JP2021065930A - Pt ALLOY PIPE MANUFACTURING METHOD - Google Patents

Abstract

To provide a method that can easily manufacture a thin Pt alloy pipe that has high dimensional accuracy and can prevent a foreign matter from intruding into an inner surface of the pipe.SOLUTION: A Pt alloy pipe manufacturing method includes: a pipe-making step of manufacturing a Pt alloy pipe by rolling a Pt alloy plate by a roll and butt-welding side parts of the plate; a pipe expanding step of repeating two times or more a step of inserting a core metal wire having hardness equal to twice or more hardness of the alloy pipe into the inside of the Pt alloy pipe and expanding the pipe without deforming the core metal wire and a step of making a plurality of rolls apply pressure to an outer surface of the Pt alloy pipe from a plurality of directions and then pulling out the core metal wire; a cutting step of cutting the expanded Pt alloy pipe into a predetermined length; and a step of polishing the cut Pt alloy pipe.SELECTED DRAWING: 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 with high dimensional accuracy.

Pt alloy pipes are used, for example, for medical purposes, for example, as contrast markers for catheter tips.

In Patent Document 1, a Cu pipe is fitted into a precious metal pipe and stretched to a required outer diameter and inner diameter to form a clad pipe, and the outer circumference of the clad pipe is processed into a required shape to obtain a required length. A method for producing a thin-walled noble metal pipe, which is characterized by cutting off the pipe and removing the Cu pipe with a chemical, is disclosed.

In Patent Document 2, a core metal wire having a diameter equal to or less than the inner diameter of the noble metal pipe base pipe is inserted (fitted) into a thin-walled noble metal pipe base pipe produced by pipe drawing, and is brought into close contact with the pipe by die processing or the like. A clad wire of a desired shape and size is produced by repeating heat treatment and wire drawing, cut to a desired length by a cutting machine, and then the core metal wire is removed with a chemical to obtain a wall thickness of 0.07 mm or less. A method for producing a micro-thin-walled precious metal pipe is disclosed.

Japanese Unexamined Patent Publication No. 5-31632 Japanese Unexamined Patent Publication No. 2009-050658 Japanese Unexamined Patent Publication No. 2001-293511

In the method of Patent Document 1, a Cu pipe is fitted into an Au pipe, the pipe is stretched, and then the outer circumference of the clad pipe 8 is cut into a required shape by a cutting tool to form a thin-walled portion. After cutting, this molded pipe is immersed in a 10% nitrate solution for 30 minutes to dissolve and remove the inner Cu to obtain a thin-walled noble metal pipe part. This method requires a step of cutting into a required shape with a cutting tool to form a thin wall portion. 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 gold pipe cannot be secured.

In the method of Patent Document 2, the PtW pipe raw pipe and the NiFe core metal wire are made into a composite clad wire, and the wire is repeatedly drawn and annealed, cut, and the core metal wire is removed with hydrochloric acid to obtain a fine thin-walled pipe. In this method, there is a problem that the inner surface of the completed pipe becomes rough depending on the condition of the clad interface, or the component of the core metal wire gets into the inner surface of the pipe and cannot be removed.

Patent Document 3 discloses that a seamless steel pipe is rolled by using a mandrel mill (stretching rolling mill). Specifically, by sequentially feeding a hollow raw pipe having a core metal wire inserted into each hole-shaped roll pair of the mandrel mill, a plurality of holes are provided by each hole-shaped roll pair and the core metal wire. Steel pipes with the same specifications are rolled. At that time, each core metal wire wears unevenly due to repeated use, and also generates heat and becomes uneven due to heat conduction from the raw pipe during rolling and processing heat due to rolling by the hole-shaped roll. Thermal expansion. For this reason, it is described that the wall thickness of the seamless steel pipe and the like fluctuate in the central axis direction due to wear and thermal expansion of each core metal wire.

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

Therefore, an object of the present invention is to provide a method having high dimensional accuracy, preventing foreign matter from entering the inner surface of the pipe, and easily producing a thin Pt alloy pipe.

As a result of diligent studies, the present inventors put a core metal wire having a Vickers hardness of twice or more inside the Pt alloy pipe and stretch the core metal wire without deforming it, and the Pt alloy pipe. By preparing core metal wires with different dimensions and repeating the process of applying pressure to the outer surface from multiple directions with multiple rolls and then pulling out the core metal wire, the above purpose (high dimensional accuracy, foreign matter enters the inner surface of the pipe). We have found that it is possible to easily manufacture a thin Pt alloy pipe), and have completed the present invention.

The present invention
A pipe making process in which a Pt alloy plate is rolled with a roll and the side surfaces are butt welded to produce a Pt alloy pipe.
Inserting a core metal wire having a hardness more than twice that of the alloy pipe inside the Pt alloy pipe and extending the core metal wire without deforming the core metal wire, and using a plurality of rolls on the outer surface of the Pt alloy pipe. A pipe drawing process in which pressure is applied from the direction and then the core metal wire is pulled out twice or more.
A cutting step of cutting the stretched Pt alloy pipe to a predetermined length, and
The polishing process of the cut Pt alloy pipe and
It is a method for manufacturing a Pt alloy pipe, which comprises.

In the above configuration
The dimensional difference between the inner diameter of the Pt alloy pipe and the outer diameter of the core metal wire at the time of the nth pipe stretching (n is an integer of 2 or more) in the pipe stretching step is the dimensional difference at the time of the n-1th pipe stretching. It may be made smaller than.

In the above configuration
In the tube drawing step, the core metal wire is not removed after the final number of times the pipe is stretched, and the core metal wire is left in place.
After the polishing step, a removal step of chemically dissolving the core metal wire may be further included.

The Pt alloy pipe may be used for medical purposes.

According to the present invention, it is possible to provide a method having high dimensional accuracy, preventing foreign matter from entering the inner surface of the pipe, and easily producing a thin Pt alloy pipe.

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

(First Embodiment)
<Pipe making process>
In the pipe making process, a Pt alloy plate is rolled and the side surface portions (end faces of both sides) are butt welded to produce a Pt alloy pipe. A Pt alloy plate is made by a pipe manufacturing equipment.

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 predetermined dimensions 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 wall thickness of the pipe to be manufactured. For example, if you want to obtain a pipe with an outer diameter of φ3.0 mm and a wall thickness of 0.15 mm, prepare a Pt alloy plate with a thickness of 0.15 mm and a width of 9.1 mm.

In the following description, a PtIr alloy plate will be described as an example. The PtIr alloy plate is transferred to a pipe manufacturing apparatus from the left, for example, and is first passed through a plurality of sets of vertical rolls and side rolls to be rolled up little by little from a flat plate state, and then passed through a plurality of sets of fin rolls to form a side surface. Is molded into a butt-shaped tubular shape.

Next, the abutted side surface portion of the tubular molded body of PtIr is melted by means such as TIG welding and passed through a squeeze roll. The squeeze roll applies lateral pressure to the tubular molded body, and adjusts the side surfaces in the heat-melted state so as to have a predetermined molten layer width.

<Heat treatment process>
The formed PtIr alloy pipe is subjected to a heat treatment step of heat-treating at 900 to 1100 ° C., if necessary. Specifically, heat treatment is performed in a mixed atmosphere of hydrogen gas and nitrogen gas, for example, at 1000 ° C. The heat treatment process reduces machining strain and homogenizes the weld and other structures.

<Pipe extension process>
In the pipe drawing process, a core metal wire having a Vickers hardness more than twice that of the alloy pipe is inserted inside the PtIr alloy pipe to extend the pipe without deforming the core metal wire, and a plurality of core wires are formed on the outer surface of the PtIr alloy pipe. After applying pressure from multiple directions with a roll, pulling out the core metal wire is repeated alternately.

The Vickers hardness of the core metal wire may be one having a Vickers hardness of twice or more that of the material of the Pt alloy pipe. By selecting the Pt alloy and the core wire in this way, the Pt alloy can be stretched without deforming the core wire, and the dimensional accuracy of the Pt alloy tube can be improved. For example, the Vickers hardness of the 90 wt% PtIr alloy ranged from 126 to 182. Therefore, a core metal 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 the 90 wt% PtIr alloy that is a pipe.

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

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

The above steps of stretching and pulling out the tube are repeated. The outer diameter of the SKH51 core metal wire at the time of the second pipe extension is made smaller than the outer diameter of the SKH51 core metal wire at the time of the first pipe extension. 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 pipe stretching in the pipe stretching step is the dimensional difference at the time of the pipe stretching the number of times before the pipe stretching. Try to make it smaller. That is, the dimensional difference between the inner diameter of the PtIr alloy pipe and the outer diameter of the core metal wire is gradually reduced as the pipe is stretched for the second time and the pipe is stretched for the third time.

As a result of the pipe drawing step, 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 can be a PtIr alloy pipe having a diameter of about 0.5 to 3 mm and a wall thickness of about 0.025 to 0.1 mm.

In this way, by inserting the core metal wire having a hardness more than twice that of the alloy pipe inside the PtIr alloy pipe, the core metal wire does not wear or deform, and the core metal wire can be attached to the inner surface of the PtIr alloy pipe. There is no entry. The inner and outer diameters with high dimensional accuracy can be obtained by processing the core metal wire multiple times without deforming it.

<Cutting process>
In the cutting step, the PtIr alloy pipe is cut to a predetermined size with, for example, a wire saw. Specifically, a plurality of wire saws having an abrasive adhered to the surface are arranged, and a plurality of PtIr alloy pipes arranged in parallel are simultaneously cut to obtain a plurality of cut PtIr alloy pipes.

<Polishing process>
In the polishing process, the cut PtIr alloy pipe is polished. Specifically, by putting a large number of PtIr alloy pipes in the barrel grinding machine, putting the abrasive, the compound, and water, and rotating the container for a predetermined time (for example, 30 to 60 minutes) in that state. Polish the PtIr alloy pipe.

(Second Embodiment)
In the second embodiment, in the tube drawing step, the core metal wire is not removed after the final number of times of tube drawing, and the core metal wire is left inserted, and the core metal wire is chemically dissolved after the polishing step. The removal step is further provided. The degree of adhesion between the PtIr alloy pipe and the core metal wire after the final pipe drawing step is the same as in the case of the first embodiment (the core metal wire can be pulled out using a plurality of roller die sets). The state), and the heat treatment was not performed to form the diffusion layer of the PtIr alloy pipe and the core metal wire. In that state, a method of chemically dissolving the core metal wire after the polishing step is adopted. Therefore, there is no problem that the inner surface of the completed pipe is roughened or the component of the core metal wire enters the inner surface of the pipe and cannot be removed.

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

In the second embodiment, in addition to processing the core metal wire a plurality of times without deforming the core metal wire, a step of removing the core metal wire is provided after the final number of pipe drawing steps, cutting steps, and polishing steps, so that high dimensional accuracy is achieved. The inner and outer diameters of are obtained.

Next, the method for producing the PtIr alloy pipe of the present invention will be described in more detail with reference to Examples.

(Example 1)
^t 0.15mm × ^w 9.1mm × ^l 1,500mm 90wt% PtIr plate material is rolled and the side parts are butted by fin roll, and then the butt part is TIG welded continuously. Outer diameter φ3.0mm Pipe was made.

Next, insert a SKH51 core metal wire with an outer diameter of φ2.30 mm and a hardness of 700, and die it to an outer diameter of φ2.5 mm with a draw wire drawing machine (no deformation of the core metal wire). ], Pressure was applied from eight directions to peel off the inner surface of the pipe and the outer surface of the core metal wire, and the core metal wire was pulled out. The above processing was repeated 4 times to obtain a pipe having an outer diameter of φ2.00 mm. The core metal wire was pulled out last. Table 1 shows the pipe outer diameter, pipe inner diameter, core metal wire outer diameter, {pipe inner diameter}-{core metal wire outer diameter}, and surface reduction rate (reduction rate of pipe cross-sectional area).

Next, the pipe was cut to a length of 2 mm, and the cut portion was deburred and the outer surface of the PtIr alloy pipe was polished with a barrel grinding machine. The produced PtIr alloy pipe had a dimensional tolerance of ± 1% or less for both the outer diameter and the inner diameter, and the core metal wire component did not enter the inner surface. No change in the outer diameter of the core metal wire was observed in the pipe drawing step.

(Example 2)
The three tube extensions in Table 1 are the same as in the examples. After the fourth tube drawing, the core metal wire is not removed and the core metal wire is left in place, and a removal step of chemically dissolving the core metal wire after the polishing step is further provided.

In the fourth tube drawing, the outer diameter was φ2.00 mm with a draw wire drawing machine. The tube drawing process was completed with the core wire still in place. 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 surface reduction rate are the same as in Table 1.

Next, the pipe is cut to a length of 2 mm, the cut portion is deburred and the outer surface of the PtIr pipe is polished with a polishing machine, and then immersed in a 50% nitric acid aqueous solution to dissolve and remove the core metal wire, and washed with water. 90 wt% PtIr capillary tube was prepared. The produced PtIr pipe had a dimensional tolerance of ± 1% or less for both the outer diameter and the inner diameter, and the core metal wire component did not enter the inner surface. No change in the outer diameter of the core metal wire was observed in the pipe drawing step.

Claims (4)

A pipe making process in which a Pt alloy plate is rolled with a roll and the side surfaces are butt welded to produce a Pt alloy pipe.
Inserting a core metal wire having a hardness more than twice that of the alloy pipe inside the Pt alloy pipe and extending the core metal wire without deforming the core metal wire, and using a plurality of rolls on the outer surface of the Pt alloy pipe. A pipe drawing process in which pressure is applied from the direction and then the core metal wire is pulled out twice or more.
A cutting step of cutting the stretched Pt alloy pipe to a predetermined length, and
The polishing process of the cut Pt alloy pipe and
A method for manufacturing a Pt alloy pipe, which comprises. A claim characterized in that the dimensional difference between the inner diameter of the Pt alloy pipe and the outer diameter of the core metal wire at the time of the second and subsequent pipe stretching in the pipe stretching step is smaller than the dimensional difference at the time of the previous pipe stretching. Item 2. The method for manufacturing a Pt alloy pipe according to Item 1. In the tube drawing step, the core metal wire is not removed after the final number of times the pipe is stretched, and the core metal wire is left in place.
A removal step of chemically dissolving the core metal wire after the polishing step is further included.
The method for producing a Pt alloy pipe according to claim 1 or 2, wherein the Pt alloy pipe is manufactured. The Pt alloy pipe is for medical use.
The method for producing a Pt alloy pipe according to any one of claims 1 to 3.