Preparation method of medical stainless steel narrow thin strip

Abstract

The invention relates to the technical field of medical instruments, in particular to a preparation method of a medical stainless steel narrow and thin strip. The preparation method of the medical stainless steel narrow and thin strip specifically comprises the following steps that S1, a wire rod is prepared, specifically, medical stainless steel is subjected to vacuum melting, a medical stainless steel cast ingot is machined into the wire rod through forging and rolling combined heat treatment, and the wire rod is subjected to annealing treatment; s2, a wire material is prepared, specifically, the wire material is drawn into a thick wire, the thick wire is subjected to vacuum continuous annealing treatment, the thick wire is drawn into a thin wire, the thin wire is drawn into an ultra-thin wire, and the ultra-thin wire is drawn into a micro wire; s3, preparing a narrow and thin strip: finally rolling the ultrafine wire into the narrow and thin strip; and S4, the mechanical property is adjusted, specifically, the narrow and thin strip is subjected to vacuum continuous annealing treatment. The material has the advantages of high plasticity and capability of meeting mechanical property requirements.

Description

Technical Field

[0001] The invention relates to the technical field of medical devices, and in particular to a method for preparing a medical stainless steel narrow thin strip. Background Art

[0002] Medical stainless steel narrow and thin strips have excellent strength, dimensional accuracy, surface finish, biocompatibility and other characteristics. They are widely used in high-end medical devices and are mainly used as base braiding materials for three types of medical devices such as microcatheters, guidewires and stents.

[0003] With the development of minimally invasive medical technology, the size of medical stainless steel narrow and thin strips is getting smaller and smaller, and the application prospects are becoming more and more broad. In the implantable medical industry that requires light, thin and short, in addition to carrying the application of traditional structures, medical stainless steel narrow and thin strips are currently developing in the direction of function and electricity.

[0004] my country's high-end medical metal materials industry started late and has a weak foundation. Domestic micron-level medical stainless steel narrow and thin strips often have problems such as difficulty in plastic deformation and poor forming quality. The main reason is the lack of in-depth and systematic research on alloy solidification defect control, plastic deformation process optimization, and heat treatment performance regulation. The microstructure, dimensional accuracy, surface quality, and performance consistency of medical stainless steel narrow and thin strip products are still far behind those of foreign countries. For strict requirements of implantable medical devices, they cannot meet the performance requirements, which restricts the development of my country's high-end cardiovascular and cerebrovascular implantable medical materials industry.

[0005] Therefore, in view of the shortcomings of the prior art, a method for preparing a medical stainless steel narrow thin strip is provided. Summary of the invention

[0006] In order to overcome the deficiencies of the prior art, the present invention provides a method for preparing a medical stainless steel narrow thin strip, aiming to solve the problems of difficult plastic deformation and poor forming quality.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for preparing a medical stainless steel narrow thin strip comprises the following steps:

[0009] S1: Preparation of wire: vacuum melting of medical stainless steel, processing of medical stainless steel ingots into wires by forging and rolling combined with heat treatment, and annealing of the wires;

[0010] S2: preparing wires: drawing the wires into thick wires, performing vacuum continuous annealing on the thick wires, drawing the thick wires into thin wires, drawing the thin wires into ultra-fine wires, and drawing the ultra-fine wires into micro-wires;

[0011] S3: Preparation of narrow and thin strips: Finally, the ultrafine wires are rolled into narrow and thin strips;

[0012] S4: Adjusting mechanical properties: Vacuum continuous annealing of narrow and thin strips.

[0013] As a further improvement of the technical solution of the present invention, in step S1, the diameter of the wire is 5 to 8 mm, the annealing temperature is 800 to 1200° C., and the time is 20 to 60 min.

[0014] As a further improvement of the technical solution of the present invention, in step S2,

[0015] S2.1: Use a disc wire drawing machine and a tungsten carbide wire drawing die to draw the medical stainless steel wire into a thick wire with a diameter of 0.5 to 1 mm at a speed of 1 to 20 m / min;

[0016] S2.2: Use a medium drawing machine and a tungsten carbide drawing die to draw the thick wire after vacuum continuous annealing at a speed of 100 to 500 m / min to a thin wire with a diameter of 0.1 mm;

[0017] S2.3: Use a fine drawing machine and a natural diamond drawing die to draw the filament at a speed of 100 to 900 m / min to an ultra-fine filament with a diameter of 0.05 mm;

[0018] S2.4: Use a micro-drawing machine and a natural diamond drawing die to draw the ultra-fine wire into a micro-wire with a diameter less than 0.05mm.

[0019] As a further improvement of the technical solution of the present invention, in step S2.1, a vacuum continuous annealing furnace is used to anneal the thick wire, and an inert gas is filled into the continuous annealing furnace during annealing. The annealing temperature is 850-1100°C, and the annealing speed is 2-20m / min.

[0020] As a further improvement of the technical solution of the present invention, in step S2, before rolling the narrow thin strip, the diameter of the stainless steel wire corresponding to the required narrow thin strip size is calculated according to the volume invariance principle.

[0021] As a further improvement of the technical solution of the present invention, in step S2.1, an oily lubricant is used during the rough drawing process;

[0022] In steps S2.2-S2.4, a water-based lubricant is used during the wire drawing process;

[0023] Wire drawing machines include slip wire drawing machines and non-slip wire drawing machines.

[0024] As a further improvement of the technical solution of the present invention, in step S3: a precision calender is used to roll the ultrafine wire into a narrow and thin strip at a speed of 50 to 200 m / min.

[0025] As a further improvement of the technical solution of the present invention, in step S3, an online width measuring instrument is provided at the rear end of the roller of the precision calender, and the real-time width change on the width sensor is obtained by adjusting the roller pressing amount;

[0026] The width of the narrow thin strip is 0.038-0.304 mm, and the thickness is 0.012-0.076 mm.

[0027] As a further improvement of the technical solution of the present invention, in step S4, a vacuum continuous annealing furnace is used to anneal the narrow thin strip to adjust the mechanical properties of the narrow thin strip. During the annealing, an inert gas is filled into the continuous annealing furnace. The annealing temperature is 850-1100°C and the annealing speed is 2-20m / min.

[0028] As a further improvement of the technical solution of the present invention, the present invention further includes step S5: inspecting the narrow thin strip: inspecting the dimensional accuracy, surface quality and mechanical property consistency of the narrow thin strip.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] In the preparation method of the medical stainless steel narrow and thin strip of the present invention, the medical stainless steel ingot is purified and smelted by high vacuum, and the medical stainless steel wire is prepared by forging, rolling and homogenization heat treatment; then the medical stainless steel wire is prepared by rough drawing, medium drawing, fine drawing and micro drawing; the medical stainless steel narrow and thin strip with a width of 0.038mm to 0.304mm and a thickness of 0.012mm to 0.076mm is prepared by precision rolling, and finally the mechanical properties of the medical stainless steel narrow and thin strip are adjusted by vacuum continuous annealing. The preparation method of the medical stainless steel narrow and thin strip has the characteristics of strong plasticity and meeting the requirements of mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The technology of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0032] Figure 1 Schematic diagram of the strain morphology of Example 1 of the medical stainless steel narrow thin strip of the present invention;

[0033] Figure 2 is a metallographic diagram of Example 1 of the medical stainless steel narrow thin strip of the present invention;

[0034] Figure 3 Schematic diagram of the annealing morphology of Example 2 of the medical stainless steel narrow thin strip of the present invention;

[0035] Figure 4 It is the metallographic diagram of Example 2 of the medical stainless steel narrow thin strip of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the embodiments and drawings to clearly and completely describe the concept, specific structure and technical effects of the present invention, so as to fully understand the purpose, scheme and effect of the present invention. It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other without conflict. The same reference numerals used throughout the drawings indicate the same or similar parts.

[0037] It should be noted that, unless otherwise specified, when a feature is referred to as being "fixed" or "connected" to another feature, it may be directly fixed or connected to the other feature, or it may be indirectly fixed or connected to the other feature. In addition, the descriptions of up, down, left, right, etc. used in the present invention are only relative to the relative positional relationship of the components of the present invention in the drawings.

[0038] Example 1

[0039] Reference Figures 1 to 4 A method for preparing a medical stainless steel narrow thin strip comprises the following steps:

[0040] S1: Preparation of wire: vacuum melting of medical stainless steel, processing of medical stainless steel ingots into wires by forging and rolling combined with heat treatment, and annealing of the wires;

[0041] S2: preparing wires: drawing the wires into thick wires, performing vacuum continuous annealing on the thick wires, drawing the thick wires into thin wires, drawing the thin wires into ultra-fine wires, and drawing the ultra-fine wires into micro-wires;

[0042] S3: Preparation of narrow and thin strips: Finally, the ultrafine wires are rolled into narrow and thin strips;

[0043] S4: Adjusting mechanical properties: Vacuum continuous annealing of narrow and thin strips;

[0044] S5: Inspection of narrow and thin strips: Inspection of the dimensional accuracy, surface quality and consistency of mechanical properties of the narrow and thin strips.

[0045] Among them, medical stainless steel ingots are purified and smelted by high vacuum, and medical stainless steel wires are prepared by forging, rolling and homogenization heat treatment; then medical stainless steel wires are prepared by rough drawing, medium drawing, fine drawing and micro drawing; medical stainless steel narrow and thin strips with a width of 0.038mm to 0.304mm and a thickness of 0.012mm to 0.076mm are prepared by precision rolling, and finally the mechanical properties of the medical stainless steel narrow and thin strips are adjusted by vacuum continuous annealing. The preparation method of the medical stainless steel narrow and thin strip has the characteristics of strong plasticity and meeting the requirements of mechanical properties. The prepared medical stainless steel narrow and thin strip is straight and curl-free in a free state, with a bright and flat surface, no obvious oxidation, no defects such as pits, scratches and cracks, and a tensile strength between 800 and 2700MPa, which meets the requirements of mechanical properties.

[0046] In one embodiment, in step S1, a vacuum melting furnace is used to melt the medical stainless steel ingot, and the melting temperature, melting time and melting times can be controlled to ensure the purity and cleanliness of the medical stainless steel ingot. The diameter of the wire is 5 to 8 mm, the annealing temperature is 800 to 1200° C., and the time is 20 to 60 min.

[0047] In one embodiment, in step S2,

[0048] S2.1: Use a disc wire drawing machine and a tungsten carbide wire drawing die to draw the medical stainless steel wire into a thick wire with a diameter of 0.5 to 1 mm at a speed of 1 to 20 m / min;

[0049] S2.2: Use a medium drawing machine and a tungsten carbide drawing die to draw the thick wire after vacuum continuous annealing at a speed of 100 to 500 m / min to a thin wire with a diameter of 0.1 mm;

[0050] S2.3: Use a fine drawing machine and a natural diamond drawing die to draw the filament at a speed of 100 to 900 m / min to an ultra-fine filament with a diameter of 0.05 mm;

[0051] S2.4: Use a micro-drawing machine and a natural diamond drawing die to draw the ultra-fine wire into a micro-wire with a diameter less than 0.05mm.

[0052] In step S2.1, the rough wire is annealed in a vacuum continuous annealing furnace, in which an inert gas is filled, the annealing temperature is 850-1100°C, and the annealing speed is 2-20 m / min. During the rough drawing process, an oil lubricant is used.

[0053] In one embodiment, in step S2, before rolling the narrow strip, the diameter of the stainless steel wire corresponding to the required narrow strip size is calculated according to the volume invariance principle. The length of the narrow strip remains unchanged before and after rolling, so it is only necessary that the cross-sectional area of ​​the narrow strip is the same as that of the ultrafine wire. Assuming that the required width of the narrow strip is a and the thickness is b, the diameter of the ultrafine wire for rolling the narrow strip is

[0054] In one embodiment, in step S2.1, an oil-based lubricant is used in the rough drawing process; in steps S2.2-S2.4, an aqueous lubricant is used in the wire drawing process; the wire drawing machine includes a slippery wire drawing machine and a non-slippery wire drawing machine.

[0055] In one embodiment, in step S3: a precision calender is used to roll the ultrafine wire into a narrow and thin strip at a speed of 50 to 200 m / min. An online width measuring instrument is provided at the rear end of the roller of the precision calender. By adjusting the roller pressure, the real-time width change on the width sensor is obtained; the width of the narrow and thin strip is 0.038 to 0.304 mm, and the thickness is 0.012 to 0.076 mm. Preferably, the key to rolling the ultrafine medical stainless steel wire into a narrow and thin medical stainless steel strip that meets the size requirements is to adjust the rolling pressure. Preferably, an oily lubricant is used during the rolling process of the narrow and thin medical stainless steel strip. The precision rolling speed of the narrow and thin medical stainless steel strip is between 40 and 60 m / min. If the speed is too slow, the production efficiency is low, and if the speed is too fast, the wire will shake, affecting the rolling stability.

[0056] In one embodiment, in step S4, a vacuum continuous annealing furnace is used to anneal the narrow thin strip to adjust the mechanical properties of the narrow thin strip. During the annealing, an inert gas is filled into the continuous annealing furnace. The annealing temperature is 850-1100° C. and the annealing speed is 2-20 m / min.

[0057] In one embodiment, referring to Figure 2 As shown, a narrow and thin strip of medical stainless steel with a width of 0.100 mm and a thickness of 0.033 mm is prepared:

[0058] A vacuum melting furnace is used to refine medical stainless steel ingots, and the ingots are processed into medical stainless steel wires with a diameter of 5 mm through forging, rolling and heat treatment. The annealing temperature is 900°C and the time is 30 minutes. A disc wire drawing machine and a tungsten carbide wire drawing die are used to draw the medical stainless steel wires to a thick wire with a diameter of 0.5 mm at a speed of 10 m / min, and the pass reduction rate is 10% to 15%. Under helium protection, a vacuum continuous annealing furnace with a tube length of 2 meters is used to anneal the medical stainless steel thick wires at an annealing temperature of 1000°C and a speed of 2 m / min. According to the principle of constant volume, the diameter of the medical stainless steel wire corresponding to the required narrow and thin strip product size is calculated to be 0.0648 mm, and a non-slip center drawing machine and tungsten carbide wire drawing are used. The medical stainless steel wire material is drawn into a 0.1mm diameter fine wire at a speed of 500m / min after continuous annealing, and the surface reduction rate is 10% to 15%; the medical stainless steel wire material with a diameter of 0.1mm is drawn into an ultra-fine wire with a diameter of 0.0648mm at a speed of 500m / min by a non-slip fine drawing machine and a natural diamond drawing die, and the medical stainless steel wire material with a diameter of 0.5mm is drawn into an ultra-fine wire with a diameter of 0.1mm at a speed of 500m / min, and the surface reduction rate is 10% to 15%; the medical stainless steel ultra-fine wire material is rolled into a medical stainless steel narrow and thin strip with a width and thickness of 0.100mm and 0.033mm at a rolling speed of 50m / min by adjusting the distance between the two rollers and adjusting the rolling pressure. The medical stainless steel narrow and thin strip is straight and curl-free in a free state, with a bright and flat surface, no obvious oxidation, no pits, scratches and cracks, and the average tensile strength is 2622MPa. The tensile curve and metallographic structure of the medical stainless steel narrow thin strip product are shown in the attached Figure 1 As shown, the horizontal axis is strain % and the vertical axis is stress MPa.

[0059] Example 2

[0060] In one embodiment, referring to Figure 4 As shown, a medical stainless steel narrow and thin strip with a width of 0.0635 mm and a thickness of 0.0127 mm is prepared:

[0061] A vacuum melting furnace is used to refine medical stainless steel ingots, and the ingots are processed into stainless steel wires with a diameter of 5 mm through forging, rolling and heat treatment. The annealing temperature is 900°C and the time is 30 minutes. A disc wire drawing machine and a tungsten carbide wire drawing die are used to draw the medical stainless steel wires to a thick wire with a diameter of 0.5 mm at a speed of 10 m / min, and the pass reduction rate is 10% to 15%. Under the protection of helium, a vacuum continuous annealing furnace with a tube length of 2 meters is used to anneal the medical stainless steel thick wires. Annealing, annealing temperature is 1000℃, speed is 2m / min; according to the principle of constant volume, the diameter of the medical stainless steel wire corresponding to the required narrow and thin strip product size is calculated to be 0.0321mm, and a non-slip medium drawing machine and a tungsten carbide wire drawing die are used to draw the medical stainless steel wire with a diameter of 0.5mm after continuous annealing at a speed of 500m / min to a thin wire with a diameter of 0.1mm, and the pass reduction rate is 10% to 15%; a non-slip fine drawing machine and a natural diamond are used. The medical stainless steel wire drawing die is used to draw the medical stainless steel wire with a diameter of 0.1mm at a speed of 500m / min to an ultra-fine wire with a diameter of 0.05mm, and the surface reduction rate is 10% to 15%; the ultra-fine wire with a diameter of 0.05mm at a speed of 100m / min is used to draw the medical stainless steel micro wire with a diameter of 0.0321mm at a speed of 100m / min; the surface reduction rate is 10% to 15%; the fine wire drawing die is used to draw the medical stainless steel wire with a diameter of 0.1mm at a speed of 500m / min to an ultra-fine wire with a diameter of 0.05mm, and the surface reduction rate is 10% to 15%; the fine wire drawing die is used to draw the medical stainless steel wire with a diameter of 0.0321mm at a speed of 100m / min; the surface reduction rate is 10% to 15%; the fine wire drawing die is used to draw the medical stainless steel wire with a diameter of 0.1mm at a speed of 500m / min. The dense calender adjusts the distance between the two rollers and the rolling reduction to roll the medical stainless steel ultrafine wire into medical stainless steel narrow and thin strips with a width and thickness of 0.0635mm and 0.0127mm at a rolling speed of 50m / min; the mechanical properties of the medical stainless steel narrow and thin strips are adjusted by vacuum continuous annealing. Under the protection of helium, a vacuum continuous annealing furnace with a tube length of 2 meters is used to anneal the stainless steel thick wire. The annealing temperature is 900℃ and the speed is 20m / min. The medical stainless steel narrow and thin strip is straight and curl-free in a free state, with a bright and flat surface, no obvious oxidation, no defects such as pits, scratches and cracks, and the average tensile strength is 840MPa. The tensile performance curve and metallographic structure of the medical stainless steel narrow and thin strip product are shown in the attached figure. Figure 2 As shown, the horizontal axis is strain % and the vertical axis is stress MPa.

[0062] The other contents of the preparation method of the medical stainless steel narrow thin strip described in the present invention refer to the prior art and will not be repeated here.

[0063] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Therefore, any modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention are still within the scope of the technical solution of the present invention.

[0064] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0065] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. A method for preparing a medical stainless steel narrow thin strip, characterized in that: The following steps are involved: S1: Preparation of wire: vacuum melting of medical stainless steel, processing of medical stainless steel ingots into wires by forging and rolling combined with heat treatment, and annealing of the wires; S2: preparing wires: drawing the wires into thick wires, performing vacuum continuous annealing on the thick wires, drawing the thick wires into thin wires, drawing the thin wires into ultra-fine wires, and drawing the ultra-fine wires into micro-wires; S3: Preparation of narrow and thin strips: Finally, the ultrafine wires are rolled into narrow and thin strips; S4: Adjusting mechanical properties: Vacuum continuous annealing of narrow and thin strips.

2. The method for preparing a medical stainless steel narrow thin strip according to claim 1, characterized in that: In step S1, the diameter of the wire is 5 to 8 mm, the annealing temperature is 800 to 1200° C., and the time is 20 to 60 min.

3. The method for preparing a medical stainless steel narrow thin strip according to claim 1, characterized in that: In step S2, S2.1: Use a disc wire drawing machine and a tungsten carbide wire drawing die to draw the medical stainless steel wire into a thick wire with a diameter of 0.5 to 1 mm at a speed of 1 to 20 m / min; S2.2: Use a medium drawing machine and a tungsten carbide drawing die to draw the thick wire after vacuum continuous annealing at a speed of 100 to 500 m / min to a thin wire with a diameter of 0.1 mm; S2.3: Use a fine drawing machine and a natural diamond drawing die to draw the filament at a speed of 100 to 900 m / min to an ultra-fine filament with a diameter of 0.05 mm; S2.4: Use a micro-drawing machine and a natural diamond drawing die to draw the ultra-fine wire into a micro-wire with a diameter less than 0.05mm.

4. The method for preparing a medical stainless steel narrow thin strip according to claim 3, characterized in that: In step S2.1, the thick wire is annealed in a vacuum continuous annealing furnace. During the annealing, an inert gas is filled into the continuous annealing furnace. The annealing temperature is 850-1100° C. and the annealing speed is 2-20 m / min.

5. The method for preparing a medical stainless steel narrow thin strip according to claim 1, characterized in that: In step S2, before rolling the narrow thin strip, the diameter of the stainless steel wire corresponding to the required narrow thin strip size is calculated according to the volume invariance principle.

6. The method for preparing a medical stainless steel narrow thin strip according to claim 3, characterized in that: In step S2.1, an oil-based lubricant is used during the rough drawing process; In steps S2.2-S2.4, a water-based lubricant is used during the wire drawing process; Wire drawing machines include slip wire drawing machines and non-slip wire drawing machines.

7. The method for preparing a medical stainless steel narrow thin strip according to claim 1, characterized in that: In step S3: a precision calender is used to roll the ultrafine wire into a narrow and thin strip at a speed of 50 to 200 m / min.

8. The method for preparing a medical stainless steel narrow thin strip according to claim 7, characterized in that: In step S3, an online width measuring instrument is provided at the rear end of the roller of the precision calender, and the real-time width change on the width sensor is obtained by adjusting the roller pressing amount; The width of the narrow thin strip is 0.038-0.304 mm, and the thickness is 0.012-0.076 mm.

9. The method for preparing a medical stainless steel narrow thin strip according to claim 1, characterized in that: In step S4, a vacuum continuous annealing furnace is used to anneal the narrow thin strip to adjust the mechanical properties of the narrow thin strip. During the annealing, an inert gas is filled into the continuous annealing furnace. The annealing temperature is 850-1100° C. and the annealing speed is 2-20 m / min.

10. The method for preparing a medical stainless steel narrow thin strip according to claim 1, characterized in that: The method further comprises step S5: inspecting the narrow thin strip: inspecting the dimensional accuracy, surface quality and mechanical property consistency of the narrow thin strip.

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