JPH0610318B2 - Copper alloy manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for producing a copper alloy.

[Technical background of the invention and its problems] Conventionally, a vacuum melting method has been known as a method for producing a copper alloy, particularly a low oxygen copper alloy. However, vacuum melting requires a special device, and has a drawback that it is complicated and requires a long time in operation. Therefore, the present inventors have previously proposed a manufacturing method (Japanese Patent Publication No. 54-99884) in which a carbon crucible is melted in the air to obtain a material equivalent to vacuum melting. However, this method also has a problem that the carbon crucible is worn and must be replaced after several tens of uses. Further, when a carbon crucible is used, it is preferable to use a high-purity carbon crucible in order to increase the deoxidizing power, but on the other hand, it has a property that abrasion is likely to occur. Further, when a carbon crucible containing a large amount of alumina or the like is used, abrasion resistance is improved, but there is a problem that deoxidation is likely to be insufficient.

[Object of the Invention] In view of the above points, the present invention provides a method for producing a copper alloy that contains segregated substances in a copper alloy and does not cause defects such as swelling easily and at low cost. It is provided.

[Summary of the Invention] As a result of earnest studies, the inventors of the present application have found that the oxygen concentration in the mother alloy is reduced to a certain extent by adding carbon, and then an active metal or the like is further added to increase the oxygen content. It was found that a good ingot with few inclusions and holes can be obtained by the two-stage reduction of oxygen content, which is to reduce

That is, the present invention is a mother alloy made of copper or a copper alloy,
With respect to the total amount of the mother alloy, 0.1% by weight or more of carbon converted to C is added and dissolved, and the oxygen concentration in the mother alloy is adjusted to 10%.
The first step of reducing the concentration to 0 ppm or less, and then further adding an element having a standard formation energy of oxide of 1100 ° C. or higher and 1400 ° C. or lower of −500 kJ / molO ₂ or less,
And a second step of adjusting the oxygen concentration in the master alloy to 50 ppm or less, and melting is carried out in the atmosphere to produce a copper alloy.

More specifically, first, in order to prevent consumption, Al
Carbon crucible containing ₂ O ₃ , SiO _2, etc., Al ₂ O ₃
Prepare a crucible, etc. Next, the standard free energy of formation of copper or copper alloy as raw material, carbon, and oxide,
-500 kJ / m at 1100 ° C or higher and 1400 ° C or lower
Elements of olO ₂ or less are sequentially charged into the crucible and melted.

At this time, with oxygen in the molten metal of the mother alloy such as copper or copper alloy,
It reacts sufficiently with carbon and is first released as a gas such as CO or CO ₂ so that the oxygen concentration of the copper alloy is about 100 pp.
m or less.

Next, the standard free energy of formation of the oxide is 1100 ° C. or higher and 1400 ° C. or lower, and by adding Zr or the like as an element of −500 kJ / molO ₂ or lower, it reacts with oxygen in the copper alloy or the like to generate ZrO ₂ or the like. As a result, the oxygen concentration in the mother alloy is further reduced to 50 ppm.

As the mother alloy used in the present invention, copper or a copper alloy can be used. As the copper alloy, it is preferable to use an extrusion hardening type copper alloy, which is 0.1 to 2% in practical use.
A copper alloy containing Cr, Zr, Be, Ti, Fe—Co and the like to a certain extent is used.

The carbon used in the present invention is preferably as pure as possible, and the addition amount thereof is preferably 0.1% by weight or more in terms of C based on the total amount of the copper alloy. Is preferably 0.1 to 5% by weight.

Further, the standard free energy of formation of the oxide in the present invention is −500 kJ / at 1100 ° C. or higher and 1400 ° C. or lower.
Elements of molO ₂ or less include Zr, Y, Nb, and T.
a, V, Sm, U, B, Ho, Sc, La, Mg, L
i, Al, Ba, Ce, Hf, Be, Ca, Ti and the like are listed, and in practical use, Zr, Y, Nb, Ta, V, Sm,
It is preferable to use U. The addition amount is 0.01
It is preferable to add at least wt%, and in practical use,
It is preferably 0.01 to 1.0% by weight.

Carbon and predetermined elements to be added to the method of the present invention,
Carbon is first added to generate gases such as CO and CO ₂ and then elements such as Zr and Y are further added to perform melting.

Further, when a copper-based alloy containing various additive components is obtained by using the method of the present invention, it can be preliminarily contained in the mother alloy, but in practice, the copper alloy was obtained by the method of the present invention. later,
It is preferable to add additional components.

[Examples of the Invention] A carbon crucible containing 30% of SiO ₂ was used, and for example, a mother alloy composed of electrolytic copper (420 Kg) and a Cr-Cu-based copper alloy (30 Kg) containing 10% Cr was added to a high purity carbon (5 K).
g, 2 to 3 cm of lump) is added, and atmospheric high frequency melting is performed.

After the mother alloy composed of the electrolytic copper and the 10% Cr—Cu-based copper alloy is melted and heated at 1200 ° C. for 10 minutes, 0.5 kg of Zr as a predetermined element according to the present application is added to perform deoxidation. The slag generated at this time is solidified with cryolite or the like and removed to obtain a copper alloy by the method of the present invention.

Next, if necessary, Zr as an additive component was added at a speed of 2 Kg, and the mixture was stirred well, and after about 10 seconds, 50 Kg of electrolytic copper was further added, and the molten metal temperature was lowered to 1180 ° C. before casting in a mold.

The composition of the obtained copper alloy is Cr 0.54 wt%, Zr 0.31 wt%,
Oxygen becomes 8ppm, and the oxygen content is the same as the conventional value (50-100pp
It was able to be suppressed significantly lower than m). Further, FIG. 1 shows the present invention, and FIG. 2 shows a conventional carbon crucible as a comparative example to prepare a copper alloy ingot and roll it to obtain a microstructure photograph (× 400) of the copper alloy obtained by an optical microscope. Indicates. The striped and linear portions that are clearly seen in FIG. 2 are inclusions. The figure shows that the copper alloy obtained by the present invention has less inclusions than the conventional one.

As described above, when high-purity carbon and an element such as Zr having a standard free energy of formation of an oxide of −500 kJ / molO ₂ or less are combined and dissolved, the content of oxygen is small and inclusions and holes are not formed. A small amount of good ingots can be melted in the air, and as a melting method for various copper alloys,
It can be regarded as a very useful technique industrially.

[Effects of the Invention] When the copper alloy obtained by the method of the present invention and the copper alloy obtained by the conventional method using a carbon crucible are compared, the following characteristics are different.

[Brief description of drawings]

FIG. 1 is a photograph of the structure of a copper alloy obtained according to the present invention. FIG. 2 is a microstructure photograph of a copper alloy obtained by the conventional method shown for comparison.

Front page continuation (72) Haruka Mabori, Inventor Haruka Machidori 1-26-5 Toranomon, Minato-ku, Tokyo Tokyo Shibaura Electric Co., Ltd. Minato Branch Room (72) Fuzo Sugai 8 Shinsugita-cho, Isogo-ku, Yokohama, Kanagawa Prefecture Shibaura, Tokyo Electric Co., Ltd. Yokohama Metal Factory (72) Inventor Shigumi Yamane 8 Shinsugita-cho, Isogo-ku, Yokohama, Kanagawa Prefecture Tokyo Shibaura Electric Co., Ltd. Yokohama Metal Factory (56) Reference JP-A-56-25940 (JP, A)

Claims (2)

[Claims] 1. A master alloy made of copper or a copper-based alloy is added with 0.1% by weight or more of carbon, calculated as C, based on the total amount of the master alloy and melted, and the oxygen concentration in the master alloy is set to 100 p.
pm or less, and then the standard formation energy of the oxide is 1100 ° C. or more and 1400 ° C. or less, and an element of −500 kJ / molO ₂ or less is added to make the oxygen concentration in the mother alloy 50 ppm or less. And a second step, which is performed by melting in the air to produce a copper alloy. 2. The copper-based alloy is Cr, Zr, Be, Ti,
The method for producing a copper alloy according to claim 1, containing at least one of Fe and Co.