JPH0120018B2

JPH0120018B2 -

Info

Publication number: JPH0120018B2
Application number: JP58235628A
Authority: JP
Inventors: Shigeo Ezaki; Minoru Yokota; Kazuo Sawada; Kenji Masuyama
Original assignee: Sumitomo Electric Industries Ltd
Current assignee: Sumitomo Electric Industries Ltd
Priority date: 1983-12-13
Filing date: 1983-12-13
Publication date: 1989-04-13
Also published as: JPS60127924A

Description

[Detailed description of the invention]

発明の分野この発明は、ワイヤカツト放電加工用電極線お
よびその製造方法に関する。先行技術の説明ワイヤカツト放電加工用電極線として、黄銅
線、黄銅に類似した合金線、銅線、タングステン
線等が使用されている。これらの電極線にとつて
必要なことは、言うまでもなく、良好な加工速度
および良好な加工精度を保証し得ることである。
そして、近年のワイヤカツト放電加工機の進歩と
ともに、加工中に断線し難いことや、たとえもし
断線したとしても自動的に結線して加工を続行で
きることが、電極線に必要とされる重要なフアク
タとして加えられるようになつた。ここで、自動
結線がなされるためには、電極線の直線性が重要
となつてくる。すなわち、ワイヤカツト放電加工
に用いられる電極線には、高強度を有し、かつ、
いわゆる線癖がなく、さらに直線になろうとする
性質を有することが強く要望される。しかしながら、従来、この直線性について十分
に配慮されておらず、そのため自動結線がなされ
ず、あるいは加工部に超音波振動を付与したりす
るダイス部への線通しに関し作業性が優れなかつ
た。発明の目的それゆえに、この発明の主たる目的は、従来か
ら要求されている特性を満足するとともに、近年
装置面において改良された「自動結線」というメ
カニズムにも対応し得るワイヤカツト放電加工用
電極線およびその製造方法を提供することであ
る。発明の構成および効果この発明は、ワイヤカツト放電加工に用いられ
る電極線であつて、少なくともZnを25〜40重量
％含有する銅合金からなることと、引張強さが80
Kg／mm²以上であることと、0.2％耐力と引張強さ
との比が0.85〜0.95であることとを特徴とする。「少なくともZnを25〜40重量％含有する」と
したのは、この範囲内でZnを含有すれば放電加
工速度および伸線加工性の点において良好な結果
が得られるからである。しかし、Zn含有量が25
％未満であるならば放電加工速度が小さくなり、
40％を起えるならば伸線加工性が悪くなる。「銅合金」を用いるのは、良好な導電性を得る
ためである。なお、この銅合金は、上記Zn以外
に、Al、Mg、Sn、Ag、Ｐ、Zr、Ti、Be、Fe、
希土類元素を含む群から選ばれた少なくとも一種
以上の元素を合計で５％まで含有するものであつ
てもよい。Zn以外にこのような元素を添加すれ
ば、強度の向上、真直性の向上および加工速度の
向上が期待され得る。しかし、それらの元素が合
計で５％を越えるようならば、加工性が悪化する
おそれがある。「0.2％耐力と引張強さとの比が0.85〜0.95」と
したのは、この範囲内の比率のときに良好な自動
結線性が得られるからである。「引張強さが80Kg／mm²以上」としたのは、ワイ
ヤカツト放電加工用電極線には当然に高張力性が
要求されるからである。特に、厚い鋼板（たとえ
ば厚さ80mm）を切断する場合、電極線に高張力を
付与しなければ振動等によつて寸法精度が得難く
なる。そのために高張力性が要求される。もし
も、引張強さが80Kg／mm²未満であるならば、加工
時に断線するか、または高張力付与を行なうこと
が困難となる。そして、上述の特徴を有するワイヤカツト放電
加工用電極線を得るために、この発明に従つたワ
イヤカツト放電加工用電極線の製造方法は、以下
の工程を備えている。すなわち、少なくともZn
を25〜40重量％含有する銅合金からなり、90〜
99.99％の減面率でワイヤカツト放電加工用電極
線として適した直径となるまで冷間加工された線
材を、直線状に保つ工程と、直線状に保たれた前
記線材を、絶対温度で表わされた加熱温度と秒で
表わされた加熱時間との積が500〜3000の範囲に
ある加熱雰囲気下に置いて熱処理を行なう工程
と、を備えている。ここで、もし「減面率」が90％未満であるなら
ば、強度と直線性とが両立し難くなり、99.99％
を越えるようならば加工し難くなり直線性を得る
ことが困難とる。また、「絶対温度と加熱時間との積」が500未満
であるならば直線性が劣るようになり、3000を越
えるようならば強度の低下を招きやすくなる。上述の方法によつて製造されたワイヤカツト放
電加工用電極線は、良好な加工速度および良好な
加工精度を保証し得るとともに、自動結線がなさ
れるために必要とされる直線状においても良好な
結果を呈する。これは、線材を直線状の状態で再
結晶の生じない温度範囲で加熱するものであるの
で、まず第１に、直線形状を維持するのに悪影響
を及ぼす残留応力が除去されること、第２に、直
線形状を維持するのに好都合なように転位を再配
列しその分布状態を安定化させ、さらに、Zn等
の放電加工性に有効な元素が転位と結合した配置
がなされること、とが理由として考えられる。この発明に従つて得られたワイヤカツト放電加
工用電極線の優秀性は、以下に記述される実施例
のデータから明らかとなろう。実施例第１表に示される組成の合金を表中の最終冷間
加工度で直径0.25mmの線材になるまで伸線加工し
た後、表中の熱処理条件で通電加熱または炉中加
熱して伸直処理を行なつた。なお、試料番号１〜
６がこの発明に従つて製造された電極線、試料番
号７が従来の電極線、試料番号８〜11が比較例で
ある。上述のようにして得られた各電極線の引張強
さ、0.2耐力、および0.2％耐力／引張強さを、第
２表に示す。試料番号１〜11の各電極線を使用して80mmの鋼
板を切断した。そのときの高張力付与での作業性
および自動結線性を第３表に示す。以上の結果から、この発明に従つたワイヤカツ
ト放電加工用電極線は、高張力性、作業性および
自動結線性において優れていることが判明する。 FIELD OF THE INVENTION The present invention relates to a wire cut electrode wire for electric discharge machining and a method for manufacturing the same. Description of Prior Art Brass wires, alloy wires similar to brass, copper wires, tungsten wires, etc. are used as electrode wires for wire-cut electrical discharge machining. Needless to say, it is necessary for these electrode wires to be able to guarantee good processing speed and good processing accuracy.
With the progress of wire-cut electrical discharge machines in recent years, the important factors required for electrode wires are that they are difficult to break during machining, and even if they do break, they can be automatically connected and continue machining. Now it can be added. Here, in order to perform automatic wire connection, the linearity of the electrode wire is important. In other words, the electrode wire used in wire cut electric discharge machining has high strength and
It is strongly desired that the material has no so-called linear tendency and has the property of becoming straight. However, in the past, sufficient consideration has not been given to this linearity, and as a result, automatic wire connection has not been possible, or workability has not been excellent in threading the wire through the die portion, which involves applying ultrasonic vibrations to the processed portion. OBJECTS OF THE INVENTION Therefore, the main object of the present invention is to provide a wire-cut electrical discharge machining electrode wire and a wire-cut electrical discharge machining electrode wire that satisfy the conventionally required characteristics and that are also compatible with the "automatic wiring" mechanism that has been improved in recent years in terms of equipment. An object of the present invention is to provide a manufacturing method thereof. Structure and Effects of the Invention The present invention provides an electrode wire used in wire cut electrical discharge machining, which is made of a copper alloy containing at least 25 to 40% by weight of Zn, and has a tensile strength of 80% by weight.
Kg/mm ² or more, and the ratio of 0.2% proof stress to tensile strength is 0.85 to 0.95. The reason for "containing at least 25 to 40% by weight of Zn" is that if Zn is contained within this range, good results can be obtained in terms of electrical discharge machining speed and wire drawability. However, the Zn content is 25
If it is less than %, the electrical discharge machining speed will decrease,
If it increases by 40%, wire drawability will deteriorate. The reason for using "copper alloy" is to obtain good conductivity. In addition to the above Zn, this copper alloy also contains Al, Mg, Sn, Ag, P, Zr, Ti, Be, Fe,
It may contain up to 5% in total of at least one element selected from the group containing rare earth elements. If such an element is added in addition to Zn, it can be expected to improve strength, straightness, and processing speed. However, if the total content of these elements exceeds 5%, workability may deteriorate. The reason why the ratio of 0.2% proof stress to tensile strength is set to 0.85 to 0.95 is that good automatic wireability can be obtained when the ratio is within this range. The reason why the tensile strength is 80 Kg/mm ² or more is because wire cut electrode wires for electrical discharge machining naturally require high tensile strength. In particular, when cutting a thick steel plate (for example, 80 mm thick), unless high tension is applied to the electrode wire, it becomes difficult to obtain dimensional accuracy due to vibrations and the like. Therefore, high tensile strength is required. If the tensile strength is less than 80 kg/mm ² , the wire will break during processing or it will be difficult to apply high tension. In order to obtain a wire-cut electric discharge machining electrode wire having the above-mentioned characteristics, a method for manufacturing a wire-cut electric discharge machining electrode wire according to the present invention includes the following steps. That is, at least Zn
It consists of a copper alloy containing 25 to 40% by weight of
The process of maintaining a wire rod that has been cold-worked to a diameter suitable for a wire-cut electrical discharge machining electrode wire with an area reduction rate of 99.99% in a straight shape, and the process of maintaining the wire rod in a straight shape in terms of absolute temperature. and a step of performing heat treatment under a heating atmosphere in which the product of the heating temperature and the heating time expressed in seconds is in the range of 500 to 3000. Here, if the "area reduction rate" is less than 90%, it will be difficult to achieve both strength and linearity, and 99.99%
If it exceeds this, it becomes difficult to process and it becomes difficult to obtain linearity. Furthermore, if the "product of absolute temperature and heating time" is less than 500, the linearity will be poor, and if it exceeds 3000, the strength will tend to decrease. The wire cut electrode wire for electrical discharge machining manufactured by the above method can guarantee good machining speed and good machining accuracy, and also have good results in the straightness required for automatic wire connection. exhibits. This involves heating the wire in a straight state in a temperature range that does not cause recrystallization, so firstly, residual stress that has an adverse effect on maintaining the straight shape is removed, and secondly, In addition, the dislocations are rearranged in a way that is convenient for maintaining the linear shape, and their distribution state is stabilized, and furthermore, elements such as Zn, which are effective for electrical discharge machinability, are arranged in combination with the dislocations. could be the reason. The superiority of the wire-cut electrical discharge machining electrode wire obtained according to the present invention will become clear from the data of the examples described below. Example After drawing the alloy having the composition shown in Table 1 until it becomes a wire rod with a diameter of 0.25 mm at the final degree of cold working shown in the table, it was drawn by electrical heating or heating in a furnace under the heat treatment conditions shown in the table. Direct processing was performed. In addition, sample numbers 1~
6 is an electrode wire manufactured according to the present invention, sample number 7 is a conventional electrode wire, and sample numbers 8 to 11 are comparative examples. Table 2 shows the tensile strength, 0.2 proof stress, and 0.2% proof stress/tensile strength of each electrode wire obtained as described above. An 80 mm steel plate was cut using each electrode wire of sample numbers 1 to 11. Table 3 shows the workability and automatic wire connection performance under high tension application. From the above results, it is clear that the wire-cut electrode wire for electric discharge machining according to the present invention is excellent in high tensile strength, workability, and automatic wire connection.

【表】【table】

【table】

Claims

[Claims] 1. An electrode wire used in wire cut electric discharge machining, which is made of a copper alloy containing at least 25 to 40% by weight of Zn, has a tensile strength of 80 Kg/mm ² or more, and has a yield strength of 0.2%. A wire cut electrode wire for electric discharge machining, characterized in that the ratio to tensile strength is 0.85 to 0.95. 2 The copper alloy includes Al, Mg, Sn, Ag, P, Zr,
The wire cut electrode wire for electrical discharge machining according to claim 1, which contains up to 5% in total of at least one element selected from the group including Ti, Be, Fe, and rare earth elements. 3 A wire made of a copper alloy containing at least 25 to 40% by weight of Zn and cold-worked to a diameter suitable for a wire-cut electrical discharge machining electrode wire with an area reduction rate of 90 to 99.99% is kept in a straight shape. The wire rod kept in a straight shape is heat treated by placing it in a heating atmosphere where the product of the heating temperature expressed in absolute temperature and the heating time expressed in seconds is in the range of 500 to 3000. A method for manufacturing an electrode wire for wire cut electrical discharge machining, comprising the steps of: