JP6675555B1 - Method for manufacturing Pt alloy pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method with high dimensional accuracy, capable of easily manufacturing a thin Pt alloy pipe while preventing foreign matter from entering the inner surface of the pipe. A Pt alloy pipe is manufactured by rolling a Pt alloy plate with a roll and butt-welding side surfaces of the Pt alloy plate to produce a Pt alloy pipe; Inserting a wire into the core wire without deforming the core wire, and applying pressure to the outer surface of the Pt alloy pipe from a plurality of rolls in a plurality of directions, and then pulling out the core wire is repeated twice or more. A method of manufacturing a Pt alloy pipe, comprising: a step, a step of cutting the stretched Pt alloy pipe into a predetermined length, and a step of polishing the cut Pt alloy pipe. [Selection diagram] None

Description

  The present invention relates to a method for manufacturing a Pt alloy pipe, and more particularly to a method for manufacturing a Pt alloy pipe having high dimensional accuracy.

  The Pt alloy pipe is used, for example, for medical purposes, for example, as an imaging marker for a catheter tip.

  In Patent Literature 1, a Cu pipe is inserted into a noble metal pipe, drawn to a required outer diameter and inner diameter to form a clad pipe, and the outer periphery of the clad pipe is processed into a required shape and has a required length. And a method of manufacturing a thin-walled noble metal pipe characterized by removing a Cu pipe with a chemical.

  In Patent Document 2, a core metal wire having a diameter equal to or less than the inner diameter of the noble metal pipe tube is inserted (fitted) into a thin-walled noble metal pipe tube manufactured by drawing, and brought into close contact with a die process or the like. Heat treatment and wire drawing are repeated to produce a clad wire of a desired shape and dimensions, cut to a desired length by a cutter, and then the core wire is removed with a chemical to a thickness of 0.07 mm or less. A method for producing a small thin precious metal pipe is disclosed.

JP-A-5-31632 JP 2009-050658 A JP 2001-293511 A

  According to the method of Patent Document 1, a Cu pipe is inserted into an Au pipe, and the Cu pipe is drawn, and then the outer periphery of the clad pipe 8 is cut into a required shape by a cutting tool to form a thin portion. After cutting, the molded pipe is immersed in a 10% nitric acid solution for 30 minutes to dissolve and remove the Cu inside to obtain a thin precious metal pipe part. In this method, a step of forming a thin portion by cutting into a required shape with a cutting tool is required. Further, since the core metal wire is a soft Cu pipe, there is a possibility that the roundness of the inner circumference of the finished precious metal pipe cannot be secured.

  In the method of Patent Literature 2, a PtW pipe tube and a NiFe core metal wire are used as a composite clad wire, and drawing and annealing are repeated, cut, and the core metal wire is removed with hydrochloric acid to obtain a fine thin pipe. According to this method, there is a problem that the inner surface of the completed pipe is roughened or a component of the core metal wire enters the inner surface of the pipe and cannot be removed depending on the condition of the clad interface.

  Patent Literature 3 discloses that a seamless steel pipe is rolled using a mandrel mill (drawing rolling mill). Specifically, a plurality of hollow rolls into which a core metal wire has been sent are sequentially sent to each hole type roll pair of the mandrel mill, so that each of the hole type roll pairs and the core metal wire form a plurality of pieces. Rolled steel pipe of the same specifications. At this time, each cored wire is worn unevenly due to repeated use, and heat is generated unevenly due to heat conduction from the raw tube during rolling and processing heat accompanying rolling down by the hole type roll. Thermally expands. For this reason, it is described that the wall thickness and the like of the seamless steel pipe fluctuates in the central axis direction due to wear, thermal expansion, and the like of each cored wire.

  As described above, in a seamless steel pipe, when a core wire is inserted into a pipe and drawn, when the same core wire is used repeatedly, the core wire may be worn and the shape may be partially changed. In addition, there is a problem that if a part of the worn cored wire enters the inner surface of the pipe, it may not be removed. Therefore, a method of manufacturing a metal pipe in which a core metal wire is inserted into a pipe based on the manufacture of a steel pipe and drawn is strictly required for dimensional accuracy and foreign matter, for example, a thin PtIr alloy pipe for medical use having a diameter of 5 mm or less. It was difficult to apply it to manufacturing as it is.

  Accordingly, an object of the present invention is to provide a method that can easily produce a thin Pt alloy pipe with high dimensional accuracy, no foreign matter entering the inner surface of the pipe, and more.

  The present inventors have conducted intensive studies and as a result, put a core wire having a Vickers hardness of twice or more inside the Pt alloy pipe, and extend the pipe without deforming the core wire, and The above purpose (high dimensional accuracy, foreign matter enters the pipe inner surface by repeatedly preparing core wires with different dimensions and applying the pressure from multiple directions to the outer surface with multiple rolls and then pulling out the core wire And a thin Pt alloy pipe can be easily produced), and the present invention has been completed.

The present invention
A pipe forming process of rolling a Pt alloy plate with a roll and butt-welding the side portions to produce a Pt alloy pipe,
Inserting a core metal wire having a hardness twice or more as high as that of the alloy pipe inside the Pt alloy pipe and drawing it without deforming the core metal wire, and forming a plurality of rolls on the outer surface of the Pt alloy pipe with a plurality of rolls. A pipe drawing step of repeating the drawing of the cored wire twice or more times by applying pressure from a direction,
A cutting step of reducing the drawn Pt alloy pipe to a predetermined length,
Polishing the cut Pt alloy pipe,
And a method for producing a Pt alloy pipe.

In the above configuration,
The dimensional difference between the inner diameter of the Pt alloy pipe and the outer diameter of the cored wire at the time of the n-th drawing (n is an integer of 2 or more) in the drawing process is the dimensional difference at the time of the (n-1) th drawing. May be smaller.

In the above configuration,
In the drawing process, while leaving the cored wire without removing the cored wire after the final number of times of drawing,
After the polishing step, a removing step of chemically dissolving the core wire may be further included.

  The Pt alloy pipe may be used for medical purposes.

  ADVANTAGE OF THE INVENTION According to this invention, the dimensional accuracy is high, a foreign substance does not enter into the pipe inner surface, and the method which can manufacture a thin Pt alloy pipe easily can be provided.

  Hereinafter, the method for producing a Pt alloy pipe of the present invention will be described in more detail.

(First embodiment)
<Tubing process>
In the pipe making process, a Pt alloy plate is rolled with a roll, and the side surfaces (end surfaces of both sides) are butt-welded to produce a Pt alloy pipe. A Pt alloy plate is formed by a pipe manufacturing device.

  As the Pt alloy, a Pt alloy such as a PtIr alloy or a PtRh alloy can be used. For example, a PtIr alloy plate having a predetermined size is prepared. A PtIr alloy containing 5 to 30 mass% of Ir can be used.

  The thickness and width of the alloy plate are appropriately selected based on the diameter and thickness of the pipe to be manufactured. For example, to obtain a pipe having an outer diameter of φ3.0 mm and a wall thickness of 0.15 mm, a Pt alloy plate having a thickness of 0.15 mm and a width of 9.1 mm is prepared.

  In the following description, a PtIr alloy plate will be described as an example. For example, the PtIr alloy plate is transferred to the pipe manufacturing apparatus from the left direction, first passed through a plurality of sets of upper and lower rolls, side rolls, gradually rounded from a flat plate state, and then passed through a plurality of sets of fin rolls to obtain a side portion. Are formed into a butted tube.

  Next, the butted side portions of the PtIr tubular molded body are melted by means such as TIG welding or the like and passed through a squeeze roll. The squeeze roll applies side pressure to the tubular molded body, and is adjusted so that the side portions in the heated and molten state have a predetermined molten layer width.

<Heat treatment process>
A heat treatment step of heat-treating the formed PtIr alloy pipe at 900 to 1100 ° C. is performed as necessary. Specifically, heat treatment is performed at, for example, 1000 ° C. in a mixed atmosphere of hydrogen gas and nitrogen gas. By the heat treatment step, the processing strain is reduced, and the weld and the other structure are made uniform.

<Drawing process>
In the drawing process, a core metal wire having a Vickers hardness twice or more that of the alloy pipe is inserted inside the PtIr alloy pipe and drawn without deforming the core metal wire. The process of applying pressure from a plurality of directions with a roll and then pulling out the core metal wire is alternately repeated.

  The Vickers hardness of the core metal wire may be any material having a Vickers hardness of twice or more the material of the Pt alloy pipe. By selecting the Pt alloy and the cored wire in this way, the Pt alloy can be drawn without deforming the cored wire, and the dimensional accuracy of the Pt alloy tube can be increased. For example, the Vickers hardness of a 90 wt% PtIr alloy was 126 to 182. Therefore, a cored wire having a Vickers hardness of twice or more is used. For example, SKH51 is used. Its Vickers hardness is about 700, which is more than three times the Vickers hardness of a 90 wt% PtIr alloy as a pipe.

  First, an SKH51 core wire is inserted into a PtIr alloy pipe. Here, the difference between the inner diameter of the PtIr alloy pipe and the outer diameter of the SKH51 core wire ({pipe inner diameter}-{outer diameter of core metal wire}) is set to, for example, 0.2 to 0.6 mm. The PtIr alloy pipe into which the core wire has been inserted is drawn by a die having a predetermined size. Drawing can be performed by a draw wire drawing machine. In the draw wire drawing machine, a PtIr alloy pipe in which an SKH51 core wire is inserted is passed through a fixed die, and one end of the pipe is swept (drawn) at a constant speed to draw the PtIr alloy pipe. At this time, the outer diameter of the core wire is set slightly smaller than the inner shape of the PtIr alloy pipe ({pipe inner diameter} − {outer diameter of core wire} = 0.2 to 0.6 mm). The tube is stretched without deformation.

  Next, a PtIr alloy pipe is passed through a plurality of roller dice sets arranged at different angles and laminated (referred to as “different angle laminated roller dice set”), and pressure is sequentially applied to the outside of the PtIr alloy pipe from a plurality of angular directions. Add. By doing so, it becomes easier to pull out the core wire from the PtIr alloy pipe. Then the core wire is pulled out.

  The above steps of drawing and drawing are repeated. The outer diameter of the SKH51 core wire at the time of the second drawing is smaller than the outer diameter of the SKH51 core wire at the time of the first drawing. Further, the dimensional difference between the inner diameter of the PtIr alloy pipe and the outer diameter of the core metal wire at the time of the second and subsequent drawing in the drawing process is larger than the dimensional difference at the time of drawing the number of times before the drawing. Try to be smaller. That is, the dimensional difference between the inner diameter of the PtIr alloy pipe and the outer diameter of the cored wire is gradually reduced as the second and third tube drawing are performed.

  As a result of the drawing process, a PtIr alloy pipe having a diameter of about 0.5 to 5 mm and a wall thickness of about 0.025 to 0.2 mm can be obtained. However, but not limited to, another embodiment may be a PtIr alloy pipe having a diameter of about 0.5-3 mm and a wall thickness of about 0.025-0.1 mm.

  In this way, by inserting a cored wire having a hardness twice or more that of the alloy pipe inside the PtIr alloy pipe, the cored wire does not wear or deform, and the cored wire is applied to the inner surface of the PtIr alloy pipe. There is no entry. By processing a plurality of times without deforming the cored wire, it is possible to obtain an inner diameter and an outer diameter with high dimensional accuracy.

<Cutting process>
In the cutting step, the PtIr alloy pipe is cut into a predetermined size by, for example, a wire saw. Specifically, a plurality of wire saws having abrasives attached to the surface are arranged, and a plurality of PtIr alloy pipes arranged in parallel are simultaneously cut at a plurality of locations to obtain a plurality of cut PtIr alloy pipes.

<Polishing process>
In the polishing step, the cut PtIr alloy pipe is polished. Specifically, a number of PtIr alloy pipes are put into a barrel polishing machine, and at the same time, an abrasive, a compound, and water are put into the barrel polishing machine, and the container is rotated for a predetermined time (for example, 30 minutes to 60 minutes) in this state. Polishing of PtIr alloy pipe.

(Second embodiment)
In the second embodiment, in the drawing process, the core wire is kept inserted without removing the core wire after the final number of drawing processes, and the core metal wire is chemically dissolved after the polishing process. The removing step is further provided. The degree of close contact between the PtIr alloy pipe and the mandrel after the final drawing process is the same as in the first embodiment (the mandrel can be pulled out using a plurality of roller die sets). State), and the heat treatment was not performed to form the diffusion layer of the PtIr alloy pipe and the core wire. In this state, a method of chemically dissolving the core metal wire after the polishing step is employed. Therefore, there is no problem that the inner surface of the completed pipe is roughened or the component of the cored wire enters the inner surface of the pipe and cannot be removed.

<Removal process>
In the PtIr alloy pipe cut in the cutting step and polished in the polishing step with the cored wire inserted, the cored wire is chemically dissolved and removed in the removing step. In the removing step, for example, the core wire is immersed in a 50% nitric acid aqueous solution to dissolve and remove the core wire, and then washed with water.

  In the second embodiment, the core wire is processed a plurality of times without being deformed, and the core wire is removed after the final number of the drawing, cutting, and polishing steps, thereby achieving high dimensional accuracy. The inner and outer diameters are obtained.

  Next, a method for manufacturing a PtIr alloy pipe of the present invention will be described more specifically with reference to examples.

(Example 1)
^t 0.15mm x ^w 9.1mm x ^l 1,500mm 90wt% PtIr plate material is rolled and butt rolled to butt roll side surfaces, then TIG welding of the butt portion is performed continuously by a pipe making machine with an outer diameter of φ3.0mm Was manufactured.

  Next, an SKH51 core wire having an outer diameter of 2.30 mm and a hardness of 700 was inserted, and diced to an outer diameter of 2.5 mm with a draw wire drawing machine (no deformation of the core wire). ", Pressure was applied from eight directions to peel off the inner surface of the pipe and the outer surface of the core wire, and the core wire was pulled out. The above processing was repeated four times to obtain a pipe having an outer diameter of 2.00 mm. The core wire was pulled out last. Table 1 shows the outer diameter of the pipe, the inner diameter of the pipe, the outer diameter of the core wire, the {inner diameter of the pipe}-{the outer diameter of the core wire}, and the area reduction rate (reduction rate of the cross-sectional area of the pipe).

  Next, it was cut into a length of 2 mm, and the cut portion was deburred and the surface of the outer surface of the PtIr alloy pipe was polished with a barrel polishing machine. The manufactured PtIr alloy pipe had a dimensional tolerance of ± 1% or less in both the outer diameter and the inner diameter, and the core metal wire component did not enter the inner surface. Note that no change in the outer diameter of the cored wire was observed in the above drawing process.

(Example 2)
The three times of extension in Table 1 are the same as in the example. The method further includes a removing step of chemically dissolving the core metal wire after the polishing step, while leaving the core metal wire in place without removing the core metal wire after the fourth drawing.

  In the fourth drawing, the outer diameter was 2.00 mm using a draw wire drawing machine. The drawing process was completed with the cored wire inserted. At this time, the pipe outer diameter, pipe inner diameter, core metal wire outer diameter, {PtIr pipe inner diameter}-{core metal wire outer diameter}, and the area reduction rate are the same as in Table 1.

  Next, after cutting to a length of 2 mm, deburring of the cut part and polishing the surface of the outer surface of the PtIr pipe with a polishing machine, immersing in a 50% nitric acid aqueous solution, dissolving and removing the cored wire, washing with water Example 1 Of 90wt% PtIr capillary was prepared. The manufactured PtIr pipe had a dimensional tolerance of ± 1% or less in all of the outer diameter and the inner diameter, and there was no penetration of the core metal wire component into the inner surface. Note that no change in the outer diameter of the cored wire was observed in the above drawing process.

Claims (4)

A pipe forming process of rolling a Pt alloy plate with a roll and butt-welding the side portions to produce a Pt alloy pipe,
Inserting a core metal wire having a hardness twice or more as high as that of the alloy pipe inside the Pt alloy pipe and drawing it without deforming the core metal wire, and forming a plurality of rolls on the outer surface of the Pt alloy pipe with a plurality of rolls. A pipe drawing step of repeating the drawing of the cored wire twice or more times by applying pressure from a direction,
A cutting step of reducing the drawn Pt alloy pipe to a predetermined length,
Polishing the cut Pt alloy pipe,
A method for producing a Pt alloy pipe, comprising:   The dimensional difference between the inner diameter of the Pt alloy pipe and the outer diameter of the core wire during the second and subsequent drawing in the drawing process is smaller than the dimensional difference during the previous drawing. Item 4. The method for producing a Pt alloy pipe according to Item 1. In the drawing process, while leaving the cored wire without removing the cored wire after the final number of times of drawing,
The method further includes a removing step of chemically dissolving the core metal wire after the polishing step.
The method for producing a Pt alloy pipe according to claim 1 or 2, wherein: The Pt alloy pipe is for medical use,
The method for producing a Pt alloy pipe according to claim 1.