JPH03191003A - Elastic member containing intermetallic compound as essential body and manufacture thereof - Google Patents

Abstract

PURPOSE:To easily manufacture an elastic member containing intermetallic compound as essential body by locally pressing a mixing pressed body, which is obtd. by mixing plural elements at the prescribed composition ratio, and sequentially subjecting it to plastic-deformation and heat-treating it to form the intermetallic compound. CONSTITUTION:The raw material containing plural elements obtd. by mixing plural elements at the composition ratio for forming the intermetallic compound of TiNi, etc., is pressurized to obtain the mixing pressed body. This pressed body A is fitted to a forming device 10 composed of a core metal 11 fitted to a head 12 and a roller 13 through chuck 14. Successively, compressive force P is applied on the roller 13 while rotating the core metal 11 around the axial line. By this method, the above pressed body A is locally pressed between a spiral groove 15 in the core metal 11 and a groove 16 in the roller 13, and gradually subjected to plastic-deformation from upper end part toward the other end part to form the formed body A'. After that, the spring-like formed body A' obtd. with this is charged into a heating device and treated under temp. condition of forming the intermetallic compound. By this method, the elastic member of spring, etc., containing the intermetallic compound as the essential body, is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an elastic member such as a spring mainly composed of an intermetallic compound, and a method for manufacturing the same.

[Prior Art] The raw materials for conventional springs or elastic members that exhibit spring-like properties are generally metals such as steel or FRP.
It was a non-metal such as. However, recently, attention has been focused on intermetallic compounds that are lightweight and have excellent properties such as heat resistance and oxidation resistance. As an example of an intermetallic compound, T1^1.
Ti3Al, ^13 Ti.

Ni, ^I, and T1Ni having a shape memory effect are known. There are examples of coil spring manufacturing using bending for T1Ni, but although old Ti has good formability among intermetallic compounds, multiple heat treatments (softening annealing) are required for actual forming. It is much more difficult to form springs than metal. Furthermore, it was thought that it would be difficult to put other intermetallic compounds into practical use in springs.

It has also been considered to perform molding in advance before forming the intermetallic compound. For example, JP-A-61-2703
As seen in Japanese Patent Publication No. 53, an intermetallic compound having a desired shape is obtained by hot-pressing the raw material of the intermetallic compound and then firing it, and JP-A No. 62-7
As seen in Japanese Patent No. 0531, it has been proposed that the raw material for the intermetallic compound is degassed and then treated under predetermined molding pressure and temperature conditions.

[Problems to be Solved by the Invention] Even if preforming is performed before forming the intermetallic compound as in the prior art, it is impossible to obtain a product that requires bending with large deformation, such as a coil spring. It was possible.

The reason for this is that the three-dimensional objects made from the raw materials for intermetallic compounds are less uniform in their state before forming intermetallic compounds than normal metal materials, and may contain many vacancies and defects. This is because deformation tends to be uneven, and it cannot withstand plastic deformation or elongation caused by large bending processes.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method of manufacturing an elastic member of a desired shape mainly composed of an intermetallic compound without any problems, and an elastic member such as a spring mainly composed of an intermetallic compound.

[Means for Solving the Problems] The method of the present invention developed to achieve the above object includes a step of obtaining a raw material containing a plurality of elements mixed in a composition ratio that forms an intermetallic compound, and a step of adding the raw material to the raw material. a step of obtaining a mixed press-bonded body by applying pressure; and a step of locally pressing the mixed press-bonded body with a mold and moving the mixed press-bonded body from one end side of the mixed press-bonded body to the other end side in the above-mentioned pressing part. The method includes a step of obtaining a molded object having a desired shape by gradually plastically deforming it along a mold, and a step of treating the molded object under temperature conditions that form an intermetallic compound.

Examples of the elastic member include a coil spring, a leaf spring, a torsion bar, or a member exhibiting spring-like properties. The substance constituting the intermetallic compound may have at least one element as a metal.

The raw material needs to be mainly composed of a metal material, but may partially contain an intermetallic compound. Further, appropriate elements or compounds may be added for the purpose of improving various properties as a spring or facilitating molding. The raw material does not need to be a pure metal lump, and may be a solid solution or a composite made by plating or the like. The form of the raw materials before mixing is powder, flake, wire, foil, etc.

When the raw materials are in the form of powder or flakes, the mixture is extruded using a V-type mixer, ball mill, mixer, etc., or the mixture is compressed by hot pressing or CIP. Alternatively, the mixed raw materials may be packed into a metal pipe and forged using a swaging machine until it reaches a predetermined outer diameter.

In the case of linear raw materials, the raw material wires can be bundled or twisted together and then crimped together using a wire drawing machine or the like. In the case of foil-like raw materials, the foils can be laminated in the thickness direction or rolled after lamination and then crimped by rolling.

The mixed crimped body obtained by the above process has a considerably nonuniform structure compared to ordinary metal materials, and may contain many defects and pores, so if it is bent as it is, it will not be deformed. Progresses locally. For this reason, it is difficult to bend it to a predetermined curvature.

Therefore, in the present invention, the mixed pressure-bonded body is locally pressed by a die consisting of a core bar, a roller, etc., and the mixed pressure-bonded body is gradually bent while moving this pressing part relatively along the die. By doing so, a molded article having a desired shape is obtained.

[Function] Since the mixed crimped body is formed as described above, the deformation region of the mixed crimped body can be sufficiently shortened, and most of the deformed region is bent while being restrained, so there is no cracking in the deformed region. The mixed pressed body can be molded into a desired shape without causing problems such as deformation or non-uniform deformation.

Further, since compressive force is applied to the mixed press-bonded body by the mold at the same time as bending, it also has the effect of crushing the pores inherent in the mixed press-bonded body.

The above molding step may be performed cold, but the molding step may be performed warmly to reduce deformation resistance during molding.

When forming at a warm temperature, it is preferable that the temperature is below the temperature at which intermetallic compounds are formed. The molding may be performed at a warm temperature higher than the temperature at which the molding is performed.

In addition, before carrying out the said shaping|molding process, you may perform a pre-molding heat treatment. This treatment is, for example, annealing performed in a vacuum. By performing the pre-forming heat treatment, the processing strain that occurs when manufacturing the mixed pressed body is removed. In addition, the deformation resistance during molding is reduced, and the crimping surface of the mixed crimped body becomes stronger due to diffusion, so that the strength can be improved.

Further, this pre-forming heat treatment has the effect of diffusing or removing impurity components in the pressed mixed body. The pre-forming heat treatment is performed in air, inert gas, vacuum atmosphere, or a combination of these atmospheres. The processing temperature is generally below the temperature at which intermetallic compounds are formed, or, if the heating is short enough to form an intermetallic compound on a part of the bonded surface, it should be above the temperature at which the intermetallic compound is formed. It doesn't matter.

The molded body that has been plastically worked into a desired shape through the above molding process is heated to a temperature at which an intermetallic compound is formed. This heat treatment causes diffusion or self-combustion sintering and the formation of intermetallic compounds.

The heating temperature is in the temperature range below the common phase line of the intermetallic compound.

To complete the formation of intermetallic compounds, it is necessary to maintain the above temperature for a certain period of time. The lower the temperature, the longer it takes. Further, for the purpose of reducing pores, the molded body may be heated to a temperature higher than the temperature at which an intermetallic compound is formed while the molded body is kept under pressure.

After the intermetallic compound is formed, a post-formation heat treatment may be performed if necessary. By performing this heat treatment, the number of pores can be reduced, the uniformity of the structure can be promoted, and furthermore, impurities can be diffused or removed.

The treatment temperature is in the temperature range below the solidus line of the intermetallic compound. This heat treatment (heat treatment after the formation of the intermetallic compound) may be performed in the atmosphere, but more preferable results may be obtained if it is performed in an inert gas or vacuum atmosphere. Furthermore, these atmospheres may be combined. Depending on the material, this heat treatment may be performed under pressure using an appropriate pressure means.

[Example 1] An example of the present invention will be described below with reference to FIGS. 1 to 3. An example of the manufacturing process shown in FIG.
A mixing step 1 of raw materials, a manufacturing step 2 of the mixed pressed body, a pre-forming heat treatment step 3 performed as necessary, a molding step 4, a heat treatment step 5 of heating to the formation temperature of an intermetallic compound, and as necessary. Heat treatment step 6 after compound formation carried out accordingly
and finishing step 7.

In the raw material mixing step 1, A1 powder of 350 mesh or less produced by gas atomization method and sponge Ti powder of 350 mesh or less were mixed in a weight fraction of Ti:Al=3.
7.2%: Mix at a ratio of 62.8% using a gas-substituted dry ball mill.

Next, in step 2 of manufacturing the mixed and crimped body, the mixed powder is packed into a stainless steel pipe with an outer diameter of 20 cm and a wall thickness of 0.5 cm, and the pipe is reduced to an outer diameter of 8 I using a rotary swaging machine. Thereafter, the vibrator is removed by cutting. In this way, a linear mixed pressed body (in this case, a green compact) is obtained. After performing the first swaging process, the mixed crimped body is reduced in diameter to an outer diameter of 1 mm by a second swaging process. In addition, the above step 2
After that, a heat treatment step 3 such as annealing may be performed to remove processing distortion when the mixed pressed body is manufactured.

In the forming step 4, the mixed press-bonded body A is coiled using the forming apparatus 10 shown in FIG.

This device 10 includes a core metal 11 as an example of a mold, a head 12, a roller 13 as an example of a mold, and a chuck 14.
It is configured with the following. The core metal 11 and the head 12 can be moved toward and away from each other in the axial direction, and are rotated together in the same direction and at the same rotational speed by a drive mechanism (not shown). The roller 13 has the function of pressing the mixed pressure-bonded body A against the core bar 11 and gradually bending it, and applying a predetermined compression pressure JP.

On the outer periphery of the core bar 11, a coil spring molded body A to be molded is placed.
A spiral groove 15 corresponding to the pitch of ' is provided. A groove 16 is also provided on the roller 13 facing the spiral groove 15. A desired cross-sectional shape is formed in the width direction of these grooves 15,16. For example, in FIG. 2, the cross section of the mixed crimped body A is circular, and the cross sections of the grooves 15 and 16 are each approximately semicircular. It is also possible to omit the grooves 15,16.

Since the roller 13 is rotatably provided, the frictional force between the mixed pressure-bonded body A and the roller 13 can be reduced. Furthermore, it is possible to prevent problems such as excessive deformation or scratches occurring when the mixed crimped body A is bent. Further, the force required to rotate the core metal 11 while bending the mixed crimped body A can be reduced.

To coil the mixed press-bonded body A using the above-described forming apparatus 10, the end portion of the mixed press-bonded body A is held by the chuck 14 while the core metal 11 and the head 12 are stopped. Then, the roller 13 presses the mixed crimped body A into the groove 1 of the core metal 11.
Press it to 5.

While rotating the core metal 11 and the head 12 together and pressing the mixed pressure-bonded body A locally between the roller 13 and the core metal 11,
The mixed crimped body A is bent along the core bar 11 at the pressing portion 11a. Further, the roller 13 is moved in the axial direction of the core metal 11 according to the pitch of the spiral groove 15, and the mixed crimped body A is guided so that it is wrapped around the spiral groove 15.

After the coiling is completed, the roller 13 is separated from the core metal 11, and the molded body A' is released from being restrained by the chuck 14. Then, the head 12 is separated from the core metal 11, and the outer peripheral part of the molded body A' is held by a holder (not shown).
By rotating the core metal 11 in the opposite direction to that during coiling, the coiled molded body A' is removed from the core metal 11.

The coil-shaped molded body A' obtained in the above-mentioned molding step 4 is subjected to a heat treatment step 5 using a heating device 2 shown in FIG.
0 and heated to a temperature at which intermetallic compounds are formed. This heating device 20 includes a pressure-resistant stainless steel pot 22 filled with silica sand 21, a Kanthal heater 23 which is a coil-shaped resistance heating element built into the pot 22, a thermocouple 24 for temperature detection, and a stainless steel pot 22 filled with silica sand 21. Lid made of 25
and pressurizing means 2 such as a hydraulic cylinder that pressurizes this M2S.
6.

A coil-shaped molded body A' is set inside the heater 23 housed in the pot 22, and the coil-shaped molded body A' is 15
A pseudo-isotropic pressure of 0 kgf'/am2 is applied.

Then, it is heated to 700° C. by the heater 23.

The temperature of the coiled molded body A' at this time is measured by a thermocouple 24. When the coiled compact A' was heated to the above temperature, heat generation due to the formation of intermetallic compounds due to self-combustion sintering was observed. In addition, depending on HIP, HP, etc.
Pressure may be applied using gas, powder, or liquid, or may be applied mechanically.

After the intermetallic compound is formed, the molded body A' is held at 900° C. while maintaining the above pressure, and heat treatment step 6 is performed for 2 hours. By performing this heat treatment step 6, it is possible to reduce the pores contained in the molded body A', promote uniformity of the structure, and further diffuse or remove impurities.

Through the above series of steps, the wire diameter is 11I11. A coil spring mainly composed of an intermetallic compound with an average coil diameter of 121 m and a number of turns of 10 was obtained. It was found from the results of X-ray analysis that this coil spring was made of an intermetallic compound of Al1Ti. It was confirmed that this coil spring completely maintained its original shape even after being unloaded after being subjected to 5 cm of compressive deformation at 700° C., and exhibited good spring action.

Note that the finishing step 7 may be performed on the coil spring obtained through the above manufacturing process. For example, the surface of the spring can be made smooth by barrel-cutting. Alternatively, the surface of the spring may be polished by mechanical processing, or the shape may be modified by removing surface scratches 1, such as the surface layer, or by cutting, grinding, or the like. Further, by performing shot peening to generate compressive residual stress in the surface layer of the spring, the durability of the spring can be further improved.

Note that using a molding device 30 as shown in FIG.
The mixed pressed body A may be plastically worked into a desired shape. This molding device 30 includes a fixed roller 31 as an example of a mold,
It includes a movable roller 33 as an example of a mold attached to the holder 32, a chuck 34 for holding the mixed pressure-bonded body A, and the like.

=J-dynamic flora 33 It is configured to be able to rotate around the shaft 35 and to revolve around the fixed roller 31 around the support 35. One end of the mixed crimped body A is chuck 3.
4 to the fixed roller 31, and the movable roller 33
The fixed roller 3 rotates in the direction of arrow F in the figure.
1 and the movable roller 33, the mixed pressure-bonded body A is locally pressed.

By being bent at the pressing portion 31a, shaping is performed with a curvature that corresponds to the outer diameter of the fixed roller 31.

Note that, as in the molding apparatus 40 shown in FIG. 5, the movable roller 33 is transferred in the outer circumferential direction of the fixed mold 31 while applying a pressing force in the direction of force indicated by the arrow P to the mixed and pressed body A by the movable roller 33. Accordingly, the molding may be performed with a curvature that corresponds to the outer peripheral shape of the fixed mold 31.

The molding device 50 shown in FIG. 6 includes a fixed mold 51 and a pressing member 52. The fixed mold 51 in the illustrated example includes a non-circular molding surface 53 with a curvature corresponding to the shape of the molded object A' to be molded. The pressing member 52 is a mixed crimped body A
It functions to press the fixed mold 51 against the fixed mold 51. When the pressing member 52 presses the pressed mixed body A against the molded surface 53, the point of contact with the pressed mixed body A moves along the molded surface 53.

Note that the present invention can be similarly applied to manufacturing elastic bodies other than coil springs.

[Effects of the Invention] According to the present invention, it becomes possible to easily and accurately form an elastic part mainly composed of an intermetallic compound into a desired shape, and it becomes possible to easily and accurately form an elastic part mainly composed of an intermetallic compound. An elastic member can be obtained.

[Brief explanation of drawings]

Fig. 1 is a process explanatory diagram showing one embodiment of the method of the present invention;
The figure is a perspective view of an apparatus for forming a mixed press-bonded body, FIG. 3 is a cross-sectional view of a heating device, and FIGS. 4 to 6 are respective schematic diagrams showing other examples of the apparatus for forming a mixed press-bond body. . A...Mixed pressed body, A'... Molded body, 10... Molding device, ]1... Core metal (mold) 13... Roller (
type) 20... heating device, 23... heater, 26...
Pressure means, 30... Molding device, 31... Roller (mold), 33... Roller (mold), 40.50... Molding device, 51... Mold, 52... Pressing member .

Claims (3)

[Claims] (1) After obtaining a mixed pressed body by applying pressure to raw materials containing multiple elements mixed in a composition ratio that forms an intermetallic compound, the mixed pressed body is locally pressed with a mold. This mixed pressed body is gradually plastically deformed from one end of the mixed pressed body to the other end along the mold in the pressing section to obtain a molded body of a desired shape. An elastic member mainly composed of an intermetallic compound, which is treated under temperature conditions that allow the formation of intermetallic compounds. (2) A step of obtaining a raw material containing a plurality of elements mixed in a composition ratio that forms an intermetallic compound, a step of obtaining a mixed crimped body by applying pressure to the raw material, and a step of molding the mixed crimped body. A molded body having a desired shape is obtained by gradually plastically deforming the mixed pressed body from one end of the mixed pressed body to the other end along the mold while locally pressing the mixed pressed body at the pressing part. 1. A method for manufacturing an elastic member mainly composed of an intermetallic compound, the method comprising: a step of treating the molded body under temperature conditions such that an intermetallic compound is formed. (3) The mold used when molding the mixed crimped body presses the mixed crimped body between the core metal and the core metal while moving relatively in the circumferential direction of the core metal to mix the mixture. 3. The method of manufacturing an elastic member mainly composed of an intermetallic compound according to claim 2, further comprising a pressing member for bending the crimped body along the core metal.