JP3011324B2 - Titanium wire for living body and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a titanium wire for use in a living body, for example, for fastening a human bone, and a method of manufacturing the same.

[0002] Such a titanium wire is required to be able to be easily and firmly fastened during the operation and to have high safety in a living body.
An excellent titanium wire suitable for such a purpose is provided.

[0003]

2. Description of the Related Art In recent years, in the field of orthopedic surgery or oral surgery, implanting artificial bones, artificial roots, and the like into a living body has been performed. Especially when bone damage occurs
Implant artificial bone in the damaged area, or reinforce or fix until the bone recovers. In spine surgery and the like, bone transplantation and the like are performed.

In general, stainless steel and chromium-cobalt based materials are often used for such artificial bones or joint materials. However, there have been many reports that stainless steel has been associated with malignant tumors after artificial joint replacement, and the elution of toxic metal ions in vivo has recently been regarded as a problem.

[0005] As described above, stainless steel is generally referred to as a corrosion-resistant material. However, the corrosion-resistant film (passive film) on the surface is partially destroyed by surgery or the generation of scratches on the stainless steel itself during use. In the atmosphere, the passive film regenerates rapidly, but the body has a low oxygen partial pressure, so the fabric is exposed for a long time, and metal ions such as nickel, which is a major additive element of stainless steel, are eluted. It is possible that you are doing. It has been reported that metallic nickel itself has toxicity as an allergic or carcinogenic substance.

[0006] In addition to the above, as a metal to be buried in the body, a metal wire is used to fix or reinforce the bone or the bone and the artificial bone or the implanted bone. As the metal wire, a stainless steel wire is often used, taking advantage of its high strength. However, there is a danger that galvanic corrosion occurs between the above-mentioned metallic artificial bone and metal ions are more easily eluted. Due to the occurrence of such a problem, the following properties are required as a fastening wire for a living body.

Biocompatibility No cytotoxicity or no toxicity per se. No elution as metal ions. Good compatibility with living tissue. No carcinogenicity and no antigenicity. No metabolic abnormalities. Do not cause blood clotting or hemolysis

[0008] Mechanical properties: To have appropriate static strength and ductility. To have sufficient fatigue strength.

[0009]

Because of the above problems, the use of toxic metals or alloy materials containing them as a component has been avoided.

For these reasons, attention has been focused on titanium materials which are excellent in corrosion resistance and lighter as a material replacing stainless steel and chromium-cobalt materials.

This titanium material is roughly divided into pure titanium and titanium alloy. Pure titanium varies in strength depending on the amount of oxygen, and is defined in JIS standards as being divided into one to three types from those having a low oxygen amount.

On the other hand, titanium alloys include V, Mo, Fe, Cr
As β-stabilizing elements increase, a β-phase becomes present up to room temperature.
It is classified into three types, β-type and β-type. Among the titanium alloys, Ti-6Al-4V is known for medical use. It is defined in the American ASTM and ISO standards as a surgical implant material. However, since this alloy contains V, which is said to exhibit strong cytotoxicity when used alone, some researchers have pointed out the dangers. Is being done.

With respect to pure titanium, the impurity content of oxygen is 1500 ppm or less, nitrogen is 500 ppm or less,
Although it is 3000 ppm or less of iron and 130 ppm or less of hydrogen, it is considered that there is no particular concern about cytotoxicity due to such impurity content.

In any case, since the titanium material is clearly superior to other materials in characteristics, the use as a biomaterial and the research on new materials are rapidly increasing in recent years.

However, if the artificial bone and the fastening wire for a living body are used in the same place, the contact portion between the two is immersed in the body fluid in the living body, and there is a great risk of galvanic corrosion occurring. This is particularly noticeable when using dissimilar materials such as stainless steel. Therefore, when using pure titanium or a titanium alloy as an implant material for a living body such as an artificial bone, it is desirable to use the same type of titanium wire.

[0016] However, it is said that titanium material is inferior in mechanical strength and elongation as compared with stainless steel wire, and it has not yet been concluded whether titanium-based material is a material suitable as a fastening wire for living body. Is the current situation.

A particular problem with such a fastening wire for a living body is the fastening of the wire. Generally, when fixing a bone with a wire, it is generally performed by torsion.However, the fastening by this torsion can be tightly wound around the object so that it does not loosen, and during and during fastening. It is necessary that the wire does not break even afterwards. For that purpose, it is necessary that the tensile strength and the proof stress be sufficiently high as well as the flexibility of the wire.

As such a fastening wire, one kind of JIS standard pure titanium or two kinds of J with increased strength by increasing oxygen.
The IS standard has been proposed and research reports have shown that it shows relatively good fastening properties. However, as shown above,
S-grade pure titanium has problems such as breaking with several twists or breaking with a gap left without being tightly wound around the object. Pure titanium has no problem with cytotoxicity, etc., but the fact remains that such unsolved problems remain.

In view of such problems, a method of fastening has been devised to improve the fastening method, and a mechanical fixing method by caulking has been proposed. However, a special tool for caulking is required in addition to many surgical tools, and There is a drawback that the fastening work is inevitably complicated, such as requiring a certain level of skill, and thus there is a face that cannot be said to be a fundamental solution.

[0020]

As a result of diligent tests and studies on the above-mentioned problems, the present inventors have added a predetermined amount of iron to titanium and strictly prepared trace impurities contained in titanium. As a result, an excellent material that can be used as a living body fastening wire without loosening or breakage when fastening the wire was found, and the present invention was achieved.

That is, the first aspect of the present invention relates to iron (super)
The present invention relates to a fastening titanium wire for a living body, which has a gas component of 250 ppm or less, oxygen of 250 ppm or less, hydrogen of 50 ppm or less, nitrogen of 170 ppm or less, carbon of 340 ppm or less, impurities of 100 ppm or less excluding iron and gas components, and a balance of titanium.

Next, a second aspect of the present invention relates to iron (100 (super)) ppm
The present invention relates to the fastening titanium wire for a living body according to the first aspect of the present invention, in which the content is set to 800 ppm.

Next, a third aspect of the present invention relates to iron (100 (super)) ppm.
The present invention relates to the fastening titanium wire for a living body according to the first aspect of the present invention.

Next, a fourth invention relates to the invention corresponding to each of the above items 1 to 3 in which oxygen is set to 200 ppm or less.

Next, the fifth invention relates to the invention corresponding to each of the above items 1 to 3 in which oxygen is set to 150 ppm or less.

Next, the sixth invention relates to the invention corresponding to each of the above-mentioned 1 to 5, wherein hydrogen is set to 30 ppm or less.

Next, a seventh invention relates to the invention corresponding to each of the above 1 to 5, wherein hydrogen is set to 30 ppm or less.

Next, an eighth invention relates to the invention corresponding to each of the above 1 to 7, wherein nitrogen is set to 100 ppm or less.

Next, a ninth invention relates to the invention corresponding to each of the above 1 to 7, wherein nitrogen is set to 50 ppm or less.

Next, a tenth invention relates to the invention corresponding to each of the above 1 to 7, wherein nitrogen is set to 20 ppm or less.

Next, an eleventh aspect of the present invention relates to a method of manufacturing
The present invention relates to the inventions corresponding to the above 1 to 10 described below.

Next, a twelfth aspect of the present invention relates to 100 ppm of carbon.
The present invention relates to the inventions corresponding to the above 1 to 10 described below.

Next, a thirteenth invention relates to the invention corresponding to each of the above items 1 to 10 in which carbon is set to 50 ppm or less.

Next, a fourteenth invention relates to the invention corresponding to each of the above items 1 to 13 in which impurities other than iron and gas components are set to 20 ppm or less.

Further, the fifteenth invention is characterized in that impurities other than iron and gas components are set to 20 ppm or less.
The invention pertains to each of the above.

Further, the sixteenth invention relates to the invention corresponding to each of the above 1 to 15, wherein the average crystal grain size is 2 μm to 150 μm.

Further, a seventeenth invention is characterized in that after the final cold drawing, annealing is performed in a temperature range of 400 ° C. to 900 ° C., in which iron is 100 (super) to 1000 ppm and oxygen as a gas component is 250 ppm or less. , Hydrogen 50 ppm or less, nitrogen 1
The present invention relates to an invention of a method for manufacturing a fastening titanium wire for a living body, in which 70 ppm or less, carbon 340 ppm or less, impurities other than iron and gas components are 100 ppm or less, and the balance is titanium. Further, the present invention relates to an invention of a method for manufacturing a fastening titanium wire for a living body configured in combination with the above 1 to 15. (Here, the number of inventions counted in the section of “Means for Solving the Problems” is omitted for convenience of explanation, and the actual number of inventions is a combination thereof. To do.)

[0038]

The details of the present invention and its operation will be described below. First, the reasons for limiting the chemical components such as iron and oxygen contained in the present fastening titanium wire for living body will be described in detail.

Iron (Fe): In the present invention, the amount of iron to be added is 100 (exceeding) to 1000 ppm of iron. It was thought that iron content was one of the impurities that reduced ductility, but the actual cause of the decrease in ductility was greatly affected by gas components and impurities other than iron.Rather, iron had a large effect on ductility without significantly affecting ductility. It has been found that it is a suitable element for improving the strength and proof stress. Further, as described later, addition of iron has an effect of suppressing the growth of crystal grains, and has an effect of increasing toughness by reducing the crystal grain size.

However, as the amount of iron added increases, the ductility gradually decreases, and if it exceeds 1000 ppm, the gap is wide open without winding up to the root of the fixing object at the time of torsion fastening as described later. Or, even if the wire is forcibly wound, the wire is broken before the winding is completed (breakage of type B in an explanatory diagram described later). In some cases, a break occurs at a transition portion with a single wire instead of a twisted portion (a breakage of type C in an explanatory diagram described later), which is unsuitable as a living body fastening wire. Therefore, the upper limit of the amount added is set to 1000 ppm.

When such a wire is used, in addition to the fact that the fastening is not sufficient, breakage is apt to occur particularly during the operation, so that the operation must be performed again and it takes a long time.

The iron is preferably from 100 (super) ppm to 8 ppm.
00 ppm, more preferably iron (super) 100 ppm to 60
It is 0 ppm. As a result, as shown in the test results described below, it has sufficient ductility (elongation) to wrap around the root of the object to be fixed, and also has high tensile strength and proof stress, and has sufficient strength. It is suitable as a fastening titanium wire for a living body.

Oxygen (O): In the present invention, oxygen is 25
0 ppm or less. 100 (super) to 1000 ppm iron
When added, the proof stress and tensile strength slightly increase with an increase in the oxygen content, but when oxygen exceeds 250 ppm, the ductility deteriorates, and the minimum required elongation becomes less than 30%.

Further, as described later, when the torsion is fastened,
There is a problem that the gap is widened without winding up to the root of the fixed object, or even if it is forcibly wound, it will be broken before the winding is completed (breakdown of type B in an explanatory diagram described later). Occurs. In some cases, a break occurs at a transition portion with a single wire instead of a twisted portion (a breakage of type C in an explanatory diagram described later), which is unsuitable as a living body fastening wire.

As with the presence of excess iron, the use of such a wire not only results in insufficient fastening, but also tends to cause breakage, especially during surgery, which necessitates re-operation and takes time. And other problems occur.

This oxygen is preferably at most 200 ppm,
More preferably, it is 150 ppm or less. As a result, as shown in the test results described later, the titanium wire has sufficient ductility (elongation) to be wound around the root of the object to be fixed, and is suitable as a living body fastening titanium wire.

Hydrogen (H): In the present invention, hydrogen is 50
ppm or less. Hydrogen affects ductility in smaller amounts than oxygen. When the hydrogen content exceeds 50 ppm, the ductility rapidly deteriorates even if other impurities are reduced, and the minimum required elongation becomes less than 30%.

Similarly to the above-described oxygen, at the time of torsion fastening as described later, the gap is widened without winding up to the root of the fixed object, or the winding is performed even if it is forcibly wound. There is a problem of breaking before completion (breakdown of type B in an explanatory diagram described later). In some cases, a break occurs at a transition portion with a single wire instead of a twisted portion (a breakage of type C in an explanatory diagram described later), which is unsuitable as a living body fastening wire.

Similarly, when such a wire is used, in addition to insufficient fastening, breakage tends to occur particularly during the operation, and the operation has to be performed again, which takes time. This hydrogen is preferably at most 30 ppm, more preferably at most 20 ppm.

As described above, as shown in the test results described below, the wire has sufficient ductility (elongation) to be wound around the root of the object to be fixed, and is suitable as a fastening titanium wire for a living body.

Nitrogen (N): In the present invention, nitrogen is 17
0 ppm or less. Nitrogen has a ductility reduction of about 1.5 times that of oxygen. As with the above oxygen, iron
When 0 (super) to 1000 ppm is added, the yield strength and tensile strength slightly increase with an increase in the content of nitrogen, but when nitrogen exceeds 170 ppm, the ductility rapidly deteriorates even if other impurities are reduced. , 30% minimum required elongation
Less than.

Similarly to the above-mentioned oxygen, at the time of torsion fastening as described later, the gap is widened without winding up to the root of the object to be fixed, or the winding is performed even if it is forcibly wound. There is a problem of breaking before completion (breakdown of type B in an explanatory diagram described later). In some cases, a break occurs at a transition portion with a single wire instead of a twisted portion (a breakage of type C in an explanatory diagram described later), which is unsuitable as a living body fastening wire.

When such a wire is used, in addition to the fact that the fastening is not sufficient, breakage is apt to occur particularly during the operation, so that the operation must be performed again and it takes a long time.

This nitrogen is preferably 100 ppm or less,
More preferably, it is 50 ppm or less. More preferably, it is 20 ppm or less. As described above, as shown in the test results described later, the wire has sufficient ductility (elongation) to be wound around the root of the object to be fixed, and is suitable as a living body fastening titanium wire.

Carbon (C): In the present invention, carbon is 34
0 ppm or less. Carbon exists as an interstitial solid solution element in Ti and has the function of increasing the strength of Ti.
Conversely, this results in about 0.75 times lower ductility at the same concentration than oxygen.

When the content of carbon exceeds 340 ppm, as in the case of the above oxygen, when iron is added in an amount of 100 (super) to 1000 ppm, the proof stress and the tensile strength slightly increase with the increase of the carbon content. The ductility suddenly worsens even if the value is reduced, and the minimum required elongation becomes less than 30%.
And, like the above-mentioned oxygen, at the time of torsion fastening as described below, the gap is wide open without winding up to the root of the fixed object, or even if it is forcibly wound, before winding is completed This causes a problem of breaking (breakdown of type B in an explanatory diagram described later). In some cases, a break occurs at a transition portion with a single wire instead of a twisted portion (a breakage of type C in an explanatory diagram described later), which is unsuitable as a living body fastening wire.

The use of such a wire not only results in insufficient fastening, but also tends to cause breakage particularly during the operation, which causes a problem that the operation must be performed again and it takes time.

This carbon is preferably less than 200 ppm,
More preferably, it is 100 ppm or less. More preferably, it is 50 ppm or less. As described above, as shown in the test results described later, the wire has sufficient ductility (elongation) to be wound around the root of the object to be fixed, and is suitable as a living body fastening titanium wire.

Impurities other than iron and gas components: In the present invention, impurities other than iron and gas components are 10
0 ppm or less.

Generally, iron (Fe) is a typical impurity other than the gas component contained in titanium. However, a proper content of iron has a role of improving proof stress and tensile strength without reducing ductility, and is a suitable element. As described above, iron has tended to be regarded as a harmful impurity, but it is actually the ductile that is harmful to iron rather than iron and other impurity elements other than gas and gas components (usually containing more than 100 ppm). When these contents exceed 100 ppm, the ductility rapidly deteriorates, and the minimum required elongation becomes less than 30%. And, like the above-mentioned oxygen, at the time of torsion fastening as described later, the gap is wide open without winding up to the root of the fixing object, or the winding is not completed even if it is forcibly wound. (A type B breakage in an explanatory diagram described later). In some cases, a break occurs at a transition portion with a single wire instead of a twisted portion (a breakage of type C in an explanatory diagram described later), which is unsuitable as a living body fastening wire.

The use of such a wire not only results in insufficient fastening, but also tends to cause breakage, particularly during surgery, which leads to problems such as necessitating re-operation and taking time. The impurities other than the gas components are preferably at most 50 ppm, more preferably at most 20 ppm.

As described above, as shown in the test results described later, it has sufficient ductility (elongation) to be wound around the root of the object to be fixed, and is suitable as a fastening titanium wire for a living body.

Description of Tensile Strength and Yield Strength (Yield Stress) of the Wire In the above, the limitation of impurities in the living body fastening titanium wire has been described. However, the living body fastening wire is sufficient for fixing or fastening bone. Tensile strength and proof stress are required. It is desirable to have a tensile strength of 180 MPa, preferably 200 MPa or more, and a proof stress of 70 MPa or more, preferably 100 MPa or more.

The presence of some of the impurities described above is rather preferred, as the impurities described above are more or less likely to generally increase the strength of titanium. However, the presence of excess tends to lose the properties of high ductility and pliability required for biomedical fastening wires. If the strength is increased at the expense of ductility, the risk of breaking the fastening wire arises and must be avoided.

As described above, high ductility is indispensable for the fastening wire for living body. Generally, if the tensile strength and the proof stress are 180 MPa and 70 MPa or more, respectively, there is no practical inconvenience and it is suitable as a fastening wire for living body. And, as in the present invention, the proof stress and the tensile strength can be further improved by the inclusion of iron.

When the strength is to be further increased, for example, when the bone is used for joining a bone which is subjected to a large load, it is necessary to increase the diameter of the wire or to braid several wires to form a fastening wire having increased strength. Therefore, such a method can be adopted as necessary. The fastening titanium wire for living body of the present invention sufficiently satisfies the above conditions.

Next, the average crystal grain size and the like will be described. In the present invention, the average crystal grain size is 2 μm to 150 μm.
m is desirable. The smaller the crystal grain size, the higher the toughness. As described above, iron can be cited as an element that suppresses the growth of crystal grains. However, in practice, it is difficult to manufacture an element having a particle diameter of less than 2 μm, and even if it can be manufactured, a part remains strained and the ductility value decreases. I do. On the other hand, when the average crystal grain size is large, especially when it exceeds 150 μm, the number of crystal grains becomes small with respect to the wire diameter, and the ductility is locally deteriorated. From the above, the average crystal grain size was 2 μm
To 150 μm.

Next, details of the manufacturing method will be described.
A titanium ingot is prepared by melting and casting a titanium material for which a predetermined component has been prepared. The gas components oxygen, nitrogen,
In order to remove impurities such as hydrogen and carbon to a predetermined amount or less, a vacuum arc melting method, an electron beam melting method, or the like can be used. After forging the obtained titanium ingot as necessary, groove rolling, swaging, and wire drawing are performed, and for example, φ1.7, φ1.0, φ0.8, φ
It is made into a wire having a predetermined diameter such as 0.4. The diameter of the wire is adjusted by appropriately changing the diameter of the die and performing wire drawing. The area reduction rate is about 30 to 90%.

In the course of this processing step, intermediate annealing (400 to
(In a temperature range of 900 ° C., preferably in a temperature range of 500 to 700 ° C., more preferably in a temperature range of 550 to 650 ° C., for about 5 seconds to 5 hours).

In place of the above-described manufacturing process, a plate-like product obtained by rolling is cut into a square rod, and the corners of the square bar are cut off with a grinder or the like, followed by swaging and drawing. You can also.

After the final processing, a temperature range of 400 to 900 ° C., preferably 500 to 700 ° C., more preferably 5 to 700 ° C.
The final annealing is performed in a temperature range of 50 to 650 ° C. for about 5 seconds to 5 hours. Predetermined crystal grains (for example, having an average crystal grain size of 2 μm to 150 μm) are formed through the above processing and annealing. Intermediate annealing and final annealing can be used either continuously or batchwise. Thus, a titanium wire having a predetermined diameter is manufactured.

The above-described fastening titanium wire for a living body according to the present invention described above is used for fastening a human bone or an artificial bone in a living body, and has sufficient ductility (elongation) to be wound around the root of an object to be fixed. It can be easily and firmly fastened during surgery, and has excellent characteristics of high in-vivo safety.

[0073]

Examples and Comparative Examples Hereinafter, the present invention will be described with reference to Examples (compared with Comparative Examples). Titanium ingots were prepared by melting and casting the titanium materials for which the components had been prepared. An electron beam melting method was used to remove impurities such as oxygen, nitrogen, hydrogen, and carbon as gas components.

After forging the obtained titanium ingot,
Groove roll rolling, swaging, wire drawing, φ
Wires having diameters of 1.0 and φ0.8 were produced. The area reduction rate is about 30 to 90%. During this processing step,
Intermediate annealing was performed in a temperature range of 400 to 900 ° C. After the final processing, final annealing was performed in a temperature range of 400 to 900 ° C. The average crystal grain size was 2 μm to 150 μm.

Table 1 shows the component analysis values of the test materials of the titanium wire prepared as described above. The values shown in the sample numbers (1 to 20) in Table 1 are average values of 20 samples. Component analysis values are rounded to the nearest single digit.

In addition, instead of the above-described manufacturing process, the plate-shaped material obtained by rolling is cut into a square rod shape, cut off with a square grinder of the square bar, and then swaged and drawn. Went to make a titanium wire,
There was no difference in characteristics between components whose analytical values fell within the range of the present invention.

Further, due to the difference between the annealing temperature range of 500 ° C. to 700 ° C. and 550 ° C. to 650 ° C. and the average crystal grain size, those which depart from the numerical range described as “more preferable range” in the description of the present invention are as follows: There is a tendency for the dispersion to be slightly larger than the characteristic value in the “more preferable range”, but there is no particular difference in the characteristic when the component analysis value falls within the range of the present invention.

For comparison, a similar manufacturing process was performed to produce a titanium wire in which impurities were prepared.

Table 1 also shows the component analysis values of the test materials. The values shown in the sample numbers (21 to 33) in Table 1 are average values of 20 samples as in the examples of the present invention. Similarly, the component analysis values are obtained by rounding one digit.

[0080]

[Table 1]

Next, the test described below was performed using each test material. (1) Tensile test (measurement of elongation and measurement of proof stress and tensile strength) Distance between gauge points: 70 mm, tensile speed 10 mm / mi
A tensile test was performed on two types of wires having n and a diameter between the reference points: 1.0 mm and 0.8 mm.

(2) Twist (Torsion) Test A jig to be wound: a round bar fixing jig having a diameter of 20 mm, the number of rotations: 60 rpm, and two kinds of wires having a wire diameter of 1.0 mm and 0.8 mm were twisted. (Torsion) test.

The results of elongation measurement by the above tensile test are shown in Table 1 and FIGS. As is clear from Table 1, all of the samples 1 to 20 of the present invention have an elongation of 30% or more and exhibit good ductility. Even when iron is contained in a predetermined amount, particularly 200 ppm of oxygen which is a gas component
Hereinafter, the ductility is higher when hydrogen is 30 ppm or less, nitrogen is 100 ppm or less, carbon is 100 ppm or less, and impurities other than iron and gas components are 50 ppm or less. More preferably, oxygen is at most 150 ppm, hydrogen is at most 20 ppm, nitrogen is at most 20 ppm, carbon is at most 50 ppm, and impurities other than iron and gas components are at most 20 ppm, all of which exhibit extremely high ductility.

On the other hand, Sample 2 presented as a comparative example
In each of Nos. 1 to 33, the elongation was less than 30%, indicating that the ductility was extremely poor. Samples 21 to 33 of these comparative examples all exceeded 1000 ppm of iron or 300 ppm of oxygen, 50 ppm of hydrogen, and 20 ppm of nitrogen.
0 ppm, carbon 400 ppm and impurities other than iron and gas components exceed 100 ppm, which are unsuitable materials for fastening titanium wires for living bodies.

FIG. 1 shows Samples 1, 2, 3, 4, 5, 6 and Comparative Examples 21, 22, and 23, showing the change in elongation depending on the iron content.

FIG. 2 shows Samples 1, 7, and 8 and Comparative Example 24,
25 shows the change in elongation due to the oxygen content.

FIG. 3 shows Samples 1, 9, and 10 and Comparative Example 2.
6 and 27 show changes in elongation depending on the nitrogen content.

FIG. 4 shows Samples 1, 11, and 12 and Comparative Example 2.
8, 29 show changes in elongation with carbon content.

FIG. 5 shows Samples 1 and 14 and Comparative Examples 30 and 3.
1 shows the change in elongation depending on the hydrogen content.

FIG. 6 shows Samples 1, 15, and 16 and Comparative Example 3.
2 and 33 show changes in elongation depending on the content of impurities other than iron and gas components. In each case, it is obvious that the elongation of the example of the present invention is better than that of the comparative example.

The tensile strength and proof stress in the same tensile test are 180 MPa and 70 MPa, respectively, and there is no practical inconvenience and it is suitable as a fastening wire for living body.

Table 1 and FIGS. 7 to 12 show the measurement results of the proof stress and the tensile strength by the tensile test. As is clear from Table 1, Samples 1 to 20 of the present invention all have a proof stress of 70 MPa or more and a tensile strength of 180 MPa or more, and show good strength. In particular, when iron is 300 ppm or more, the proof stress is 100 MPa or more, and the tensile strength is 200 MPa or more, and the increase in strength is remarkable. In addition, it exhibits excellent characteristics that ductility decreases little and there is almost no gap in a torsion test described later. Further, when the iron content is 400 ppm or more, the proof stress and the tensile strength continue to further increase, but similarly, there is a preferable property that a decrease in ductility is not significantly observed.

FIG. 7 shows samples 1, 2, 3, and 4 according to the present invention.
4, 5, 6 and Comparative Examples 21, 22, 23 show changes in proof stress and tensile strength depending on the iron content.

FIG. 8 shows Samples 1, 7, and 8 and Comparative Examples 24 and 25 according to the present invention, and shows changes in proof stress and tensile strength depending on the oxygen content.

FIG. 9 shows Samples 1, 9, and 10 and Comparative Examples 26 and 27 according to the present invention, and shows changes in yield strength and tensile strength depending on the nitrogen content.

FIG. 10 shows samples 1, 11, 1 according to the present invention.
2 and Comparative Examples 28 and 29 show changes in proof stress and tensile strength depending on the carbon content.

FIG. 11 shows samples 1, 13, 1 according to the present invention.
4 and Comparative Examples 30 and 31, showing changes in proof stress and tensile strength depending on the hydrogen content.

FIG. 12 shows samples 1, 15, and 1 according to the present invention.
6 and Comparative Examples 32 and 33 showing changes in proof stress and tensile strength depending on the content of impurities other than iron and gas components.

It can be seen that the proof stress and the tensile strength of the examples and comparative examples according to the present invention both increase almost in proportion to the component contents. However, as described below, the presence of excess causes a rapid decrease in ductility, so it is necessary that the amount is not more than the predetermined amount shown in the present invention.

[0100]

[Table 2]

Next, the results of the torsion (torsion) test are shown in Tables 1 and 2, FIGS. 13 to 18, and FIG. 19 shows the classification of the fracture modes.

As shown in FIG. 19, by a torsion test, a round bar fixing jig having a diameter of 20 mm was rotated at a rotational speed of 60 r.
It shows the state wound by pm. Type A shows a state in which the jig is wound neatly to the base of the jig with little gap (less than 1.0 mm gap).

When the fracture occurs (by excessive winding), the form of the fracture is in the middle of the twisted portion, that is, the place where the processing strain is concentrated, and shows a favorable fracture form.

On the other hand, in the case of type B, the jig is broken when it cannot be wound up to the base of the jig (a gap of 1.0 mm or more). This occurs when the ductility of the wire is not sufficient. In this case, loosening occurs in the fastening.

Further, in the case of type C, breakage occurs at the transition between the winding portion and the single wire (elementary wire). This condition is completely unsuitable for a fastening wire.

As is evident from Table 2, in Samples 1 to 20 shown in Examples of the present invention, both the 1.0 mm diameter and the 0.8 mm diameter show the fracture mode of Type A, and almost no gap was formed. (The gap is less than 1.0 mm) This indicates that the jig can be wound neatly to the base.

The details of the gap for winding around the jig are shown in Table 1 and FIGS. As is clear from these, in Samples 1 to 20, the gap 1.0
mm, the better the ductility is, the better. Some samples have a gap of 0 and are even wound tightly to the root.

On the other hand, the samples 21 to 33 of the comparative examples show the broken form of the type B or the type C, and as shown in Table 1 and FIGS. (With a gap of 1.0 mm or more) or breakage at the transition between the wound part and the single wire (elementary wire). Although the yield strength and the tensile strength are required for the fastening titanium wire, it is fatal for the wire to have a large looseness in the fastening or to be broken during insufficient winding. These are unsuitable as fastening titanium wires for living bodies, and there is a risk that the wires may break during or after surgery or that the fastening may not be sufficient.

[0109]

It is known that titanium has good fatigue strength, a certain degree of tensile strength (not always sufficient), corrosion resistance and biocompatibility, but it has been a problem in the present invention. It solves the important problems of proof stress, tensile strength and fastening performance. Moreover, no toxic or soluble constituent elements are used in this solution.

As described above, the living body fastening titanium wire of the present invention is used for fastening human bones or artificial bones in a living body, and has sufficient ductility to be wound around the root of an object to be fixed ( (Elongation), can be easily and firmly fastened during surgery, and have excellent properties that are highly safe in vivo. In particular, it exerts an excellent function in fixing bone grafts and the like.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a change in elongation according to an iron content.

FIG. 2 is an explanatory diagram of a change in elongation due to an oxygen content.

FIG. 3 is an explanatory diagram of a change in elongation depending on a nitrogen content.

FIG. 4 is an explanatory diagram of a change in elongation according to a carbon content.

FIG. 5 is an explanatory diagram of a change in elongation due to a hydrogen content.

FIG. 6 is an explanatory diagram of a change in elongation depending on an impurity content excluding iron and gas components.

FIG. 7 is an explanatory diagram of changes in proof stress and tensile strength depending on the iron content.

FIG. 8 is an explanatory diagram of changes in proof stress and tensile strength depending on the oxygen content.

FIG. 9 is an explanatory diagram of changes in proof stress and tensile strength depending on the nitrogen content.

FIG. 10 is an explanatory diagram of changes in proof stress and tensile strength depending on the carbon content.

FIG. 11 is an explanatory diagram of changes in proof stress and tensile strength depending on the hydrogen content.

FIG. 12 is an explanatory diagram of changes in proof stress and tensile strength depending on the content of impurities except iron and gas components.

FIG. 13 is an explanatory diagram of a change in a gap depending on an iron content.

FIG. 14 is an explanatory diagram of a change in a gap due to an oxygen content.

FIG. 15 is an explanatory diagram of a change in a gap due to a nitrogen content.

FIG. 16 is an explanatory diagram of a change in a gap due to a carbon content.

FIG. 17 is an explanatory diagram of a change in a gap due to a hydrogen content.

FIG. 18 is an explanatory diagram of a change in a gap due to an impurity content excluding iron and gas components.

FIG. 19 is an explanatory diagram showing classifications of fracture modes.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-211164 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61L 17/00-31/00

Claims (34)

(57) [Claims] 1. Iron (more than) 1000-1000 ppm, oxygen 250 ppm or less as a gas component, hydrogen 50 ppm or less,
A living body fastening titanium wire comprising 170 ppm or less of nitrogen, 340 ppm or less of carbon, 100 ppm or less of impurities other than iron and gas components, and the balance being titanium. 2. The fastening titanium wire for a living body according to claim 1, wherein the iron content is 100 (super) ppm to 800 ppm. 3. The fastening titanium wire for a living body according to claim 1, wherein the iron content is 100 (super) ppm to 600 ppm. 4. The living body fastening titanium wire according to claim 1, wherein oxygen is 200 ppm or less. 5. The fastening titanium wire for a living body according to claim 1, wherein oxygen is 150 ppm or less. 6. The fastening titanium wire for a living body according to claim 1, wherein hydrogen is 30 ppm or less. 7. The fastening titanium wire for a living body according to claim 1, wherein hydrogen is 20 ppm or less. 8. The fastening titanium wire for a living body according to claim 1, wherein the nitrogen content is 100 ppm or less. 9. The living body fastening titanium wire according to claim 1, wherein the nitrogen content is 50 ppm or less. 10. The fastening titanium wire for a living body according to claim 1, wherein nitrogen is 20 ppm or less. 11. The fastening titanium wire for a living body according to claim 1, wherein the carbon content is 200 ppm or less. 12. The fastening titanium wire for a living body according to claim 1, wherein the carbon content is 100 ppm or less. 13. The fastening titanium wire for a living body according to claim 1, wherein the carbon content is 50 ppm or less. 14. An amount of impurities other than iron and gas components is 50.
The living body fastening titanium wire according to any one of claims 1 to 13, wherein the titanium wire is at most ppm. 15. An amount of impurities other than iron and gas components is 20.
The living body fastening titanium wire according to any one of claims 1 to 13, wherein the titanium wire is at most ppm. 16. The fastening titanium wire for a living body according to claim 1, wherein the average crystal grain size is 2 μm to 150 μm. 17. After final cold drawing, at 400 ° C. to 90 ° C.
Iron 100 (super) characterized by annealing in a temperature range of 0 ° C.
A method for producing a fastening titanium wire for a living body, which comprises -1000 ppm, gas component oxygen 250 ppm or less, hydrogen 50 ppm or less, nitrogen 170 ppm or less, carbon 340 ppm or less, impurities other than iron and gas components 100 ppm or less, and the balance being titanium. 18. After the final cold drawing, at 500 ° C. to 70
The method according to claim 17, wherein annealing is performed in a temperature range of 0 ° C. 19. 550 ° C.-65 after final cold drawing
The method according to claim 17, wherein annealing is performed in a temperature range of 0 ° C. 20. The method for producing a fastening titanium wire for a living body according to claim 17, wherein the iron content is 100 ppm (super) to 800 ppm. 21. The method for producing a fastened titanium wire for a living body according to claim 17, wherein the iron content is 100 (super) ppm to 600 ppm. 22. The method according to claim 17, wherein oxygen is 200 ppm or less. 23. The method according to claim 17, wherein oxygen is not more than 150 ppm. 24. The method according to claim 17, wherein the hydrogen content is 30 ppm or less. 25. The method according to claim 17, wherein the hydrogen content is 20 ppm or less. 26. The method according to claim 17, wherein the nitrogen content is 100 ppm or less. 27. The method for producing a fastened titanium wire for a living body according to claim 17, wherein the nitrogen content is 50 ppm or less. 28. The method according to claim 17, wherein nitrogen is 20 ppm or less. 29. The method for producing a fastened titanium wire for a living body according to claim 17, wherein the carbon content is 200 ppm or less. 30. The method according to claim 17, wherein the carbon content is 100 ppm or less. 31. The method according to claim 17, wherein the carbon content is 50 ppm or less. 32. An amount of impurities other than iron and gas components is 50.
32 ppm or less.
The method for producing a fastened titanium wire for a living body according to any one of the above. 33. An impurity other than iron and gas components containing 20 impurities
32 ppm or less.
The method for producing a fastened titanium wire for a living body according to any one of the above. 34. The method according to claim 17, wherein the average crystal grain diameter is 2 μm to 150 μm.