JP3981574B2 - One side quenching method of square member by induction heating - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for quenching one surface of a square member by induction heating so that only one required surface is heated and the other portions are not heated.
[0002]
[Prior art]
When induction heating and quenching one side of a square member, moving quenching is the mainstream, but when the square member is small, one-time quenching is preferred.
[0003]
[Problems to be solved by the invention]
However, for example, as shown in FIGS. 3 and 4, when the entire surface of one surface A of the corner member 1 is induction-heated in one shot, not only the quenching surface A but also the corner B on the opposite surface as shown in the drawing. Heated. For this reason, the inconvenience that even the corner part B is hardened by hardening occurs. Further, when the jig 2 holding the corner member 1 shown in FIG. 4 is made of a material having a high electrical resistance such as a steel material, a spark is generated between the corner B and the jig 2 due to a potential difference during induction heating. There is a problem.
[0004]
Therefore, an object of the present invention is to provide a method for quenching one side of a square member by induction heating, in which only a required one side of the square member is heated without quenching other surfaces than the quenching surface.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present inventors have conducted experiments. As a result, the cause described above is that an induced current is generated in the corner member, and a current C as shown in FIG. Was found to be heated.
[0006]
Therefore, the inventors short-circuited both ends of the corner member 1 with the conductor 3 disposed on the back side of the heating surface A as shown in FIG. 1 so that the induced current C does not flow on the back surface of the corner member 1. 3 is made to flow except for the heating surface of the corner member 1.
[0007]
In order to achieve the above object, according to the method of quenching one side of a square member by induction heating according to the present invention, when one side of the square member is induction-heated, both ends in the longitudinal direction of the square member are disposed on the back side of the heating surface. The conductive member is short-circuited, and a conductive path is formed on the back side of the heating surface of the corner member by the corner member and the conductor, so that the heating surface is induction- heated.
[0008]
In other words, the one-surface quenching method of the corner member according to the present invention forms the conductive path by the conductor and the corner member disposed on the back side of the heating surface of the corner member, and thereby induces the induced current generated in the corner member. Heating the back side of the corner member is prevented by flowing to the conductor without flowing to the back surface.
[0009]
In order to achieve the object with a simple structure, it is desirable for the conductor to form a holding jig for holding the corner member across both end faces of the corner member.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be specifically described with reference to an illustrated embodiment. FIG. 1 is a perspective view of a jig used for one-side heating and hardening of a corner member of the present invention.
[0011]
In FIG. 1, a jig 10 is provided with a fixed grip 12 and a movable grip 22 on a base 11. The fixed grip 12 is fixed to the base 11, and the movable grip 22 is slid on the base 11 by pressing means such as an air cylinder (not shown). The movable gripping portion 22 slides on the base 11 while being guided by a wedge-shaped rail 11 a on the upper surface of the base 11. As for the contact portion between the fixed grip portion 12 and the movable grip portion 22, the convex portion 22c is fitted into the concave portion 12c, and the movable grip portion 22 slides. The base 11, the fixed grip 12 and the movable grip 22 are all made of copper, which is a good conductor. Thereby, the fixed holding part 12 and the movable holding part 22 are electrically connected and connected.
[0012]
The fixed grip portion 12 and the movable grip portion 22 are provided with contact portions 12a and 22a and receiving steps 12b and 22b, respectively, and the movable grip portion 22 is opened between the fixed grip portion 12 and the movable grip portion 22. A square member (hereinafter referred to as a workpiece) is placed on the receiving steps 12b and 22b, and the movable gripping portion 22 is moved by pressing means such as an air cylinder (not shown) to sandwich both ends of the workpiece 1 with the contact portions 12a and 22a.
[0013]
As a result, a conductive path is formed by both ends of the workpiece 1, the fixed gripping portion 12 and the movable gripping portion 22, and when the quenching surface A of the workpiece 1 is induction-heated, the induced current generated in the workpiece 1 is as shown in FIG. Since it flows between the fixed holding part 12 and the movable holding part 22, parts other than the heating surface A are not heated by an induced current.
[0014]
【Example】
A comparison of induction heating and quenching was performed for the case where the jig having the above-described configuration and the conventional jig were used using a S45C sample of 10 × 10 × 50 mm. The hardness measurement results after quenching are shown in FIG. In the figure, d-DEFGH is a quenching surface, and e-DEFGH is a bottom surface. From FIG. 5, the hardness of the quenching surface d-DEFGH is equivalent at about Hv720 in both the method of the present invention and the conventional method. On the other hand, the hardness of the bottom surface e-DEFGH is about Hv 220 to 240 with the material hardness remaining, but in the case of the conventional method, the hardness of the corner portions e-D and e-H of the bottom surface becomes Hv 600 and the corner portion. It can be seen that is hardened. In addition, a slight after-sparking by the induced current was observed in this part. In the case of this method, the hardness of the corners e-D and e-H of the bottom surface was about Hv220, and the temperature did not increase.
[0015]
As described above, according to the one-surface quenching method of the square member by induction heating according to the present invention, when one surface of the square member is induction-heated, a conductive path is formed by the conductor and the square member disposed on the back side of the heating surface. By preventing the heating of the back side of the square member by causing the induced current generated in the square member to flow through the conductor without flowing to the back side of the square member, surfaces other than the required heating surface are heated. No corners on the back surface are hardened and hardened as in the conventional method, and no sparks fly between the holding jig and the work or jig is damaged.
[0016]
Further, in the method of the present invention, since the holding jig that holds the corner member forms the conductor, the above object can be achieved only by placing the workpiece on the holding jig.
[0017]
【The invention's effect】
As described above, according to the one-surface quenching method of a square member by induction heating according to the present invention, only a required surface can be quenched by a simple method, so that the application of the single-surface heating and quenching of the square member is expanded.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a method of quenching one side of a square member by induction heating according to the present invention.
FIG. 2 is a diagram of a quenching jig for forming a conductor according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a state in which a corner member is quenched by induction heating.
FIG. 4 is a diagram illustrating a state in which a corner member is quenched by induction heating.
FIG. 5 is a diagram showing a hardness distribution after quenching according to an embodiment of the present invention.
[Explanation of symbols]
1, work (square member) 2, holding jig, 3 conductor, 10 jig, 11 base, 12 fixed gripping part, 22 movable gripping part

Claims (2)

When induction heating one surface of a square member, both ends in the longitudinal direction of the square member are short-circuited by a conductor disposed on the back side of the heating surface, and the heating surface of the square member is formed by the square member and the conductor. one surface hardening method of the angular member by induction heating, characterized in that the rear side to form a conductive path for inductively heating the heating surface.   The method of claim 1, wherein the conductor forms a holding jig for holding the corner member across both end surfaces of the corner member.

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