JPH07268574A - Production of iridium wire - Google Patents

Abstract

PURPOSE:To stably produce a iridium wire without causing wire breakage while preventing the occurrence of tucking and flaw by providing sufficient hardness. CONSTITUTION:Pure iridium is arc-melted, hot-forged, and subjected to recrystallization heat treatment. Subsequently, stress relief heat treatment, hot seizure, stress relief heat treatment, and hot wiredrawing are successively applied, by which the iridium wire can be obtained. It is preferable that hot wiredrawing is executed by subjecting a die, having a hole shape satisfying 1<=d/2 when (1) denotes the length of a die hole and (d) denotes the diameter of a die hole, to temp. rise up to 600-800 deg.C and then performing wiredrawing by means of this die at (60 to 160)cm/min working speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an iridium wire used as a pin tip of a precision instrument, especially a dot printer.

[0002]

2. Description of the Related Art Conventionally, in the manufacture of iridium wire, it is difficult to set the temperature and the pass schedule during wire drawing. If this is inappropriate, the wire will be broken or broken, and the hardness will be insufficient. If there is, it will cause fogging and scratches. That is,
Iridium has no workability in the cold (normal temperature), so if the heating temperature is low, it will not be processed at all or will be cut. On the other hand, if the heating temperature is too high, the crystal grains become coarse and the workability becomes poor, resulting in cutting. Furthermore, if the processing rate from intermediate annealing to finishing is small, if the intermediate annealing temperature is too high and the softening is large, if the heating during wire drawing is too high, the hardness becomes insufficient and fogging and scratches occur. Resulting in.

[0003]

SUMMARY OF THE INVENTION Therefore, according to the present invention, the iridium wire is stably manufactured so that the wire is not broken or cut, has sufficient hardness, and does not cause fogging or scratches. It is intended to provide a manufacturing method that can be performed.

[0004]

A method for producing an iridium wire according to the present invention for solving the above-mentioned problems is obtained by subjecting pure iridium to arc melting, then hot forging, and then recrystallization heat treatment. Iridium wire is produced by post hot working. The hot working preferably comprises steps of strain relief heat treatment, hot saver, strain relief heat treatment, and hot wire drawing. Further, the hot wire drawing is performed with a die having a hole shape such that the length 1 of the die hole and the diameter d of the die hole are 1 ≦ d / 2.
After raising the temperature to 00-800 ℃, the processing speed is 60 with this die.
It is preferable that the wire is drawn at a rate of up to 160 cm / min. The reason why the hole shape of the die for hot drawing is a length l and a diameter d, where l ≦ d / 2 is preferable, is that the wire is cut when the length l is 1/2 or more of the diameter d. Because. Also,
The reason for raising the temperature of the die to 600 to 800 ° C is to keep the wire at a high temperature during wire drawing and smooth it. Furthermore, the reason for setting the wire drawing speed to 60 to 160 cm / min is that if it is less than 60 cm / min, overheating and uneven heating occur, crystal grains become coarse and wire breakage easily occurs, and if it exceeds 160 cm / min, insufficient heating occurs. In addition, the lubricant does not work effectively and is easily broken.

[0005]

In the method for producing an iridium wire according to the present invention, since the wire material is made by hot working after performing the recrystallization heat treatment,
The process control in this hot working is easy, and in particular, it becomes easy to set the appropriate temperature and pass schedule in the hot drawing of the process, and the iridium wire will not break or break, and the hardness will be sufficient. Thus, it is possible to manufacture an iridium wire with stable dimensional accuracy and good quality without causing fogging or scratches.

[0006]

EXAMPLES Examples and comparative examples of the method for producing an iridium wire of the present invention will be described. First, an example will be described. Pure iridium 140 g lot was arc-melted, and then hot forged at 1500 ° C. to obtain 8.0 mm length, 8.0 mm width, 96 length.
mm forged product, then recrystallization annealing at 1500 ℃ for 30 minutes, then pass through a groove roll at 1200 ℃ to form a rod, then strain at 1200 ℃ for 30 minutes. Pre-anneal, then 1100 ° C, 7-pass sager, then 11
Strain relief annealing was performed at 00 ° C for 10 minutes, after which the hole-shaped cemented carbide die having a die hole length l = 1.1 mm and a die hole diameter d = 2.4 mm was heated to 700 ° C. This carbide die is drawn at a processing speed of 100 cm / min to form a wire with an outer diameter of 2.4 mm, which is annealed at 1100 ° C for 30 minutes, and then the hole length and hole diameter are sequentially changed under the same conditions. 17 wire drawing with a small die
When it was turned around, an iridium wire with an outer diameter of 0.65 mm could be processed for 100 m without breaking. And the hardness of this iridium wire was 580 to 620 Hv. Next, a comparative example will be described. Pure iridium (140 g) was arc-melted, and then hot forged at 1500 ° C. to obtain 8.0 mm length, 8.0 mm width, 96 mm length.
After making a forged product of 1,500 ℃, recrystallization annealing is performed over 30 minutes, then through a groove roll to form a rod-shaped body, 1200 ℃, strain relief annealing is performed over 30 minutes, Then 11
Perform a 7-pass sager at 00 ° C, then strain relief annealing at 1100 ° C for 10 minutes, after which die hole length l = 2.0
mm, die hole diameter d = 2.4 mm
When the temperature was raised to 00 ° C and 1000 ° C, respectively, and wire drawing was performed with these carbide dies at a processing speed of 10 cm / min and 200 cm / min, respectively, the wire was broken in the middle and could not be processed.

[0007]

As can be seen from the above description, according to the method for producing an iridium wire of the present invention, the wire is not broken or cut, and the hardness is sufficient to cause fogging and scratches. In addition, the iridium wire can be manufactured stably.

Claims (3)

[Claims] 1. A method for producing an iridium wire, in which pure iridium is arc-melted, then hot forged, then recrystallization heat treatment is performed, and then hot working is performed to form an iridium wire. 2. The method for producing an iridium wire according to claim 1, wherein the hot working comprises steps of heat treatment for strain relief, hot sager, heat treatment for strain relief, and hot wire drawing. 3. A hot-wire drawing die having a hole shape of 1 ≦ d / 2 where the length of the die hole is 1 and the diameter of the die hole is d ≦ 600.
Up to ~ 800 ° C, the processing speed is 60 ~ with this die.
The method for producing an iridium wire according to claim 2, wherein the wire is drawn at 160 cm / min.