JPS6323913Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a heating coil for use in hardening the surface of a long, large-diameter roller whose circumferential surface is continuously formed with high-height corrugations to a depth equal to or higher than the bottom of the corrugations.

For example, when a long bar or tube is fed in the axial direction, the drive roller R has a continuous wave pattern on its circumferential surface, as shown in FIG. This is to prevent it from rolling in any direction. The drive roller R has a large diameter for the transported material.
In the case of M ₁ , the crest of the wave, and in the case of small diameter M ₂ , the antinode or the vicinity of the wave bottom contact the transferred material and rotate, so at least the entire corrugation is imparted with wear resistance. It is desirable to be present.

By the way, the wave height of this type of drive roller is generally 20 mm or more. Therefore, in the same way as when induction heating and hardening the surface of a normal bar or tube material with a smooth circumferential surface, the roller R is rotated on its axis as shown in FIG. The shaped heating coil C' is wound in the circumferential direction of the roller R and moved relative to it to sequentially heat the circumferential surface, and the heated surface is sequentially rapidly cooled and quenched with the cooling fluid injected from the cooling ring J that follows this. However, since the magnetic flux is concentrated at the crest of the wave (even if heating is performed at various frequencies), if an attempt is made to heat the entire waveform, the area near the crest of the wave will overheat. For this reason, it is unavoidable that the area near the wave crest is rapidly cooled and quenched to form the hardened layer shown by h in Figure 2b when the temperature rises to the appropriate quenching temperature, and a hardened layer is formed from the midpoint to the bottom of the wave. Therefore, the object to be transferred has a large diameter. In the case of shared use with small diameters, extension of service life cannot be expected. If it is desired to form a hardened layer on the entire corrugated shape, the entire roller is hardened, but in this case, the entire roller is heated in an electric furnace to a specified hardening temperature and then cooled and hardened. Not only does it take a long time, but it also causes extremely large quenching distortions, so a straightening process is essential.

The present invention was developed to solve the above-mentioned problems, and the entire corrugation of the roll is hardened by induction heating means that requires a short processing time and hardly causes hardening distortion. A corrugated roller moving heating coil capable of forming a hardened layer is provided.

The corrugated roller moving heating coil according to the present invention will be explained according to an embodiment shown in FIGS. 3a and 3b.

As shown, the heating coil C is composed of parallel heating conductors 1a and 1b and oblique heating conductors 2a and 2b. The parallel heating conductors 1a and 1b
are conductors each extending a predetermined length in the axial direction apart from the wave crest of the roller R with a predetermined gap, with the axis X of the roller R being treated as the axis of symmetry. The diagonal heating conductor 2a connects the illustrated upper end of the parallel heating conductor 1a and the illustrated lower end of the parallel heating conductor 1b, and connects the roller R
It is a conductor that draws an elliptical major axis semicircular curve with a predetermined gap between the wave crest and the insulating material 3 at an intermediate position.
The leads 4 and 4 of the power supply E are connected near the respective insulated ends. The diagonal heating conductor 2b is a conductor that connects the illustrated upper end of the parallel heating conductor 1b and the illustrated lower end of the parallel heating conductor 1a, and forms an elliptical major axis semicircumferential curve with a predetermined gap from the wave crest of the roller R. be. Therefore, the heating coil C has a lead 4 connected to a power source E, one half of the diagonal heating conductor 2a, a parallel heating conductor 1b, a diagonal heating conductor 2b, and a parallel heating conductor 1.
A closed circuit consisting of the other half of the diagonal heating conductor 2a and the lead 4 is formed. Of course, the connection portion with the lead 4 is not limited to the intermediate position of the diagonal heating conductor 2, and the connection portion with the lead 4 may be provided on the parallel heating conductor 1.

In the heating coil c of the present invention constructed as described above, the magnetic flux φ ₁ generated from the parallel heating conductors 1a and 1b is perpendicular to the axis of the roller R as shown in FIG. Regardless of the wave bottom, the magnetic flux φ 2 is transmitted almost uniformly, although there is a difference in distance, and the magnetic flux φ ₂ generated from the diagonal heating conductors 2a and 2b is transmitted diagonally in a wave pattern as shown in FIG. 4b. Moreover, the heating coil C of the present invention is characterized in that it surrounds the roller R to be treated over a predetermined length range in the axial direction. The point is that the entire waveform in the vicinity of the connection with the diagonal heating conductor 2 (for example, the entire waveform in the portion indicated by R) is housed in a magnetic closed loop caused by the flow of locally countercurrent currents.

Therefore, if the roller R to be processed is rotated around its axis and the roller R and the heating coil C which is energized are moved relative to each other at a predetermined speed, the circumferential surface of the roller R facing the heating coil C will be sequentially waved over the entire circumference. Top. Antinode of the wave.
The roller R is heated almost uniformly to a predetermined hardening temperature regardless of the wave bottom, for example, by injecting cooling fluid from a cooling ring (not shown) that follows the heating coil C.
The entire circumferential corrugation is sequentially hardened to form a hardened layer.

An example of hardening a large diameter and long corrugated roller using the heating coil C of the present invention is shown below.

Example〇 Material to be treated Material: SCMnCr3 equivalent material Material hardness Hs38~40 Dimensions: Outer diameter…303mm Inner diameter…200mm Length…1350mm Wave height…20mm Wavelength…76mm 〇 Quenching device Power source: 3KHz 600KW Heating coil: Inventive heating coil Parallel heating conductor length: 300mm Cooling device: Tracking type cooling ring Heat treatment method: While rotating the above-mentioned material to be treated, the material to be treated is moved relative to the heating coil from one end to the other, and as the material moves relative to the heating coil. The peripheral surface of the heated material to be treated was rapidly cooled and hardened. The relative movement speed is 2mm/sec,
The cooling fluid used was a 0.5% PVA solution. The surrounding surface temperature of the material to be treated before quenching is 950 to 960℃ at the wave crest and 920 to 930℃ at the wave bottom.
It was showing.

The above-mentioned hardened material was subjected to tempering treatment for a predetermined time in an electric furnace.

〇 Accuracy test: A sample was cut out from the heat-treated material, and the hardness of the cross section was measured from the surface of each wave crest and wave bottom in the direction perpendicular to the axis, as shown in Figure 5a. Measure from the surface
The measurement was carried out every 0.5 mm from a depth of 0.5 mm, and the measured value from the wave crest is shown as A, and the measured value from the wave bottom is shown as B in Figure 5b. In addition, in Fig. 5c, the formed effective hardened layer (Hs65 or higher) pattern is indicated by crossed diagonal lines H.
The hardened layer (Hs55 or higher) pattern is indicated by diagonal lines h.

From the above reliability test results, the heating coil of the present invention can almost uniformly heat the circumferential surface of the large-diameter corrugated roller to the predetermined hardening temperature from the surface to a considerable depth, including the wave bottom, regardless of the wave crest, wave antinode, or wave bottom. It has been confirmed that it is possible to harden the entire corrugation of the corrugated roller and form a sufficiently thick hardened layer along the corrugation.

Meanwhile, the remarkable effectiveness of the heating coil of the present invention can be further demonstrated by comparing it with numerous experiments conducted by the inventor during the process of perfecting the heating coil. Examples of comparative experiments are shown below.

Comparative Experimental Example 1 〇 Specimen Tp...Same material and same dimensions as the previous example 〇 Power source...Same as the above example 〇 Heating coil...End face heating type coil Fc as shown in Fig. 6 Axial direction parallel conductor fp length; 300mm Circumferential arc-shaped conductor fa circumferential angle: 100゜〇 Heating method: While rotating the specimen Tp, the heating coil Fc is placed opposite the wave crest of the specimen Tp with a gap of 5 mm as shown in the figure. Electricity was applied for a minute to heat the rotating peripheral surface in place.

〇 Experimental results: The temperature did not rise to the point where it became red hot, and it was impossible to proceed with heating due to the inefficiency of the end heating type coil even if a current maximum output class power source was used for large diameter members. There was found.

Comparative Example 2 〇 Specimen Tp...Same material and same dimensions as the previous example 〇 Power source...Same as the above example 〇 Heating coil...Specimen as shown in Fig. 7
Coil Sc in the shape of two diagonal turns around the circumferential surface of Tp Inclination angle: 30゜〇 Heating method: The specimen Tp was rotated around its axis and moved relative to the current heating coil to heat the specimen. The relative movement speed was 2.5 mm/gec.

〇 Experimental results...The circumferential surface of the moving-heated specimen Tp was heated to a temperature of 1200 to 1300℃ at the wave crest, resulting in an overheated state, but the wave bottom was
It was found that the temperature could only rise to 750-780°C and quenching was impossible.

As mentioned above, the wave-shaped roller moving heating coil of the present invention, which was completed through numerous experiments including the above-mentioned comparative experiment example, suppresses the magnetic flux generated by accommodating a predetermined range of rollers entirely within a magnetic closed loop zone. In addition to using it with high efficiency, the directionality of the magnetic flux generated by the parallel heating conductor and the diagonal heating conductor is appropriately utilized, and the waveform is partially accommodated in a magnetic closed loop to sequentially move and heat the waveform. Therefore, it is characterized by being able to heat almost uniformly from the surface including the wave bottom to a considerable depth.

In addition, if the temperature of the peripheral surface to be treated cannot be raised to the specified quenching temperature by one movement heating due to the relationship between the power supply equipment and the diameter of the roller to be treated, Preheating transfer heating may be performed one or more times while energizing with a predetermined output.

This invention does not cause quenching distortion on the circumferential surface of the large-diameter corrugated roller, and the wave crest can be achieved in a short time. Antinode of the wave. Since it is possible to form a hardened layer of sufficient depth regardless of the corrugation bottom, it is highly effective in contributing to lowering the manufacturing cost and extending the service life of large-diameter corrugated rollers.

[Brief explanation of the drawing]

Fig. 1 is a front view of a large-diameter corrugated roller to which the present invention is applied, Figs. 2 a and b are a front view and a partial sectional view showing the quenched state using a conventional heating coil, and Figs. 3 a and 4b is a front view and a perspective view, respectively, of the corrugated roller moving heating coil of the present invention, FIGS. A partial cross-sectional view showing the hardness measurement position of the corrugated roller in which the present invention was implemented, a partial cross-sectional view showing a line graph of hardness measurement values, and a partial cross-sectional view showing the tendency of the hardened layer, and FIGS. 6 and 7 respectively show comparative experimental examples. FIG. 1a, 1b...Parallel heating conductor, 2a, 2b...
Diagonal heating conductor, C...corrugated roller moving heating coil, R...corrugated roller.

Claims (1)

[Scope of utility model registration request] When hardening a large-diameter roller that has a continuous wave pattern with high wave height on its circumferential surface to a considerable depth from the surface including the wave bottom, the heating coil is used to harden the surface of a large diameter roller to a considerable depth from the surface including the wave bottom. and a parallel heating conductor that can extend a predetermined length in the axial direction with a predetermined gap between the parallel heating conductors, and one end on one side and the other end on the other side of each of the parallel heating conductors are connected to each other by drawing an elliptical long axis semicircle curve. 1. A wave-type roller moving heating coil comprising an oblique heating conductor that can face the wave crest of a roller with a predetermined gap therebetween.