阅读说明：本技术 Cu-Ni-Sn合金的制造方法及用于其的冷却器 (Method for manufacturing Cu-Ni-Sn alloy and cooler used for same ) 是由 石井健介 于 2021-03-15 设计创作，主要内容包括：本发明提供一种Cu-Ni-Sn合金的制造方法以及用于其的冷却器,通过在缩短铸块的冷却时间的同时减少内部裂纹,从而兼顾生产率和品质。一种Cu-Ni-Sn合金的制造方法,其为利用连续铸造法或半连续铸造法的Cu-Ni-Sn合金的制造方法,包括：使熔融的Cu-Ni-Sn合金从两端开放的铸模的一端流入,一边使该合金的铸模附近的部分凝固,一边作为铸块从铸模的另一端连续地抽出的工序；以及通过向抽出的铸块吹送雾状的液体来进行冷却,制成Cu-Ni-Sn合金的铸造品的工序。(The invention provides a method for manufacturing a Cu-Ni-Sn alloy and a cooler used for the same, which can shorten the cooling time of an ingot and reduce internal cracks so as to achieve both the productivity and the quality. A method for producing a Cu-Ni-Sn alloy by a continuous casting method or a semi-continuous casting method, comprising: a step of continuously taking out a molten Cu-Ni-Sn alloy as an ingot from one end of a mold, both ends of which are open, while solidifying a portion of the alloy in the vicinity of the mold; and a step of blowing a mist of liquid to the extracted ingot to cool the ingot, thereby producing a cast product of a Cu-Ni-Sn alloy.)

1. A method for producing a Cu-Ni-Sn alloy by a continuous casting method or a semi-continuous casting method, comprising:

a step of pouring a molten Cu-Ni-Sn alloy into a mold having both open ends from one end thereof, solidifying a portion of the alloy in the vicinity of the mold, and continuously taking out the alloy as an ingot from the other end of the mold, and

and a step of cooling the ingot by spraying a mist of liquid onto the ingot, thereby producing a cast product of a Cu-Ni-Sn alloy.

2. The method for producing a Cu-Ni-Sn alloy according to claim 1, wherein the Cu-Ni-Sn alloy is a Cu-Ni-Sn alloy containing Ni: 8-22 wt% and Sn: 4-10 wt%, and the balance of Cu and inevitable impurities.

3. The method for producing a Cu-Ni-Sn alloy according to claim 1 or 2, wherein the Cu-Ni-Sn alloy is a Cu-Ni-Sn alloy containing Ni: 14-16 wt% and Sn: 7-9 wt%, and the balance of Cu and unavoidable impurities.

4. The method for producing a Cu-Ni-Sn alloy according to any one of claims 1 to 3, wherein the ingot passed through the mold is cooled to 50 ℃ or lower within 2 hours after the end of casting.

5. The method for producing a Cu-Ni-Sn alloy according to any one of claims 1 to 4, wherein the cooling is performed by passing the ingot through a cooler disposed directly below the mold.

6. The method for manufacturing a Cu-Ni-Sn alloy according to claim 5, wherein the cooler comprises:

a cylindrical main body having a cylindrical shape and a cylindrical shape,

a liquid supply part which is provided at an upper part of the cylindrical body and is configured to drop the liquid downward, and

and an air injection unit provided below the liquid supply unit and injecting air toward a central axis of the cylindrical body.

7. The method of manufacturing a Cu-Ni-Sn alloy according to claim 6, wherein the cooler is configured such that the liquid dropped downward is mixed with the air without being in direct contact with the ingot.

8. The method for producing a Cu-Ni-Sn alloy according to any one of claims 1 to 7, wherein the ingot is supported by a susceptor, and the susceptor descends at a speed of 25 to 40 mm/min.

9. The method for producing a Cu-Ni-Sn alloy according to any one of claims 1 to 8, wherein the liquid is water.

10. A cooler used in a continuous casting method or a semi-continuous casting method, comprising:

a cylindrical main body having a cylindrical shape and a cylindrical shape,

a liquid supply part provided at an upper part of the cylindrical body and configured to drop the liquid downward, and

and an air injection unit provided below the liquid supply unit and injecting air toward a central axis of the cylindrical body.

11. The cooler according to claim 10, wherein a position of the liquid dropped from the liquid supply portion is configured to be a position closer to the cylindrical body than a position of the air ejection portion.

Technical Field

The present invention relates to a method for producing a Cu-Ni-Sn alloy and a cooler used for the same.

Background

Conventionally, copper alloys such as Cu — Ni — Sn alloys have been produced by a continuous casting method or a semi-continuous casting method. As is the case with the semi-continuous casting method, the continuous casting method is one of the main casting methods, in which molten metal is poured into a water-cooled mold and continuously solidified, and is extracted as an ingot having a predetermined shape (rectangular shape, circular shape, etc.) and then extracted downward in many cases. This method is excellent in mass production of ingots of a certain composition, quality and shape because the ingots are produced completely continuously, but is not suitable for mass production of various kinds. On the other hand, the semi-continuous casting method is a batch-type casting method in which the length of an ingot is limited, and the variety and shape and size can be variously changed. In recent years, a large-sized coreless furnace has been used, and since the ingot cross section can be increased in size and elongated and a large number of ingots can be cast at one time, the productivity comparable to that of the continuous casting method can be achieved.

For example, patent document 1 (jp 2007-a 1699741) discloses that, in the production of a copper alloy, a copper alloy having a predetermined chemical composition is melted in a coreless furnace, and then cast into an ingot by a semi-continuous casting method to obtain an ingot. Then, the obtained ingot is cooled and subjected to a predetermined step such as rolling, thereby obtaining the target alloy.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2007-1699741

Disclosure of Invention

However, when an ingot obtained by solidifying a molten metal is cooled in a casting process, the cooling rate thereof affects the productivity and quality of the finally obtained alloy. For example, if the cooling rate is high, internal cracks occur in the ingot, and the quality of the obtained alloy is poor. On the other hand, if the cooling rate is slow, internal cracking of the ingot can be suppressed, but cooling takes time and productivity of the obtained alloy deteriorates. Therefore, in the production of an alloy, productivity and quality of the alloy have a trade-off relationship, and it is desired to achieve both of them.

In particular, in the case of a copper alloy (Cu — Ni — Sn alloy or the like) containing Sn having a low melting point, when an ingot is formed, the internal stress during solidification becomes large on the outer side and the inner side thereof. For example, when an ingot is cooled by water-cooled spraying or immersion in a water tank, which is a conventional cooling method, the cooling rate is too high, and the ingot is likely to have internal cracks. Even if the cooling rate is reduced by performing air cooling, for example, to suppress the occurrence of internal cracks, cooling may take 12 hours or more, which significantly deteriorates the productivity.

Further, as Cu — Ni — Sn alloys, those known in UNS: cu-15Ni-8Sn alloy defined in C72900, UNS: a Cu-9Ni-6Sn alloy defined in C72700, and a Cu-Ni-6 Sn alloy composition as defined in UNS: and a Cu-21Ni-5Sn alloy defined in C72950. As described above, a copper alloy containing Sn having a low melting point is likely to cause internal cracking, and particularly, in the case of producing a Cu-15Ni-8Sn alloy having a large Sn content, the influence of the cooling rate of an ingot on the productivity and quality of the obtained alloy is particularly great. In this way, in the production of a Cu — Ni — Sn alloy, it is desired to achieve both productivity and quality by appropriately selecting the cooling conditions of the ingot.

The present inventors have obtained the following findings: a method for producing a Cu-Ni-Sn alloy, which can reduce the cooling time of an ingot and reduce internal cracks and which can achieve both productivity and quality, is provided by using spray cooling in which a liquid is sprayed in a mist form onto the ingot.

Accordingly, an object of the present invention is to provide a method for producing a Cu — Ni — Sn alloy, which can reduce internal cracks while shortening the cooling time of an ingot, thereby achieving both productivity and quality.

According to one aspect of the present invention, there is provided a method for producing a Cu-Ni-Sn alloy by a continuous casting method or a semi-continuous casting method, including:

a step of pouring a molten Cu-Ni-Sn alloy into a mold having both open ends from one end thereof, solidifying a portion of the alloy in the vicinity of the mold, and continuously taking out the alloy as an ingot from the other end of the mold, and

and a step of blowing a mist of liquid to the extracted ingot to cool the ingot, thereby producing a cast product of a Cu-Ni-Sn alloy.

According to another aspect of the present invention, there is provided a cooler used in a continuous casting method or a semi-continuous casting method, including:

a cylindrical main body having a cylindrical shape and a cylindrical shape,

a liquid supply part which is provided at an upper part of the cylindrical body and is configured to drop the liquid downward, and

and an air injection unit provided below the liquid supply unit and injecting air toward a central axis of the cylindrical body.

Drawings

Fig. 1 is a sectional view of a manufacturing apparatus including a mold and a cooler used in the manufacturing method of the present invention.

FIG. 2 is a photograph showing cut surfaces (top and bottom surfaces) of samples cut out from castings of Cu-Ni-Sn alloys obtained in examples 1 to 3.

FIG. 3 is a photograph showing dendrites present in a cross section perpendicular to a cut surface of a sample cut out from a cast product obtained in examples 1 to 3.

Detailed Description

The manufacturing method of the present invention is a method for manufacturing a Cu-Ni-Sn alloy by a continuous casting method or a semi-continuous casting method. The Cu — Ni — Sn alloy produced by the method of the present invention is preferably a spinodal alloy containing Cu, Ni, and Sn. The spinodal alloy preferably contains Ni: 8-22 wt% and Sn: 4 to 10% by weight, the balance being Cu and unavoidable impurities, more preferably Ni: 14-16 wt% and Sn: 7 to 9 wt%, the balance being Cu and unavoidable impurities, and further preferably Ni: 14.5 to 15.5 wt% and Sn: 7.5 to 8.5 wt%, and the balance of Cu and unavoidable impurities. Such a Cu — Ni — Sn alloy is preferably exemplified by UNS: cu-15Ni-8Sn alloy defined in C72900. In this way, in the case of producing a copper alloy containing Sn having a low melting point, internal cracks are likely to occur in the cooling step of the ingot, but according to the method for producing a Cu — Ni — Sn alloy of the present invention, the cooling time of the ingot can be shortened and the internal cracks can be reduced, and productivity and quality can be both achieved.

The method for producing a Cu-Ni-Sn alloy of the present invention comprises (1) a melt-casting step and (2) a cooling step. In the melt casting step, a molten Cu — Ni — Sn alloy is poured from one end of a mold having both open ends, and the alloy is continuously withdrawn as an ingot from the other end of the mold while solidifying a portion of the alloy in the vicinity of the mold. In the subsequent cooling step, the extracted ingot is cooled by spraying a mist of liquid, thereby producing a cast product of a Cu — Ni — Sn alloy. In this way, by cooling, i.e., spray cooling, the ingot obtained by melt casting by spraying a mist of liquid, the cooling time of the ingot can be shortened, and the internal cracks can be reduced, thereby producing a Cu — Ni — Sn alloy that achieves both productivity and quality.

As described above, in the production of a copper alloy containing Sn having a low melting point, the cooling rate of an ingot affects the productivity and quality of the obtained alloy, and therefore, it is difficult to achieve both the productivity and the quality, but the method of the present invention has the following advantages: the cooling time of the ingot can be shortened, internal cracks can be reduced, and a Cu-Ni-Sn alloy which has both productivity and quality can be manufactured.

FIG. 1 is a sectional view of a manufacturing apparatus and an ingot in an example of the manufacturing method of the present invention. The above-described steps are explained below with reference to fig. 1.

(1) Melting and casting process

First, a molten Cu — Ni — Sn alloy is poured from one end of a mold 12 (for example, through a graphite nozzle 14) having both ends open, and is continuously withdrawn as an ingot 16 from the other end of the mold 12 while solidifying a portion of the alloy in the vicinity of the mold 12. The temperature of the molten Cu-Ni-Sn alloy is preferably 1200 to 1400 ℃, more preferably 1250 to 1350 ℃, and further preferably 1300 to 1350 ℃.

The mold 12 is not particularly limited as long as it is a general mold used for casting a copper alloy, and is preferably a mold made of copper. Preferably, a cooling medium such as water is circulated inside the mold 12. This allows the molten, high-temperature Cu — Ni — Sn alloy to be rapidly solidified from the surface layer and continuously withdrawn as an ingot 16 from the other end of the mold 12.

The melt casting step is preferably oxidation-inhibited by an industrially available method. For example, in order to suppress oxidation of the ingot 16, it is preferable to perform the reaction in an inert atmosphere such as nitrogen, Ar, or vacuum.

After melting the Cu-Ni-Sn alloy and before casting, a pretreatment for obtaining a desired Cu-Ni-Sn alloy, such as a slag treatment or a composition analysis, may be performed. For example, the Cu-Ni-Sn alloy may be melted at 1300 to 1400 ℃, stirred for 15 to 30 minutes to homogenize the components, and then subjected to slag treatment and then cast. After the slag treatment, a part of the Cu — Ni — Sn alloy may be collected as a sample for component analysis, and the component value may be measured. According to the measurement results, when the target component value is deviated, the Cu — Ni — Sn alloy may be added again to adjust the target component value.

(2) Cooling Process

The ingot 16 drawn out from the other end of the mold 12 is cooled by spraying a mist of liquid (i.e., spray cooling) to produce a cast product of Cu — Ni — Sn alloy. By performing the spray cooling, the cooling time of the ingot 16 can be shortened and the internal cracks can be reduced, thereby obtaining a Cu-Ni-Sn alloy having both productivity and quality. That is, as examples of conventional cooling methods of the ingot 16 containing Cu, Ni, and Sn, air shower or shower-like liquid may be directly applied; while direct immersion in a liquid or the like is difficult to reduce internal cracking while shortening the cooling time of the ingot 16 in these methods, the spray cooling according to the production method of the present invention can reduce internal cracking while shortening the cooling time of the ingot 16.

In the cooling step, the liquid is not particularly limited as long as it can be used as a cooling medium such as water or oil, and water is preferred from the viewpoint of ease of handling and production cost. From the viewpoint of adjusting the cooling rate, oil may be used as the cooling medium.

The ingot 16 having passed through the mold 12 is preferably cooled to 50 ℃ or lower within 2 hours after the end of casting, more preferably to 100 ℃ or lower within 1 hour after the end of casting, and still more preferably to 500 ℃ or lower within 0.5 hour after the end of casting. By cooling the ingot 16 in a short time in this manner, the casting cycle by the continuous casting method and the semi-continuous casting method can be shortened, and productivity can be improved.

In the cooling step, the ingot 16 is preferably cooled by passing it through a cooler 18 disposed directly below the mold 12. Accordingly, the spray cooling is performed immediately after the ingot 16 is extracted from the other end of the mold 12, and not only the surface layer but also the inside of the ingot 16 can be rapidly cooled without being cracked. When the ingot 16 is drawn out from the other end of the mold 12 and lowered by the cooler 18, the ingot 16 may be lowered while being supported by a receiving table (not shown). Preferably, the ingot 16 is supported by a support table, and the support table is lowered at a speed of 25 to 40 mm/min, more preferably 25 to 35 mm/min, and still more preferably 25 to 30 mm/min.

The cooler 18 preferably includes a cylindrical body 18a, a liquid supply portion 18b, and an air injection portion 18 c. The liquid supply portion 18b is provided above the cylindrical body 18a and configured to drop the liquid W downward, while the air ejection portion 18c is provided below the liquid supply portion 18b and configured to eject the air a toward the central axis of the cylindrical body 18 a. According to this configuration, the liquid W dropped from the liquid supply portion 18b is mixed with the air a to form a mist-like liquid (i.e., a spray), and the mist is sprayed onto the ingot 16 located inside the cylindrical body 18 a. Further, the cooling time of the ingot 16 by spray cooling can be shortened and the internal cracks can be suppressed, and the productivity and quality of the Cu — Ni — Sn alloy can be achieved at the same time. Further, since the dropped liquid W contains impurities such as carbon, it is desirable to adjust the diameter of the nozzle so as not to block the nozzle (also referred to as a hole) for ejecting the air a. The diameter of the nozzle is preferably 2 to 5mm, more preferably 3 to 4 mm. The flow rate of the liquid W dropped from the liquid supply portion 18b is preferably 7 to 13L/min, and more preferably 9 to 11L/min. The pressure of the air A ejected from the air ejection part 18c is preferably 2.0 to 4.0MPa, and more preferably 2.7 to 3.3 MPa.

The cooler 18 is preferably configured such that the liquid W dropping downward is mixed with the air a without coming into direct contact with the ingot 16. This can prevent the dripping liquid W from directly contacting the ingot 16 and locally quenching, and can uniformly spray-cool the entire ingot 16, thereby further suppressing the occurrence of internal cracks. The cooler 18 is preferably configured such that the position of the liquid W dropped from the liquid supply portion 18b is closer to the cylindrical body 18a than the position of the air ejection portion 18 c. Thus, when the liquid W drops from the liquid supply portion 18b, the air a of the air ejection portion 18c is just blown, and the atomized liquid (i.e., mist) can be efficiently generated.

The air injection portion 18c of the cooler 18 is preferably configured such that the air a is injected obliquely downward. If the momentum of the liquid W from the liquid supply portion 18b is weak, the liquid W drops downward by gravity, and the position where the liquid W contacts the ingot as a mist of liquid decreases, which causes unevenness in the cooling rate. However, by forming the air a so as to be injected obliquely downward, the cooling rate can be made uniform without causing a difference in the position where the liquid W contacts the ingot due to the momentum (amount of liquid) of the liquid W.

Examples

The present invention is further specifically described by the following examples.

Example 1(comparison)

UNS was produced as a Cu-Ni-Sn alloy by the following steps: the Cu-15Ni-8Sn alloy defined in C72900 was evaluated.

(1) Weighing machine

Pure Cu nuggets, Ni matrix, Sn matrix, electric manganese, and Cu-Ni-Sn alloy scrap, which were raw materials of Cu-Ni-Sn alloy, were weighed so as to have a target composition. That is, 163kg of Cu, 30kg of Ni, 15kg of Sn and 1450kg of Cu-Ni-Sn alloy scrap were weighed and mixed to prepare a mixture.

(2) Melting and slag treatment

The weighed raw materials of the Cu-Ni-Sn alloy are melted in a high-frequency melting furnace for air at 1200 to 1400 ℃ and stirred for 30 minutes, thereby homogenizing the components. And after the melting is finished, scraping and fishing out the slag.

(3) Composition analysis (before casting)

A part of a Cu-Ni-Sn alloy obtained by melting and slag treatment was collected as a sample for component analysis, and the component value thereof was measured. As a result, the sample for component analysis contained Ni: 14.9 wt% and Sn: 8.0 wt%, and the balance of Cu and inevitable impurities. This composition satisfies UNS: the Cu-15Ni-8Sn alloy condition defined in C72900.

(4) Semi-continuous casting

The molten metal of the Cu-Ni-Sn alloy obtained by melting and slag treatment is tapped at 1250 to 1300 c, as schematically shown in fig. 1, into one end of a mold 12 having both ends open through a graphite nozzle 14. At this time, water is circulated through the inside of the mold 12, so that the molten metal flowing in is solidified from one end of the mold 12 to the other end, thereby producing an ingot 16. At this time, mainly the surface layer of the ingot 16 is solidified.

(5) Cooling (Water-Cooling (immersion Cooling))

The solidified surface layer ingot 16 is sprayed with liquid water by a cooler 18 provided directly below the mold 12 and then immersed in a water tank. At this time, no air a is blown from the air ejection portion 18 c. By such a cooling method, after the semi-continuous casting of the above (4), the ingot 16 is cooled to 50 ℃ or lower within 2 hours.

(6) Taking out of cast articles

The ingot 16 obtained by water cooling was taken out at a temperature of less than 50 ℃ to obtain a Cu-Ni-Sn alloy as a cast product. The dimensions of the cast article were 320mm in diameter by 2m in length.

(7) Various evaluations

The obtained ingot and cast product were evaluated as follows.

< identification of internal crack >

As shown in fig. 2, in order to confirm the internal cracks of the cast product, disc-shaped samples having a diameter of 320mm × a thickness of 10mm were cut out from positions 250mm from the top surface and 150mm from the bottom surface in the longitudinal direction of the cast product, and both surfaces thereof were subjected to visual observation and red penetrant inspection (red pick). Photographs showing the Top surface (labeled "Top (Top) side" in the figure) and the Bottom surface (labeled "Bottom (Bottom) side" in the figure) of the sample.

< 2 DAS determinations >

The sample was measured for 2 DAS (2 dendrite arm spacing) cycles, and the cooling rate until the molten Cu-Ni-Sn alloy solidified to become an ingot was estimated. First, in a cross section perpendicular (casting direction) to the position of the cut surface 1/2R of the sample, dendrites in which 4 or more dendrite arms are continuous 2 times were selected. The 1/2R position refers to a position located at the center of the cut surface (circle) of the disc-shaped sample and the center of the circumference (i.e., the position of radius 1/2). Next, the interval of 4 or more successive 2 dendrite arms was measured for the dendrite. This was taken as 2 DAS. The dendrite and DAS 2 times of the sample confirmed on the Top surface (labeled as "Top (Top) side" in the figure) and the Bottom surface (labeled as "Bottom (Bottom) side" in the figure) of a cross section perpendicular to the cut surface are shown in table 3.

Example 2

The preparation and evaluation of the sample were carried out in the same manner as in example 1 except that the water cooling in (5) was replaced by the spray cooling as follows. The dimensions of the resulting cast article were 320mm in diameter × 2m in length.

(5') Cooling (spray Cooling)

As schematically shown in fig. 1, the solidified ingot 16 is continuously drawn out while being sprayed with mist-like water by a cooler 18 provided directly below the mold 12. At this time, 7 to 13L/min of water W is dropped from a water supply part 18b located at the upper part of the cylindrical body 18a of the cooler 18, and air A is blown at a pressure of 2.7 to 3.3MPa through 120 holes having a diameter of 3.5mm provided downstream of the cylindrical body 18a of the cooler 18 as air jetting parts 18c, whereby the dropped water W is atomized to form mist water (i.e., mist), and blown to the ingot 16. The ingot 16 is lowered while being received by a receiving table (not shown) lowered by 25 mm/min. By such a cooling method, after the semi-continuous casting of the above (4), the ingot 16 is cooled to 50 ℃ or lower within 2 hours.

Example 3(comparison)

Samples were prepared and evaluated in the same manner as in example 1, except that air cooling was performed in the following manner instead of the spray cooling of (5). The dimensions of the resulting cast article were 320mm in diameter × 2m in length.

(5') Cooling (air-cooled)

The solidified ingot was continuously extracted while blowing air through a cooler provided directly below the mold. At this time, air was blown through 120 holes having a diameter of 3.5mm provided in the cylindrical body of the cooler, and the ingot was lowered while being received by a receiving table lowered at 25 mm/min. By such a cooling method, after the semi-continuous casting of the above (4), the ingot was cooled to 50 ℃ for 12 hours. In the case of air cooling, since the cooling rate of the ingot is slow, internal cracks are hard to occur, but it takes a long time to cool, and thus the productivity is poor.

In examples 1 to 3, as shown in fig. 2, internal cracks were observed in example 1 in which the cooling method was water cooling, but no internal cracks were observed in example 2 in which the cooling method was spray cooling and example 3 in which the cooling method was air cooling. In addition, as shown in FIG. 3, the DAS measured 2 times was the same in examples 1 to 3. Thus, it is estimated that the solidification rate of the molten Cu-Ni-Sn alloy is about the same as that of the ingots of example 1 (water cooling) and examples 2 (spray cooling) and 3 (air cooling).