JPS60230955A - Material for electrode for electric discharge machining - Google Patents

Abstract

PURPOSE:To obtain a material for an electrode for electric discharge machining having a higher rate of electric spark machining and a further reduced consumption ratio by adding Sr to a Cu-W alloy. CONSTITUTION:A material for an electrode for electric discharge machining is obtd. by adding 0.1-10wt%, especially 0.5-5wt% Sr or its composite oxide to a conventional Cu-W alloy having a composition consisting of, by weight, about 20-50%, preferably about 30-35% Cu and about 80-50%, preferably about 70-65% W. Sr may be used as simple substance, but it is preferable that Sr is used in the form of a composite oxide such as SrZrO2, SrWO4 or SrMoO4. When Sr alone is added, the desired improving effect is attained, but the improving effect can be increased more considerably by adding Sr together with Zr.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrode material for electric discharge machining. More specifically, the present invention relates to an electrode material for electrical discharge machining made of a copper-tungsten alloy.

Important conditions for electrode materials for electric discharge machining include low wear of the electrode itself and high machining speed for the workpiece during machining, as well as good machinability (cutting workability). is also naturally required. Conventionally, silver-tungsten alloys or copper-tungsten alloys manufactured by powder metallurgy have been commonly used as electrode materials for electrical discharge machining of hard steel and super steel alloys. However, although the former alloy has better overall performance than the latter alloy, recently, in order to further shorten the machining time and extend the life of the electrode, electrodes with higher machining speeds and lower electrode wear ratios have been developed. Materials are becoming more in demand.

The object of the present invention is to improve the performance of an electrode material for electrical discharge machining made of a copper-tungsten alloy, further increase the electrical discharge machining speed, and further reduce the electrode wear ratio. It has been found that the object of the present invention can be effectively achieved by incorporating strontium or strontium and zirconium into a copper-tungsten alloy. Accordingly, the present invention relates to such a copper-tungsten alloy.

The copper-tungsten alloy, as conventionally used, contains about 20-50% copper, preferably about 30-35% by weight copper.
, about 80-50% by weight tungsten, preferably about 70%
It is formed from an alloy having a composition of ~65% by weight. Strontium is further contained in this.

Although strontium may be used alone, strontium is preferably used in the form of a complex oxide such as those listed below.

5rZr03 Strontium zirconate 5rWO, Strontium tungstate SrMoO4 Strontium molybdate 5rTiO, Strontium titanate 5rA1204 Strontium aluminate SrCrO
4 Strontium chromate 5rTeO3 Strontium tellurate 5r (Ta03)2 Strontium tantalate Sr (
Mn04), strontium manganate 5r (VO3)
, strontium vanadate When these strontium or its composite oxide is contained alone in the copper-tungsten alloy, it is 0.1 to 10% by weight in the ternary alloy.
, preferably at a ratio of 0.5 to 5%. If the content is more than this, the sintering properties when alloying these three components by powder metallurgy will be inhibited, causing expansion and poor sintering, and the electrode wear rate will increase, while if the content is less than this, the paper No additive effect was observed.

Strontium is added alone in this way,
The desired improvement effect can be achieved, and by adding it together with zirconium, the improvement effect can be further greatly improved. As zirconium, zirconium alone can be used, but it is preferably used in the form of its nitride, boride, or oxide.

Thus, when strontium and zirconium are used together, strontium is present in the quaternary alloy.
．． It is contained in a proportion of 1 to 5% by weight, preferably 0.2 to 1.0% by weight, and zirconium is contained in a proportion of 0.1 to 10% by weight.
, preferably in a proportion of 0.5 to 3% by weight. If the zirconium content is higher than this, the formed alloy will become brittle, difficult to machine, the electrical conductivity will be significantly reduced, and the discharge performance will be adversely affected; If the content is small, no particular effect can be seen from the combined use of zirconium.

When strontium is used alone or together with zirconium in such a content, the electronic work function of the electrode decreases, improves electron emissivity, stabilizes discharge, and reduces radiation. This has the effect of concentrating energy on the workpiece side. Therefore,
The effects of improving the machining efficiency during electrical discharge machining, increasing the machining speed, and reducing the wear ratio of the electrode are particularly remarkable. In addition, the electrode material according to the present invention has very good machinability (cutting workability), and the machined surface of the workpiece subjected to electrical discharge machining is also better than that using conventional electrode materials. It was also confirmed that the surface roughness was small.

Next, the present invention will be explained with reference to examples.

Example 1 Predetermined amounts of composite oxides of copper, tungsten, and various types of strontium were blended and mixed, then a binder was added thereto, and a green compact was produced at a compacting pressure of 2 tons/d. This was placed in an atmosphere of 700°C to evaporate the binder, then a copper infiltration material (pure copper plate or green compact) was placed on top and infiltration was performed at 1250°C in a hydrogen gas atmosphere. Then, an alloy body was produced. The blending ratio of each component and the amount of infiltration were adjusted so that the final composition (% by weight) after infiltration was as follows.

Kidney 8 Copper 34.1 Tungsten 63.4 Strontium composite oxide 2.5 A cylindrical test piece with a diameter of 11wn and a height of 9wn is cut out from approximately the center of the prepared alloy body, and a diameter A cylindrical brass shank of 8 nn and height of 60 rrtn was brazed with copper to form an electrode. Then, a cemented carbide G2 plate (thickness 10 mm, pilot hole diameter 2
An electric discharge machining test was conducted using

The electric discharge machine and electric discharge machining conditions used are as follows.

Electric discharge machine body: Juvax DH-15OA Power supply: UF10'5C Electric discharge machining conditions] New set: CuW-WC (MWS) R1 (MC8
) MA switch = 3, no jump Processing voltage: 5 to 28 V (center value) Liquid pressure: Jet, 0.2 to 0.25 kg/a # (gauge pressure) Selector 2 unused Polarity: Electrode (-), Workpiece (+) Machining fluid: Daphne HL35 Electric discharge machining time = 30 minutes 00 seconds The results obtained are shown in Table 1 below. In addition, No. 5
No. 6 is a copper (35% by weight)-tungsten (65% by weight) alloy, and No. 6 is a silver (35% by weight)-tungsten (
65% by weight) alloy.

Table 1 From the results in Table 1 above, it can be seen that the electric discharge machining performance was significantly improved by incorporating strontium composite oxide into the conventional material copper-tungsten alloy.
In particular, the electrode wear ratio is reduced to about 173 degrees of that of the conventional material. As a result, copper-tungsten alloy as a conventional material was inferior to silver-tungsten, but by adding strontium to it, it showed electrical discharge machining performance equal to or superior to expensive silver-tungsten alloy. Alloys can now be obtained at low prices.

Example 2 An alloy having the following final composition (% by weight) was produced in the same manner as in Example 1 using copper, tungsten, strontium, zirconium, or a compound thereof.

Using the produced alloy, an electric discharge machining test was conducted in the same manner as in Example 1 using it as an electrode. The results obtained are
It is shown in Table 2 below. Note that No. 6 is a comparative example.

Table 2 From the results of Table 2 above, it can be said that the same results as those of Cloth 1 can be said, but especially from the comparison between No. 1 to 4 and No. 5 or No. 6, it is clear that zirconium or strontium is added to the copper-tungsten alloy. It can be seen that the electric discharge machining performance is further improved when both are used in combination rather than when added alone.

Procedure name iE*=i: (Voluntary) November 22, 1980 Commissioner of the Japan Patent Office Gakudon Shiga 2 Name of the invention Electrode material for electrical discharge machining 3 Relationship to the person making the amendment Name of patent applicant (438) Japan Oil Seal Kogyo Co., Ltd. 4 Agent (105) Address 1-2-7-5 Shiba Daimon, Minato-ku, Tokyo Column 6 for detailed explanation of the invention in the specification subject to amendment 6 Contents of amendment (1) Page 8 No. 4 Correct "5-28" in the row to "25-28".

(2) W 5r rsrTio3J on page 8, bottom line 33
Corrected to TiO, Jl.

Claims (1)

[Claims] (1) An electrode material for electric discharge machining, which contains strontium in a copper-tungsten alloy. 2. The electrode material for electric discharge machining according to claim 1, which uses strontium in the form of a composite oxide. 3. The electrode material for electric discharge machining according to claim 1 or 2, which contains strontium in an amount of 0.1 to 10% by weight. 4. The electrode material for electric discharge machining according to claim 1, which is manufactured by a powder metallurgy method. 5. Electrode material for electric discharge machining containing strontium and zirconium in a copper-tungsten alloy. 6. The electrode material for electrical discharge machining according to claim 5, which uses strontium in the form of a composite oxide. 7. The electrode material for electric discharge machining according to claim 5 or 6, which contains strontium in an amount of 0.1 to 5% by weight. 8. The electrode material for electrical discharge machining according to claim 5, wherein zirconium is used in the form of nitride, boride, or oxide. 9. The electrode material for electrical discharge machining according to claim 5 or 8, which contains zirconium in an amount of 0.1 to 10%. 10. The electrode material for electrical discharge machining according to claim 5, which is manufactured by a powder metallurgy method.