JP4146364B2 - Method for manufacturing plastic working member - Google Patents

Description

The present invention relates to plastic working member and a manufacturing method thereof consisting age hardening type aluminum alloy, in particular, to a method for manufacturing a plastic working member for use in a scroll member for a compressor.

  Conventionally, scroll members used in compressors and the like are manufactured by forging using an aluminum alloy as a raw material. As an aluminum alloy used here, for example, an Al—Si—Cu—Mg age-hardening type alloy having a final strength by precipitation hardening of Cu can be exemplified.

  FIG. 13 shows a perspective view of the scroll member, and FIG. 14 shows a perspective view of a mold used when the scroll member is manufactured. As shown in FIG. 13, the scroll member (plastic working member) 1 is composed of a disc-shaped flange 2 and a spiral fin 3 erected on one surface 2 a of the flange 2. As shown in FIG. 14, a mold (tool) 4 used for manufacturing the scroll member 1 includes a lower mold 5 for molding the fins 3 of the scroll member 1, and a billet ( It is composed of an upper punch 7 forging and forging the alloy lump 6.

FIG. 15 shows a conventional manufacturing process of the scroll member 1. The manufacturing process of the conventional scroll member 1 is comprised from the forge process, the solution treatment process, and the age hardening process (T6) process.
In the forging process, a cast bar is first manufactured by continuous casting, and this cast bar is cut into rounds to form billets 6. Next, the billet 6 is forged with the mold 4 shown in FIG. At the time of forging, the mold 4 is preheated to 200 to 350 ° C., and then the billet 6 is heated to about 400 ° C., then the billet 6 is put into the lower mold 5 and the upper punch 7 is pushed in from above. The forging material is taken out from the mold 4 and air-cooled.
Next, in the solution treatment step, the forged material is heated, for example, at 510 ° C. for 5 hours to completely dissolve Cu, and then rapidly quenched by water quenching to obtain a solid solution. Thereafter, as an age hardening treatment step, an Al ₂ Cu compound is precipitated by performing a T6 treatment at 170 ° C. for 6 hours. Thereafter, final finishing is performed to obtain a scroll member 1 as shown in FIG.

  As described above, in the conventional manufacturing method, plastic processing (forging) for processing into a predetermined shape and solution treatment are performed separately, but recently, plastic processing and solution treatment are performed in order to save the process. Attempts have been made to carry out the above continuously. The following Patent Documents 1 to 3 disclose a method of continuously performing plastic working and solution treatment.

JP 2000-212708 A JP 2000-239810 A Japanese Patent Laid-Open No. 11-12705

However, in the methods described in Patent Documents 1 and 2, the temperature of the product after the plastic working is as high as 540 to 560 ° C., and the product temperature is maintained at 520 ° C. or higher until the subsequent cooling tub is reached. Therefore, it takes a long time to cool. During this time, strain due to plastic working is released, recrystallization and grain growth occur, resulting in a coarse grain structure, and there is a problem that sufficient toughness cannot be obtained.
Also, in the method described in Patent Document 3, since the quenching treatment is performed before the aluminum alloy after hot forging is less than 420 ° C., strain due to plastic working is released before quenching, As a result, the recrystallized grains become coarse and there is a problem that sufficient toughness cannot be obtained.

The present invention has been made in view of the above circumstances, to provide a method of manufacturing a plastic working member the crystal grain size is made of excellent age hardening type aluminum alloy to reduce toughness, while significantly saving short manufacturing process With the goal.

In order to achieve the above object, according to the present invention, after casting an alloy lump made of an age-hardening type aluminum alloy, the alloy lump is heated to 400 ° C. or higher and lower than the melting point, and then held at −100 to 100 ° C. in advance. A process of obtaining a supersaturated and supercooled molding material in which the aging precipitation elements are solid-dissolved by plastic working the alloy lump with the prepared tool and high density dislocations are maintained as it is, There is provided a method for producing a plastically processed member, comprising the step of performing age hardening. The age hardening treatment can be selected from T5 treatment, T6 treatment, etc., corresponding to the alloy composition.

According to the present invention, an alloy lump heated to a predetermined temperature is molded into a predetermined shape by a tool previously held at −100 to 100 ° C., and at the same time, the alloy lump is rapidly cooled by a tool having a low temperature. And the solid solution (molding material) of a supercooled state is obtained. An aging precipitation element such as Cu is dissolved in the molding material. Further, in this molding material, the high-density dislocation accumulated by the alloy lump undergoing plastic deformation at a high temperature can be maintained as it is (referred to as structure freezing in the present specification). When an age hardening treatment is performed on a molding material in such a special state, precipitation of an aging precipitation element such as Cu and recrystallization starting from a (high density) dislocation portion occur simultaneously, and the precipitated Al ₂ The recrystallized grain boundary is pinned by the Cu compound, and coarsening of the recrystallized grains is suppressed. As a result, an extremely fine crystal structure with an average crystal grain size of 10 μm or less can be obtained, and at the same time, strengthening by aging precipitation of the Al ₂ Cu compound is possible. Thus, according to the present invention, the aging precipitation strengthening and the fine crystal grain structure of the molding material can be achieved at the same time, and a plastic working member having high strength and excellent toughness can be provided.

Further, according to the present invention, since a tool previously held at −100 to 100 ° C. is used, plastic processing and solution treatment are performed at the same time, so that the conventional solution treatment after plastic processing is performed. The process can be shortened. In order to enjoy the effect of the present invention, the cooling of the alloy lump performed simultaneously with the plastic working is preferably performed at 170 ° C. or less immediately after the plastic working.

Moreover, in this invention, it is desirable to hold | maintain the said tool in the range of -10-10 degreeC previously . By doing so, dislocations frozen in the structure of the molding material do not become excessive, precipitation of aging precipitation elements and precipitation of recrystallized grains can be caused in a well-balanced manner, and the average particle diameter is 5 μm or less. A finer fine crystal structure can be obtained.

  In the present invention, the alloy ingot can be plastically processed with a tool, and then the molding material can be put into water to be rapidly cooled (hereinafter referred to as underwater quenching). With this configuration, even when the temperature of the tool is relatively high, the alloy lump can be sufficiently quenched, and a supersaturated and supercooled solid solution can be easily obtained. When quenching in water, there is a case where it is not necessary to substantially hold the molding material with a tool after the plastic working.

Furthermore, in the present invention, after the plastic working is completed, the molding material may be taken out from the tool after the molding material is sufficiently cooled by holding for several seconds to several minutes. Further, as the plastic working, a technique such as forging or extrusion can be used. Furthermore, examples of the tool include a forging die and an extrusion molding die.
In the present invention, the temperature for heating the alloy ingot may be lower than the solid solution temperature of the additive element such as Cu, but may be higher than the solid solution temperature, for example, 400 ° C. or higher, and further 500 It may be higher than ° C. Furthermore, in order to make the crystal grains sufficiently fine, it is desirable that the aging treatment is performed under a condition of holding for a predetermined time in a holding temperature range of 160 to 180.

  Moreover, as an age-hardening type aluminum alloy applicable to this invention, what is necessary is just to have the intensity | strength and elongation which can be plastically processed. In particular, those containing Cu or the like as an aging precipitation element are desirable. Specifically, it is desirable to use 2000 series, 6000 series aluminum alloy or 7000 series aluminum alloy. Further, an aluminum alloy for castings defined by JIS, for example, AC8C can be used.

According to the method for producing a plastic working member of the present invention, fine crystal grains having an average particle size of 10 μm or less can be precipitated in the metal structure of the plastic working member, and a plastic working member having excellent toughness can be produced. Moreover, since the plastic working and the solution treatment are performed simultaneously, the manufacturing process can be omitted as compared with the conventional method, and the productivity of the plastic working member can be improved.
In addition, the plastic working member produced according to the present invention has a fine crystal structure with an average crystal grain size of 10 μm or less, and can improve toughness.
Furthermore, according to the scroll member to which the plastic working member manufactured according to the present invention is applied, a high-performance scroll member having high toughness and fatigue strength can be obtained.

  Hereinafter, the example which applied the manufacturing method of the plastic working member of the present invention to the scroll member for compressors is explained. As shown in FIG. 1, this manufacturing method includes a process of obtaining a molding material by forging and solution treatment of an alloy lump, and a process of obtaining a scroll member by age-hardening the molding material. Hereinafter, each process will be described with reference to FIG.

  First, in the step of forging and solution treatment of the alloy lump, an alloy lump made of an age-hardening aluminum alloy is cast, and the alloy lump is heated in advance to a temperature range of 400 ° C. to a melting point, and then −100 to 100 ° C. Forging (plastic working) with a mold held in Since the mold is held in the range of −100 to 100 ° C., the alloy ingot is rapidly cooled simultaneously with the start of forging. This rapid cooling is performed, for example, up to 170 ° C., which is the retention temperature of the age hardening treatment. By this step, an aging precipitation element such as Cu is solid-dissolved, and a supersaturated and supercooled solid solution (molding material) in which high-density dislocations are frozen as they are is obtained.

  As the age-hardening type aluminum alloy as a material, one having at least Cu as an additive element can be used. Moreover, what has intensity | strength and elongation to such an extent that plastic processing, such as forging, is possible is preferable. Specific examples of such alloys include JIS 2000 series and JIS 6000 series alloys (for example, A6061, A6063) and JIS 7000 series (for example, A7075) alloys. Moreover, the aluminum alloy for castings containing Cu can also be used.

  The alloy lump is previously heated to 400 ° C. or higher, preferably 450 ° C. or higher, more preferably 500 ° C. or higher. By heating the alloy lump, the additive element contained in the alloy lump can be solid-solved before forging. Note that it is not preferable to make the alloy ingot at or above the melting point temperature of aluminum because it becomes difficult to forge the alloy ingot.

Next, a die 4 shown in FIG. 14 can be used as a tool used for forging. The mold 4 is preferably maintained in the range of −100 to 100 ° C. in advance, and more preferably in the range of −10 to 10 ° C. In order to lower the temperature of the mold 4, for example, the mold 4 may be immersed in liquid nitrogen. In this way, by setting the mold 4 in the range of −100 to 100 ° C. in advance, the alloy lump can be rapidly cooled at the same time as forging. Thereby, an aging precipitation element such as Cu can be kept in solid solution in aluminum. In addition, it is possible to freeze structure of high-density dislocations accumulated due to the alloy lump undergoing plastic deformation at high temperature. By carrying out like this, when the age hardening process mentioned later is performed, a fine crystal grain structure can be expressed in the structure | tissue of a scroll member.
If the temperature of the mold 4 exceeds 100 ° C., the alloy lump cannot be sufficiently cooled, and additional elements such as Cu are precipitated, and a complete solid solution cannot be obtained. On the other hand, when the temperature of the mold 4 is lower than −100 ° C., excessive dislocations are formed in the structure, and on the contrary, the crystal grains become coarse, which is not preferable.

  Moreover, when the molding material after forging is in a high temperature state, dislocations generated by forging are released and Cu may be precipitated. Therefore, it is desirable to rapidly cool the molding material to 170 ° C. or lower, more preferably 100 ° C. or lower simultaneously with forging. Usually, if the temperature of the mold 4 is cooled to 50 ° C. or lower, the molding material can be easily cooled to 170 ° C. or lower. However, if the molding material is not cooled to 170 ° C. or lower, It is desirable to quench the water immediately after taking out the molding material.

If the molding material is cooled to 170 ° C. or lower, preferably 100 ° C. or lower, it is desirable to immediately transfer to age hardening. By carrying out like this, compared with the case where a shaping | molding material is cooled to room temperature, the temperature rising time at the age hardening process becomes short, and manufacturing cost can be reduced.
Moreover, even when it is expected that the molded material after forging is cooled to 170 ° C. or lower, further cooling in water allows the molded material to be cooled to room temperature, thereby facilitating handling of the molded material and increasing productivity. You can also.

  In order to sufficiently cool the molding material, the molding material may be held in the mold 4 for about 60 seconds after forging. By bringing the molding material into contact with the mold 4, heat of the molding material is radiated to the mold 4 to cool the molding material. However, it is not limited to 60 seconds, and the same effect can be obtained even if it exceeds 60 seconds, and the effect can be obtained even if it is less than 60 seconds.

  Further, at the time of forging, the extrusion speed of the upper punch 7 is preferably set to 20 mm / second or more. This is because if the extrusion speed is too low, cooling progresses during forging, resulting in an increase in deformation resistance, resulting in cracks during molding, which may prevent successful molding.

  Next, an age hardening treatment is performed on the molded material after forging. By this step, a fine crystal structure having an average crystal grain size of 10 μm or less is formed in the structure of the molding material. At the same time, precipitation strengthening is possible.

The age hardening treatment can be selected from T5 treatment and T6 treatment corresponding to the alloy composition. When performing the T6 treatment as an age hardening treatment, it is desirable to keep the temperature at a holding temperature of 160 ° C. or higher and 180 ° C. or lower for 2 hours or longer. Insufficient holding temperature and holding time are not preferable because aging precipitation and recrystallization of Al ₂ Cu are insufficient, and if the holding temperature and holding time are excessive, crystal grains may be coarsened. Absent.

When age-hardening treatment is performed on a forged / solution-treated molding material, precipitation of an aging precipitation element such as Cu and recrystallization starting from dislocations frozen in the structure occur simultaneously, and precipitated Al ₂ The recrystallized grain boundary is pinned by Cu, and coarsening of the recrystallized grains is suppressed. In this manner, the scroll member 1 having a fine crystal structure with an average crystal grain size of 10 μm or less is obtained. The obtained scroll member 1 has high toughness and excellent fatigue strength.

The obtained scroll member 1 is an age-hardened forged product having a fine crystal structure with an average crystal grain size of 10 μm or less, preferably 5 μm or less, more preferably 3 μm or less. Conventionally, there is no other forged product that is an age-hardening type aluminum alloy and has such a fine grain structure after aging effect treatment. There are conventional plastic processed products in which crystal grains are refined by repeating plastic processing, but since these conventional plastic processed products have not undergone a heat treatment step, the crystal grains easily become coarse when heated. Toughness is greatly reduced. Since the recrystallized grain boundary is pinned by the precipitated Al ₂ Cu compound, the scroll member 1 according to the present invention is less likely to be coarsened even after heat treatment. Therefore, in order to distinguish the plastic working member according to the present invention from the conventional product, the crystal structure may be observed after heat treatment.

Hereinafter, the present invention will be described in more detail with reference to examples.
Casting aluminum alloy (JIS AC8C-T6 equivalent (Al-9Si-2Cu-0.4Mg) is cast into a casting rod. The casting rod is peeled and rounded to give a diameter of 79mm and a thickness of 28mm. Next, the mold 4 shown in Fig. 14 is kept at about room temperature (25 ° C), and the mold 4 is placed between the upper punch 7 and the lower mold 5 at 500 ° C. The heated alloy lump is placed on the upper punch 7 at the extrusion speed of 20 mm / second and pushed into the lower die 5 for about 1 second to complete the forging, and then held for 30 seconds as it is. The temperature of the molding material after being held for 30 seconds was 110 ° C., and immediately after the molding material was taken out from the mold 4, the molding material was quenched in water.
Next, T6 heat treatment was performed on the obtained molding material under the conditions of a holding temperature of 170 ° C. and a holding time of 6 hours. Thus, the scroll member of Experimental Example 1 (Example) was manufactured.

Next, the scroll member of Experimental Example 2 (Comparative Example) was manufactured by the following steps.
First, the mold 4 shown in FIG. 14 is heated to 250 ° C., and the same alloy lump as previously heated to 500 ° C. is placed between the upper punch 7 and the lower mold 5 of the mold 4 and 20 mm / second. After pressing the upper punch 7 toward the lower mold 5 at an extrusion speed of about 1 second and finishing forging, the molded body was immediately taken out. The temperature of the molding material immediately after taking out was 360 ° C., and the molding material was taken out from the mold 4 and then air-cooled. Next, the air-cooled molding material was subjected to a solution treatment under the conditions of holding temperature 510 ° C., holding time 5 hours, and water quenching after holding. Further, T6 heat treatment was performed on the molded material after the solution treatment in the same manner as in Experimental Example 1. Thus, the scroll member of Experimental Example 2 (Comparative Example) was manufactured.

  About the scroll member of Experimental example 1 and 2, metal structure observation was performed with the optical microscope. FIG. 2 shows a photomicrograph of Experimental Example 1, and FIG. 3 shows a photomicrograph of Experimental Example 2. Moreover, the age hardening curve at the time of T6 heat processing was measured about the scroll member of Experimental example 1 and 2. FIG. FIG. 4 is a graph showing the relationship between Vickers hardness (Hv) and heat treatment time for Experimental Examples 1 and 2.

As shown in FIG. 2, in Experimental Example 1 (Example), it can be seen that a fine crystal structure having an average particle diameter of about 2 to 3 μm is formed. On the other hand, as shown in FIG. 3, in Experimental Example 2 (Comparative Example), it can be seen that coarse crystal grains having an average grain size of 100 μm or more are formed. The reason why the crystal grains coarsened in Experimental Example 2 (Comparative Example) was that an Al ₂ Cu compound phase was formed by air cooling after forging, and this Al ₂ Cu compound phase remained as it was without being solutionized by the solution treatment. However, it is understood that a complete solid solution was not obtained.
Further, as shown in FIG. 4, in Experimental Example 1 (Example), the hardness immediately increased with the start of the T6 heat treatment, and a hardness of Hv 150 or higher was obtained. In Experimental Example 2 (Comparative Example), the hardness increased. The hardness is low and the hardness is about Hv140, which is lower than that of Experimental Example 1 (Example). This is thought to be due to the difference in crystal grain size.

A scroll member of Experimental Example 3 (Example) was manufactured in the same manner as in Experimental Example 1 except that the holding time in the mold after completion of forging was 0 second.
Further, a scroll member of Experimental Example 4 (Example) was manufactured in the same manner as Experimental Example 1 except that the holding time in the mold after the forging was set to 15 seconds.
Further, in the same manner as in Experimental Example 1, a scroll member of Experimental Example 5 (Example) in which the holding time in the mold after forging was 30 seconds was manufactured.
Furthermore, the scroll member of Experimental Example 6 (Example) was manufactured in the same manner as Experimental Example 1 except that the holding time in the mold after the forging was changed to 60 seconds.

  About the scroll member of Experimental example 3 (Example), metal structure observation was performed with the optical microscope. 5 and 6 show micrographs of Experimental Example 3. Moreover, about the scroll member of Experimental example 2 (comparative example) and Experimental example 3-6 (Example), the measurement result of the age hardening curve at the time of T6 heat processing is shown in FIG.

As shown in FIGS. 5 and 6, in Experimental Example 3 (Example), a fine crystal structure having an average particle size of about 2 to 3 μm is formed, which is finer than Experimental Example 2 (Comparative Example) in FIG. 3. It can be seen that it has a fine grain structure.
Further, as shown in FIG. 7, in Experimental Examples 3 to 6 (Examples), the hardness immediately increased with the start of the T6 heat treatment, and a hardness of Hv145 or higher was obtained. In Experimental Example 2 (Comparative Example), the hardness was Rise is slow, and the hardness is about Hv140, which is lower than Experimental Examples 3 to 6 (Examples). This is thought to be due to the difference in crystal grain size. Moreover, the influence of the difference in the holding time at the time of forging is not especially seen among Experimental Examples 3-6 (Example).

The temperature of the alloy lump was set to 420 ° C., the mold was cooled with liquid nitrogen to −50 ° C., and the holding time in the mold after forging was set to 0 second. A mold was obtained. The molding material immediately after forging was taken out of the mold and immediately quenched in water.
Next, T6 heat treatment was performed on the molding material after quenching in water under the conditions of a holding temperature of 170 ° C. and a holding time of 6 hours. Thus, the scroll member of Experimental Example 7 (Example) was manufactured.

  About the scroll member of Experimental example 7 (Example), the microscopic observation of the metal structure was performed with the optical microscope. The results are shown in FIGS. Moreover, the age hardening curve at the time of T6 heat processing was measured about the scroll member of Experimental example 7 (Example) and said Experimental example 2 (comparative example). The results are shown in FIG.

As shown in FIGS. 8 and 9, in Experimental Example 7 (Example), a fine crystal structure having an average particle size of about 3 to 4 μm is formed, which is finer than Experimental Example 2 (Comparative Example) in FIG. It can be seen that it has a fine grain structure.
In addition, as shown in FIG. 10, in Experimental Example 7 (Example), it can be seen that the hardness decreases when the heat treatment time exceeds 5 hours. Therefore, it can be seen that the T6 heat treatment should be performed for about 5 hours under the manufacturing conditions of Experimental Example 7.

Moreover, in the manufacturing conditions of Experimental Example 7, since the mold is set to −50 ° C., the molding material can be sufficiently quenched. For this reason, holding | maintenance in a metal mold | die can be abbreviate | omitted and the time required for a process can be reduced significantly.
Furthermore, in the manufacturing conditions of Experimental Example 7, it is possible to precipitate fine crystal grains despite the fact that the temperature of the alloy lump is 420 ° C. which is lower than the solid solution temperature of Cu. Thereby, in this invention, it is possible to make the temperature of an alloy lump comparatively low temperature, and can reduce manufacturing cost significantly. In addition, the life of equipment such as a heating furnace when heating the alloy lump can be extended.

The molding material was formed in the same manner as in Experimental Example 1 under the condition that the temperature of the alloy lump was 500 ° C., the mold was cooled with liquid nitrogen to about −10 to 10 ° C., and the holding time in the mold was 30 seconds. Obtained. The temperature of the molding material after holding for 30 seconds was 50 ° C. The molding material was taken out of the mold and immediately quenched with water.
Next, T6 heat treatment was performed on the molding material after quenching under conditions of a holding temperature of 170 ° C. and a holding time of 6 hours. Thus, the scroll member of Experimental Example 8 (Example) was manufactured.

  About the scroll member of Experimental example 8 (Example), metal structure observation was performed with the optical microscope. The results are shown in FIG. Moreover, the age hardening curve at the time of T6 heat processing was measured about the scroll member of Experimental example 8 (Example) and said Experimental example 2 (comparative example). The results are shown in FIG.

As shown in FIG. 11, in Experimental Example 8 (Example), a fine crystal structure having an average particle diameter of about 1 μm is formed, and a finer grain structure than in Experimental Example 2 (Comparative Example) of FIG. You can see that
Also, as shown in FIG. 12, it can be seen that Experimental Example 8 (Example) shows a hardness exceeding Hv150 when the heat treatment time is 3 hours. It can be seen that when the heating is further continued, the hardness slightly decreases, but still exhibits a hardness of Hv 150 or higher. Even when compared with other experimental examples, it can be seen that the scroll member of Experimental Example 8 exhibits excellent hardness.

It is process drawing explaining the manufacturing method of the scroll member which is embodiment of this invention. It is an optical microscope photograph of the metal structure of Experimental example 1 (Example). It is an optical microscope photograph of the metal structure of Experimental example 2 (comparative example). It is a graph which shows the relationship between the hardness of Experimental example 1 (Example) and Experimental example 2 (comparative example), and heat processing time. It is an optical microscope photograph of the metal structure of Experimental example 3 (Example). It is an enlarged photograph of FIG. It is a graph which shows the relationship between the hardness of Experimental example 2 (comparative example) and Experimental example 3-6 (comparative example), and heat processing time. It is an optical microscope photograph of the metal structure of Experimental example 7 (Example). It is an enlarged photograph of FIG. It is a graph which shows the relationship between the hardness of Experimental example 7 (Example) and Experimental example 2 (comparative example), and heat processing time. It is an optical microscope photograph of the metal structure of Experimental example 8 (Example). It is a graph which shows the relationship between the hardness of Experimental example 8 (Example) and Experimental example 2 (comparative example), and heat processing time. It is a perspective view which shows a scroll member. It is a perspective view which shows the metal mold | die used for forging of a scroll member. It is process drawing explaining the manufacturing method of the conventional scroll member.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Scroll member (plastic processing member), 2 ... Flange, 3 ... Fin, 4 ... Die (tool), 5 ... Lower die, 6 ... Billet (alloy lump), 7 ... Upper punch

Claims (5)

After casting an alloy lump made of age-hardening type aluminum alloy, the alloy lump is preliminarily heated to 400 ° C. or higher and lower than the melting point, and then the alloy lump is plastically processed with a tool previously held at −100 to 100 ° C. A step of obtaining a supersaturated and supercooled molding material in which the aging precipitation elements are dissolved and the high density dislocations are maintained as they are,
Performing an age hardening treatment on the molding material;
A method for producing a plastically processed member, comprising: The method for manufacturing a plastic working member according to claim 1, wherein the tool is held at −10 to 10 ° C. in advance .   The method of manufacturing a plastic working member according to claim 1 or 2, wherein the molding material is held with a tool for a predetermined time after the plastic working is completed.   The method for producing a plastic working member according to any one of claims 1 to 3, wherein after the plastic working is finished, the molding material is put into water and rapidly cooled.   5. The method of manufacturing a plastic working member according to claim 4, wherein after the plastic working is completed, the molding material is poured into water and rapidly cooled without substantially holding the molding material with the tool. .

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