Intravascular nickel-titanium alloy guide wire and welding method thereof

Abstract

The present invention discloses an intravascular nickel-titanium alloy guide wire and a welding method thereof. The intravascular nickel-titanium alloy guide wire comprises a coaxially arranged nickel-titanium alloy wire and a stainless steel tube, the nickel-titanium alloy wire is provided with a step inserted into the stainless steel tube, the step is welded to the stainless steel tube through a plurality of welding points, and the plurality of welding points are not on the same cross section. The beneficial effects of the present invention are as follows: the welding of nickel-titanium alloy and stainless steel can be realized without filler, the spiral arrangement of welding points can avoid the formation of brittle faults due to continuous concentrated heating of the section, and the heat-affected zone is controlled during the welding process, so that the nickel-titanium alloy is less affected by heat and its superelasticity is avoided from being destroyed.

Description

Technical Field

[0001] The invention relates to the technical field of guidewires, and in particular to an intravascular nickel-titanium alloy guidewire and a welding method thereof. Background Art

[0002] The function of the guidewire in the process of intravascular interventional diagnosis and treatment is to enter the blood vessel cavity, first pass through the intravascular channels, branches and winding parts, and sometimes break through the narrow part to reach the target part, and guide other interventional medical devices such as catheters and microcatheters to the corresponding parts or areas. When the guidewire selectively enters the coronary artery of coronary heart disease, the tiny cerebral arteries in the skull, vascular malformations and small blood supply vessels in tumors, it plays an irreplaceable guiding role.

[0003] The Chinese patent application number CN201610071913 discloses an intravascular nickel-titanium alloy guidewire, a guidewire welding tool and a guidewire welding method. The guidewire in the patent is welded by nickel-titanium alloy wire and stainless steel wire. The patent has the following disadvantages:

[0004] 1) Fillers are needed to assist welding of nickel-titanium alloy wire and stainless steel wire. The composition of fillers is unclear. For interventional devices, introducing too much unclear material may have an impact on the patient's body.

[0005] 2) When welding nickel-titanium alloy wire and stainless steel wire, they are welded in a circular pattern on the connecting surface after the two are assembled. This method will cause the cross section to be continuously heated and form a brittle fault, which can easily cause the guide wire to break;

[0006] 3) If the welding temperature is too high when welding nickel-titanium alloy wire and stainless steel wire, the superelasticity of the nickel-titanium alloy will be destroyed.

[0007] Currently, no effective solution has been proposed for the problems in the related technologies. Summary of the invention

[0008] In response to the above technical problems in the related art, the present invention proposes an intravascular nickel-titanium alloy guide wire and a welding method thereof, which can avoid the use of fillers, solve the problem of easy brittle fracture of nickel-titanium alloy and stainless steel welding, and solve the problem of excessively high fusion welding temperature during the welding process.

[0009] To achieve the above technical objectives, the technical solution of the present invention is implemented as follows:

[0010] An intravascular nickel-titanium alloy guide wire comprises a coaxially arranged nickel-titanium alloy wire and a stainless steel tube, wherein the nickel-titanium alloy wire is provided with a step inserted into the stainless steel tube, the step is welded to the stainless steel tube via a plurality of welding points, and the plurality of welding points are not on the same cross section.

[0011] Furthermore, the diameter of the step is 0.01 mm smaller than the inner diameter of the stainless steel tube, and the length of the step ranges from 10 mm to 20 mm.

[0012] Furthermore, the plurality of welding spots are arranged in a spiral shape, and the axial distance between two adjacent welding spots is at least 0.5 mm.

[0013] The present invention also discloses a method for welding an intravascular nickel-titanium alloy guide wire, comprising the following steps:

[0014] S1: processing a step matching the stainless steel tube at the end of the nickel-titanium alloy wire, and inserting the step into the stainless steel tube so as to coaxially assemble the nickel-titanium alloy wire and the stainless steel tube;

[0015] S2 welds the step and the stainless steel pipe together through a plurality of welding points, and ensures that the plurality of welding points are not on the same cross section.

[0016] Furthermore, the diameter of the step is 0.01 mm smaller than the inner diameter of the stainless steel tube, and the length of the step ranges from 10 mm to 20 mm.

[0017] Furthermore, the plurality of welding spots are arranged in a spiral shape, and the axial distance between two adjacent welding spots is at least 0.5 mm.

[0018] Furthermore, in S2, during welding, it is necessary to ensure that the heat-affected zone area of ​​each welding spot only occupies less than 20% of the cross-sectional area of ​​the nickel-titanium alloy wire where the welding spot is located.

[0019] Furthermore, the heat-affected depth of the weld on the nickel-titanium alloy wire is within 0.05 mm, and the heat-affected area of ​​the weld on the nickel-titanium alloy wire is within 0.1 mm. 2 Within.

[0020] Furthermore, in S2, an inert gas is used as a shielding gas during welding, the temperature range of the shielding gas is -5°C to 10°C, the gas outlet rate of the shielding gas is 20L / min-50L / min, and the ambient humidity is ensured to be lower than 20% during welding.

[0021] Furthermore, the shielding gas starts blowing 1s-3s before welding for pre-protection, and continues blowing for 2s-5s after welding.

[0022] The beneficial effects of the present invention are as follows: the welding of nickel-titanium alloy and stainless steel can be achieved without fillers, the spiral arrangement of welding points can avoid the continuous concentrated heating of the cross section to form a brittle fault, and the heat-affected zone is controlled during the welding process to minimize the thermal impact on the nickel-titanium alloy and avoid the destruction of its superelasticity. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 is a front view of an intravascular nickel-titanium alloy guidewire according to an embodiment of the present invention;

[0025] Figure 2 is based on Figure 1 AA cross-sectional view of the intravascular nickel-titanium alloy guide wire;

[0026] Figure 3 is based on Figure 2 The enlarged view of point B of the intravascular nickel-titanium alloy guide wire is shown;

[0027] Figure 4 is a front view of the distribution of solder joints according to an embodiment of the present invention;

[0028] Figure 5 is a side view of the distribution of solder joints according to an embodiment of the present invention;

[0029] Figure 6 Schematic diagram of the relationship between the focal position and the size of the heat affected area according to an embodiment of the present invention Figure 1 ;

[0030] Figure 7 Schematic diagram of the relationship between the focal position and the size of the heat affected area according to an embodiment of the present invention Figure 2 .

[0031] In the figure:

[0032] 1. NiTi alloy wire; 2. Step; 3. Stainless steel tube; 4. Welding point; 5. Heat affected zone; 6. Focus. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0034] like Figure 1-7As shown, an intravascular nickel-titanium alloy guidewire according to an embodiment of the present invention includes a coaxially arranged nickel-titanium alloy wire 1 and a stainless steel tube 3, the nickel-titanium alloy wire 1 is provided with a step 2 inserted into the stainless steel tube 3, the step 2 is welded to the stainless steel tube 3 through a plurality of welding points 4, and the plurality of welding points are not on the same cross-section.

[0035] In a specific embodiment of the present invention, the diameter of the step 2 is 0.01 mm smaller than the inner diameter of the stainless steel tube 3, and the length of the step 2 is in the range of 10 mm to 20 mm.

[0036] In a specific embodiment of the present invention, the plurality of welding spots 4 are arranged in a spiral shape, and the axial distance between two adjacent welding spots 3 is at least 0.5 mm.

[0037] The present invention also discloses a method for welding a nickel-titanium alloy guide wire in a blood vessel, which is characterized by comprising the following steps:

[0038] S1: processing a step 2 matching with the stainless steel tube 3 at the end of the nickel-titanium alloy wire 1, and inserting the step 2 into the stainless steel tube 3 to coaxially assemble the nickel-titanium alloy wire 1 and the stainless steel tube 3;

[0039] S2 welds the step 2 and the stainless steel pipe 3 together through a plurality of welding points 4, and ensures that the plurality of welding points 4 are not on the same cross section.

[0040] In a specific embodiment of the present invention, the diameter of the step 2 is 0.01 mm smaller than the inner diameter of the stainless steel tube 3, and the length of the step 2 is in the range of 10 mm to 20 mm.

[0041] In a specific embodiment of the present invention, the plurality of welding spots 4 are arranged in a spiral shape, and the axial distance between two adjacent welding spots 3 is at least 0.5 mm.

[0042] In a specific embodiment of the present invention, in S2, during welding, it is necessary to ensure that the area of ​​the heat-affected zone 5 of each welding spot 4 occupies only within 20% of the cross-sectional area of ​​the nickel-titanium alloy wire 1 where the welding spot 4 is located.

[0043] In a specific embodiment of the present invention, the heat-affected depth of the weld 4 on the nickel-titanium alloy wire 1 is within 0.05 mm, and the heat-affected zone 5 of the weld 4 on the nickel-titanium alloy wire 1 is within 0.1 mm. 2 Within.

[0044] In a specific embodiment of the present invention, in S2, an inert gas is used as a shielding gas during welding, the temperature range of the shielding gas is -5°C to 10°C, the gas outlet rate of the shielding gas is 20L / min-50L / min, and the ambient humidity is ensured to be lower than 20% during welding.

[0045] In a specific embodiment of the present invention, the shielding gas starts blowing 1s-3s before welding for pre-protection, and continues blowing for 2s-5s after welding.

[0046] In order to facilitate understanding of the above technical solutions of the present invention, the above technical solutions of the present invention are described in detail below through specific usage methods.

[0047] The steps of the welding method of the intravascular nickel-titanium alloy guide wire described in the present invention are as follows: assembling the nickel-titanium alloy wire 1 and the stainless steel tube 3 → determining the focal length by laser → connecting the protective gas → emitting laser light → adjusting the position of the stainless steel tube 3 and the nickel-titanium alloy wire 1. Repeating the above steps can realize the welding of the nickel-titanium alloy wire 1 and the stainless steel tube 3.

[0048] The welding method of the intravascular nickel-titanium alloy guide wire of the present invention is used for butt welding of the nickel-titanium alloy part and the stainless steel part of the intravascular nickel-titanium alloy guide wire.

[0049] The stainless steel part is a single-lumen stainless steel tube 3, and its wall thickness is 0.05mm-0.2mm.

[0050] The nickel-titanium alloy part is a nickel-titanium alloy wire 1, the diameter of the nickel-titanium alloy wire 1 is the same as the diameter of the stainless steel tube 3, and a step 2 with a diameter 0.01 mm smaller than the inner diameter of the stainless steel tube 3 is machined at the end of the nickel-titanium alloy wire 1 by a machining method. The length of the step 2 ranges from 10 mm to 20 mm. The nickel-titanium alloy wire 1 can be assembled concentrically with the stainless steel tube 3 through the step 2.

[0051] The step 2 and the stainless steel pipe 3 are welded together through multiple welding points 4. The multiple welding points 4 are arranged in a spiral shape, or in other shapes or irregularly. The advantage of arranging the welding points 4 in a spiral shape is that it can ensure that there is only one welding point in the cross section where each welding point 4 is located. By ensuring that the number of welding points 4 arranged in a spiral shape is consistent with the number of welding points 4 in circular welding in the traditional method, the cumulative connection strength can be made to have no obvious difference from circular welding.

[0052] The step 2 and the stainless steel tube 3 are welded by laser welding. The heat-affected depth of the nickel-titanium alloy wire 1 and the size of the heat-affected zone 5 can be changed by changing the position of the laser focus 6 .

[0053] During welding, the heat affected depth of the weld point 4 on the nickel-titanium alloy wire 1 should be controlled within 0.05 mm, and the heat affected zone 5 on the nickel-titanium alloy wire 1 should be controlled within 0.1 mm.2 In this way, the heat-affected zone 5 of a single solder joint 4 only occupies 20% of the cross-sectional area of ​​the nickel-titanium alloy wire 1 where the solder joint 4 is located, and the distance between two adjacent solder joints 4 is at least 0.5 mm to ensure that no heat interaction occurs between the two adjacent solder joints 4.

[0054] Through the above method, more than 80% of the cross-section of the nickel-titanium alloy wire 1 where each welding point 4 is located is not affected by the heat of the welding process, and there is no mutual thermal influence between two adjacent welding points 4, thereby effectively avoiding the destruction of the superelasticity of the nickel-titanium alloy due to the large thermal influence.

[0055] During the welding process, the humidity of the welding environment must be controlled below 20% to avoid condensation on the sample surface.

[0056] Inert gas is required as shielding gas during welding, such as nitrogen, argon, helium, krypton or xenon. The shielding gas needs to be kept in the range of -5℃ to 10℃ during welding. Low temperature shielding gas is conducive to taking away the excess heat generated during welding. The outflow rate of shielding gas is 20-50L / min. Setting a higher outflow rate is conducive to taking away the excess heat generated during welding. Shielding gas starts blowing 1s-3s before laser light emission for pre-protection to isolate oxygen around welding point 4; continuing to blow for 2s-5s after laser light emission can effectively take away the excess heat left after welding.

[0057] In summary, with the help of the above-mentioned technical scheme of the present invention, the welding of nickel-titanium alloy and stainless steel can be achieved without fillers. The spiral arrangement of welding points can avoid the continuous concentrated heating of the cross section to form a brittle fault. The heat-affected zone is controlled during the welding process to minimize the thermal impact on the nickel-titanium alloy and avoid the destruction of its superelasticity.

[0058] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An intravascular nickel-titanium alloy guide wire, characterized in that: The invention comprises a coaxially arranged nickel-titanium alloy wire (1) and a stainless steel tube (3), wherein the nickel-titanium alloy wire (1) is provided with a step (2) inserted into the stainless steel tube (3), the diameter of the step (2) is 0.01 mm smaller than the inner diameter of the stainless steel tube (3), the length of the step (2) ranges from 10 mm to 20 mm, the step (2) is welded to the stainless steel tube (3) via a plurality of welding points (4), and the plurality of welding points (4) are not on the same cross section, the plurality of welding points (4) are arranged in a spiral shape, the axial distance between two adjacent welding points (4) is at least 0.5 mm, the heat-affected depth of the welding point (4) on the nickel-titanium alloy wire (1) is within 0.05 mm, and the heat-affected zone (5) of the welding point (4) on the nickel-titanium alloy wire (1) is within 0.1 mm. 2 Within.

2. A method for welding a nickel-titanium alloy guide wire in a blood vessel, characterized in that: The following steps are involved: S1: processing a step (2) on the end of the nickel-titanium alloy wire (1) to match the stainless steel tube (3), and inserting the step (2) into the stainless steel tube (3) to coaxially assemble the nickel-titanium alloy wire (1) and the stainless steel tube (3); S2: welding the step (2) and the stainless steel pipe (3) together through a plurality of welding points (4), and ensuring that the plurality of welding points (4) are not located on the same cross section; The plurality of welding points (4) are arranged in a spiral shape, and the axial distance between two adjacent welding points (4) is at least 0.5 mm; In S2, during welding, it is necessary to ensure that the heat-affected zone (5) of each welding point (4) occupies no more than 20% of the cross-sectional area of ​​the nickel-titanium alloy wire (1) where the welding point (4) is located; The heat-affected depth of the weld (4) on the nickel-titanium alloy wire (1) is within 0.05 mm, and the heat-affected zone (5) of the weld (4) on the nickel-titanium alloy wire (1) is within 0.1 mm. 2 Within.

3. The method for welding a nickel-titanium alloy guide wire in a blood vessel according to claim 2, characterized in that: The diameter of the step (2) is 0.01 mm smaller than the inner diameter of the stainless steel tube (3), and the length of the step (2) ranges from 10 mm to 20 mm.

4. The method for welding a nickel-titanium alloy guide wire in a blood vessel according to claim 2, characterized in that: In S2, an inert gas is used as a shielding gas during welding. The temperature range of the shielding gas is -5°C to 10°C, the gas outlet rate of the shielding gas is 20L / min-50L / min, and the ambient humidity is kept below 20% during welding.

5. The method for welding a nickel-titanium alloy guide wire in a blood vessel according to claim 4, characterized in that: The shielding gas starts blowing 1s-3s before welding for pre-protection and continues blowing for 2s-5s after welding.

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