JPS6142298Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a heater for heating a hot forged part, and more particularly to a so-called partial heater for induction heating a part of a hot forged part.

Conventionally, as an apparatus for partially heating a metal material for hot forging, an apparatus configured as shown in FIGS. 1 and 2 is known. That is, in FIGS. 1 and 2, the reference numeral 1 indicates a partial heater as a whole, and this partial heater 1 forms a rectangular heating chamber 3 with a fireproof plate 2, and the upper and lower surfaces of this heating chamber 3 are A water-cooled induction coil 5 is arranged on the back side of the side fireproof plate 2 via an insulating plate 4, and a metal material is partially inserted into one side of the heating chamber 3 by a supply cylinder 6. 7
(for example, a round bar material) is intermittently pressed and moved toward the other side of the heating chamber 3 by a cross-feeding cylinder 8 disposed on one side of the heating chamber 3, and during the movement, the metal material 7 is heated by induction to reach the other side of the heating chamber 3 and to a predetermined temperature (e.g.
The metal material 7 heated to a temperature of 1230° C.±30° C. is taken out from the heating chamber 3 by a discharge cylinder 9.

By the way, as shown in FIG. 3, the heating chamber 3 has a top surface and a bottom surface formed by combining two fireproof plates 2a, 2a', 2b, and 2b', and both left and right ends of these top and bottom surfaces. Side fireproof plate 2 installed in the section
c, 2c', and the upper surface of the fireproof plate 2b, 2b' forming the bottom part is changed from one side to the other side (third
In the figure, the metal material moves from the left side to the right side. The fireproof plates 2b and 2b' forming the bottom surface are not directly heated by the induction coil 5, but the metal material 7 moves on the upper surface thereof while being heated, and ultimately the metal material 7 is heated, for example. Since the temperature reaches a high temperature of about 1230°C ± 30°C, the upper surface side of the fireproof plate 2b', especially the fireproof plate 2b' located on the front side in the moving direction of the metal material 7, is exposed to the heat from the heated metal material 7. It becomes quite high temperature due to heat conduction. On the other hand, on the lower surface side of the fireproof plates 2b and 2b', an induction coil 5 having a water-cooled structure is installed on the insulating plate 4.
Since the fireproof plates 2b,
The bottom side of 2b' is cooled, suppressing the temperature rise,
As a result, the temperature difference between the upper and lower surfaces of the fireproof plates 2, 2b' forming the bottom surface of the partial heater 1 becomes large. Further, the partial heater 1 as described above does not heat the entire metal material 7, but heats a part of the metal material 7, such as the tip, by inserting it into the heating chamber 3. The metal material 7 is the fireproof plate 2b forming the bottom part,
2b' and therefore its fireproof plate 2
b, 2b' will increase the temperature of the part that is in contact with the metal material 7, but in the conventional partial heater 1 described above, the fireproof plate 2 forming the bottom part
Since b and 2b' are substantially flat plate-like integral parts as shown in FIG. 4, the temperature difference between the part that is in contact with the high-temperature metal material 7 and the part that is not is large.

In this way, in the above conventional partial heater, the fireproof plates 2b, 2 forming the bottom part of the heating chamber 3 are
A large temperature difference occurs in b' not only in the thickness direction but also in the longitudinal direction, and as a result, the fireproof plates 2b and 2b' tend to break or crack due to internal stress due to the difference in thermal expansion. Therefore, there were problems such as a short service life of the fireproof plates 2b and 2b' and an increase in the frequency of their replacement.

This idea was made in view of the above circumstances, and aims to prevent breakage and cracking of the fireproof plate, especially the bottom part that comes into contact with heated metal materials, and to extend the service life of the fireproof plate. The object of the present invention is to provide a heating heater for hot forging that can be used for hot forging.

In other words, in a heater that inductively heats a metal material inserted into a heating chamber while moving it over the bottom surface, it is difficult to avoid a temperature difference between the top and bottom sides of the fireproof plate that forms the bottom surface. By absorbing the difference in the amount of thermal expansion based on the slits formed on the bottom surface of the fireproof board, and by dividing the fireproof board into multiple pieces in the longitudinal direction, the difference in temperature between each divided piece, that is, the difference in the amount of thermal expansion, can be absorbed by the slits formed on the bottom surface of the fireproof board. This minimizes the internal stress and prevents breakage and cracks from occurring.

An embodiment of this invention will be described below with reference to FIGS. 5 to 7. FIG. 5 is a schematic cross-sectional view showing the heating chamber 10 of the heater for hot forging according to this invention, and the induction coil and the insulating plate are omitted in this figure. Heating chamber 1 shown in Figure 5
0 is two fireproof plates 11a, 11 forming the upper surface part.
a', two fireproof plates 11b, 11b' forming the bottom part, and side fireproof plates 11c, 11c' arranged at both left and right ends of these top and bottom parts, forming a rectangular shape; Among these fireproof plates, the fireproof plates 11b and 11b' forming the bottom part are shown in FIGS. 3 and 4.
Unlike the conventional fireproof plates 2b and 2b' shown in the figure, a plurality of slits 12 are formed on the lower surface and the structure is divided into a plurality of pieces in the longitudinal direction. The same structure as the conventional fireproof board is used.

That is, the lower surfaces of the fireproof plates 11b and 11b' forming the bottom surface of the heating chamber 10 are provided with
As shown in FIGS. 5 and 6, a plurality of semicircular groove-shaped slits 12 are formed along the longitudinal direction. In addition, the fireproof plates 11b and 11 forming the bottom part
Of b', the fireproof plate 11' on the right in FIG. It is divided into a plurality of parts (divided into four in FIG. 7) in the direction of
A gap 14 of mm width (for example, about 2 mm) is provided,
The divided pieces 13a...13d are designed not to interfere with each other when any of the divided pieces 13a...13d thermally expands. Furthermore, the divided pieces 13a...13
The divided piece 13d located on the tip end side of the metal material 7 to be heated among the divided pieces 13d is different from the other divided pieces 13a...13c.
It is formed slightly thinner than the upper surface of the other divided pieces 13a...13c by several mm (for example, 5 mm).
Therefore, the tip of the metal material 7 inserted into the heating chamber 10 is placed away from the upper surface of the divided piece 13d.

The heating chamber 10, especially its bottom part, is covered with the above-mentioned fireproof plate 11.
According to the heating heater for hot forging (partial heater) constructed of the heaters 11b and 11b', the refractory plates 11b and 11b' forming the bottom part are heated from the metal material 7 which is heated by induction while moving on the upper surface side thereof. It receives heat and rises in temperature, and the lower side is cooled to some extent by an induction coil with a water-cooled structure, resulting in a temperature difference between the upper side and the lower side, resulting in a difference in the amount of thermal expansion. Since slits 12 for absorbing thermal expansion are formed on the lower surfaces of the plates 11b and 11b', expansion on the upper surface side and contraction on the lower surface side are allowed, and therefore internal stress due to the temperature difference between the upper surface side and the lower surface side is allowed. is not excessive, so no breaks or cracks occur. Note that the fireproof plates 11b, 1
1b' is allowed to expand and contract as described above, so it is conceivable that the fireproof plates 11b and 11b' may be curved so as to swell toward the upper surface. What is necessary is to make it concave and set it so that it becomes flat due to expansion and contraction that occurs during use. In addition, in a partial heater in which the heating chamber 10 is configured as described above, the heating chamber 10
The fireproof plates 11b and 11b' forming the bottom part of
As shown in FIG. 7, it is divided into a plurality of parts in the longitudinal direction, and gaps 14 are provided between each divided piece 13a...13d, so that, for example, the tip of the metal material 7 can be locally heated. , even if a temperature difference occurs in the longitudinal direction of the fireproof plate 11b' as a whole, each divided piece 1
3a...13d thermally expand independently, and the temperature difference of each divided piece 13a...13d itself becomes smaller, so the internal stress of the fireproof plate 11b' is
Even if there is a temperature difference in the longitudinal direction, it will not become excessive. In any case, the fireproof plate 11
b, 11b' will not break or crack even if a temperature difference occurs in the thickness direction and longitudinal direction. Furthermore, in the fireproof plate 11b', the divided piece 13d located on the tip side of the metal material 7 is thin,
Since its upper surface is lower than the upper surfaces of the other divided pieces 13a...13c, the moving metal material 7 will not get caught, and the tip of the metal material 7 can be locally heated for hot forging. When heated, the tip portion does not come into contact with the divided piece 13d, so the temperature distribution is made uniform, and the quality of the final product can therefore be improved.

In the above embodiment, the slit 12 is semicircular, but the slit in this invention may be of any shape other than the semicircular shape, such as rectangular or triangular, and the direction in which the slit is formed is The lower surface of the plates 11b, 11b' is not limited to the longitudinal direction, but may be inclined at a predetermined angle with respect to the longitudinal direction, and two types of slits may be provided along the longitudinal direction and the width direction.

As is clear from the above explanation, according to the heating heater for hot forging of this invention, a part of the metal material to be heated is inserted, and the heating chamber is used for induction heating while moving the metal material. A slit for absorbing thermal expansion is formed on the lower surface of the fireproof plate forming the bottom part, especially on the front side in the direction of movement of the metal material,
In addition, the fireproof plate is divided into a plurality of parts in a direction perpendicular to the direction of movement of the metal material, and a gap is provided between each divided piece, so that the thickness direction of the fireproof plate and the direction of movement of the metal material are perpendicular to each other. Even if a temperature difference and an accompanying difference in thermal expansion occur in both directions, the difference in thermal expansion is absorbed by the slits and gaps, and as a result, the internal stress of the fireproof plate does not become excessive, so that the fireproof plate does not break. It is possible to prevent the occurrence of cracks and cracks, and as a result, the service life of the fireproof plate can be extended.

[Brief explanation of the drawing]

Figure 1 is a plan view schematically showing the general structure of a conventional heating heater for hot forging, Figure 2 is a sectional view taken along the - line in Figure 1, and Figure 3 shows the structure of the heating chamber. 4 is an enlarged perspective view showing one of the fireproof plates forming the bottom of the heating chamber, FIG. 5 is a sectional view showing the structure of the heating chamber in an embodiment of the invention, and FIG. 6 5 is an enlarged view of the portion shown in FIG. 5, and FIG. 7 is an enlarged perspective view showing one of the fireproof plates forming the bottom portion of the heating chamber. 7...Metal material to be heated, 10...Heating chamber, 11
a, 11a', 11b, 11b', 11c, 11c'...
...Fireproof plate, 12...Slit, 13a, 13b,
13c, 13d...divided piece, 14... gap.

Claims (1)

[Scope of utility model registration request] Hot forging in which a part of the metal material to be heated is inserted into one side of a heating chamber formed by combining a plurality of fireproof plates, and the metal material is moved to the other side of the heating chamber and heated by induction. In the bottom-side fireproof plate on which the metal material is placed and moved, a slit for absorbing thermal expansion is formed on the lower surface of at least the fireproof plate on the front side in the direction of movement of the metal material, and the fireproof plate is A heating heater for hot forging, characterized in that it is divided into a plurality of parts in a direction perpendicular to the moving direction of the metal material, and a gap is provided between each divided piece.