JP7845903B2 - Induction heating quenching method and induction heating quenching apparatus - Google Patents

Description

This invention relates to an induction heating quenching method and apparatus for quenching the ends of plate-shaped members.

Conventionally, when induction heating is performed on components requiring partial quenching, induction elements are used that match the shape of the component to be treated and the shape of the area to be quenched. Each component is then individually induction heated and quenched (see Patent Documents 1-3).

Patent Document 1 describes how to simultaneously induce heating of one or more heated regions 11 or multiple heated regions 41, 42 defined in an elongated shape on a thin plate article 10 or 40 by facing induction parts 21 or 51, 52 toward them and passing a high-frequency current through these induction parts (Abstract, Claims 1, 2; see Figures 1, 4).

Patent Document 2 describes a method for high-frequency induction hardening of a stepped member, such as a pole parking structure, which has a material region M and a processing region N adjacent to the material region M via a stepped portion 6. The method involves applying a pair of electrode contacts 7 and 8 to a portion of the material region M, near the stepped portion 6, and directly energizing the processing region N to heat it. Then, the processing region N, heated to a required hardening temperature, is cooled with a hardening coolant 9 to form a hardened layer S in the processing region (Abstract, Claims 1, 3; see Figures 1, 2).

Patent Document 3 describes an induction heating and quenching method for a long material 10 in which a first side portion 11 and a second side portion 12 are adjacent at a corner 13, a recess is provided in the first side portion 11 spaced apart from the corner 13, and the first and second side portions 11 and 12 and the recess 14 are continuous in the longitudinal direction. The method uses a heating coil 21 for the long material 10, which is arranged along the longitudinal direction to induce heating of the first side portion 11 and the recess 14. The coil includes a wide conductor 24 facing the first side portion 11 and a narrow conductor 23 facing the recess 14 and protruding from the wide conductor 24 toward the recess 14 (Abstract, Claim 1; see Figure 1).

On the other hand, in order to efficiently perform induction heating quenching, multiple workpieces are sometimes quenched simultaneously (see Patent Documents 4 and 5).

Patent Document 4 describes a process in which multiple base metals 8, which are the workpieces to be processed, are stacked, electrodes 4 and 5 are pressed against their upper and lower surfaces, the outer periphery of the base metals 8 is covered with a case to create a nearly sealed environment, an inert gas is supplied into the case, and then a high-frequency current is supplied between the electrodes to quench the base metals 8 (see abstract, claim 1, and Figure 1).

Patent Document 5 describes a method of simultaneously hardening the hardening regions 11, 11 of multiple workpieces 10 by connecting multiple workpieces 13, 14 with conductive connections 15 such that a closed circuit is formed in which the hardening target regions 11 of each workpiece are connected in a series-endless manner, and the positional relationship between each workpiece is fixed, thereby temporarily assembling them into a workpiece assembly 13 + 14. An inductor 17 that generates a magnetic flux in the same direction as the axis of the assembly is placed on the outside of the assembly, and a high-frequency current is applied to the inductor 17 to generate an induced current that circulates around the closed circuit in a manner that increases the coupling coefficient, which is an indicator of the degree of coupling between the inductor and the workpiece (Abstract, Claim 1; see Figure 1).
Furthermore, Patent Document 5 states, "In the conventional quenching methods for thin steel sheet formed products described above, in all cases the workpiece is a single object. For this reason, when processing a large number of items, processing them one by one takes time, and simply increasing the number of items to be processed in parallel or in parallel processing would increase equipment costs and so on." (Paragraph [0006])

Japanese Patent Publication No. 2005-054225 Japanese Patent Publication No. 2005-105301 Japanese Patent Publication No. 2013182840 Japanese Patent Application Publication No. 7-216457 Japanese Patent Publication No. 2008-45183

The quenching methods described in Patent Documents 1 to 3 involve quenching each workpiece individually. Therefore, they have the problem of not being able to increase production efficiency and being unsuitable for mass production.
Patent documents 4 and 5 describe quenching multiple workpieces at once.
However, the quenching method described in Patent Document 4 is applicable to workpieces such as base metals with a certain thickness that can be pressure-welded, and cannot be said to be generalizable to plate-shaped members with various shapes. Furthermore, since pretreatment is required to seal the processing atmosphere and replace it with an inert gas, it is difficult to increase production efficiency.
The quenching process described in Patent Document 5 requires a complex pre-process to assemble the workpieces in a conductive connection that forms a closed circuit by connecting multiple workpieces in a series in an endless manner, and in which the positional relationship between each workpiece is fixed. Therefore, this process also lacks versatility and makes it difficult to improve production efficiency.
Furthermore, while Patent Document 5 describes parallel processing as a method for quenching a large number of thin steel sheet formed products (plate-shaped members) as prior art, it does not specify the exact processing method.

In view of the above problems, the present invention aims to provide an induction heating quenching method and an induction heating quenching apparatus that can efficiently perform partial quenching of multiple plate-shaped members.

To solve the above problems, the present invention employs the following means.
(1) An induction heating quenching method for quenching the ends of plate-shaped members by high-frequency induction heating, wherein a plurality of plate-shaped members are placed in parallel on a jig, and the ends of the plurality of plate-shaped members are simultaneously induction heated with a single quenching coil.
(2) The induction heating quenching method according to (1), wherein a plurality of plate-shaped members are placed in two parallel rows on the jig with their ends facing each other, with the quenching coil in between, and the ends of the plurality of plate-shaped members are simultaneously induction heated by the quenching coil in each row by moving the jig.

(3) One hardened coil,
A jig having two lines on either side of the aforementioned hardened coil, on which multiple plate-shaped members are placed in parallel so that their ends face each other,
A moving mechanism moves the ends of multiple plate-shaped members in the first line of the jig between a hardening position where the ends of other multiple plate-shaped members in the second line are hardened by the hardening coil,
It has a detachment mechanism for unloading a plurality of plate-shaped members that have been high-frequency hardened in each of the aforementioned lines,
An induction heating quenching apparatus having a loading/unloading mechanism that, while the ends of the plurality of plate-shaped members in the first line are in the quenching position, unloads the plurality of quenched plate-shaped members in the second line and places a plurality of plate-shaped members to be quenched in parallel on the second line such that their ends face the ends of the plurality of plate-shaped members in the first line, and a mechanism that, while the ends of the plurality of plate-shaped members in the second line are in the quenching position, unloads the plurality of quenched plate-shaped members in the first line and places a plurality of plate-shaped members to be quenched in parallel on the first line such that their ends face the ends of the plurality of plate-shaped members in the second line.
(4) The induction heating and quenching apparatus described in (3), wherein a distance is ensured between the quenching position in the first line and the quenching position in the second line such that the induced magnetic field during induction heating by the quenching coil does not interfere.

According to the present invention, partial quenching of multiple plate-shaped members can be performed without requiring special pre-processing steps, thus providing an induction heating quenching method and apparatus with improved production efficiency.

Schematic plan view of an induction heating and quenching apparatus according to one embodiment of the present invention. Schematic plan view showing the quenching position and detachment position of an induction heating quenching apparatus according to one embodiment of the present invention.

(Induction heating quenching method)
An induction heating quenching method according to an embodiment of the present invention (hereinafter referred to as "this embodiment") is an induction heating quenching method for quenching the end of a plate-shaped member by high-frequency induction heating, wherein a plurality of plate-shaped members are placed in parallel on a jig, and the ends of the plurality of plate-shaped members are induction heated at the same time with a single quenching coil.
In this way, induction heating and quenching can be performed in a single coil at once, eliminating the need for special pre-processing steps and thus improving production efficiency.

More specifically, the induction heating quenching method according to this embodiment involves placing multiple plate-shaped members in two parallel rows on a jig with their ends facing each other, flanking one quenching coil, and then moving the jig to induce-heat the ends of the multiple plate-shaped members in each row at once using the one quenching coil.
In this way, a single heat treatment coil can induce-heat multiple plate-shaped members arranged in two rows, one row at a time, further improving production efficiency.

The quenching method according to this embodiment will be described in detail below with reference to Figure 1.
(1) Multiple plate-shaped members are placed in parallel in two rows on two lines provided on the jig (hereinafter referred to as the "first line" and the "second line"), with the ends that are to be hardened facing each other.
(2) The hardening coil and the jig are moved relative to each other, and the ends of multiple plate-shaped members on the first line (shown as "line A" in the figure; the same applies hereinafter) are simultaneously induction heated with the hardening coil and cooled to complete the hardening process (cooling jacket is not shown). During this time, the multiple plate-shaped members placed on the second line (shown as "line B" in the figure; the same applies hereinafter) are not affected by the induction magnetic field generated when the hardening coil is induction heating on the first line.
(3) Next, the one quenching coil and the jig are moved relative to each other, and the ends of the multiple plate-shaped members in the second line are simultaneously induction heated by the quenching coil and then cooled to complete the quenching process. Meanwhile, the multiple plate-shaped members that have been quenched in the first line are removed, and the multiple plate-shaped members to be quenched are placed on the first line. The newly placed multiple plate-shaped members are also not affected by the induction magnetic field generated when the quenching coil is induction heating on the second line.
(4) Again, by moving the quenching coil and the jig relative to each other, the ends of the multiple plate-shaped members in the first line are simultaneously induction heated by the quenching coil and then cooled to complete the quenching process. Meanwhile, the multiple plate-shaped members that have been quenched in the second line are removed, and the multiple plate-shaped members to be quenched again are placed in the second line.
(5) The steps in (3) and (4) are repeated the desired number of times, and production is stopped when the desired number of hardened products are obtained.

(Plate-shaped member)
The material of the plate-shaped member can be any material that can be hardened, and is not limited, but steel members are preferred. The method and apparatus of this embodiment can be used, for example, for hardening S48C (C: 0.45 to 0.51, Si: 0.15 to 0.35, Mn: 0.60 to 0.90, P: 0.030 or less, S: 0.035 or less), which is a carbon steel for machine structures.

(Induction heating quenching apparatus)
Figure 1 shows a schematic plan view of the induction heating quenching apparatus according to this embodiment.
This device comprises a hardening coil, a jig having two lines on either side of the hardening coil, each line on which multiple plate-shaped members are placed in parallel with their ends facing each other, a moving mechanism (not shown) that moves the ends of multiple plate-shaped members in the first line of the jig between a hardening position where the ends of other multiple plate-shaped members in the second line are hardened by the hardening coil, and a detachment mechanism (not shown) that unloads the multiple plate-shaped members that have been hardened by high-frequency induction induction in each of the lines.

The moving mechanism and the attachment/detachment mechanism will be described based on Figure 2.
The left diagram of Figure 2 shows a state in which a jig and one hardening coil are moved relative to each other by a moving mechanism (not shown), and the ends of multiple plate-shaped members placed on the first line are in the hardening position by the one hardening coil.
While in this state, if multiple plate-shaped members that have completed hardening are placed on the second line, they are removed by a detachment mechanism (not shown) and new members to be hardened are placed on top.
The right-hand diagram of Figure 2 shows a state in which the jig and one hardening coil are moved relative to each other by a moving mechanism (not shown), and the ends of multiple plate-shaped members placed on the second line are in the hardening position by the one hardening coil.
While in this state, if multiple plate-shaped members that have completed hardening are placed on the first line, they are removed by a detachment mechanism (not shown) and new members to be hardened are placed on top.

In other words, the attachment/detachment mechanism includes a mechanism for removing multiple plate-shaped members that have been hardened in the second line while the ends of multiple plate-shaped members in the first line are in the hardening position, and for placing multiple plate-shaped members to be hardened in the second line in parallel so that their ends face each other; and a mechanism for removing multiple plate-shaped members that have been hardened in the first line while the ends of multiple plate-shaped members in the second line are in the hardening position, and for placing multiple plate-shaped members to be hardened in the first line in parallel so that their ends face each other.

The hardening coil is typically configured in conjunction with a high-frequency power supply, cooling device, etc. Therefore, it is preferable that the moving mechanism fixes one hardening coil and moves the jig, but it may also fix the jig and move one hardening coil.
Furthermore, the hardening coil is not particularly limited as long as it has a shape in which multiple plate-shaped members are placed in parallel on a jig and the ends of the multiple plate-shaped members are simultaneously induction heated by a single hardening coil.

Furthermore, to improve the uniformity of the hardening process, it is preferable to ensure a distance between the hardening position in the first line and the hardening position in the second line that prevents the induced magnetic field from hardening in one line of the hardening coil from interfering with the material in the other line.

The induction heating quenching method and apparatus according to the present invention can significantly improve productivity and can therefore be effectively used for mass production of steel parts.

Claims (1)

An induction heating quenching method for hardening the ends of plate-shaped members by high-frequency induction heating, wherein multiple plate-shaped members are placed in parallel on a jig, and the ends of the multiple plate-shaped members are simultaneously induction heated by a single quenching coil.