JP5913792B2 - Molding method and molding apparatus - Google Patents

Description

  The present invention relates to a technique for forming a titanium alloy material. In particular, the present invention relates to a spinning forming technique of a titanium alloy material.

  Ironing spinning forming (including rotating ironing processing) and draw spinning forming are representative processing techniques for low-cost forming and low-cost production of plate products. This type of processing technology has heretofore been mainly applied to rotationally symmetric products. However, in recent years, an eccentric NC spinning molding technique (apparatus) has been developed (see, for example, Japanese Patent Application Laid-Open No. 2005-211969) and has been put into practical use. As a result, products having shapes other than simple rotational symmetry, such as elliptical truncated cones and truncated pyramids, have begun to be provided.

  By the way, since pure titanium material has small proof stress and is rich in ductility, it has been processed by the above spinning molding.

  However, titanium alloys have been said to be impossible to process by spinning molding because of their high yield strength and poor ductility.

  Carbon reinforcement fibers (CFRP) are attracting attention as structural materials for aircraft. However, CFRP alone does not constitute an aircraft. For example, a blade leading edge that requires a destructive energy absorption characteristic or a location (member) around a nacelle that requires high-temperature strength cannot be configured with CFRP. At present, such a part must be made of a metal material. By the way, for example, when the part is constituted by an Al alloy plate and the Al alloy plate and CFRP are joined, the potential difference between the Al alloy and the carbon fiber is relatively large in the joined part. Corrosion is likely to occur. Moreover, there is a large difference in thermal expansion between the Al alloy and CFRP. On the other hand, if a titanium alloy is employed, the above-described drawbacks are greatly improved. That is, the titanium alloy and the carbon fiber have similar electrochemical characteristics, and the titanium alloy and CFRP have a characteristic that a difference in thermal expansion is small. For these reasons, there has been a strong demand for the above-mentioned parts and the like to be made of a titanium alloy. However, as described above, titanium alloy has a high yield strength and poor ductility, so it was difficult to form the blade leading edge portion and the nacelle surrounding portion with the titanium alloy by spinning molding. .

JP-A-5-38525 JP-A-5-104160

  Patent Document 1 discloses a method of forming a workpiece from sheet metal in a forming apparatus, particularly a spinning apparatus that heat-treats the sheet metal before, during or after the forming step, wherein the heat treatment is performed by induction heating of the workpiece. "Method implemented in" "The apparatus is operated as follows: after clamping the workpiece 2, heat treatment is performed immediately or spinning is performed as usual using a spinning roller (not shown). When the heat treatment is performed, the induction heating coil 5 and the rapid cooling nozzle 6 are moved toward the workpiece 2 by a predetermined method, and the workpiece maintains its spinning process rotation speed. The induction heating coil 5 is actuated via an opening / closing device (not shown) and further supplies water to the quenching nozzle 6 (not shown). When the workpiece 2 passes under the induction heating coil 5, the workpiece 2 is heated to the required temperature in the cross-sectional direction and then immediately quenched by passing it through the quench nozzle 6. This step is carried out until at least one revolution of the workpiece 2. In this way, the partially molded workpiece is to achieve the desired degree of strain hardening in sufficient deformation or finish spinning. The finished workpiece can be solution heat treated, and another spinning step can be performed to remove the distortion caused by the heat treatment. Is imposed. "

  From this Patent Document 1, it can be seen that when spinning forming a titanium alloy material, it is heated by induction heating. However, it is unclear what kind of heating is performed by induction heating. That is, referring to the description of the cited document 1, it is unclear how to make the blade leading edge portion or the nacelle surrounding portion with the titanium alloy plate. Therefore, even with reference to Patent Document 1, the blade leading edge portion and the nacelle surrounding portion could not be formed by spinning forming with a titanium alloy plate.

  Patent Document 2 states that “a method of spinning a material plate into a secondary molded product, in particular, at the bottom of a container, and tightening the material plate around it and pushing it into the clearance until a finished dimension is obtained”. The high temperature operating temperature for spinning is below the recrystallization temperature of the blank by two-stage heating, and the entire blank is basically heated to the first temperature below the operating temperature and held at that temperature. Further, only a part of the material plate is heated to the operating temperature before spinning. The method of metal spinning the material plate into a secondary molded product. “The material plate is heated to the first temperature by circulating hot air. There is disclosure of "the above method wherein the individual parts are heated to operating temperature for non-coherent light or coherent light (infrared)". However, the metal material described in Patent Document 2 is only an Al alloy. There is no disclosure of titanium alloys.

  By the way, using the apparatus disclosed in Patent Document 2, it was not possible to configure the blade leading edge portion or the nacelle surrounding portion with a titanium alloy plate. For example, damage such as a crack occurred in a titanium alloy plate.

  Therefore, the problem to be solved by the present invention is to provide a technique capable of constructing, for example, a part of an aircraft wing leading edge or a nacelle by spinning forming from a titanium alloy plate having a high yield strength and poor ductility. It is to be.

  This is because, as a result of studies conducted by the inventors of the present application on the difficulty in spinning a titanium alloy, the titanium alloy has high yield strength and poor ductility. Came to understand. Therefore, in order to reduce the yield strength and increase the ductility, an attempt was made to perform spinning forming in a state where the titanium alloy was heated. However, contrary to expectations, the resulting molded product was greatly damaged. As a result of further investigation on the cause, it has been found that the titanium alloy is generally heated. In other words, since the spinning molded part was also heated, the proof strength of the molded part was also small, and therefore it was found that damage was caused by the stress associated with processing. And even if it heated a titanium alloy material, it turned out that the shape | molded location is preferably released | released from a heating state as quickly as possible. In other words, it has been found that it is important that the heating site is a local point of action (near the point of action) on which the rod-shaped tool of the spinning forming apparatus acts.

  The present invention has been achieved based on the above findings.

That is, the above problem is
A method of forming a titanium alloy material by spinning forming using a rod-shaped tool,
The present invention is solved by a spinning method of titanium alloy material characterized by comprising a heat forming step of locally heating and forming an action point on the titanium alloy material by the rod-shaped tool by high-frequency induction heating at the time of spinning forming. .

Also, a method of forming a titanium alloy material by spinning forming using a rod-shaped tool and a mold,
At the time of spinning molding, a high temperature induction heating, a heating molding step for locally heating and molding the action point on the titanium alloy material by the rod-shaped tool,
The titanium alloy material spinning molding method comprising: a cooling step in which a molded part in the heat forming step abuts on the mold and the molded part is cooled by heat radiation from the mold. Is done.

  The titanium alloy material spinning forming method is preferably characterized in that a high-frequency induction heating coil is set between an unformed portion of the titanium alloy material and a rod-shaped tool to perform local heating. This is solved by the titanium alloy material spinning forming method.

  The titanium alloy material spinning forming method is preferably solved by a titanium alloy material spinning forming method characterized in that heating is not performed in a formed part.

  Further, the titanium alloy material spinning forming method described above is solved by the titanium alloy material spinning forming method, wherein the spinning forming is draw spinning forming or iron spinning forming.

The above issues are
A titanium alloy material spinning molding apparatus for molding a titanium alloy material by spinning molding,
The molding device includes:
A rod-shaped tool;
A high frequency induction heating device,
The titanium is configured such that when the rod-shaped tool is allowed to act on the titanium alloy material, the high-frequency induction heating device locally heats the point of action of the rod-shaped tool on the titanium alloy material. It is solved by an alloy material spinning forming apparatus.
Further, the titanium alloy material spinning forming apparatus, preferably, the forming apparatus further includes a forming die having a predetermined shape, and the rod-shaped tool is disposed on the titanium alloy material arranged in the forming die. This is solved by a spinning apparatus for spinning a titanium alloy material, wherein the high-frequency induction heating device is configured to locally heat the point of action of the rod-shaped tool on the titanium alloy material.

  Further, in the titanium alloy material spinning forming apparatus, preferably, the induction heating coil of the high frequency induction heating device is disposed between the unformed portion of the titanium alloy material and the rod-shaped tool to perform local heating. This is solved by a titanium alloy material spinning forming device.

  High-strength titanium alloy material can be formed by spinning forming. Up to now, it has been considered difficult to spin-form titanium alloy materials, but it is possible to use spinning molding technology that does not cost much, and although the titanium alloy cost of the material itself is high, Since the cost does not increase, titanium alloy products can be obtained at a relatively low cost. For products in the field of high-mix low-volume production, such as aircraft parts, the gospel is very large.

  In the high-frequency induction heating device adopted by the present invention, the amount of heat generated in the titanium alloy material is inversely proportional to the square of the distance between the induction coil and the titanium alloy material, so that the temperature is high at locations where the distance from the induction coil is short. And is hardly heated at locations far from the induction coil. Therefore, if the induction coil is disposed between the rod-shaped member of the spinning forming apparatus and the titanium alloy material (titanium alloy material in an unprocessed portion) and close to the titanium alloy material, spinning forming will be performed. Only the position to be touched is heated locally. And the temperature in other parts becomes comparatively low. In particular, at the location where the spinning molding has been completed, the heating is weak because it is far from the induction coil. As a result, that is, the proof stress of the titanium alloy material is recovered as the temperature decreases, and damage is unlikely to occur.

  By the way, as a heating means, a hot air spraying technique can be considered besides the induction heating method. However, in the hot air spray technique, even if the hot air spray location is local, the hot air sprayed spreads in all directions, and local heating is difficult to obtain. For this reason, the feature “the rate of occurrence of defective products such as fractures” exhibited by the present invention was not obtained.

  As a heating means, a spot laser beam irradiation technique is also conceivable. However, it is difficult to irradiate a titanium alloy material that rotates together with a rotating mandrel in a spot manner without being obstructed by a rod-shaped tool, and it is far from practical use.

  The present invention does not require expensive equipment. With simple equipment, titanium alloy products can be obtained easily and at low cost.

Schematic of titanium alloy material spinning forming apparatus according to the present invention

  The first invention is a molding method. In this method, a titanium alloy material is formed by spinning forming using a rod-shaped tool (for example, a spatula: a processing roller: a roller member). In particular, it is a method of forming a titanium alloy material by spinning forming using a rod-shaped tool and a forming die (mandrel). Spinning molding includes draw spinning molding and ironing spinning molding, which can be applied in any case. However, considering that local heating is required, it is preferably the case of ironing and spinning because of its ease. The titanium alloy material is particularly a high-strength titanium alloy material. For example, it is a titanium alloy material having a proof stress of 340 MPa or more (particularly 900 MPa or more, 1500 MPa or less: the value is a value at 25 ° C.). This method has a thermoforming step of forming by locally heating an action point on a titanium alloy material (plate) by a rod-shaped tool by high-frequency induction heating during spinning forming. Preferably, the method further includes a cooling step in which the molded portion by the heat molding step is brought into contact with the mold and the molded portion is cooled by heat radiation from the mold. The local heating by the high frequency induction heating is executed by, for example, arranging (setting) a high frequency induction heating coil between an unformed portion of a titanium alloy material (plate) and a rod-shaped tool. If the local heating method as described above is employed, heating is not performed at the molded portion.

  The second invention is a molding apparatus. This is a titanium alloy material spinning molding apparatus for molding a titanium alloy material by spinning molding. In particular, it is a titanium alloy material spinning forming apparatus in which the above forming method is executed. This apparatus has a predetermined-shaped forming die, a rod-shaped tool, and a high-frequency induction heating apparatus. And when making the said rod-shaped tool act with respect to the said titanium alloy material distribute | arranged to the said shaping | molding die, the action point with respect to the said titanium alloy material by the said rod-shaped tool is locally heated by the said high frequency induction heating apparatus. Has been. Preferably, the induction heating coil of the high-frequency induction heating device is arranged between the unformed portion of the titanium alloy material and the rod-shaped tool, and thereby the local heating is performed from the unformed portion to the formed portion. Has been.

  Hereinafter, the present invention will be described more specifically.

  FIG. 1 is a schematic view of a titanium alloy material spinning forming apparatus according to the present invention.

  In FIG. 1, 1 is a metal mold (mandrel). Reference numeral 2 denotes a bar-shaped tool (a spatula). Since the spinning molding apparatus having the above structure (the iron spinning molding apparatus) is well known in the art, detailed description thereof is omitted.

  3 is a high strength titanium alloy (for example, Ti-6Al-4V) plate.

  Reference numeral 4 denotes a high-frequency induction heating coil provided so as to be able to move in synchronization with the spatula 2 that moves along with the spinning molding. The high-frequency induction heating coil 4 is bent so that the tip portion 4a is as close as possible to the spatula 2 action point P with respect to the high-strength titanium alloy plate 3. For example, it is bent in such a manner that it is substantially “H” -shaped, substantially “K” -shaped, substantially “J” -shaped, or substantially “L” -shaped. The base end side 4 b of the high frequency induction heating coil 4 is disposed substantially parallel to the spatula 2. And between the spatula 2 and the portion 3a on the unformed side of the high strength titanium alloy plate 3, and in the vicinity of the point of action P by the spatula 2 (the spatula tip 2a) with respect to the high strength titanium alloy plate 3 The high frequency induction heating coil 4 is disposed so that the tip end portion 4a of the high frequency induction heating coil 4 is positioned.

  Spinning molding by the titanium alloy material spinning molding apparatus configured as described above (FIG. 1 shows an example of ironing spinning) will be described.

  The mandrel 1 is rotating around the axis. A high strength titanium alloy plate 3 is attached to the mandrel 1. Accordingly, the high yield strength titanium alloy plate 3 is also rotated with the rotation of the mandrel 1. At this time, as shown by the arrow in FIG. 1, the spatula 2 is moved as the molding progresses. Of course, the tip 2a of the spatula 2 is in pressure contact with the high strength titanium alloy plate 3. Thereby, the high yield strength titanium alloy plate 3 is formed along the shape of the mandrel 1. Up to this point, except for the use of the high-strength titanium alloy plate 3, the details are omitted because it is substantially the same as the conventional ironing spinning process.

  In the present embodiment, particularly during the forming process, a high-frequency current is passed through the high-frequency induction heating coil 4, and the high-strength titanium alloy plate 3 is locally heated (induction heating). That is, the high yield strength titanium alloy plate 3 with which the tip 2a of the spatula 2 is in pressure contact is locally heated. Here, the term “local” refers to a location near the point of action (pressure contact) P by the spatula tip 2a. Although it is in the vicinity of the action point P, it is mainly the portion 3a on the unformed side in the high yield strength titanium alloy plate 3 from the action point (pressure contact) P. Comparing the molded portion 3b and the unmolded portion 3a of the high strength titanium alloy plate 3, the molded portion 3b is relatively far from the high frequency induction heating coil 4 as can be seen from FIG. The degree to which the molded portion 3b is heated by high frequency induction heating is relatively low. In other words, it can also be said that the point of action (pressure contact) P and the part 3a on the unmolded side are heated by induction heating, and the other parts are not heated. .

  The spatula 2 gives a pressure (load) to a portion (working point: pressure contact) P) whose yield strength is reduced by high-temperature heating and whose ductility is improved, so that deformation (molding) is caused even with a small force. . That is, molding is performed with a small load. And reduction of the spatula load resulted in suppressing the surface roughness of the high yield strength titanium alloy plate 3, and a high quality product with good surface properties was obtained.

  Now, after the load by the spatula 2 is applied and the ironing process of the high-strength titanium alloy plate 3 to about half the thickness is performed, the portion 3b on the molded side is in the progress of molding (movement of the spatula 2). Along with this, it moves away from the high frequency induction heating coil 3. As a result, the portion 3b on the molded side is not heated. Moreover, the portion 3b on the molded side of the high-strength titanium alloy plate 3 is in close contact with the metal mandrel 1 (the portion 3a on the unmolded side is separated from the mandrel 1), so that the portion radiates heat. Is carried out effectively and the temperature drops rapidly. As a result, the proof stress of the portion 3b on the molded side is restored, and the proof stress is high. And even if a little stress is applied, damage such as cracks does not occur.

  In order to check the reproducibility, the ironing spinning process was repeated many times. As a result, damage such as a crack that occurred in the conventional case was not recognized at all in the titanium alloy product obtained in this embodiment.

1 Mandrel (molding die)
2 Spatula (bar-shaped tool)
2a Spatula tip 3 High strength titanium alloy plate 3a High strength titanium alloy plate unformed side portion 3b High strength titanium alloy plate formed side portion 4 High frequency induction heating coil 4a High frequency induction heating coil tip

Claims (8)

A method of forming a titanium alloy material having a yield strength at 25 ° C. of 340 MPa or more by iron spinning using a rod-shaped tool and a mold,
In ironing spinning molding, from previously locally heating the working point for the titanium alloy material according to the rod-shaped tool by a high-frequency induction heating by the high frequency induction coils, and hot forming step of forming,
A titanium alloy material spinning molding method, comprising: a cooling step in which a molded portion in the heat forming step abuts on the mold and the molded portion is cooled by heat radiation from the mold. The titanium alloy material spinning forming method according to claim 1, wherein the forming die is made of metal. The titanium alloy material spinning forming method according to claim 1 or 2, wherein a high-frequency induction coil is set between an unformed portion of the titanium alloy material and the rod-shaped tool to perform local heating. The titanium alloy material spinning forming method according to any one of claims 1 to 3, wherein heating is not performed in the formed portion. Strength at 25 ° C. by spinning molding ironing is a titanium alloy ironing spinning molding apparatus for molding a more titanium alloy 340 MPa,
The molding device includes:
A rod-shaped tool;
A high-frequency induction heating device;
A mold having a predetermined shape,
When the rod-shaped tool is allowed to act on the titanium alloy material disposed in the mold, the high-frequency induction heating device is configured to locally heat the point of application of the rod-shaped tool to the titanium alloy material in advance. together comprising Te, molding already place by heat radiation from the high-frequency induction heating device the molded portion is the mold that is molded from the action point is pre-heated locally for the titanium alloy material according to the rod-shaped tool by cooling A titanium alloy material spinning forming apparatus, characterized in that it is configured as described above. The titanium alloy material spinning forming apparatus according to claim 5, wherein the forming die is made of metal. The titanium alloy material spinning forming apparatus according to claim 5 or 6, wherein the high-frequency induction heating device includes a high-frequency induction coil. 8. The high-frequency induction coil of the high-frequency induction heating device is arranged between an unformed portion of the titanium alloy material and the rod-shaped tool so as to perform local heating. Titanium alloy material spinning forming equipment.

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