JP2508504B2 - Method for manufacturing thick cylindrical hollow body made of copper-based memory alloy - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a thick hollow cylindrical hollow body made of a copper-based memory alloy used for pipe joints and the like.

(Prior Art and Problems Thereof) Conventionally, a thick-walled cylindrical hollow body made of a shape memory alloy used for a joint or the like is difficult to work, so that a seamless pipe can be obtained by ordinary plastic working. No, it has been manufactured by cutting a cast round bar or a hot extruded round bar.

Therefore, such a conventional technique has the following problems.

(1) The material yield is poor.

(2) The cutting cost is greatly added to the processing cost of the round bar, which increases the overall processing cost.

(3) In hot casting, crystal grains tend to become coarse, and in hot extrusion, it is difficult to control the structure over the entire length of the round bar. Difficult and large variations.

(Object of the Invention) An object of the present invention is to solve the above-mentioned problems of the prior art,
It is an object of the present invention to provide a method for producing a thick hollow cylindrical hollow body made of a copper-based memory alloy having fine and uniform crystal grains, excellent shape memory characteristics, good workability, and good material yield.

(Structure of the Invention) That is, according to the present invention, there is provided a method for manufacturing a thick cylindrical hollow body made of a copper-based memory alloy having the following structure.

(1) A method for producing a thick-walled cylindrical hollow body by simultaneously subjecting a circular material made of a copper-based memory alloy to deep-drawing and ironing with a conical die or streamline die and a flat bottom punch, and a die temperature of 350 ° C. To 600 ℃, punch temperature 20
A method for producing a thick-walled hollow cylindrical body, which is characterized in that the temperature of the circular raw material is maintained in the range of 350 ° C to 600 ° C while the temperature is maintained in the range of ℃ to less than 100 ° C.

(2) The manufacturing method according to (1) above, wherein the die cone angle is 20 to 40 ° and the ironing rate is 20% at maximum.

(3) The manufacturing method according to (1) or (2) above, wherein the copper-based memory alloy is a Cu-Zn-Al-based memory alloy.

In the present invention, the circular material made of copper-based memory alloy as described above, using a conical die or a streamline die and a flat bottom punch, simultaneously subjected to deep drawing and ironing, by producing a thick cylindrical hollow body, It is possible to improve the material yield, and in the present invention, it is possible to mold at a relatively low temperature, so the crystal grains become fine and uniform, the structure control is easy, and the one with excellent shape memory characteristics is manufactured. It will be possible.

When processing with the above deep drawing and ironing, dies,
Each temperature of punch and circular material is important, die temperature is in the range of 350-600 ℃, punch temperature is between 20 ℃ and less than 100 ℃, and circular material temperature is good in the temperature range of 350-600 ℃. Sex is obtained. Furthermore, the dice cone angle is 20 ° -40
The workability is improved under the conditions of the range of ° and the maximum ironing rate of 20%.

In the present invention, a Cu-Zn-Al-based memory alloy can be used as the copper-based memory alloy.

Next, the present invention will be specifically described with reference to Examples.
The scope of the invention is not limited by these examples.

Example 1 A sample having the following composition was melted by high frequency induction heating and air melting.

Cu: balance, Zn: 26.0%, Al: 4.1% (wt%) After the obtained ingot was face-cut, hot rolled (650 ° C) to make a plate material with a thickness of 2 mm, which was circularly machined. The material was used for the test. In order to see the effect of mold temperature on formability, deep drawing tests were conducted by changing the die temperature, punch temperature and temperature of circular material.

(1) Test conditions Mold shape: Die cone angle 30 °, Die diameter φ19.6, Punch diameter φ15.6 Circular material size: φ28.0, 2.0 ^t Punch speed: 10mm / sec (2) Test result Example 2 In order to examine the influence of the conical surface of the die using the same circular material as that prepared in Example 1, a deep drawing test was conducted at different angles.

(1) Mold shape: Die diameter φ19.6, Die cone angle 15 ° ~ 4
5 °, punch diameter φ15.6 Circular material size: φ52.8, 2.0 ^t Die heating temperature: 450 ℃, Punch temperature: 20 ℃, Circular material: 450 ℃ Punch speed: 20mm / sec (2) Test result From this result, it was found that the die cone angle of 20 ° to 40 ° is suitable.

Example 3 The same circular material as that prepared in Example 1 was used, and the ironing ratio was changed by changing the plate thickness, and drawing and ironing were performed.

(1) Test conditions Mold shape: Die cone angle 30 °, Die diameter φ19.6,
Punch diameter φ15.6 Circular material size: φ35.0, Plate thickness 2.0 to 2.6mm Die heating temperature: 450 ℃, Punch temperature: 20 ℃, Circular material temperature: 450 ℃ Punch speed: 10mm / sec (2) Test result As is clear from this result, it was found that a good cylindrical hollow body can be obtained when the maximum ironing ratio is within the range of about 20% at maximum.

The ironing rate is {plate thickness- (die diameter-punch diameter) /
2} ÷ plate thickness.

Example 4 Similar to Example 1, Zn: 20.6%, Al: 6.1%, Fe: 0.3%, Ti:
0.08%, Cu: create a Ingotsuto balance a composition, by the hot rolling and machining a circular material 53φ × 2.2 ^t, die cone angle: 30 °, die diameter: 15.6Fai, mold and the circular material After hot drawing and ironing at a temperature of 450 ℃, the ends were machined to give a joint material with an inner diameter of 15.6φ, a wall thickness of 2 ^t and a length of 25 mm. In addition, this 650
After heating at 0 ° C for 20 minutes, quenching in 0 ° C water, and then at 100 ° C for 2 minutes
Heat treatment was performed by heating for 0 minutes.

Next, by inserting a mandless into the inner diameter at -38 ° C (the transformation temperature of the present alloy is -33 ° C), the diameter was expanded by 4%. Furthermore, with the core metal jig of 15.90 mm inserted, the temperature was raised to 17 ° C. and the pull-out force of the core metal jig was measured. For comparison, a pipe obtained by obtaining a 25φ round bar from the same ingot by hot forging and machining it to the same size was subjected to the same heat treatment and pipe expansion for the same drawing test.

As a result of measuring the crystal grain size after heat treatment of both, the average grain size of the conventional method was 3.5 mm, and the average grain size of the method of the present invention was 0.2 mm. Further, the result of the pull-out test was 650 kg by the conventional method, whereas the improvement by 870 kg by the method of the present invention was about 30%.

FIG. 1 is a front view including a partial cross section of a mold used in the above embodiments.

(Effects of the Invention) With the above-described configuration, the present invention can provide a thick hollow cylindrical hollow body made of a copper-based memory alloy having the following advantages.

(1) Good material yield and low processing cost.

(2) The crystal grain size is fine and uniform, and the shape memory performance is excellent.

[Brief description of drawings]

FIG. 1 is a front view including a partial cross section of a mold used in one embodiment of the present invention. In the figure, 1 ... Circular material, 3 ... Die, 2 ... Punch, 3a ... Die diameter 2a ... Punch diameter, 4 ... Die cone angle

Claims (3)

(57) [Claims] 1. A method for producing a thick-walled cylindrical hollow body by simultaneously subjecting a circular material made of a copper-based memory alloy to deep-drawing and ironing with a conical die or a streamline die and a flat-bottom punch. Thick cylindrical hollow, characterized by holding the punch temperature from 350 ° C to 600 ° C, the punch temperature in the range from 20 ° C to less than 100 ° C, and heating the circular material temperature in the range from 350 ° C to 600 ° C. Body manufacturing method. 2. The manufacturing method according to claim 1, wherein the die cone angle is 20 to 40 ° and the ironing ratio is 20% at maximum. 3. The method according to claim 1 or 2, wherein the copper-based memory alloy is a Cu-Zn-Al-based memory alloy.