JPH069717Y2 - Anvil electrode for electric upsetter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an anvil electrode for electrically heating and upsetting a rod-shaped material.

(Prior Art) Conventionally, a conductive material such as a copper alloy, a die steel, and an austenitic stainless steel has been used as an anvil electrode for an electric upsetter. In such anvil electrodes, the part where the material first comes into contact has the highest temperature and is subject to severe wear, so for the purpose of improving durability, ion nitriding and other surface treatments that are common means in molds are used. It has been attempted to increase hardness by applying.

However, the electric upsetter is required to have electric conductivity and heat retention to prevent heat transfer from the material, unlike the ordinary mold, because the electric heating molding is performed. With a simple Cu-based or Fe-based electrode, the electrical resistance is small, so the amount of heat generated by the anvil itself is small and the thermal conductivity is high. Therefore, it lacks heat retention and the heat drawn from the material is large. In the part away from the heat, heat may move to the anvil side, and defects such as wrinkles, uneven thickness and buckling may occur on the product.

Especially when molding the intake and exhaust valves of the engine, it is necessary to increase the ratio of the umbrella diameter to the shaft diameter, that is, the upset ratio in order to increase the intake and exhaust efficiency, so use a heat-resistant alloy with poor formability such as Inconel. When the exhaust valve used is upset, the above defects are likely to occur.

Therefore, the present inventors have proposed an anvil electrode made of a Ni-based or Co-based heat-resistant superalloy according to Japanese Patent Laid-Open No. 64-57940 as a suitable material for processing an Inconel material.

In addition, as a heat-insulating material, Japanese Patent Laid-Open No. 62-22023
There are those in which a conductive ceramic plate (Cyan) is fixed on the surface as in 9, and those in which a heat resistant insulating layer is lined on the inner peripheral surface of the die that regulates the outer peripheral surface of the product, as in the case of Shokai 56-122532. .

(Problems to be Solved by the Invention) In the above-mentioned conventional example, it is difficult to firmly fix the ceramic plate firmly to the one using the conductive ceramic plate, and a certain thickness is required to withstand the molding load. Is required. However, it is considered that it is not easy to set the resistance value of the anvil within a desired range because the electric resistance of the ceramic plate is high although it is conductive.

In addition, the former one using the heat-resistant superalloy has the same drawbacks. Moreover, even if it is suitable for forming the exhaust valve, if the same anvil electrode is used for the upset of the intake valve, the intake valve will be exhausted. A material having a lower heat resistance than that of the valve is used, and since the material also has a low electric resistance, the amount of current increases, but the amount of heat generated by the material decreases, and conversely the amount of heat generated by the anvil electrode increases. For this reason, the amount of heating of the material is insufficient, resulting in a defective product, and the electrode is overheated, which is likely to cause early wear and damage, and large power loss.

As described above, even though it is suitable for the exhaust valve, there is a problem for the intake valve, and it is difficult to deal with it.

Further, the one having an insulating layer lined on the inner peripheral surface of the die is
It is suitable for processing to increase the diameter of the material to form a cylindrical surface, but it cannot be applied to processing that does not use a die such as intake and exhaust valves.

(Means for Solving the Problems) The present invention has been made in view of the above points, and an electric upsetter for upsetting a material by pressing the end surface of a rod-shaped material made of a heat-resistant superalloy against an electrode to electrically heat the material. In the anvil electrode of, in the portion where the rod-shaped material of the electrode abuts,
An intermetallic compound comprising at least one of TiAl, Ni ₃ Al, and Ni ₃ (AlTi) is used.

(Function) By using the above-mentioned material for the anvil electrode, an appropriate amount of heat generation and heat retention can be obtained, and since the heat is not drawn from the material, the deformation of the material is not hindered.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, 1 is an anvil electrode, W is a material to be processed,
It is made of a heat-resistant superalloy for forming an intake / exhaust valve of an engine, and 2 is a power source that heats the material W inside and contact surfaces of the anvil electrode 1 while applying pressure to the anvil electrode 1 to perform upset processing. The contact position of the material W with respect to the anvil electrode 1 is sequentially changed and used so that wear is averaged.

The material of the anvil electrode 1 is TiAl, Ni ₃ Al, Ni ₃ (AlTi)
An intermetallic compound consisting of at least one of
The stress, that is, the proof stress when a constant permanent strain occurs, for example, in TiAl, the proof stress against a permanent set of 0.2% is as shown in FIG. The material is approximately 1000, for example
Since the anvil electrode 1 has a large heat capacity even if it begins to soften at ℃, its surface is kept at about 600 ℃ at a lower temperature and shows the highest proof stress, but at other temperatures, the proof stress decreases.
Wear is less likely to occur because the pressure is reduced by softening and increasing the diameter of the material. Moreover, since the electric resistance and the heat transfer resistance are appropriately high, both the heat generating property and the heat retaining property are good. In addition, Ni ₃ (AlT
i) has the highest yield strength at about 800 to 1000 ° C and Ni ₃ Al at about 1000 ° C, and is suitable for use in a higher temperature range than TiAl, and such properties have been conventionally known.

Next, in the anvil electrode 5 in the embodiment shown in FIG. 2, the working part 7 is detachably fixed to the base part 6 made of carbon steel with the bolts 8, and the intermetallic compound is used only in the working part 7. By doing so, the amount of expensive materials used can be reduced without degrading the performance.

When the conventional anvil having low heat retention is used, the work W is deformed by heat drawing of the contact portion and wrinkles a are generated as shown in FIG. 4 (a).
As shown in (b), a product with no wrinkles is formed and a product without scratches is obtained.

Next, an embodiment will be described in which the working rate is increased by increasing the amount of electricity applied to the material while utilizing the heat retaining properties of ceramics such as metal nitrides, carbides, borides, and oxides.

The anvil electrode 10 shown in FIG. 5 has a plurality of ring grooves scattered on the surface of the base of the intermetallic compound, the conductive portion 12 is left in the center, and the heat retaining ring 13 is embedded in the ring groove. The ceramics are thermally sprayed, press-fitted into the heat retaining ring 13,
It can be attached by brazing.

In the anvil electrode 10, the tip of the rod-shaped work W is pressed against the conductive portion 12 to be energized, and the work tip is upset by the heat generated in the pressed portion. Although the anvil electrode also rises in temperature during work, it is colder than the work.Therefore, the work tends to be cooled, but since the expanded diameter part contacts the heat retaining ring 13 with high heat transfer resistance, it is not cooled and the expansion effect is delayed. Proceed without. Immediately after the start of the upset, the pressure receiving area is small and thus the surface pressure against the heat retaining ring is large, but the heat insulating material has a large amount of wear resistance, and therefore the amount of wear is small.

The anvil electrode 15 in FIG. 6 is a conductive portion concentric with the electrode 15.
17 and heat retaining rings 18 and 19 embedded in concentric annular grooves provided inside and outside thereof, and the materials thereof are the same as those in FIG. In this embodiment, since a part of the expanded diameter portion of the material W is separated from the heat retaining rings 18 and 19, the heat retaining action is reduced, but the conductive portion 17 has a large area and may be brought into contact with any of the ring-shaped portions. Therefore, the wear is small.

In the anvil electrode 20 of FIG. 7, a plurality of columnar portions 22 extend upward from the conductive portion 21, and a disc-shaped heat insulating material 23 that surrounds the outer periphery of all the columnar portions 22 is attached. The operation of this electrode 10 is the same as that of FIG.

In the embodiment of FIGS. 5 to 7, most of the pressure applied to the material W is transmitted from the expanded diameter portion to the heat retaining portion, and the pressure of the conductive portion is gradually reduced. Since the heat retaining portion is made of a material having heat resistance and wear resistance, the heat retaining portion is less worn, and the pressure of the conductive portion is low, so that the wear of the portion is also reduced. FIG. 8 compares the anvil electrode 15 of FIG. 6 with an electrode made of stainless steel SUS303 only, which does not use an intermetallic compound at the base. It is shown in.

In FIG. 8, a curve A shows the change in the number of shots and the step h of the product W using the anvil electrode 15 of the present invention, and a curve B.
Indicates that with an anvil electrode of SUS303, and the quality limit is h = 0.9 mm, the former is about 3500, whereas the latter is only about 400.

(Effect of the invention) As described above, since the work surface of the anvil electrode is upset by using an intermetallic compound having high heat resistance and abrasion resistance, there is little wear of the electrode and high quality products are continuously produced. Can be produced.

[Brief description of drawings]

1 (a) and 1 (b) are a plan view and a vertical sectional view of an embodiment of the present invention,
2 (a) and (b) show another embodiment, FIG. 3 shows a yield strength temperature curve of anvil material, and FIGS. 4 (a) and (b) are longitudinal sectional views of products according to the prior art and the present invention. FIGS. 5, 6, and 7 show different examples, and FIG. 8 is a comparative chart of anvil life. 1,5,10,15,20 …… Anvil electrode, W …… Material

Claims (1)

[Scope of utility model registration request] 1. An anvil electrode of an electric upsetter for pressing an end face of a rod-shaped material made of a heat-resistant superalloy against an electrode to electrically heat the material to TiAl, Ni at a portion where the rod-shaped material of the electrode abuts. An anvil electrode for an electric upsetter characterized by using an intermetallic compound comprising at least one of ₃ Al and Ni ₃ (AlTi).