JP3915543B2 - Partly superelastic parts and method of manufacturing the same - Google Patents

Description

【００１９】
【発明の効果】
本発明の部分的に超弾性を有する部品の製造方法は、Ｎｉ−Ｔｉ合金に第三成分として、Ｍ（Ｆｅ、ＶまたはＣｏ）から選んだ１種または２種以上を添加し、Ｎｉ＋ＭとＴｉとの割合とＭの添加量とを選択した形状記憶合金を材料として使用することにより、変態温度を−５０℃〜−５℃の範囲で用途に応じて調節し、かつ機械加工に適した硬さが得られ、それによって、冷間加工を受けた部分だけが、続く形状記憶処理により部分的に超弾性を発揮するという特性を有する。
【００２０】
したがってこの合金を材料として、これを所望の部品形状に加工した後、焼鈍して形状記憶特性を失わせ、ついで特定の部分だけ冷間加工し、最後に形状記憶のための熱処理を行なうことにより、加工部分だけが超弾性を有する部品を製造することができる。従来の部分的に超弾性を有する部品の製造は、全体に超弾性を与えた後、一部に超弾性を失わせるための熱処理を施すという工程が最後に必要であり、これがコストを高くしていたが、本発明によりこの工程が不要になったから、部分的に超弾性を有する部品が、低減されたコストで製造できるようになった。
【００２１】
本発明は、実例として挙げためがねフレームの腕の製造に適用したとき、とくに有意義であるが、それに限らず、一体であってその一部が超弾性を有し、残りの一部が塑性加工可能である部品の製造に、広く応用可能である。
【図面の簡単な説明】
【図１】 Ｎｉ−Ｔｉ−Ｍ（Ｍ＝Ｆｅ）合金において、［Ｎｉ＋Ｆｅ］％と溶体化処理後の変態温度（Ａｓ）との関係を示すグラフ。[0001]
BACKGROUND OF THE INVENTION
The present invention generally relates to parts that are partially superelastic, and also relates to shape memory alloys for producing such parts and methods for producing such parts. A particular subject of the present invention is the “arm” portion of the eyeglass frame.
[0002]
[Prior art]
Various parts are manufactured and used by utilizing the superelastic characteristics of shape memory alloys. One important example is the glasses frame. Of the parts that make up the glasses frame, we want superelasticity for the bridge part and the temple part of the arm. The frame that holds the lens and the modern part of the arm, that is, the part that hangs on the ear, is superelastic. If so, it is rather undesirable. Needless to say, the lens frame needs to maintain a certain shape, and the modern part is deformed in the eyeglass store in accordance with the shape of the ear of the eyeglass user.
[0003]
Thus, an integral part manufactured from a shape memory alloy is required to have a part that is superelastic and the remaining part is not shown. Similarly, there are cases where different shape memory characteristics are required depending on the part of the integral part, and a shape memory alloy coil spring that meets the demand has been proposed (Japanese Patent Laid-Open No. Hei 8-232004). The coil spring is a coil made of a Ni—Ti alloy with Ni of 50.3 atomic% or more, and subjected to a shape memory process in which the temperature or processing time varies depending on the part.
[0004]
Regarding the arm of the eyeglass frame, a single Ni—Ti alloy wire is used as the material, but as described above, only the temple portion is required to exhibit superelasticity, and the modern portion is required to be plastically deformable. . Conventionally, the arm is manufactured as follows.
1) An Ni-Ti shape memory alloy wire having a diameter of 2 to 3 mm is used as a base material, and an annealing treatment is performed by heating the wire to a temperature of 700 to 900 ° C.
2) Cold swaging is performed on the annealed wire to obtain a stepped material in which the part that becomes a temple is different from, for example, a diameter of 1.5 mm and the part that becomes a modern is different from a diameter of 1.0 mm.
3) After strain-annealing this material, only the temple part is pressed to make the cross-sectional shape almost rectangular and the modern part is curved. Next,
4) Perform shape memory processing to give superelasticity. The heat treatment conditions are usually heating at a temperature of 300 to 550 ° C. and a time of 1 to 60 minutes.
5) Only the modern part is partially annealed to remove superelasticity.
[0005]
Each of the above processes has many steps and is expensive. Eyeglass frames are also trending toward lower prices, and rationalization is necessary to reduce costs accordingly. Therefore, the inventor paid attention to the process 5 of the final partial annealing. This process is an important issue for Ni-Ti alloys that are active at high temperatures, and how to prevent the effect of partial annealing of the modern part on the temple part. This is because high cost is required.
[0006]
The inventor conceived that in the manufacturing method of the above-mentioned glass frame, step 5, that is, partial annealing is omitted, and superelasticity is exhibited only by the shape memory processing in step 4. As a result of research, a shape memory alloy with a specific alloy composition is selected, and after machining and cold working, appropriate heat treatment is performed, so that only the part that has undergone cold working exceeds the result of heat treatment following machining. The present inventors have found the fact that a portion that has developed elasticity and has not been cold worked remains capable of plastic deformation.
[0007]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for producing a partly superelastic part at a reduced cost by utilizing the above-described new knowledge obtained by the inventors. . A particular object of the present invention is to provide a method of manufacturing the “arm” portion of the spectacle frame in a simplified process and therefore at a low cost.
[0008]
[Means for Solving the Problems]
The method of manufacturing the part of the present invention that can achieve the above-mentioned object and can exhibit a part of super-elasticity is a Ni-Ti-M ( M is Fe, V or Co ) alloy. , Wt%, Ni + M: 55.0-55.9% and Ti: balance, M: 0.2-1.2% when M is Fe or V, M: 0 when M is Co By selecting an alloy composition that is 1 to 2.0%, an alloy with a controlled transformation temperature and hardness after solution treatment is processed into a desired part shape and then annealed to lose shape memory characteristics. Then, the specified part is cold processed to 10% or more, and finally the whole part is heat treated at a temperature of 300 to 550 ° C. for 1 to 60 minutes, so that only the cold processed part is super elastic. To produce parts with superelasticity, which are made to exhibit It is.
[0009]
Another embodiment of the shape memory alloy capable of exhibiting superelasticity partially according to the present invention is a Ni-Ti-M (M is Co) alloy, and Ni + M: 55.0-55. 9%, M: 0.1 to 2.0% and Ti: The balance is an alloy composition consisting of the balance. By selecting the contents of Ni and M, the transformation temperature after solution treatment is -50 ° C to- Only the part which has been adjusted to 5 ° C. and the hardness Hv = 280 or less and which has undergone cold working can exhibit superelasticity partially by the subsequent shape memory process.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The method for producing a partly superelastic part according to the present invention is obtained by processing an alloy having any of the above alloy compositions and having the transformation temperature and hardness adjusted as described above into a desired part shape. After that, annealing is performed to lose the shape memory characteristics, and then a specific portion is cold processed at 10% or more, and finally a heat treatment is performed at a temperature of 300 to 550 ° C. for a time of 1 to 60 minutes. Only to exhibit superelasticity.
[0011]
The addition of M (Fe, V or Co) as the third component is intended to lower the transformation temperature of the solution-treated alloy. As the addition amount increases, the effect of lowering the transformation temperature increases. The temperature range in which the part should exhibit superelasticity naturally depends on the application of the part, but in order to achieve the transformation temperature required in normal applications, 0.2 to 1.2 when M is Fe and V. % And Co may be selected from an addition amount in the range of 0.1 to 2.0%.
[0012]
On the other hand, the addition of M tends to increase the hardness of the Ni—Ti shape memory alloy. However, parts are often subjected to machining such as cutting, drilling, and threading. For easy machining, it is inconvenient if the material is too hard. From this point of view, the hardness after the solution treatment is determined to be Hv, 250 or less, and at most 280 or less. When M is Fe, V, the condition of Hv 250 or less can be achieved with the addition in the range of 0.2 to 1.2%. Also when M is Co, Hv280 or less can be obtained by selecting the addition amount in the range of 0.1 to 2.0% and the solution temperature.
[0013]
In the case of Ni-Ti-M (M = Fe) alloy, when Fe is 0.2%, 0.5%, and 0.9%, when [Ni + Fe]% is changed, after solution treatment The graph of FIG. 1 was obtained by examining how the transformation temperature (As) of A changed. For these alloys, the region where superelasticity occurs in [cold working + heat treatment] and the region where the hardness exceeds an unfavorable limit for working are also shown on the graph.
[0014]
The arm of the eyeglass frame, which is a specific object of the present invention, is a component in which only the temple portion is desired to have superelasticity, and the modern portion should not be superelastic. It is desired that the superelastic property is exhibited at room temperature. Therefore, it is preferable that the transformation temperature after the heat treatment is located between −30 ° C. and −10 ° C. In order to manufacture such an arm, the alloy composition may be selected accordingly and the above-described steps 1) to 4) may be performed. As a result, super-elasticity occurs in the temple portion by [cold working + heat treatment], and super-elasticity does not occur in the modern portion that has undergone only heat treatment. In this way, the partial annealing in step 5) can be omitted.
[0015]
【Example】
A Ni—Ti—M alloy having the alloy composition shown in Table 1 was melted in a vacuum induction furnace. Table 1 shows the measured values of the transformation temperature (As) after the solution treatment of each alloy.
[0016]
Each alloy was drawn into a wire having a diameter of 3 mm and annealed by heating at 800 ° C. for 10 minutes. The annealed material cut to about 2000mm in length was swaged in order from one end. The larger diameter was 1.9mm in diameter x 70mm in length, and the smaller diameter was 1.5mm in diameter x 70mm in length. Were sequentially cut to a total length of 140 mm to obtain a material having a step in the center. This material is subjected to strain relief annealing, which is heated at 800 ° C for 10 minutes, and then the large diameter portion (which becomes the temple portion) is pressed in a cold manner to form a 2.5 x 1.0 mm rectangular cross section. I had it. No processing was applied to the small-diameter part (which becomes the modern part).
[0017]
Finally, the whole was heated at 400 to 530 ° C. for 30 minutes to perform shape memory treatment. The heating temperature was selected according to the alloy composition within the above range. The cold-worked temple part showed superelasticity that restored its original shape even when bent at a right angle at room temperature, while the modern part kept its original shape when bent and was capable of plastic working.
[0018]
Table 1

[0019]
【The invention's effect】
The method for producing a partly superelastic component according to the present invention comprises adding one or more selected from M (Fe, V or Co) as a third component to a Ni—Ti alloy, and adding Ni + M and Ti. By using a shape memory alloy with a selected ratio and the addition amount of M as a material , the transformation temperature is adjusted in the range of −50 ° C. to −5 ° C. according to the application, and is suitable for machining. It is is obtained, whereby only the portion receiving the cold working, has the property that exerts partially superelastic followed by shape memory process.
[0020]
Therefore, using this alloy as a material, after processing it into the desired part shape, it is annealed to lose its shape memory characteristics, then cold-work only certain parts, and finally perform heat treatment for shape memory Thus, it is possible to manufacture a part in which only the processed part has superelasticity. Conventional production of a partly superelastic part requires a final process of giving superelasticity to the whole and then applying heat treatment to partially lose superelasticity, which increases costs. However, this process is not necessary according to the present invention, so that a part having superelasticity can be manufactured at a reduced cost.
[0021]
The present invention is particularly meaningful when applied to the manufacture of the arm of the eyeglass frame as an example. However, the present invention is not limited to this, and it is integral and part thereof has superelasticity, and the remaining part is plastic working. Widely applicable to the production of possible parts.
[Brief description of the drawings]
FIG. 1 is a graph showing a relationship between [Ni + Fe]% and a transformation temperature (As) after solution treatment in a Ni—Ti—M (M = Fe) alloy.

Claims (3)

Ni-Ti-M ( M is Fe, V, or Co ) alloy, which is by weight, consisting of Ni + M: 55.0-55.9% and Ti: balance, and when M is Fe or V, M: When the alloy composition is 0.2 to 1.2% and M is 0.1 to 2.0% when M is Co, the alloy is adjusted in transformation temperature and hardness after solution treatment. After processing into the desired part shape, annealing is performed to lose the shape memory characteristics, and then a specific part is cold processed at 10% or more, and finally, the temperature is 300 to 550 ° C., and the time is 1 to 60 minutes. by applying a heat treatment to the entire component consists to exert only the super-elastic cold working part, partially method for producing a component having a superelastic. A part that exhibits superelasticity partially by the manufacturing method according to claim 1. 3. The component according to claim 2, wherein the component is an arm of a spectacle frame, which imparts superelasticity only to the temple portion and the modern portion does not cause superelasticity.

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