated. Specifically, the first and second connection beams 2 and 3 are disposed at intervals along the third direction z, and short-circuiting of the induction heat treatment apparatus can be avoided. Alternatively, the first connection beam 2 and the second connection beam 3 may be provided with tapered portions or diverging portions according to the connection structure.

According to the embodiment, the space layout of the first connecting beam 2 and the second connecting beam 3 is optimized, so that the stable connection of each induction frame can be ensured, the structural stability of the induction heat treatment device is enhanced, and the short circuit of the induction heat treatment device is avoided; the air circulation can be facilitated, and the heat dissipation is promoted; the compactness of the induction heat treatment device can be improved, and the space utilization rate can be improved.

In some embodiments, as shown in fig. 1 and 2, the first sensing frame 11, the second sensing frame 12, the third sensing frame 13, the first connection beam 2 and the second connection beam 3 are hollow structures, and the induction heat treatment apparatus further includes:

Two cooling water connectors 4 are respectively arranged at one end of the first connecting beam 2 and one end of the second connecting beam 3, which are far away from the inductor assembly 1, wherein one cooling water connector 4 is used for flowing in cooling water, and the other cooling water connector 4 is used for flowing out cooling water.

Specifically, the hollow structure allows cooling water to circulate inside the induction frame and the connecting beam, and the hollow structure and the external cooling water joint are designed to facilitate periodic inspection and maintenance, such as scale cleaning and the like. Specifically, the use of the circulating cooling water can take away heat generated in the induction heating process, reduce heat stress accumulation, increase the overall stability and safety of the induction heat treatment device, and particularly under the working condition of continuous operation for a long time, good cooling can effectively prevent deformation or failure of the induction frame caused by overheating, so that the uniformity of induction heating of the workpiece 101 by the inductor assembly 1 is ensured.

According to the embodiment, through the arrangement of the hollow structure and the circulating cooling water, the maintenance is simple and convenient, the heat dissipation efficiency of the induction heat treatment device can be improved, the service life is prolonged, the stability and the safety are enhanced, and the uniformity of induction heating of the workpiece 101 is improved.

In some embodiments, as shown in fig. 1 and 2, the induction heat treatment apparatus further comprises:

A bottom plate 5 perpendicular to the second direction y, the bottom plate 5 being connected to the first connection beam 2 and the end of the second connection beam 3 remote from the inductor assembly 1, the bottom plate 5 being connected to a power source; and

An insulating plate 6 connected to the bottom plate 5 and perpendicular to the third direction z, the insulating plate 6 being provided between the first connection beam 2 and the second connection beam 3.

Specifically, the ends of the first connecting beam 2 and the second connecting beam 3 near the power source may be provided with a bending portion, the bending portion is connected to the bottom plate, and the bending portion extends at least partially along the first direction x. Alternatively, the bending portion may be bent in a direction away from the insulating plate 6, and an end of the bending portion away from the insulating plate 6 is provided with the cooling water joint 4. Optionally, the insulating plate 6 is provided with a fixing member 7, such as a fixing bolt or the like.

Specifically, the bottom plate 5, which serves as a supporting base of the induction heat treatment apparatus, is connected between the connection beam and the power source, and can ensure stable installation of the connection beam, improving reliability of current transmission. Specifically, the insulating plate 6 plays an electric insulating role, and can prevent a short circuit from occurring between the first connection beam 2 and the second connection beam 3, improving the safety of the induction heat treatment apparatus.

Alternatively, the insulating plate 6 may be made of polytetrafluoroethylene or the like.

This embodiment can enhance structural stability and electrical safety by providing the bottom plate 5 and the insulating plate 6, optimize layout and facilitate maintenance, and ensure high quality and high efficiency of the efficient cooling and heat treatment process.

In some embodiments, as shown in fig. 1 and 2, the inductor assembly 1 further comprises:

the first connecting section 111 extends along the second direction y, the first connecting section 111 is connected to the first induction frame 11, and the first connecting section 111 and the first connecting beam 2 are arranged at intervals along the third direction z;

The two second connecting sections 122 extend along the second direction y, the two second connecting sections 122 are connected to the second induction frame 12, and the two second connecting sections 122 are arranged at intervals along the third direction z; and

The two third connecting sections 133 extend along the second direction y, the two third connecting sections 133 are connected to the third sensing frame 13, and the two third connecting sections 133 are arranged at intervals along the third direction z.

Specifically, the first sensing frame 11, the second sensing frame 12 and the third sensing frame 13 each have a first opening, a second opening and a third opening, the first connecting section 111 and the first connecting beam 2 are respectively connected to the first end and the second end of the first opening, the two second connecting sections 122 are respectively connected to the first end and the second end of the second opening, and the two third connecting sections 133 are respectively connected to the first end and the second end of the third opening.

Specifically, by providing the first, second and third connection sections 111, 122 and 133 extending in the second direction y, it is possible to facilitate the second and third sensing frames 12 and 13 to be connected in parallel. Specifically, the first connecting section 111, the second connecting section 122 and the third connecting section 133 are all located outside the area surrounded by the induction frame, so that the influence on the induction magnetic field can be reduced, and the damage of the connection structure to the induction magnetic field is avoided.

According to the embodiment, through the structural design that a plurality of connecting sections are arranged in parallel, current can be distributed according to requirements, the defect of sharp angle effect is overcome, and the uniformity of induction heat treatment is improved; the arrangement of the connecting sections can strengthen the rigidity and the stability of the induction heat treatment device; the plurality of connecting sections extend along the second direction y and are positioned outside the area surrounded by the induction frame, so that the damage of the connecting structure to the induction magnetic field can be avoided; through setting up along third direction z interval, can provide more area of contact for the cooling water when avoiding the short circuit, improve cooling efficiency.

In some embodiments, as shown in fig. 1 and 2, the inductor assembly 1 further comprises:

a first transition section 110 connected between the first connection section 111 and a second connection section 122 adjacent to the first connection beam 2, the first transition section 110 extending in a first direction x; and/or

A second transition section 120 connected between the first connection section 111 and a third connection section 133 adjacent to the first connection beam 2, the second transition section 120 extending in the first direction x; and/or

A third transition section 130 connected between the second connection section 122 and the second connection section 122 remote from the first connection beam 2, the third transition section 130 extending in the first direction x; and/or

A fourth transition section 140 connected between the third connection section 133 and the second connection section 122 remote from the first connection beam 2, the fourth transition section 140 extending in the first direction x.

Specifically, the plurality of transition sections are located outside the area enclosed by the induction frame. Specifically, when the inductor assembly 1 is aligned with the non-end portion of the workpiece 101 in one direction of transmission of the alternating current (as shown in fig. 3), the current from the power source flows through the bottom plate 5 and the first connection beam 2 to the first induction frame 11, surrounds the first induction frame 11, and then flows to the first connection section 111, and then the main current is split into two branch currents.

Specifically, the first branch current flows through the first transition section 110 to the second connection section 122 near the first connection beam 2, flows around the second sensing frame 12 to the second connection section 122 far from the first connection beam 2, and then flows through the third transition section 130 to the second connection beam 3.

Specifically, the second branch current flows through the second transition section 120 to the third connection section 133 close to the first connection beam, flows around the third sensing frame 13 to the third connection section 133 far from the first connection beam 2, and flows through the fourth transition section 140 to the second connection beam 3, and flows to the bottom plate 5 and the power supply after the first branch current and the second branch current are combined. Correspondingly, in the other transmission direction of the alternating current, the transmission direction of the current is opposite.

According to the embodiment, through the structural design that the transition sections are connected in parallel, current can be distributed according to requirements, the defect of sharp angle effect is overcome, and the uniformity of induction heat treatment is improved; the arrangement of the transition sections can strengthen the rigidity and the stability of the induction heat treatment device; the transition sections extend along the first direction x, and form a ladder right angle connection mode with the connection sections extending along the second direction y, so that the damage to the induced magnetic field caused by the structural change of the connection parts can be avoided.

In some embodiments, as shown in fig. 1 and 2, the inductor assembly 1 further comprises:

A magnetizer provided on at least one of the first sensing frame 11, the second sensing frame 12, and the third sensing frame 13.

Specifically, the magnetic conductor can guide and concentrate the magnetic field generated by the induction frame, so that the coupling heating efficiency is improved, and the accuracy of controlling the thickness of the hardening layer is improved. Specifically, the magnetic flux can narrow the magnetic force line escape area of the induction frame, prevent the magnetic force line from escaping, enable the magnetic field to be distributed more uniformly, narrow the induction heating influence range, reduce the local temperature to be higher due to the inherent sharp angle effect of the end part of the workpiece 101, and further improve the uniformity of the end hardening layer;

specifically, the loss of energy can be reduced by concentrating magnetic lines, so that more electric energy is effectively converted into heat required by heating a workpiece, the energy efficiency ratio of the induction heat treatment device can be improved, and the running cost of the device can be reduced.

According to the embodiment, the magnetizer is arranged on the induction frame, so that the heating efficiency can be improved, the energy consumption can be saved, and the heat treatment precision can be enhanced; the adverse effect of the inherent sharp angle effect can be reduced, and the uniformity of the end hardening layer can be improved.

In some embodiments, as shown in fig. 1 and 2, the magnetizer includes a plurality of silicon steel sheets, which are adjacently disposed along the circumferential direction of the inductor assembly 1, and the notch of the silicon steel sheet is located at a side of the inductor assembly 1 facing the workpiece 101.

Specifically, a plurality of silicon steel sheets are disposed adjacently along the circumferential direction of the first induction frame 11, and/or a plurality of silicon steel sheets are disposed adjacently along the circumferential direction of the second induction frame 12, and/or a plurality of silicon steel sheets are disposed adjacently along the circumferential direction of the third induction frame 13. Alternatively, the silicon steel sheet may be a pi-shaped silicon steel sheet or the like.

Specifically, the silicon steel sheet material has the characteristics of high magnetic conductivity and low loss, and the combination of a plurality of silicon steel sheets enhances the guidance of a magnetic field, so that the induction heating efficiency can be improved. Specifically, the notch is designed towards the workpiece 101, so that the coupling between the electromagnetic field and the surface of the workpiece can be optimized, and the induction heating is ensured to be more accurate. Specifically, the adjacent arrangement of the silicon steel sheets can enhance the structural stability of the induction frame.

According to the embodiment, the plurality of silicon steel sheets are adjacently arranged on the induction frame, so that accurate heating control can be realized, and the heating stability and the heat treatment quality are improved.

In some embodiments, as shown in fig. 1 and 2, the thickness of the sheet of silicon steel is adapted to the depth of the hardened layer and/or the frequency of induction heating.

Specifically, the thickness of the silicon steel sheet may be selected depending on the depth of the hardened layer or the value of the induction heating frequency. In particular, thinner silicon steel sheets are suitable for applications where precise control of the thickness of the hardened layer is required.

According to the embodiment, the thickness of the silicon steel sheet is adapted to the depth of the hardening layer and/or the induction heating frequency, so that the heating efficiency and the heat treatment quality can be considered, meanwhile, the economical efficiency and the process feasibility are considered, and the accuracy and the high efficiency of the induction heat treatment process are ensured.

In some embodiments, as shown in figures 1 and 2,

The first distance between the first sensing frame 11 and the second sensing frame 12 is adapted to the depth of hardened layer of the end of the workpiece 101; and/or

The second distance between the first sensing frame 11 and the third sensing frame 13 is adapted to the depth of hardened layer of the end of the workpiece 101.

Specifically, the first distance and the second distance are both distances along the first direction x. Specifically, if the first distance increases, the second induction frame 12 will be moved away from the second end of the workpiece 101 in advance in the fifth stage of the above embodiment, and the heating power of the third induction frame 13 is reduced to zero in advance, so that the induction heating power of the inductor assembly 1 to the second end can be reduced; conversely, if the first distance is reduced, the second induction frame 12 delays leaving the second end of the workpiece 101 in the fifth stage of the above embodiment, and the heating power of the third induction frame 13 is reduced to zero, so that the induction heating power of the second end of the workpiece 101 can be increased.

Correspondingly, if the second distance increases, the third induction frame 13 delays the time of being flush with the first end of the workpiece 101 in the third stage of the above embodiment, so that the time of induction heating only the first induction frame 11 is prolonged, and the maximum induction heating power of the inductor assembly 1 to the first end is delayed; conversely, if the second distance is reduced, the third induction frame 13 is aligned with the first end of the workpiece 101 in the third stage of the above embodiment, so that the induction heating time of the first induction frame 11 is shortened, and the maximum induction heating power of the inductor assembly 1 to the first end is advanced.

This embodiment enables control of the end hardening layer depth by adjusting the first distance and/or the second distance; the depth of the hardening layer at the end part of the workpiece 101 can be accurately controlled by adjusting the first distance and/or the second distance to be matched with the depth of the hardening layer at the end part of the workpiece, so that the uniformity of induction heat treatment at the end part of the workpiece is improved, the processing quality is improved, and high-precision customization of heat treatment of workpieces with different structural shapes is realized.

In some embodiments, as shown in fig. 1 and 2, the first distance is equal to the second distance.

In particular, the first distance is equal to the second distance, so that the structural configuration and the process parameter setting can be simplified, standardized production is facilitated, and the complexity of manufacturing and operation is reduced. Specifically, the first distance is equal to the second distance, so that the two ends of the workpiece are subjected to the same degree of heat treatment, and consistency of depth of hardened layers at the two ends of the workpiece is facilitated, for example, workpieces with high symmetry or identical requirements for heat treatment at the two ends of the workpiece are treated.

The embodiment is convenient for standardized production by enabling the first distance to be equal to the second distance, can simplify structural configuration and process parameter setting, ensures the consistency of the depth of the hardening layers at the two ends of the workpiece, is suitable for symmetrical workpiece processing, and can improve the uniformity of heat treatment.

In some embodiments, as shown in fig. 1 and 2, the first sensing frame 11, the second sensing frame 12, and the third sensing frame 13 are all ring-shaped.

In particular, the annular induction frame is adapted to a cylindrical workpiece 101 extending in the first direction x.

The induction frame is annular, so that a magnetic field can be effectively gathered, the whole workpiece 101 is ensured to be uniformly hardened, and the induction frame is particularly suitable for treating tubular or columnar workpieces; the annular frame can reduce energy loss in the heat treatment process, improves heating efficiency, and is beneficial to saving energy consumption.

Secondly, the present disclosure also proposes a quenching system including:

The induction heat treatment apparatus of the above embodiment; and

And the water spraying device is used for spraying cooling water to the induction-heated workpiece 101.

According to the quenching system, the water spraying device sprays cooling water to the workpiece 101 after the induction heat treatment device heats the workpiece 101, the induction heat treatment device can enable the inductor assembly 1 to automatically reduce heating power in the moving process of the end part of the workpiece 101, so that the temperature rise of the end part caused by the sharp angle effect is made up, the depth of a hardening layer of the end part of the workpiece 101 is uniform and consistent with the depth of a hardening layer of a main body part, and the uniformity of quenching treatment is improved; the inductor assembly 1 can realize uniform heating effect on the workpiece 101 by single scanning, and the efficiency of quenching treatment can be improved without reciprocating adjustment.

In addition, the disclosure further provides an induction heating method of the induction heat treatment device based on the embodiment, which comprises the following steps:

Rotating the workpiece 101 about a preset center line;

Moving the inductor assembly 1 to a first end of the workpiece 101;

moving the sensor assembly 1 along a predetermined path to be flush with the first end of the workpiece 101;

moving the inductor assembly 1 along a predetermined path from a first end of the workpiece 101 to a second end of the workpiece 101;

The sensor assembly 1 is moved along a predetermined path away from the second end of the workpiece 101.

Alternatively, the inductor assembly 1 may be moved along a preset speed.

According to the induction heating method, through combination of rotation of the workpiece 101 and movement of the sensor assembly 1, uniform heating of the workpiece 101 in the whole circumferential direction can be achieved, and heat treatment uniformity and heating efficiency are improved; the induction heating method adopts the inductor assembly 1 to heat the end part of the workpiece, so that the heating power of the inductor assembly 1 can be automatically reduced in the moving process of the end part of the workpiece 101, the problem of too fast temperature rise of the end part caused by the sharp angle effect is further solved, and the depth of the end part hardening layer of the workpiece 101 is uniform and consistent with the depth of the main body part hardening layer.

In some embodiments, during movement of the sensor assembly 1, the second sensing frame 12 is flush with the workpiece 101 before the first sensing frame 11, and moving the sensor assembly 1 along the predetermined path to be flush with the first end of the workpiece 101 comprises:

During the process of the second induction frame 12 being flush with the first end of the workpiece 101, the inductor assembly 1 is not heated to the workpiece 101;

during the process that the first induction frame 11 is flush with the first end of the workpiece 101, only the first induction frame 11 heats the workpiece 101;

In the process that the third induction frame 13 is flush with the first end of the workpiece 101, the first induction frame 11 heats the workpiece 101, so that the heating power of the second induction frame 12 and the third induction frame 13 is gradually increased, and the maximum heating power of the second induction frame 12 and the third induction frame 13 is smaller than the heating power of the first induction frame 11.

According to the induction heating method, the induction heating power is automatically increased gradually in the process of enabling the inductor assembly 1 to move along the preset path to be flush with the first end of the workpiece 101, so that the inductor assembly 1 can heat the first end of the workpiece 101 with lower heating power, further the problem that the temperature of the end part is raised too fast due to the sharp angle effect is solved, and the depth of the hardened layer of the first end of the workpiece 101 is uniform with the depth of the hardened layer of the main body part.

In some embodiments, during movement of the sensor assembly 1, the second sensing frame 12 is moved away from the workpiece 101 before the first sensing frame 11, and moving the sensor assembly 1 along the predetermined path to move away from the second end of the workpiece 101 comprises:

Gradually reducing the heating power of the third induction frame 13 during the process that the second induction frame 12 leaves the second end of the workpiece 101;

after the second induction frame 12 leaves the second end of the workpiece 101, only the first induction frame 11 is caused to heat the workpiece 101;

After the first induction frame 11 leaves the second end of the workpiece 101, the inductor assembly 1 is stopped from heating.

According to the induction heating method, the induction heating power is automatically reduced gradually in the process of moving the inductor assembly 1 along the preset path to be away from the second end of the workpiece 101, so that the inductor assembly 1 can heat the second end of the workpiece 101 with lower heating power, further, the problem of over-fast temperature rise of the end part caused by the sharp angle effect is solved, and the depth of the hardening layer of the second end of the workpiece 101 is uniform and consistent with the depth of the hardening layer of the main body part.

The induction heat treatment device, the quenching system and the induction heat treatment method provided by the present disclosure are described in detail above. Specific examples are set forth herein to illustrate the principles and embodiments of the present disclosure, and the above examples are merely intended to aid in understanding the methods of the present disclosure and the core ideas thereof. It should be noted that it would be apparent to those skilled in the art that various improvements and modifications could be made to the present disclosure without departing from the principles of the present disclosure, and such improvements and modifications would be within the scope of the claims of the present disclosure.

Claims (18)

1. An induction heat treatment apparatus for induction heating of a workpiece (101), the induction heat treatment apparatus comprising an inductor assembly (1), the inductor assembly (1) being configured to encircle the workpiece (101) and to move relative to the workpiece (101) along a predetermined path for scanning, the inductor assembly (1) comprising:

a first induction frame (11) connected to a power source;

The second induction frame (12) is arranged at intervals along the first direction (x) with the first induction frame (11) and is arranged on the first side of the first induction frame (11), and the second induction frame (12) is electrically connected with the first induction frame (11); and

The third induction frames (13) are arranged on the second side surface of the first induction frame (11) at intervals along the first direction (x), the third induction frames (13) are electrically connected to the first induction frame (11), and the third induction frames (13) are connected with the second induction frame (12) in parallel;

Wherein the current directions in the first induction frame (11), the second induction frame (12) and the third induction frame (13) are the same.

2. An induction heat treatment device according to claim 1, characterized in that the planes of the first induction frame (11), the second induction frame (12) and the third induction frame (13) are all perpendicular to the first direction (x).

3. The induction heat treatment device according to claim 1, characterized in that the central axes of the first induction frame (11), the second induction frame (12) and the third induction frame (13) coincide.

4. An induction heat treatment apparatus according to claim 3, further comprising:

-a first connection beam (2) for connecting the first induction frame (11) to the power supply, the first connection beam (2) extending along a second direction (y), the second direction (y) being perpendicular to the first direction (x); and

And a second connecting beam (3) for connecting the second sensing frame (12) and the third sensing frame (13) to the power supply, at least part of the length of the second connecting beam (3) extending along the second direction (y), the second connecting beam (3) and the first connecting beam (2) being arranged at intervals along a third direction (z), the third direction (z) being perpendicular to the first direction (x) and the second direction (y).

5. The induction heat treatment device according to claim 4, characterized in that the first induction frame (11), the second induction frame (12), the third induction frame (13), the first connection beam (2) and the second connection beam (3) are hollow structures, the induction heat treatment device further comprising:

Two cooling water joints (4) are respectively arranged at one ends of the first connecting beam (2) and the second connecting beam (3) which are respectively far away from the inductor assembly (1), wherein one cooling water joint (4) is used for flowing in cooling water, and the other cooling water joint (4) is used for flowing out cooling water.

6. The induction heat treatment apparatus of claim 4, further comprising:

-a base plate (5) perpendicular to the second direction (y), the base plate (5) being connected to the first connection beam (2) and to an end of the second connection beam (3) remote from the inductor assembly (1), the base plate (5) being connected to a power source; and

And an insulating plate (6) connected to the bottom plate (5) and perpendicular to the third direction (z), wherein the insulating plate (6) is arranged between the first connecting beam (2) and the second connecting beam (3).

7. The induction heat treatment device according to claim 4, characterized in that the inductor assembly (1) further comprises:

A first connection section (111) extending along the second direction (y), the first connection section (111) being connected to the first induction frame (11), and the first connection section (111) and the first connection beam (2) being arranged at intervals along the third direction (z);

Two second connecting sections (122) extending along the second direction (y), wherein the two second connecting sections (122) are connected to the second induction frame (12), and the two second connecting sections (122) are arranged at intervals along the third direction (z); and

Two third connecting sections (133) extend along the second direction (y), two third connecting sections (133) are connected to the third induction frame (13), and two third connecting sections (133) are arranged at intervals along the third direction (z).

8. The induction heat treatment device according to claim 7, characterized in that the inductor assembly (1) further comprises:

-a first transition section (110) connected between the first connection section (111) and the second connection section (122) close to the first connection beam (2), the first transition section (110) extending in the first direction (x); and/or

-A second transition section (120) connected between the first connection section (111) and the third connection section (133) close to the first connection beam (2), the second transition section (120) extending in the first direction (x); and/or

-A third transition section (130) connected between the second connection section (122) and the second connection section (122) remote from the first connection beam (2), the third transition section (130) extending in the first direction (x); and/or

-A fourth transition section (140) connected between the third connection section (133) and the second connection section (122) remote from the first connection beam (2), the fourth transition section (140) extending in the first direction (x).

9. The induction heat treatment device according to any one of claims 1 to 8, characterized in that the inductor assembly (1) further comprises:

And a magnetizer arranged on at least one of the first induction frame (11), the second induction frame (12) and the third induction frame (13).

10. The induction heat treatment device according to claim 9, characterized in that the magnetizer comprises a plurality of silicon steel sheets, the plurality of silicon steel sheets are adjacently arranged along the circumferential direction of the inductor assembly (1), and the notch of the silicon steel sheets is positioned on one side of the inductor assembly (1) facing the workpiece (101).

11. The induction heat treatment device according to claim 10, characterized in that the thickness of the silicon steel sheet is adapted to the depth of the hardened layer and/or the induction heating frequency.

12. An induction heat treatment apparatus according to any one of claims 1 to 8, characterized in that,

-A first distance between the first induction frame (11) and the second induction frame (12) is adapted to the depth of hardened layer of the end of the workpiece (101); and/or

A second distance between the first induction frame (11) and the third induction frame (13) is adapted to the depth of the hardened layer of the end of the workpiece (101).

13. The induction heat treatment apparatus of claim 12, wherein the first distance is equal to the second distance.

14. The induction heat treatment device according to any one of claims 1 to 8, characterized in that the first induction frame (11), the second induction frame (12) and the third induction frame (13) are all ring-shaped.

15. A quench system, comprising:

An induction heat treatment apparatus according to any one of claims 1 to 14; and

And the water spraying device is used for spraying cooling water to the induction-heated workpiece (101).

16. An induction heating method based on the induction heat treatment apparatus according to any one of claims 1 to 14, comprising:

Rotating the workpiece (101) about a preset center line;

-moving the inductor assembly (1) to a first end of a workpiece (101);

-moving the inductor assembly (1) along the preset path to be level with the first end of the workpiece (101);

-moving the inductor assembly (1) along the preset path from a first end of the workpiece (101) to a second end of the workpiece (101);

the sensor assembly (1) is moved along the predetermined path to a second end away from the workpiece (101).

17. The induction heating method according to claim 16, wherein moving the inductor assembly (1) along the predetermined path to be flush with the first end of the workpiece (101) during movement of the inductor assembly (1) with the second induction frame (12) being flush with the workpiece (101) before the first induction frame (11) comprises:

-keeping the inductor assembly (1) from heating the workpiece (101) during the second induction frame (12) being flush with the first end of the workpiece (101);

during the process that the first induction frame (11) is flush with the first end of the workpiece (101), only the first induction frame (11) heats the workpiece (101);

In the process that the third induction frame (13) is flush with the first end of the workpiece (101), the first induction frame (11) heats the workpiece (101), so that the heating power of the second induction frame (12) and the heating power of the third induction frame (13) are gradually increased, and the maximum heating power of the second induction frame (12) and the maximum heating power of the third induction frame (13) are smaller than the heating power of the first induction frame (11).

18. The induction heating method according to claim 16 or 17, characterized in that during the movement of the inductor assembly (1), the second induction frame (12) is moved away from the workpiece (101) before the first induction frame (11), moving the inductor assembly (1) along the preset path to a second end away from the workpiece (101) comprises:

Gradually reducing the heating power of the third induction frame (13) during the process that the second induction frame (12) leaves the second end of the workpiece (101);

after the second induction frame (12) leaves the second end of the workpiece (101), only the first induction frame (11) heats the workpiece (101);

After the first induction frame (11) leaves the second end of the workpiece (101), the inductor assembly (1) is stopped from heating.