JPH04198415A - High frequency quenching method for shaft-like work - Google Patents

Abstract

PURPOSE:To reduce trouble in quenching operation by cutting a work after heating and cooling the work having length of two pieces with the specific length of a saddle-shaped semi-open type high frequency heating coil at the time of quenching the work under remaining neighborhood of one end. CONSTITUTION:The saddle-shaped semi-open type high frequency heating coil 3 having length of 2l-2m to longitudinal direction descends, the center of the coil 3 in the longitudinal direction positions at the center of the steel pipe 2 holding both ends. Successively, while rotating the steel pipe 2 under condition of making the longitudinal direction the axis, after conducting the high frequency current into the coil 3 for the prescribed time, cooling liquid L is injected to the steel pipe 2 to quench the steel pipe 2. Successively, the steel pipe 2 is released from the holding and cut at the center part to obtain two pieces of the steel pipes 1 quenching the quenched part 1b having the length (n) under condition of remaining the length (m) of one end part 1a. By this method, two pieces of the works are obtd. with one time of quenching operation.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an induction hardening method for hardening a plurality of cylindrical, cylindrical, or other-shaped annular workpieces, leaving the vicinity of one end of the workpieces hardened. An example of such a workpiece is a steel pipe used for a hammer handle. In other words, the part of the hammer handle other than the tip where the hammer is inserted and fixed is hardened. When hardening a cylindrical workpiece or a shaft-like workpiece with approximately rotational symmetry while leaving the vicinity of one end of the workpiece, move the workpieces one by one for hardening, or
-The part to be hardened is hardened by quenching.

<Problems to be Solved by the Invention> It is extremely time-consuming to harden the workpieces one by one in this way.

The present invention was devised in view of the above circumstances, and includes a plurality of cylindrical or cylindrical workpieces having the same length and shape, or
It is an object of the present invention to provide an induction hardening method that does not require much effort when hardening an axial workpiece that is rotationally symmetrical while leaving the vicinity of one end of the workpiece intact.

<Means for Solving the Problems> In order to solve the above problem, the method of induction hardening axial workpieces according to the invention of claim 1 provides a method for induction hardening axial workpieces having the same shape, equal length, and a plurality of cylindrical or cylindrical axial workpieces. In an induction hardening method in which the part of the workpiece is hardened while leaving the vicinity thereof, a saddle-shaped semi-open high-frequency heating coil having a length twice the length of the part to be hardened of the workpiece is used to harden the part of the workpiece. It is placed on the center of an unhardened workpiece that has been cut to length, and then the unhardened workpiece is heated and cooled by passing a high-frequency current through a high-frequency heating coil while rotating the unhardened workpiece around its longitudinal direction. from, isometric 2
Cut and separate into individual pieces.

Further, the method for induction hardening a shaft-like workpiece according to the invention according to claim 2 includes: In the induction hardening method for a second axial workpiece consisting of a second non-hardened portion of a portion and a second hardened portion of the other end portion, the first non-hardened portion, the first hardened portion , a second hardened part and a second non-hardened part form an unhardened axial workpiece integrally formed in series in the longitudinal direction, and the first and second hardened parts of this unhardened workpiece High-frequency heating coils corresponding to the hardened parts are placed on these first and second hardened parts, and then, while rotating the unhardened workpiece around its longitudinal direction,
A high-frequency current is applied to the high-frequency heating coil to heat and cool the first and second hardened parts, and then the first and second hardened parts are cut and separated into a first shaft-like workpiece and a second shaft-like workpiece.

In the invention of claim 1, a high-frequency heating coil is placed on the central part of the unhardened workpiece, and then, while rotating the unhardened workpiece around its longitudinal direction, a high-frequency current is applied to the high-frequency heating coil. After energizing and cooling, cut into two pieces of equal length.

In the invention of claim 2, high-frequency heating coils are placed on the first and second hardened parts of the unhardened workpiece, and then, while rotating the unhardened workpiece around its longitudinal direction,
A high-frequency current is applied to the high-frequency heating coil to heat and cool the first and second hardened parts, and then the first and second hardened parts are cut and separated into a first shaft-like workpiece and a second shaft-like workpiece.

<Example> Hereinafter, the present invention will be described in detail with reference to the drawings. Taking as an example a case in which a large number of steel pipes of the same shape and a certain length are hardened, leaving the vicinity of one end, the high frequency of the first example will be explained. The hardening method will be explained.

1 to 3 are explanatory diagrams of an induction hardening method according to a first embodiment of the present invention, and FIGS. 1 and 2 are front explanatory diagrams of an induction hardening apparatus that can realize this method, respectively. FIG. 3 is a front view of the steel pipe.

The total length shown in Figure 3 below! steel pipe 1, near the - end 1
A case will be described in which a part to be hardened 1b having a length n excluding the length m of a is hardened. In advance, a plurality of steel pipes 2 shown in FIG. 1, which are cut into lengths of 2° C. and have the same diameter as the steel pipe 1, are prepared.

First, the high frequency heating device will be explained.

In Figure 1, the length of 3 in the longitudinal direction is (2ρ-2m)
This is a saddle-shaped semi-open high-frequency heating coil, and the diameter of the semicircular portions 3a formed at both ends in the longitudinal direction is selected to correspond to the diameter of the steel pipe 2. High frequency heating coil 3
A spacer (not shown) is removed, and when the high-frequency heating coil 3 heats the steel pipe 2, the high-frequency heating coil 3 is placed on the steel pipe 2 via this spacer. 4 is a jacket that injects quenching cooling liquid onto the steel pipe 2 heated by the high-frequency heating coil 3.

Next, a method of hardening the steel pipe 2 except for the vicinity of the end portion using the above-mentioned induction hardening apparatus will be described.

After gripping both ends of the steel pipe 2 with a chuck (not shown) or the like, the high-frequency heating coil 3 is lowered by a high-frequency heating coil lifting device (not shown) so that the longitudinal center of the high-frequency heating coil 3 is located at the center of the steel pipe 2. High frequency heating coil 3
is placed on the steel pipe 2.

Next, a high-frequency current is applied to the high-frequency heating coil 3 for a predetermined period of time while the steel pipe 2 is rotated about its longitudinal direction by a work rotating device (not shown). Thereafter, cooling liquid is injected from the jacket 4 onto the steel pipe 2 to harden the steel pipe 2.

Next, the high-frequency heating coil 3 is raised by the high-frequency heating coil lifting device, and then the chuck and the like are loosened and the steel pipe 2 is removed. Then, by cutting the steel pipe 2 at the center, a two-wood steel pipe 1 is obtained, in which a length m of one end portion 1a is left and a hardened portion 1b having a length n is hardened.

A large number of steel pipes 1 can be obtained by sequentially performing similar quenching on other steel pipes 2.

Next, the induction hardening method of the second embodiment will be explained using two types of stepped shaft-shaped workpieces.

4 to 8 are explanatory diagrams of an induction hardening method according to a second embodiment of the present invention, and FIGS. 4, 5, and 6 respectively show an induction hardening apparatus that can realize this method. , a front explanatory view, a plane explanatory view, a cross-sectional view taken along the line B-B in FIG. be.

As shown in FIG. 7, a stepped shaft-like workpiece (first shaft-like workpiece) 10 that is rotationally symmetrical and has a total length p has a part to be hardened 1 that has a length q.
2 (first hardened part) and non-hardened part 11 (of length pq)
(first non-quenched portion) and has a ridge. In addition, as shown in Fig. 8, a stepped shaft-like workpiece (second
The shaft-shaped workpiece 20 consists of a hardened part 22 (second hardened part) having a length r and a non-hardened part 21 (second non-hardened part) having a length rs. Note that the diameters of the hardened portions 12 and 22 are equal in this case.

As shown in FIG. 4, an unhardened shaft-like workpiece having the same shape as the stepped shaft-like workpieces 10 and 20 are brought into contact with and integrated at the ends of the hardened parts 12 and 22. 70 is formed in advance.

30 is one saddle-shaped semi-open high-frequency heating coil corresponding to the parts 12 and 22 to be hardened, and 40 is a jacket for injecting a cooling liquid onto the heated parts 12 and 22 to be hardened.

The high-frequency heating coil 30 is placed on the parts 12 and 22 to be hardened of the workpiece 70, and while the workpiece 70 is rotated about its longitudinal direction by a rotating device (not shown), a high-frequency current is applied to the high-frequency heating coil 30 for a predetermined period of time. , a cooling liquid is injected from 40 to the jacket 1 to harden the parts 12 and 22 to be hardened. After this, the hardened part 1 of the workpiece 70
Stepped shaft-shaped works 10 and 20 are obtained by cutting the boundary portion between 2 and 22.

In any of the above examples, in the last step
At the end of the hardened workpiece obtained by cutting, a uniform hardened layer 101 is formed up to the end surface of the shaft-like workpiece, as shown in FIG. 9(a).

When quenching shaft-shaped workpieces one by one as in the conventional method without using the method of the above embodiment, leaving the vicinity of one end intact, a uniform hardened layer is usually formed on the end face of the workpiece in this way. As shown in FIG. 9(C), a hardened layer 103 that is too deep may be formed and quench cracks may occur, or as shown in FIG. 9(d), the hardened layer 103 may be incompletely hardened. Layer 104 is often formed.

Therefore, in order to avoid forming a hardened layer that is too deep or incomplete, a burn-out portion 102 may be intentionally formed near the end face of the workpiece, as shown in FIG. 9(b). Even without doing such a thing, the method of this embodiment has the advantage that a desired uniform hardened layer can be formed all the way to the end surface of the workpiece.

It goes without saying that even after the workpiece has been hardened as described above, various processes can be performed on the portions that have not been hardened.

<Effects of the Invention> As explained above, the induction hardening method of the invention of claim 1 is capable of hardening a plurality of cylindrical, cylindrical, or axial workpieces of the same shape and length twice the length of the part to be hardened. Using one long saddle-shaped semi-open high-frequency heating coil, the central part of an unhardened workpiece is cut to the length of two workpieces. After hardening, the center part of the unhardened workpiece is cut into two workpieces of equal length. disconnect. Therefore, in one quenching operation, 2
Because individual workpieces can be hardened, the hardening work requires less effort than conventional induction hardening methods.

Further, in the induction hardening method of the invention of claim 2, the two types of workpieces are integrated by abutting the ends of the hardened parts of the two types of workpieces, each consisting of a hardened part and a non-hardened part. An unhardened axial workpiece with a shape of Cut the boundary of the part 2
Get different types of work. Therefore, since two types of workpieces can be hardened in one hardening operation, the time and effort required for the hardening operation is reduced compared to the conventional induction hardening method.

Furthermore, the induction hardening method of either invention has the advantage that a uniform hardened layer is formed up to the cut end surface of the workpiece.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams of an induction hardening method according to a first embodiment of the present invention, and FIGS. 1 and 2 are front explanatory diagrams of an induction hardening apparatus that can realize this method, respectively. FIG. 3 is a front view of the steel pipe. 4 to 8 are explanatory diagrams of an induction hardening method according to a second embodiment of the present invention, and FIGS. 4, 5, and 6 respectively show an induction hardening apparatus that can realize this method. , a front explanatory view, a plane explanatory view, a cross-sectional view taken along the line B-B in FIG. be. FIGS. 9(a) to 9(d) are explanatory diagrams of the hardened layer formed at the end portion of the workpiece. 1.2... Steel pipe, 1a... One end portion, 1b...
Part to be hardened, 3...High frequency heating coil, 10.20
...Stepped shaft-shaped workpiece, 11.21... Non-hardened part, 12.22... Hardened part, 30... High frequency heating coil. Patent applicant: Fuji Electronics Industry Co., Ltd., agent: Takaharu Ohnishi, patent attorney

Claims (2)

[Claims] (1) In an induction hardening method in which a plurality of cylindrical or cylindrical axial workpieces of the same shape and length are hardened, leaving the vicinity of one end of the workpieces, A long saddle-shaped semi-open high-frequency heating coil is placed on the center of the unhardened work cut into two lengths, and then the unhardened work is heated in the longitudinal direction. A method for induction hardening a shaft-like workpiece, which comprises heating and cooling the workpiece by applying a high-frequency current to a high-frequency heating coil while rotating as a shaft, and then cutting and separating the workpieces into two workpieces of equal length. (2) A first axial workpiece consisting of a first non-hardened part at one end and a first hardened part at the other end, a second non-hardened part at one end, and a second hardened part at the other end. In an induction hardening method with a second axial workpiece consisting of a hardened part, the first non-hardened part, the first hardened part, the second hardened part and the second non-hardened part are An unhardened axial workpiece is formed in series and integrally in the longitudinal direction, and high-frequency heating coils corresponding to the first and second hardened parts of the unhardened workpiece are connected to the first and second hardened parts. Place it on the part to be hardened, and then rotate the unhardened workpiece around its longitudinal direction,
A shaft-shaped workpiece characterized in that the first and second hardened parts are heated and cooled by passing a high-frequency current through the high-frequency heating coil, and then cut and separated into a first shaft-shaped workpiece and a second shaft-shaped workpiece. Induction hardening method for workpieces.