【発明の詳細な説明】[Detailed description of the invention]
本発明は導電用耐熱アルミニウム合金の製造法
に関するもので、特に従来の導電用耐熱アルミニ
ウム合金（Al−Zr系合金）と同等の強度を有し、
導電率をあまり低下させることなく耐熱性を著し
く改善したものである。
従来架空送電線には電気用Alからなる導体を
用いた鋼芯アルミニウム撚線が用いられており、
特に耐熱性が要求される送電線にはAl−Zr系合
金の固溶Zrの耐熱機構を利用した固溶型耐熱ア
ルミニウム合金からなる導体を用いた鋼芯耐熱ア
ルミニウム合金撚線が用いられている。近年電力
需要の増大から耐熱性の改善が要求されるように
なり、これに対応して固溶Zr量を増大した導電
用耐熱アルミニウム合金や固溶Zrの耐熱機構に
代つて析出Zrの耐熱機構を利用した導電用耐熱
アルミニウム合金が開発された。
しかしながら固溶Zr量の増加は導電率の低下
をまねき、また析出Zrの耐熱機構を利用するた
めには300〜450℃の温度で長時間の加熱処理を必
要とするためコスト高となる欠点があつた。また
これ等合金の導電時における使用可能な昇温温度
は300℃程度であり、更に耐熱性の向上が強く望
まれている。
本発明はこれに鑑み種々研究の結果、従来の導
電用耐熱アルミニウム合金（Al−Zr系合金）と
同等の強度を有し、導電率をあまり低下させるこ
となく耐熱性を著しく改善した導電用耐熱アルミ
ニウム合金の製造法を開発したものである。
即ち、本発明はNi2.0〜5.7wt％、Fe0.1〜2.0wt
％、Be0.03〜1.0wt％を含み、残部Alと通常の不
純物からなるアルミニウム合金を、連続又は半連
続鋳造後、熱間圧延して荒引線とし、これを冷間
で伸縮加工した後、200〜500℃の温度で0.5〜10
時間加熱処理することを特徴とするものである。
しかして本発明において対象とする合金組成を
上記の如く限定したのは次の理由によるものであ
る。
Ni含有量を2.0〜5.7wt％（以下wt％を単に％
と略記）と限定したのは、Ni添加によりAlマト
リツクス中にNiAl3を分散させた共晶組織として
強度及び耐熱性を向上させるためであるが、含有
量が2.0％未満では強度及び耐熱性が不十分であ
り、5.7％を越えると、金属組織中に初晶NiAl3の
デンドライト相を晶出し、加工性を害するばかり
か延性を低下するためである。
Fe含有量を0.1〜2.0％と限定したのはNiを添加
しただけでもNiAl3の分散により強度及び耐熱性
は向上するも、Alマトリツクスは純Alであるた
め強度が不十分で、高強度とするためにはNi含
有量を多くする必要があり、このためFeを添加
してAlマトリツクスを強化させ、Ni含有量を減
少させても同強度が得られるようにしたものであ
り、Fe含有量が0.1％未満ではその効果が不十分
であり、2.0％を越えると導電率の低下が著しく
なるためである。
またBe含有量を0.03〜1.0％と限定したのはBe
の添加により耐食性を向上させたものであるが、
0.03％未満ではその効果が小さく、1.0％を越え
ると導電率の低下が著しくなるためである。
尚その他の不純物としては通常の電気用Al地
金に含まれるもので、この程度の不純物は合金の
特性を何等損なうことはない。
本発明において対象とする合金は以上の組成か
らなり通常の連続又は半連続鋳造により鋳造し、
得られた鋳塊を熱間圧延により荒引線とし、これ
を冷間で伸縮加工した後、200〜500℃の温度で
0.5〜10時間加熱処理することにより造られる。
冷間で伸縮加工後200〜500℃の温度で0.5〜10
時間加熱処理するのは、強度及び導電率を整える
と共に耐熱性を付与するためであり、処理温度が
200℃未満でも、処理時間が0.5時間未満でも導電
率が回復せず、特に処理時間が短いと耐熱性が改
善されない。また処理温度が500℃を越えても処
理時間が10時間を越えても強度の低下が大きくな
る。
以下本発明を実施例について詳細に説明する。
純度99.8％の電気用Al地金とAl−６％Fe、Al
−10％Ni、Al−５％Beの各母合金を用い、第１
表に示す組成の合金を配合、溶製した。これをベ
ルトアンドホイール型連続鋳造機により鋳造し、
得られた鋳塊を引き続き熱間圧延して直径9.5mm
の荒引線とした。この荒引線を冷間で伸縮加工し
直径4.5mmの線に仕上げ、これを種々の温度で加
熱処理して導体を製造した。
この導体について導電率、引張強さ、耐熱性及
び耐食性を測定した。これ等の結果を従来の導電
用耐熱アルミニウム合金（Al−Zr系合金）と比
較して第１表に併記した。
尚導電率はケルビンダブルブリツジにより抵抗
を測定して算出し、強度はアムスラー型試験機に
より測定した。耐熱性は１時間の加熱処理により
強度が10％低下する温度で表わした。また耐食性
は５％NaCl噴霧試験を100日間行ない、その重量
減少率で表わした。
The present invention relates to a method for manufacturing a heat-resistant aluminum alloy for conductive use, and in particular, has strength equivalent to that of conventional heat-resistant aluminum alloy for conductive use (Al-Zr alloy),
It has significantly improved heat resistance without significantly reducing conductivity. Traditionally, overhead power transmission lines use steel-core aluminum stranded wires with conductors made of electrical grade Al.
In particular, for power transmission lines that require heat resistance, steel-core heat-resistant aluminum alloy stranded wires are used that use conductors made of solid-solution type heat-resistant aluminum alloy that utilizes the heat-resistant mechanism of solid-solution Zr in Al-Zr alloys. . In recent years, there has been a demand for improved heat resistance due to the increasing demand for electricity, and in response to this demand, heat-resistant conductive aluminum alloys with increased amounts of solid solute Zr and heat-resistant mechanisms using precipitated Zr have replaced the heat-resistant mechanisms of solid-solute Zr. A heat-resistant aluminum alloy for conductive use has been developed. However, an increase in the amount of solid solution Zr leads to a decrease in electrical conductivity, and in order to take advantage of the heat resistance mechanism of precipitated Zr, long-term heat treatment is required at a temperature of 300 to 450°C, resulting in high costs. It was hot. Furthermore, the usable heating temperature of these alloys during conduction is approximately 300°C, and further improvement in heat resistance is strongly desired. In view of this, as a result of various researches, the present invention has been developed as a conductive heat-resistant aluminum alloy that has the same strength as conventional conductive heat-resistant aluminum alloys (Al-Zr alloys) and has significantly improved heat resistance without significantly reducing conductivity. This is a method for producing aluminum alloys. That is, in the present invention, Ni2.0~5.7wt%, Fe0.1~2.0wt%
After continuous or semi-continuous casting, an aluminum alloy containing 0.03 to 1.0 wt% Be and the balance Al and normal impurities is hot rolled into a rough drawn wire, which is then cold expanded and contracted. 0.5-10 at a temperature of 200-500℃
It is characterized by heat treatment for a period of time. However, the reason why the target alloy composition of the present invention is limited as described above is as follows. Ni content 2.0~5.7wt% (hereinafter wt% simply %
The reason for this limitation is to improve the strength and heat resistance as a eutectic structure in which NiAl3 is dispersed in the Al matrix by adding Ni, but if the content is less than 2.0%, the strength and heat resistance will decrease. This is insufficient, and if it exceeds 5.7%, a dendrite phase of primary crystal NiAl 3 will crystallize in the metal structure, which will not only impair workability but also reduce ductility. The reason for limiting the Fe content to 0.1 to 2.0% is that even if only Ni is added, the strength and heat resistance will improve due to the dispersion of NiAl3 , but since the Al matrix is pure Al, the strength will be insufficient, so it is difficult to achieve high strength. In order to achieve this, it is necessary to increase the Ni content, so Fe is added to strengthen the Al matrix so that the same strength can be obtained even if the Ni content is decreased. If it is less than 0.1%, the effect is insufficient, and if it exceeds 2.0%, the conductivity will decrease significantly. In addition, the Be content was limited to 0.03 to 1.0%.
Corrosion resistance has been improved by adding
This is because if it is less than 0.03%, the effect will be small, and if it exceeds 1.0%, the conductivity will decrease significantly. The other impurities are those contained in ordinary electrical Al ingots, and impurities of this level do not impair the properties of the alloy in any way. The alloy targeted in the present invention has the above composition and is cast by normal continuous or semi-continuous casting,
The obtained ingot is hot rolled into a rough drawing wire, which is then cold expanded and contracted and then heated at a temperature of 200 to 500℃.
Produced by heat treatment for 0.5 to 10 hours. 0.5-10 at a temperature of 200-500℃ after cold stretching processing
The purpose of heat treatment is to adjust the strength and conductivity as well as impart heat resistance, and the treatment temperature is
Even if the treatment time is less than 200°C or less than 0.5 hours, the conductivity does not recover, and especially if the treatment time is short, the heat resistance is not improved. Further, even if the treatment temperature exceeds 500°C or the treatment time exceeds 10 hours, the strength decreases significantly. The present invention will be described in detail below with reference to examples. 99.8% pure electrical Al ingot, Al-6% Fe, Al
-10%Ni, Al-5%Be mother alloys, the first
An alloy having the composition shown in the table was blended and melted. This is cast using a belt and wheel type continuous casting machine,
The obtained ingot was then hot rolled to a diameter of 9.5mm.
It was set as the rough line. This roughly drawn wire was cold expanded and contracted to form a wire with a diameter of 4.5 mm, which was then heat treated at various temperatures to produce conductors. The electrical conductivity, tensile strength, heat resistance, and corrosion resistance of this conductor were measured. These results are also listed in Table 1 in comparison with a conventional conductive heat-resistant aluminum alloy (Al-Zr alloy). The conductivity was calculated by measuring resistance using a Kelvin double bridge, and the strength was measured using an Amsler type tester. Heat resistance was expressed as the temperature at which the strength decreased by 10% after 1 hour of heat treatment. Corrosion resistance was measured by performing a 5% NaCl spray test for 100 days and expressing the weight loss rate.
【表】【table】
【表】
第１表から明らかなように本発明合金を本発明
法No.１〜４で製造した導体は導電率58.2％IACS
以上、引張強さ17.2Kg／mm2以上、10％軟化温度
500℃以上、重量減少率0.72％以下の特性を示し、
Al−Zr系合金を用いた従来法No.15と比較し、耐
熱性が著しく優れ、その他の特性はほとんど変わ
らない事が判る。
これに対し比較法No.５〜10から判るように、本
発明合金の組成範囲より外れるものでは導電率、
引張強さ、耐熱性、耐食性の何れかが劣る。即ち
Ni含有量の少ない比較法No.５では耐熱性が改善
されず、Ni含有量の多い比較法No.６、Fe含有量
の多い比較法No.８及びBe含有量の多い比較法No.
10では何れも導電率の低下が著しく、Fe含有量
の少ない比較法No.７では強度が改善されず、更に
Be含有量の少ない比較法No.９では耐食性が改善
されない。
また比較法No.11〜14から判るように本発明合金
の組成範囲内でも冷間伸線加工後の加熱処理条件
が異なると導電率、強度、耐熱性の何れかが劣
る。即ち加熱処理温度の比較法No.11では導電率が
回復せず、加熱処理温度の高い比較法No.12及び加
熱処理時間の長い比較法No.14では強度が劣化し、
加熱処理時間の短い比較法No.13では導電率、強度
及び耐熱性が劣つている。
このように本発明によれば従来の導電用耐熱ア
ルミニウム合金（Al−Zr系合金）と同等の強度
を有し、導電率をほとんぼ低下させることなく耐
熱性を大幅に改善し得るもので、鋼芯耐熱アルミ
ニウム合金撚線等の導体に使用し、送電容量を増
大し得る顕著な効果を奏するものである。[Table] As is clear from Table 1, the conductors manufactured using the alloy of the present invention by the method Nos. 1 to 4 of the present invention have a conductivity of 58.2% IACS.
or more, tensile strength 17.2Kg/ mm2 or more, 10% softening temperature
Exhibits characteristics of 500℃ or higher, weight loss rate of 0.72% or less,
Compared to conventional method No. 15 using Al-Zr alloy, it can be seen that the heat resistance is significantly superior, and other properties are almost unchanged. On the other hand, as can be seen from Comparative Methods Nos. 5 to 10, the conductivity of the alloys outside the composition range of the present invention alloys is
Poor in tensile strength, heat resistance, or corrosion resistance. That is,
Comparative method No. 5 with a low Ni content did not improve heat resistance, comparative method No. 6 with a high Ni content, comparative method No. 8 with a high Fe content, and comparative method No. 8 with a high Be content.
No. 10 showed a significant decrease in conductivity, and Comparative method No. 7, which had a low Fe content, did not improve the strength.
Comparative method No. 9, which has a low Be content, does not improve corrosion resistance. Furthermore, as can be seen from Comparative Method Nos. 11 to 14, even within the composition range of the alloy of the present invention, if the heat treatment conditions after cold wire drawing are different, any of the conductivity, strength, and heat resistance will be inferior. In other words, the conductivity did not recover with Comparative Method No. 11, which had a higher heat treatment temperature, and the strength deteriorated with Comparative Method No. 12, which had a higher heat treatment temperature, and Comparative Method No. 14, which had a longer heat treatment time.
Comparative method No. 13, which requires a short heat treatment time, is inferior in conductivity, strength, and heat resistance. As described above, the present invention has strength equivalent to that of conventional heat-resistant aluminum alloys for conductivity (Al-Zr alloys), and can significantly improve heat resistance without substantially reducing conductivity. It is used in conductors such as steel-core heat-resistant aluminum alloy stranded wires, and has the remarkable effect of increasing power transmission capacity.