JP2004300568A - Copper alloy for wind instruments - Google Patents

Abstract

An object of the present invention is to provide a material for a wind instrument which is excellent in processability, hardness and corrosion resistance, has a low cost, and has a high texture.
SOLUTION: The present invention is a copper alloy for wind instruments comprising 18 to 48.5% by weight of silver, 1 to 8% of palladium, 0.5 to 3% of indium, and the balance of copper by weight%. The present invention improves corrosion resistance and texture, which are disadvantages of conventional copper alloys. According to the present invention, it is possible to manufacture a high-quality wind instrument with high durability and high quality at low cost. [Selection diagram] None

Description

  The present invention relates to a copper alloy used as a raw material for a component of a wind instrument.

  Various properties are required for the material constituting the main body or parts of wind instruments such as flute, piccolo, and saxophone. The first requirement is workability such as plastic workability, brazeability (joinability), and castability.

  Wind instruments are manufactured from raw materials through various processing steps such as plastic working, casting, and brazing. For example, as shown in FIG. 1A, a tone hole 11 is provided in the flute main body 10, and the shape of the tone hole 11 is such that the tone hole wall rises from the inner surface of the main body 10 as shown in FIG. Since the tip has a complicated shape with curled ends, good plastic workability without cracking or scratching is required in the processing. The flute mouthpiece 20 includes a plate 21 and a riser 22 as shown in FIG. 1B, and these are manufactured by integral molding by casting. Therefore, good castability without casting defects is also required. Since the flute is manufactured by brazing each of these components, it is necessary that the brazing properties be good so that the components do not fall off after joining. Furthermore, many flute members are manufactured by cutting, and the machinability is also important. For example, a post for supporting a key pipe, which will be described later, has a shape as shown in FIG. 1C, and cutting workability is required to obtain a finished part.

  In addition, hardness and corrosion resistance are required for wind instrument materials. Regarding the hardness, in addition to preventing scratches due to the use process, it is sometimes said that the hardness of the constituent materials of the musical instrument affects the tone of the musical instrument. From that point of view, a material having a high hardness is required. The hardness of the material is also related to the durability of the wind instrument. For example, a flute key pipe (key pipe) 30 is supported by a post 31 (post) and a core material 32 (generally made of stainless steel) installed on the main body 10 as shown in FIG. , A cup 33 for closing the tone hole 11 is provided at a position corresponding to the tone hole 11. At the time of playing the flute, the tone hole 11 is opened and closed by arbitrarily reciprocating the cup 33. At this time, the key pipe 30 is twisted and friction between the key pipe 30 and the core material 32 is generated. Then, the inner surface of the key pipe is worn due to the friction, causing play, and the tone hole cannot be closed accurately, so that air may leak. Therefore, a material having high hardness that is resistant to wear is required.

  On the other hand, corrosion resistance is necessary to suppress discoloration of the musical instrument due to sweat of the player or discoloration in the atmosphere during storage. Also, as described above, wind instruments are manufactured by brazing a plurality of parts, and the brazing requires burner heating of the material. At this time, since the material having poor corrosion resistance is liable to be discolored by oxidation, a polishing treatment or an acid washing treatment is required after brazing, which causes a problem that the number of manufacturing steps increases. Therefore, corrosion resistance is also required in terms of musical instrument production efficiency.

  Furthermore, texture (brightness, color) and material cost are also very important properties for wind instrument materials. Music is an art, and the texture of the instrument is one of the elements for enjoying the music for those who play and listen to the instrument. In this case, a high-quality musical instrument can be obtained by using an expensive material such as a noble metal such as gold. However, since the material cost is directly reflected in the price of a wind instrument, it is widely used (for public use). It is not appropriate to pursue a sense of luxury with this measure even for the instruments described in (2). Art should be enjoyable by the general public in general, and it is preferable to be able to obtain good quality instruments at affordable prices.

  In response to the above requirements, conventional materials for wind instruments include nickel silver, gold alloy, silver alloy (silver-7.5% copper alloy, sterling silver), and copper alloy (60% copper-silver alloy). (Refer to Patent Documents 1 and 2 for conventional wind instrument materials).

JP-A-5-33085 JP-A-5-173548

  However, there are many conventional alloys for wind instruments that are insufficient, although the above-mentioned required characteristics are considered for the time being. That is, noble metal-based alloys such as gold alloys and silver alloys cannot be said to have sufficient productivity in terms of material cost and hardness. Further, copper alloys are good in cost but have difficulty in corrosion resistance, and the discoloration due to the use process and the discoloration due to burner heating are remarkable. Further, the copper alloy has a disadvantage that the hue of copper is strong and the sense of quality is poor as compared with the silver alloy.

  The present invention has been made in view of the above background, and has an object to provide a material for a wind instrument that has excellent workability, hardness, and corrosion resistance, and that has a low texture while having a low cost. I do.

  The present inventors have studied to solve this problem, and to develop an alloy based on a copper alloy (60% copper-silver alloy) which is superior in cost among the above-mentioned conventional materials. did. The present inventors have determined that palladium is preferably added as a suitable additive element mainly for imparting corrosion resistance to copper alloys, and indium is mainly added as a preferred additive element for improving workability. The present invention was completed by conceiving that a material intended for the present application can be obtained by strictly defining the amount.

  That is, the present invention is a copper alloy for wind instruments comprising 18 to 48.5% of silver, 1 to 8% of palladium, 0.5 to 3% of indium, and the balance of copper in terms of% by weight.

  In the present invention, palladium and indium are added for the purpose of mainly improving corrosion resistance and workability, and also have the effect of improving the coloration of the copper alloy and increasing the hardness.

  Palladium has the effect of improving the corrosion resistance of the copper alloy and the coloration (texture) of the copper alloy, and also has the effect of increasing the hardness and preventing discoloration of the copper alloy. In addition, there is also an effect that the color tone of copper is weakened, and a high-grade color such as silver or gold is produced depending on the density. Here, the reason why the concentration range of palladium is set to 1 to 8% by weight is that these effects do not occur if less than 1% by weight, and if it exceeds 8% by weight, the cost of the alloy becomes too expensive; This is because various problems arise, such as a point that the specific gravity becomes too high, a color tone becomes too strong in white color, and a color tone that is not preferable for a wind instrument. Also, if it exceeds 8% by weight, no remarkable effect of improving the corrosion resistance is observed.

  Indium has the effects of improving the workability (castability, brazing properties, machinability) of the alloy, reducing the specific gravity of the alloy, and suppressing discoloration of copper in the alloy. The reason why the concentration range of indium is set to 0.5 to 3% by weight is that if the content is less than 0.5% by weight, these effects cannot be obtained. If the content exceeds 3% by weight, the alloy is softened and the corrosion resistance is deteriorated. Also, if the content exceeds 3% by weight, no remarkable effect on the workability is observed.

  Based on the above effects of palladium and indium, 30-40% of silver, 4-6% of palladium, and 1-2 of indium are required to maximize the effect of each effect and to enhance the texture as a musical instrument. %, An alloy having a balance of copper is preferable.

  The copper alloy according to the present invention is excellent in workability due to the synergistic effect of the complex addition of palladium and indium, and is unlikely to cause defects in casting, plastic working, and cutting of various parts of wind instruments. Even in brazing, it can be joined in a good state.

  Further, the copper alloy according to the present invention is excellent in corrosion resistance, can suppress discoloration during use and storage of a wind instrument, and can maintain its appearance for a long time. Further, discoloration due to burner heating during brazing during wind instrument production is also suppressed, which can contribute to an improvement in wind instrument production efficiency. The hardness is higher than that of a conventional wind instrument material, and generation of scratches and deterioration of the instrument due to use are suppressed.

  Furthermore, the copper alloy according to the present invention has a high-quality appearance of silver and gold while using low-cost copper as a main component. Therefore, a high quality wind instrument can be manufactured at low cost, and a high quality wind instrument can be provided even for the public. The color tone of the copper alloy according to the present invention can be adjusted by adjusting the concentrations of palladium and indium. Therefore, when manufacturing a wind instrument using the copper alloy according to the present invention, the copper alloy according to the present invention may be used for the entire musical instrument, or the copper alloy according to the present invention may be partially used (for example, And a case where a high-grade material based on a noble metal is used for the main body and a copper alloy according to the present invention is used for parts such as a key pipe). Even when the copper alloy according to the present invention is partially used, there is no problem because the copper alloy according to the present invention has a color tone that does not cause a sense of incongruity with the color tone of the material of other portions.

  The copper alloy according to the present invention has a lower specific gravity and is lighter than other materials for wind instruments. Therefore, for example, when the entire musical instrument is made of a gold-based alloy, in the case where the weight of the entire musical instrument becomes heavy in addition to the high cost, the main body is made of a gold-based alloy, and other parts are made of the copper alloy according to the present invention. By doing so, it is possible to measure the weight of the instrument. Even in such a case, it is possible to provide a musical instrument that does not have a sense of incongruity in color tone as described above.

  The copper alloy for wind instruments according to the present invention is a material having excellent workability and corrosion resistance and high hardness. According to the present invention, a high-quality wind instrument having high durability and high quality can be manufactured at low cost.

  Hereinafter, preferred embodiments of the present invention will be described together with comparative examples.

  In the present embodiment, two types of alloys were manufactured, and the workability, corrosion resistance, hardness, and specific gravity of these alloys were examined. The copper alloy was manufactured by a vacuum melting method. Then, various members of the flute were manufactured as described below, and workability such as plastic workability was examined. The alloys produced were an alloy of 42% by weight of silver, 2% by weight of palladium, 1% of indium and 55% by weight of copper (Example 1) and an alloy of 32% by weight of silver, 6% by weight of palladium, 2% of indium and 60% by weight of copper (Example 2).

Examination of workability In order to examine plastic workability, a round bar ingot was manufactured by melt casting, a pipe was manufactured from this, and the workability was examined from the viewpoint of cracking or disconnection during working. In the process of processing into a pipe, a round bar ingot having a diameter of 51 mm was cut (bored) into a base tube having an outer diameter of 48 mm and an inner diameter of 29 mm, and this was subjected to a heat treatment at 550 ° C. for 30 minutes in a nitrogen and hydrogen atmosphere. A pipe having an outer diameter of 19.76 mm and an inner diameter of 19 mm was obtained through rough drawing, the same heat treatment as above, and finish drawing.

  The evaluation of the machinability was evaluated by cutting a round bar having a diameter of 5.5 mm, manufacturing a key pipe supporting post, and checking the appearance of the finish.

  In addition, the castability was evaluated by producing a mouthpiece and a riser by casting, and evaluating the presence or absence of shrinkage cavities and pinholes.

  Furthermore, the brazing property was evaluated by joining the manufactured mouthpiece and the riser, and confirming the brazing flow during joining, the strength after joining, and the appearance. The brazing was performed at a joining temperature of 750 ° C. with a brazing material (silver 45% by weight-copper 25% by weight-zinc 25% -indium 5% by weight).

Examination of corrosion resistance The examination of corrosion resistance was performed by a test using artificial sweat considering the effect during use, a test considering the effect during storage, and a test regarding discoloration due to burner heating. The sample at this time was prepared by appropriately processing a pipe having an outer diameter of 19.76 mm and an inner diameter of 19 mm manufactured in the same process as the above process.

  Adjustment of artificial sweat is performed by weighing 1 ± 0.01 g of urea, 5 ± 0.01 g of sodium chloride, and 1.13 ± 0.01 g of lactic acid in a 2 L beaker, adding 900 mL of pure water to this, dissolving it, and further adding pure water. Was added to make 1000 mL. Then, the pH was adjusted to 6.5 ± 0.2 with about 10% aqueous ammonia to obtain artificial sweat. In the test method, one side of the sample was polished, ultrasonically washed with pure water and alcohol, dried, and then immersed in artificial sweat in a glass screw bottle. Then, the screw cap was placed in a thermo-hygrostat kept at a temperature of 30 ° C. and a humidity of 70%, left for a predetermined time, and the discoloration of the sample after immersion was confirmed. The immersion times were 8, 24, 48, 168 and 336 hours.

    In order to examine the corrosion resistance during storage, the washed sample was stored in a safe at room temperature and left for one year to check the surface condition.

  The discoloration due to the burner heating was examined by confirming the surface state after the burner heating (750 ° C.) performed in the above-mentioned examination of the brazing properties.

Measurement of Specific Gravity and Hardness For the pipe manufactured in this embodiment, the specific gravity and hardness (Vickers hardness) were measured.

Table 1 summarizes the above examination results. Table 1 shows, as a comparison, silver-copper 7.5 wt% alloy, copper 60 wt% -silver alloy, and gold alloy (gold 20.8 wt% -silver 25 wt%) which are conventional materials for wind instruments. -54.2% by weight of copper alloy (K5), 37.5% by weight of gold-6% by weight of silver-56.5% by weight of copper (K9), 58.5% by weight of gold-9.5% by weight of silver-Copper 32% by weight alloy (K14)).

  From the above results, it was confirmed that the two types of alloys manufactured in the present embodiment had good properties in all the balances of workability, corrosion resistance, hardness, and specific gravity.

The figure which shows the structure of each part of a flute. The figure which shows the structure around a key pipe.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 10 Main body 11 Tone hole 20 Mouthpiece 21 Plate 22 Riser 30 Key pipe 31 Post 32 Core material 33 Cup

Claims (2)

Copper alloy for wind instruments consisting of 18-48.5% silver, 1-8% palladium, 0.5-3% indium, and the balance copper in weight%. The copper alloy for wind instruments according to claim 1, comprising 30 to 40% of silver, 4 to 6% of palladium, 1 to 2% of indium, and the balance copper.

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