JP5278987B2 - Manufacturing method for eyeglass frames - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low cost method where, upon the production of a spectacles frame exhibiting superelasticity, the process of shape memorizable heat treatment can be reduced, and to provide a spectacles frame exhibiting flexibility and excellent superelasticity. <P>SOLUTION: A spectacles frame composed of a superelastic wire of an Ni-Ti alloy based shape memory alloy having &ge;3% elasticity in the temperature range of -20 to +50&deg;C is subjected to single swaging working where a final cold working ratio exceeds 50% without performing shape memorizable heat treatment, so as to produce a spectacles frame 1 exhibiting superelasticity. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

The present invention relates to a spectacle frame using a Ni-Ti alloy and a manufacturing method thereof, and in particular, exhibits superelasticity in which a plateau region appears with stress-induced martensitic transformation without performing shape memory heat treatment after final cold working. a method of manufacturing a glasses frame.

  A conventional spectacle frame using Ni-Ti alloy that exhibits superelasticity is shape memory heat-treated in a temperature range of about 300 to 550 ° C. below the recrystallization temperature in a state of being formed into a predetermined shape and held after the final cold working. In general, a manufacturing method for obtaining a super-elastic eyeglass frame that expresses stress-induced martensitic transformation has been common.

  Thus, it has been proposed to supply a spectacle frame that uses stable and supple superelasticity (for example, Patent Documents 1 to 4).

  However, in the conventional process, if shape memory heat treatment is not performed after the final cold working, it is not possible to obtain a super elastic glasses frame in which a plateau region appears with stress-induced martensitic transformation. It was necessary to spend labor, time, and energy in the process of shape memory heat treatment.

  On the other hand, a method for manufacturing an eyeglass frame in which shape memory heat treatment is not performed after final cold working has also been proposed (for example, Patent Documents 5 and 6). However, in this method, the final cold working is special, the working rate by cold drawing is about 30% at the first time, and then the second time is the total cold working by rotary swaging or forging or bending. Efforts to perform two-stage cold working are required before the working rate reaches 35 to 45% at the maximum.

  The elastic characteristic in this case is different from the form in which the plateau region accompanying the stress-induced martensitic transformation appears when shape memory heat treatment is applied, and the stress-strain curve shows a characteristic of deformation behavior called linear superelasticity. . Furthermore, in such a linear superelasticity, even when a deformation strain of 2% or more is applied, the stress continues to rise, and the superelasticity (so-called pseudoelasticity) in which the stress-induced martensitic transformation appears is excellent in flexibility. A super-elastic eyeglass frame is never obtained.

JP-A-56-95214 Japanese Patent No. 2593088 Japanese Patent No. 2574833 JP 2002-182162 A US Pat. No. 6,557,993 US Pat. No. 6,565,207

  Therefore, the object of the present invention is to solve the above-mentioned problem, without performing shape memory heat treatment at a temperature of about 300 to 550 ° C. below the recrystallization temperature after the final cold working to the Ni—Ti alloy, or Providing a supple and supple eyeglass frame that exhibits 3% elasticity and superelasticity with a plateau region with stress-induced martensitic transformation, without any special multi-stage cold working. An object of the present invention is to provide a manufacturing method for obtaining a spectacle frame at a low cost by employing a simple process.

The present invention is made of a Ni-Ti binary alloy having an elasticity of 3% or more in a temperature range from -20 to + 50 ° C. , from a super elastic wire having a Ti content of 48 to 51 at% and the balance of Ni. a method of manufacturing a spectacle frame comprising, in the alloy, and simultaneously subjected to swaging processing in excess of 50% rolling ratio final cold, subjected to shape memory heat treatment by heat generated by the swaging process, to grant superelastic it is a manufacturing method of a spectacle frame, wherein the this.

Further, the present invention, Ni-Ti- X alloy (X having 3% or more elastic in the temperature range up to -20 to + 50 ° C. The Cu, Fe, V, Co, Cr, Nb, Ta, Mo, Mn At least one of the above, Ti content is 48 to 51 at%, X content is 0.25 to 10 at%, the balance is a manufacturing method of a spectacle frame made of super elastic wire having a composition of Ni, A spectacle frame manufacturing method characterized in that the alloy is subjected to a swaging process exceeding a final cold work rate of 50%, and at the same time a shape memory heat treatment is applied by heat generated by the swaging process to impart superelasticity. is there.

  Further, the present invention is the glasses frame described above, wherein the alloy can reach a deformation rate of 5%.

  Further, the present invention is the above spectacle frame, wherein at least one of a bridge, a wading, and a temple is made of the alloy.

Spectacle frame of the present invention, Ni-Ti binary alloy or, Ni-Ti- X in alloy superelastic wire, CNC swaging cold working ratio as 50% or more plug size and shape can be obtained the desired Is a spectacle frame that exhibits superelasticity in which a plateau region associated with stress-induced martensitic transformation appears and is excellent in flexibility.

Previously, Ni-Ti binary alloy or, Ni-Ti- X alloy (X is Cu, Fe, V, Co, Cr, Nb, Ta, Mo and Mn, the content of X is 0 .25~10at% ) Is generally performed at a cold work rate of 50% or less. Adding a cold work rate of 50% or more to a Ni-Ti alloy causes cracking or cracking of the material. It was difficult to manufacture the product.

  However, recently, a swaging machine that can add a cold working rate of 50% or more, and further 80% or more to Ni-Ti alloys has been introduced. Yes. This increases the accuracy of each factor such as swaging machine, dice, lubricant and speed. When such a high-precision swaging machine is used and a cold work rate of 50% or more is added to the Ni—Ti alloy, the Ni—Ti alloy processed by the die is processed more than before. Processing heat is generated. Although this processing heat cannot be measured until now, it is presumed that the processing portion of the Ni—Ti alloy is affected by heat at approximately 300 to 550 ° C. for several tens of seconds. This thermal effect can provide the same heat treatment effect as when shape memory heat treatment is performed after the final cold working by the conventional manufacturing method.

  Therefore, the glasses exhibiting superelasticity in which the plateau region accompanying the stress-induced martensitic transformation appears without applying the shape memory heat treatment of the conventional method only by adding a cold working rate of 50% or more by one swaging process of the present invention. It became possible to obtain a frame.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of a shape memory alloy wire superelastic glasses frame according to an embodiment of the present invention. In FIG. 1, 11 is a rim, 12 is a bridge, 13 is a wading, 14 is a hinge, and 15 is a temple.

  A casting ingot is obtained by high-frequency vacuum melting of a Ni—Ti alloy having the chemical composition shown in Table 1, and after homogenization heat treatment at 900 ° C., the wire diameter is φ3.1 mm by hot forging, hot rolling, and cold drawing. Wire processing was performed. The wire was subjected to a homogenization heat treatment at 800 ° C., and the surface oxide film was removed by a centerless polishing machine to obtain a wire having a wire diameter of φ3.0 mm. By using a CNC swaging machine, a temple 15 of the eyeglass frame 1 having a cold working rate of 81% up to φ1.3 mm was obtained. A part of this temple was cut to obtain a sample for an inventive tensile test.

  FIG. 2 is a 5% stress-strain curve obtained by subjecting the inventive product to a tensile test at 50 ° C., 30 ° C., 0 ° C., and −10 ° C.

  For comparison, a cast ingot was obtained in the same manner, and after the homogenization heat treatment at 900 ° C., wire processing was performed to a wire diameter of φ2.1 mm by hot forging, hot rolling, and cold drawing. This wire was subjected to a homogenization heat treatment at 800 ° C., and the surface oxide film was removed by a centerless polishing machine to obtain a wire having a wire diameter of φ2.0 mm. By using a CNC swaging machine, a temple 1-5 of an eyeglass frame 1 having a cold working rate of 44% up to φ1.5 mm was obtained. A part of this temple was cut to be a comparative product, which was used as a tensile test sample.

  FIG. 3 is a 5% stress-strain curve of the comparative test results at 50 ° C., 30 ° C., 0 ° C., and −10 ° C.

  Fig. 2 of the invention with a cold work rate of 81% shows superelasticity in which a plateau region with a stress-induced martensitic transformation where the load becomes constant from around -10 ° C to 50 ° C where the strain exceeds 2% is shown. I understand that On the other hand, in FIG. 3 which is a comparative product with a cold working rate of 44%, it can be seen that the plateau region is not clearly seen even in the vicinity where the strain exceeds 2% from −10 ° C. to 50 ° C.

  Table 2 shows the stress at a strain of 5% obtained by conducting a tensile test at 50 ° C., 30 ° C., 0 ° C., and −10 ° C. for the above-described inventive samples and comparative samples.

  From Table 2, the product of the invention from −10 ° C. to 50 ° C. has a plateau region clearly even in the vicinity where the strain exceeds 2%, and therefore the stress at 5% is lower than that of the comparative product.

  Table 3 shows the amount of residual strain at 5% strain obtained by conducting a tensile test at 50 ° C., 30 ° C., 0 ° C., and −10 ° C. for the above-described inventive samples and comparative samples. It is.

  From Table 3, the product of the invention from −10 ° C. to 50 ° C. shows a residual strain amount of 0.8% or less.

  Therefore, from these embodiments, the invention with a cold working rate of 81% by swaging has a plateau region accompanied by stress-induced martensitic transformation, and since the residual strain is small, super-elasticity with excellent flexibility is obtained. You can see that In this way, a superelastic eyeglass frame in which a plateau region accompanying the stress-induced martensitic transformation appears by adding a cold working rate by swaging of 50% or more was obtained.

1 is a perspective view of a shape memory alloy wire super-elastic eyeglass frame according to an embodiment of the present invention. A 5% stress-strain curve obtained by subjecting the product of the invention to a tensile test at 50 ° C, 30 ° C, 0 ° C and -10 ° C. 5% stress-strain curve of the comparative product at 50 ° C., 30 ° C., 0 ° C., and −10 ° C. according to the tensile test results.

Explanation of symbols

1 glasses frame 11 rim 12 bridge 13 wading 14 hinge 15 temple

Claims (4)

An eyeglass frame comprising a Ni-Ti binary alloy having an elasticity of 3% or more in a temperature range from -20 to + 50 ° C., comprising a superelastic wire having a Ti content of 48 to 51 at% and the balance of Ni . a manufacturing method, in the alloy, and simultaneously subjected to swaging processing in excess of 50% rolling ratio final cold, subjected to shape memory heat treatment by heat generated by the swaging process, wherein the benzalkonium to impart superelastic A method for manufacturing a spectacle frame. Ni-Ti- X alloy with 3% or more elastic in the temperature range up to -20 to + 50 ° C. (at least one of X is Cu, Fe, V, Co, Cr, Nb, Ta, Mo, Mn) A spectacle frame comprising a superelastic wire having a Ti content of 48 to 51 at%, an X content of 0.25 to 10 at%, and the balance being Ni. A method for producing a spectacle frame, comprising performing a swaging process exceeding a 50% inter-working rate and simultaneously applying a shape memory heat treatment with heat generated by the swaging process to impart superelasticity. 3. The method of manufacturing a spectacle frame according to claim 1, wherein the alloy can reach a deformation rate of 5%. The method for manufacturing a spectacle frame according to any one of claims 1 to 3 , wherein at least one of a bridge, a wading, and a temple is made of the alloy.

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