JP2001164348A - METHOD FOR MANUFACTURING HIGH ELASTICITY Ni-Ti ALLOY WIRE WITH WIDE RANGE OF STRAIN USED FOR GUIDE WIRE FOR MEDICAL TREATMENT, AND HIGH ELASTICITY Ni-Ti ALLOY WIRE WITH WIDE RANGE OF STRAIN MANUFACTURED BY THE SAME METHOD AND USED FOR GUIDE WIRE FOR MEDICAL TREATMENT - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a high elasticity Ni-Ti alloy wire with a wide range of strain, used for a guide wire for medical treatment. SOLUTION: In the method for manufacturing the high elasticity Ni-Ti alloy wire with a wide range of strain used as a component element of a guide wire for medical treatment, mechanical straightening is applied under the conditions of torsional shear strain and temperature within the shaded region of Fig. 1 while applying >=18 kgf/mm2 tension to an Ni-Ti alloy wire just after cold working. By this method, dislocation density can be increased, and a guide wire for medical treatment, excellent in pushability, torque transmission characteristic, or the like, can be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a high strain Ni--Ti alloy wire having a wide strain range used for a medical guidewire, and a wide strain used for a medical guidewire manufactured by the manufacturing method. Range high elasticity N
The present invention relates to an i-Ti alloy wire.

[0002]

2. Description of the Related Art A medical guidewire is used, for example, to guide a catheter (small-diameter tube) for performing a treatment or examination into a blood vessel and place it in an affected part. Therefore, the guide wire is required to have flexibility and shape resilience so that the catheter can be fed into the meandering blood vessel in accordance with the shape of the blood vessel without being damaged. And
These properties have been increasingly demanded in recent years as catheters have been introduced closer to the end of the blood vessel. Conventionally, a stainless steel wire has been mainly used for the guide wire.However, the stainless steel wire causes permanent deformation when passed through a tightly bent blood vessel, and the wire remains bent. There is a problem that the data cannot be sent first and cannot be reinserted. Further, the stainless steel wire breaks at a strain of 1.5% (see FIG. 2e), and is inferior in reliability.

[0003] For this reason, in recent years, super-elastic wires utilizing super-elasticity of Ni-Ti alloys have been disclosed (Japanese Patent Publication Nos. H2-224550, H2-224548, H2-2-245).
No. 49) or a work hardening type wire made of a Ni—Ti alloy (Japanese Patent Publication No. 6-83726). The super-elastic wire utilizes the property that the deformation caused by stress-induced martensitic transformation returns to its original shape by reverse transformation at the time of unloading, as shown in FIG. Compared to stainless steel wire, it is very flexible and has a feature (superelasticity) with great shape recovery. However, as shown in FIG. 2d, the superelastic wire has a yield point F. If the yield point F is exceeded, the stress does not increase even if a strain is applied any more. There is a problem that the wire cannot be fed to a close place, and that the rotation at hand is difficult to be transmitted to the tip of the wire, resulting in poor maneuverability (poor torque transmission).

Further, a work hardening type wire which is subjected to a low temperature heat treatment after cold working is formed into a NiTi-based alloy wire having a working rate of 35 to 50% by a molding process (held at 350 to 450 ° C. for 10 to 30 seconds).
The stress-strain curve is shown in FIG. 2c. This work hardening type wire has a stress difference H
(Here, the stress-strain curve shows a stress difference at 2% strain between when a load is applied and when the load is unloaded.) In addition, sufficient straightness cannot be obtained by the molding process, so that torque transmission is poor. There is. In general, stress hysteresis refers to the shape of a stress-strain curve when a load is applied to a predetermined load and then the load is gradually unloaded. From the viewpoint, for convenience, attention is focused on the stress difference at a predetermined strain between when a load is applied and when the load is unloaded in a stress-strain curve, and this may be referred to as stress hysteresis.
The stress difference between the time of loading and the time of unloading in the stress-strain curve in% is defined as a stress hysteresis evaluation parameter, that is, a stress difference H.

[0005]

SUMMARY OF THE INVENTION
The present inventors have intensively studied and developed a completely new mechanism that does not exhibit superelasticity due to stress-induced martensitic transformation, exhibits high elasticity over a wide strain range, and has excellent pushability and torque transmission. A medical guidewire based on the same has been proposed (Japanese Patent Application No. 10-316690). The present invention relates to a method for producing a wide strain range high elasticity Ni-Ti alloy wire used for a medical guidewire, and a wide strain range high elasticity Ni-Ti alloy used for a medical guidewire produced by the production method. The purpose is to provide wires.

[0006]

According to the first aspect of the present invention,
Ni- used as a component of medical guidewire
1. A method for producing a Ti-based alloy wire, which comprises applying a tension of 18 kgf / mm ² or more to a cold-worked Ni—Ti-based alloy wire while maintaining a mechanical range within the range of the torsional shear strain and temperature in the hatched portion in FIG. This is a method for producing a wide-strain range high-elasticity Ni-Ti-based alloy wire used for a medical guidewire, which is characterized by performing a corrective process.

[0007] According to a second aspect of the invention, while applying a 18 kgf / mm ² or more tension to Ni-Ti-based alloy wire of cold working up, the machine in the range of the condition of the torsional shear strain and temperature of the hatched portion in FIG. 1 -Ti used as a component of a medical guidewire manufactured by subjecting to a corrective processing
A stress-strain curve in a tensile test that satisfies the following conditions (1) to (3), and (4) the straightness by the hanging method is 20 mm / 1.5 m or less. It is a wide-strain range, high elasticity Ni-Ti alloy wire used for a medical guidewire. (1) It does not show stress-induced martensitic transformation. (2) Apparent elastic modulus at 4% strain is 3000k
g / mm ² or more. (3) Residual strain is 0.15% or less when unloading after loading strain to 4%.

[0008] According to a third aspect, while applying a 18 kgf / mm ² or more tension to Ni-Ti-based alloy wire of cold working up, the machine in the range of the condition of the torsional shear strain and temperature of the hatched portion in FIG. 1 -Ti used as a component of a medical guidewire manufactured by subjecting to a corrective processing
A stress-strain curve in a tensile test that satisfies the following conditions (1) to (3) (5) (6), and
(4) A wide strain range, high elasticity Ni-Ti alloy wire used for a medical guide wire, characterized in that the straightness by the hanging method is 20 mm / 1.5 m or less. (1) It does not show stress-induced martensitic transformation. (2) Apparent elastic modulus at 4% strain is 3000k
g / mm ² or more. (3) Residual strain is 0.15% or less when unloading after loading strain to 4%. (5) The stress monotonically increases up to a strain of 4% without any yield point or inflection point. (6) Strain when unloading after loading strain to 4% 2
% Is 15 kg / mm ² when the load is applied and when the load is unloaded.
Less than.

According to a fourth aspect of the present invention, the Ni-Ti alloy wire is an alloy containing 50.2 to 51.5 at% of Ni and the balance being Ti. This is a method for producing a wide strain range high elasticity Ni-Ti alloy wire used for a medical guidewire.

According to a fifth aspect of the present invention, the Ni-Ti alloy wire contains 49.8 to 51.5 at% of Ni, and further contains one of Cr, Fe, V, Al, Cu, Co, and Mo.
2. A wide strain range high elasticity Ni-Ti used for a medical guidewire according to claim 1, wherein the alloy contains 0.1 to 2.0 at% of a seed or two or more kinds and the balance is Ti. This is a method for producing a base alloy wire.

According to a sixth aspect of the present invention, in the Ni-Ti alloy wire, 49.0 to 51.0 at% of Ni and 5 to 5 at% of Cu are contained.
12 at%, Cr, Fe, V, Al, Co,
0.1 to 2.0 at% of one or more of Mo
2. A method for producing a high strain Ni-Ti alloy wire having a wide strain range and used for a medical guide wire according to claim 1, wherein the alloy comprises Ti and the balance is Ti.

The invention according to claim 7 is characterized in that the Ni-Ti alloy wire is an alloy containing 50.2 to 51.5 at% of Ni and the balance being Ti. It is a wide strain range high elasticity Ni-Ti alloy wire used for the described medical guidewire.

[0013] The invention according to claim 8 is that the Ni-Ti alloy wire contains 49.8 to 51.5 at% of Ni and further contains one of Cr, Fe, V, Al, Cu, Co, and Mo.
4. A wide strain range high elasticity Ni used for a medical guidewire according to claim 2, wherein the alloy contains 0.1 to 2.0 at% of a species or two or more species and the balance is Ti. -Ti-based alloy wire.

According to a ninth aspect of the present invention, the Ni-Ti alloy wire has a Ni content of 49.0 to 51.0 at% and a Cu content of 5 to 5 at%.
12 at%, Cr, Fe, V, Al, Co,
0.1 to 2.0 at% of one or more of Mo
The high elasticity Ni-Ti alloy wire for a wide strain range used for a medical guidewire according to claim 2 or 3, wherein the balance is an alloy comprising Ti.

According to a tenth aspect of the present invention, the Ni-Ti alloy wire is used for at least a part of a medical guide wire.
The high strain Ni-Ti based alloy wire according to any one of the above,

An eleventh aspect of the present invention is a Ni—Ti alloy wire used as a component of a medical guidewire, which satisfies the following conditions (1) to (3), and (4)
A wide-strain range high-elasticity Ni-Ti alloy wire used for a medical guidewire, characterized in that the straightness by the hanging method is 20 mm / 1.5 m or less. (1) It does not show stress-induced martensitic transformation. (2) Apparent elastic modulus at 4% strain is 3000k
g / mm ² or more. (3) Residual strain is 0.15% or less when unloading after loading strain to 4%.

According to a twelfth aspect of the present invention, there is provided a Ni—Ti alloy wire used as a component of a medical guidewire, which satisfies the following conditions (1) to (3), (5) and (6). And (4) a high strain Ni-Ti alloy wire with a wide strain range used for a medical guide wire, characterized in that the straightness by the hanging method is 20 mm / 1.5 m or less. (1) It does not show stress-induced martensitic transformation. (2) Apparent elastic modulus at 4% strain is 3000k
g / mm ² or more. (3) Residual strain is 0.15% or less when unloading after loading strain to 4%. (5) The stress monotonically increases up to a strain of 4% without any yield point or inflection point. (6) Strain when unloading after loading strain to 4% 2
% Is 15 kg / mm ² when the load is applied and when the load is unloaded.
Less than.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION A medical guidewire manufactured according to the present invention has a stress-strain curve in a tensile test.
(1) not exhibiting stress-induced martensitic transformation; (2) apparent elastic modulus E at a strain of 4% is 3000 kg / m
m ² or more, and satisfying the expression (3) after challenge up to 4% strain, retained strain Z the following 0.15% condition when unloaded, and
(4) It is a highly elastic Ni-Ti alloy wire having a straightness of 20 mm / 1.5 m or less according to the hanging method. in particular,
In addition to the above conditions (1) to (4), the stress-strain curve in the tensile test is: (5) The stress monotonically increases without a yield point F or an inflection point up to a strain of 4%; Is a wide strain range high elasticity Ni-Ti alloy wire satisfying the condition that the stress difference H between the load and the unloading at a strain of 2% when the load is unloaded after loading to 4% is 15 kg / mm ² or less. .

FIG. 3 shows the yield point F, apparent elastic modulus E, stress difference H, and residual strain Z. The stress difference H differs depending on the type of wire as shown in FIG.

The medical guidewire manufactured according to the present invention has excellent properties such as pushability and torque transmission. These characteristics include the presence or absence of a yield point F in the stress-strain curve in the tensile test of the guide wire, the magnitude of the elastic modulus E, the magnitude of the stress hysteresis evaluation parameter H,
It depends on the magnitude of the residual strain Z, the straightness of the wire, and the like. That is, as shown in Table 1, as there is no yield point and the elastic modulus is large, the pushability is improved, and the guide wire can be sent near the distal end of the blood vessel. Also, the smaller the residual strain, the more elastic and reinsertable. Furthermore, the smaller the stress hysteresis evaluation parameter (stress difference) H is, the better the torque transmission is, and the steerability of the guide wire is improved. Further, a straightness is further improved in torque transmission.

[0021]

[Table 1] (Note for Table 1) Stress difference (stress hysteresis evaluation parameter H): 2% strain when unloaded after applying strain to 4%
The difference in stress between loading and unloading.

In the present invention, a Ni-Ti alloy ingot is subjected to hot working and cold drawing to obtain a wire, which is subjected to mechanical straightening to produce a medical guidewire. The mechanical straightening is an important step that has the greatest effect on the properties of the medical guidewire to be obtained, and the straightness of the drawn wire without mechanical straightening is low, and FIG. As shown by the stress-strain curve,
When a strain of 4% is applied, the residual strain Z increases,
There is a problem in that when a tightly bent blood vessel is passed through, permanent deformation occurs and it becomes impossible to insert the blood vessel any further, and it cannot be used for medical purposes.

In the present invention, the mechanical straightening is performed by:
The wire is applied by applying a torsional shear strain at a predetermined temperature while applying tension to the wire. In the present invention, the tension is 18 k
gf / mm ² or more, and the torsional shear strain is applied under the temperature conditions in the hatched portion in FIG.
Even if less than 8 kgf / mm ² , or even if the torsional shear strain is applied under the temperature conditions outside the hatched portion in FIG.
This is because the characteristics (1) to (4) described in 007 and 0016 or the characteristics (1) to (6) described in paragraphs 0008 and 0017 cannot be obtained. The wire temperature during the torsion process is a very important factor, and at a temperature higher than 275 ° C., a yield point due to stress-induced martensitic transformation appears and characteristics such as pushability and torque transmission are reduced,
If it is lower than 100 ° C., sufficient straightness cannot be obtained. Intermediate annealing is appropriately performed in the cold drawing, and the final cold drawing rate is preferably set to 15 to 60%, since the effect of the mechanical straightening can be sufficiently obtained. The mechanical straightening performed in the present invention and the ordinary low-temperature annealing performed while applying a tension of several kgf / mm ² to the wire are distinguished by the magnitude of the applied strain and the presence or absence of stress-induced martensite transformation. You. That is, the former differs from the former in that it does not cause stress-induced martensite transformation, whereas the latter generates stress-induced martensite transformation.

According to the present invention, a medical guidewire is obtained which does not substantially include an amnestic process and therefore does not exhibit superelasticity due to stress-induced martensitic transformation. Is the way. According to the present invention, the reason that a medical guidewire that satisfies the characteristics of the above (1) to (4) or (1) to (6) is obtained is as follows.
Dislocations introduced during wire drawing are oriented in the length direction of the wire,
This is because the dislocations introduced during mechanical straightening are oriented in the radial direction (bending and torsion directions) of the wire, and both dislocations can coexist and the dislocation density is significantly increased after the mechanical straightening.

The medical guide wire obtained according to the present invention comprises:
Unlike a conventional superelastic wire, the guide wire can be freely plastically deformed by hand into a shape that can be easily fed into a blood vessel simply by immersing the distal end of the guide wire in hot water at 60 ° C.

Hereinafter, the manufacturing method of the present invention will be specifically described with reference to the drawings. FIG. 4 is an explanatory longitudinal sectional view showing a first embodiment of the mechanical straightening method performed in the present invention. In this method, an upper end of a wire 1 is fixed to a fixture 2, and a weight 3 is attached to a lower end.
The wire 1 is tensioned to hold the wire 1 vertically, and the intermediate portion of the wire 1 is heated to a predetermined temperature by the heat treatment tank 4 and the weight 3 is rotated to apply a predetermined torsional shear strain to the wire 1. Is the way.

FIG. 5 is an explanatory longitudinal sectional view showing a second embodiment of the mechanical straightening method performed in the present invention. In this method, one end of a wire 1 is fixed to a fixture 2, the other end is arranged on a pulley 5, a weight 3 is attached to the end of the pulley 5, tension is applied to the wire 1, and the wire 1 is horizontally held. Heat treatment tank 4 in the middle
And heating the wire 2 to a predetermined temperature to apply a torsional shear strain to the wire 1.

FIG. 6 is an explanatory longitudinal sectional view showing a third embodiment of the mechanical straightening method performed in the present invention. In this method, the wire 1 wound around the bobbin 6 is continuously pulled out by a pinch roll 7, and is heated to a predetermined temperature in the heat treatment tank 4 while rotating the bobbin 6 to apply a torsional shear strain to the wire 1. The method considers mass production. The wire 1 loaded with the torsional shear strain is wound around a capstan 8 and then pulled out by a pinch roll 9 and cut to a desired length. The wire 1 may be wound without cutting.

In the present invention, the Ni—Ti alloy wire contains 50.2 to 51.5 at% of Ni, and the balance is Ti.
An alloy consisting of 49.8-51.5 at% Ni,
Further, an alloy containing 0.1 to 2.0 at% of one or more of Cr, Fe, V, Al, Cu, Co, and Mo, with the balance being Ti, and Ni of 49.0 to 51.0 at% %,
Contains 5 to 12 at% of Cu, and further contains Cr, Fe, V, A
One, two or more of l, Co, Mo
An alloy containing 2.0 at% with the balance being Ti is included.

[0030]

The present invention will be described below in detail with reference to examples. (Example 1) A Ni-Ti alloy ingot containing 51 at% of Ni and the balance being Ti is subjected to hot working and cold drawing to obtain a wire having a diameter of 0.35 mm, which is shown in Fig. 6. The medical guide wire was manufactured by performing mechanical straightening according to the above method. In the cold drawing, the drawing rate after the final annealing was 55%, in the mechanical straightening, the tension was set to 75 kgf / mm ² , and the relationship between the torsional shear strain and the temperature was shown in FIG. It was set to fit within the shaded area shown in.

(Example 2) N-Ti alloy ingot was mixed with N
i-48.9 at% Ti-0.2 at% Cr alloy or N
i-50.0at% Ti-8.0at% Cu-0.2at% F
A medical guidewire was manufactured in the same manner as in Example 1 except that the e-alloy was used.

(Comparative Example 1) A guide wire was manufactured in the same manner as in Example 1 except that the torsional shear strain and the temperature were set outside the hatched portion shown in FIG.

For each of the guide wires obtained in Examples 1 and 2 and Comparative Example 1, straightness, apparent elastic modulus E, stress hysteresis evaluation parameter (stress difference) H,
The residual strain Z was measured. The straightness was measured by the hanging method. That is, as shown in FIG. 7, a SUS tube (with an inner diameter of 0.3) arranged so that the length direction is perpendicular to the floor surface.
(8 mm, outer diameter 0.5 mm, length 50 mm) 10, one end of a test line 11 of a predetermined length is fixed, and the floor between the position of the test line 11 and the position of the completely straight line 12 is fixed. It was determined by measuring the distance b (mm) parallel to the plane. The medical guidewire is required to have a straightness in which the distance b is 20 mm or less in consideration of maneuverability (torque transmission). Table 2 shows the results. Table 2 also shows the correction processing conditions. FIG. 8 shows the relationship between straightness (distance b) and torsional shear strain. Of the straightening conditions, the torsional shear strain was determined by calculation from the number of rotations applied to the wire and the length of the wire to which the torsion was applied.

[0034]

[Table 2]

As is clear from Table 2, N of the present invention example
o. 1 to 12 have high straightness (distance b is 20
mm or less), the stress-strain curve in the tensile test is the same as that shown in FIG. 2a, and satisfies the above-mentioned specified values (1) to (4);
Useful as a medical guidewire. On the other hand, in the comparative example, the relationship between the torsional shear strain and the temperature was outside the shaded portion in FIG. For 13 to 15, residual strain Z and stress hysteresis evaluation parameter (stress difference)
H increases, the straightness decreases, and In any of 16 to 22, the straightness is lowered, and is unsuitable as a medical guidewire. From FIG. 8, it can be seen that the straightness improves as the temperature during the straightening process increases and the torsional shear strain increases.

Here, No. 1 of the present invention example. For No. 1, differential scanning calorimetry (DSC) was performed precisely using a high-sensitivity apparatus. As a result, as shown in FIG. 10A, no endothermic or exothermic peak indicating the transformation between the martensite phase and the parent phase appeared at all. That is, it was confirmed that the wire of the present invention did not undergo any stress-induced martensitic transformation. The same measurement was performed for the conventional work hardening type wire (the wire having a stress-strain curve shown in FIG. 2C) described in Japanese Patent Publication No. 6-83726, but it was broad as shown in FIG. Showed a peak indicating transformation, and it was confirmed that stress-induced martensitic transformation occurred in the work hardening type wire. In other words, the wire of the present invention does not show any stress-induced martensitic transformation, and the conventional work hardening type wire shows the stress-induced martensitic transformation. The two differ in this respect.

(Example 3) A Ni-Ti alloy ingot containing 51 at% of Ni and the balance of Ti was subjected to hot working and cold drawing in order to obtain a wire having a diameter of 0.35 mm. The wire was subjected to mechanical straightening by the method shown in FIG. 6 to produce a medical guidewire. In the cold drawing, the drawing rate after the final annealing is 55%. In the mechanical straightening, the tension is 18 to 170 kgf / mm ² , the temperature is 100 or 200 ° C., and the torsional shear strain is 20 or 30%.

Comparative Example 2 A medical guidewire was manufactured in the same manner as in Example 2 except that the tension was less than 18 kgf / mm ² .

For each of the medical guide wires obtained in Example 3 and Comparative Example 2, straightness, apparent elastic modulus E, stress hysteresis evaluation parameter (stress difference) H,
The residual strain Z was measured. Table 3 shows the results. Table 3 also shows the correction processing conditions. FIG. 9 shows the straightness (distance b).
And the relationship of tension.

[0040]

[Table 3]

As is clear from Table 3, N of the present invention example
o. 31 to 39 have high straightness (distance b is 20 mm or less), and have the same stress-strain curve in the tensile test as shown in FIG. And is useful as a medical guidewire. On the other hand, in Comparative Example No. Nos. 40 to 42 have low straightness at the time of straightening, and therefore all have low straightness and are unsuitable as medical guidewires. From FIG. 9, it is found that the straightness is low when the tension during the straightening is less than 18 kgf / mm ² (comparative example), but sharply increases when the tension is 18 kgf / mm ² or more (example of the present invention). It can also be seen that the straightness increases as the tension during the straightening process increases and as the temperature increases.

[0042]

As described above, according to the present invention, Ni
-Mechanically straightening the Ti-based alloy wire to increase straightness while applying a tension of 18 kgf / mm ² or more;
Since the application is performed within the range of the torsional shear strain and the temperature conditions in the hatched portion in FIG. 1, the dislocation density can be increased, and a medical guidewire excellent in pushability, torque transmission, and the like can be manufactured. Therefore, an industrially remarkable effect is achieved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a condition range of torsional shear strain and temperature in mechanical straightening performed in the present invention.

2A is a stress-strain curve diagram of a medical guidewire manufactured by the present invention, and FIGS. 2B to 2E are stress-strain curve diagrams of a conventional medical guidewire.

FIG. 3 is a supplementary diagram for explaining the stress-strain curve shown in FIG. 2;

FIG. 4 is an explanatory longitudinal sectional view showing a first embodiment of the mechanical straightening method performed in the present invention.

FIG. 5 is an explanatory longitudinal sectional view showing a second embodiment of the mechanical straightening method performed in the present invention.

FIG. 6 is an explanatory longitudinal sectional view showing a third embodiment of the mechanical straightening method performed in the present invention.

FIG. 7 is an explanatory diagram of how to determine the straightness of a medical guidewire.

FIG. 8 is a relationship diagram between straightness and torsional shear strain.

FIG. 9 is a relationship diagram between straightness and tension.

FIG. 10 (a) is a diagram showing a change in calorie of the medical guidewire of the present invention, and FIG. 10 (b) is a diagram showing a change in calorie of a conventional medical guidewire.

[Explanation of symbols]

 Reference Signs List 1 wire rod 2 fixture 3 weight 4 heat treatment tank 5 pulley 6 bobbin 7 pinch roll 8 capstan 9 pinch roll 10 SUS tube 11 straightness test line 12 perfect straight line b distance indicating straightness

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C22F 1/00 675 C22F 1/00 686A 686 691B 691 691Z A61M 25/00 450F (72) Inventor Kengo Mitose 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (54) [Title of the Invention] A method for manufacturing a wide strain range high elasticity Ni-Ti alloy wire used for a medical guidewire, and Strain and high elasticity Ni-Ti alloy wire used for medical guidewires manufactured by the above manufacturing method

Claims (12)

[Claims] 1. A method for producing a Ni—Ti alloy wire used as a component of a medical guide wire, comprising:
18kgf for cold-worked Ni-Ti alloy wire
/ Mm ² while applying the above tension, wide strain range, highly elastic for use in medical guide wire is characterized by subjecting the mechanical straightening at the range of the condition of the torsional shear strain and temperature of the hatched portion in FIG. 1 Ni- A method for producing a Ti-based alloy wire. 2. While applying a tension of 18 kgf / mm ² or more to the cold-worked Ni—Ti alloy wire, the wire is subjected to mechanical straightening in the range of torsional shear strain and temperature in the hatched portion in FIG. A Ni-Ti alloy wire used as a component of a manufactured medical guidewire, wherein a stress-strain curve in a tensile test is as follows:
A wide strain range high elasticity Ni-T used for a medical guidewire, characterized by satisfying the conditions of (3) to (3) and (4) straightness by the hanging method being 20 mm / 1.5 m or less.
i-based alloy wire. (1) It does not show stress-induced martensitic transformation. (2) Apparent elastic modulus at 4% strain is 3000k
g / mm ² or more. (3) Residual strain is 0.15% or less when unloading after loading strain to 4%. 3. A mechanical straightening process is performed on the Ni-Ti alloy wire after cold working while applying a tension of 18 kgf / mm ² or more in the range of torsional shear strain and temperature in the hatched portion in FIG. A Ni-Ti alloy wire used as a component of a manufactured medical guidewire, wherein a stress-strain curve in a tensile test is as follows:
(3) satisfying the conditions of (5) and (6), and (4) the straightness by the hanging method is not more than 20 mm / 1.5 m. Elasticity N
i-Ti alloy wire. (1) It does not show stress-induced martensitic transformation. (2) Apparent elastic modulus at 4% strain is 3000k
g / mm ² or more. (3) Residual strain is 0.15% or less when unloading after loading strain to 4%. (5) The stress monotonically increases up to a strain of 4% without any yield point or inflection point. (6) Strain when unloading after loading strain to 4% 2
% At the time of loading and unloading is 15 kg / mm ²
Less than. 4. The Ni—Ti alloy wire contains 5% Ni.
2. A method for producing a high strain Ni-Ti alloy wire having a wide strain range and used for a medical guide wire according to claim 1, wherein the alloy contains 0.2 to 51.5 at% and the balance is Ti. . 5. The Ni—Ti alloy wire contains 4% Ni.
9.8 to 51.5 at%, Cr, Fe, V,
2. The medical guidewire according to claim 1, wherein one or more of Al, Cu, Co, and Mo are contained in an amount of 0.1 to 2.0 at%, and the balance is Ti. Of manufacturing a high strain Ni-Ti alloy wire having a wide strain range used for a steel sheet. 6. The Ni—Ti alloy wire contains 4% Ni.
9.0 to 51.0 at%, 5 to 12 at% of Cu, and 0.1 to 2.0 at% of one or more of Cr, Fe, V, Al, Co, and Mo. The rest is Ti
2. A wide strain range high elasticity Ni used for a medical guidewire according to claim 1, wherein the Ni is an alloy comprising:
-A method for producing a Ti-based alloy wire. 7. The Ni—Ti alloy wire contains 5% Ni.
4. A wide strain range high elasticity Ni-T used for a medical guidewire according to claim 2, wherein the alloy contains 0.2 to 51.5 at% and the balance is Ti.
i-based alloy wire. 8. The Ni—Ti alloy wire contains 4% Ni.
9.8 to 51.5 at%, Cr, Fe, V,
4. The medical device according to claim 2, wherein one or more of Al, Cu, Co, and Mo are contained in an amount of 0.1 to 2.0 at%, and the balance is Ti. Wide strain range high elasticity Ni-Ti used for guide wire
Series alloy wire. 9. The Ni—Ti alloy wire contains 4% Ni.
9.0 to 51.0 at%, 5 to 12 at% of Cu, and 0.1 to 2.0 at% of one or more of Cr, Fe, V, Al, Co, and Mo. 4. The high strain Ni-Ti alloy wire according to claim 2, wherein the remainder is an alloy of Ti. 10. The wide strain range according to claim 2, wherein a Ni—Ti alloy wire is used for at least a part of the medical guide wire. High elasticity Ni-Ti alloy wire. 11. A Ni—Ti alloy wire used as a component of a medical guide wire, comprising:
A wide strain range high elasticity Ni-T used for a medical guidewire, characterized by satisfying the conditions of (3) to (3) and (4) straightness by the hanging method being 20 mm / 1.5 m or less.
i-based alloy wire. (1) It does not show stress-induced martensitic transformation. (2) Apparent elastic modulus at 4% strain is 3000k
g / mm ² or more. (3) Residual strain is 0.15% or less when unloading after loading strain to 4%. 12. A Ni—Ti-based alloy wire used as a component of a medical guide wire, comprising:
(3) satisfying the conditions of (5) and (6), and (4) the straightness by the hanging method is not more than 20 mm / 1.5 m. Elasticity N
i-Ti alloy wire. (1) It does not show stress-induced martensitic transformation. (2) Apparent elastic modulus at 4% strain is 3000k
g / mm ² or more. (3) Residual strain is 0.15% or less when unloading after loading strain to 4%. (5) The stress monotonically increases up to a strain of 4% without any yield point or inflection point. (6) Strain when unloading after loading strain to 4% 2
% Is 15 kg / mm ² when the load is applied and when the load is unloaded.
Less than.