【発明の詳細な説明】[Detailed description of the invention]
本発明は、電磁撹拌装置を設置した鋼等の連続
鋳造に用いる鋳型の材料として好適な諸性質を備
えた新規な銅合金材料に関する。
最近、鋼の連続鋳造法に電磁撹拌法が広く採用
されつつあり、鋳塊の品質改善及び高級鋼の連続
鋳造をも可能にしている。
しかし従来の鋼等の連続鋳造法に用いる鋳型材
は電気伝導率が100〜80%の高伝導率の鋳型材で
あるため、電磁撹拌装置を設置した場合、高電気
伝導率により渦電流損が生じ、このため磁力の減
衰が大きく、鋳型内溶鋼へ作用する撹拌効果が低
減される欠点があつた。
このため従来より、電磁撹拌装置を設置した鋼
等の連続鋳造において、従来の鋳型材としての要
求特性である高温強度,高温伸びを具備し、しか
も使用条件によつては電気伝導率が30〜15%
IACSの低電気伝導率鋳型材を要求されることが
ある。
本発明者等は、このような実情に鑑み、電気伝
導率を30〜15%IACSの低さに特定すると共に、
従来の析出硬化型材料であるクロム銅と比較して
も、優れた高温強度および高温伸びを有する高靭
性の鋳型材料を開発すべく鋭意研究している者で
ある。
そして先行するこの種鋳型材料(特願昭56―
182371号発明)の化学組成範囲(Cr:0.2〜1.0
%,Zr:0.1〜0.3%,Al:2.0〜4.0%,残りCuお
よび不可避不純物)を越えた組成範囲であつて
も、上記の目的を達成し得ることを見い出したの
である。
即ち、重量比でCr:0.3〜1.5%,Zr:0.03〜0.6
%,Al:2.0〜5.0%および残部Cuより構成された
銅合金材料であつて、この銅合金材料に溶体化お
よび時効の熱処理を与えて、電気伝導率が30〜15
%IACSの低電気伝導率でしかも従来の析出硬化
型材料であるクロム銅と比較して、優れた高温強
度・高温伸びを有する高靭性を具備させることが
できたものである。
従つて、本願発明鋳型材料は、上記先行鋳型材
料の組成範囲外であつて、重量比でCr:1.1〜1.5
%,Zr:0.03〜0.6%,Al:2.0〜5.0%および残部
Cuより構成された銅合金材料であつて、電気伝
導率が30〜15%IACSの低電気伝導率でかつ高強
度・高温靭性を具備させた析出硬化型連続鋳造用
鋳型材料をその要旨とするものである。
本願発明材料の組成成分のうち、Crは高温強
度の上昇を目的に添加され、0.3%以下ではその
効果が小さく、また1.5%以上では添加量の割に
は高温強度上昇の効果が少なく、逆に溶湯酸化が
激しく鋳造性を悪くしてしまう。
Zrは再結晶粒の微細化と高温強度の上昇およ
び高温伸びを改善するために添加されるが、0.03
%以下ではその効果が小さく、また0.6%以上で
は添加量の割には効果の向上が少ないうえ、やは
り溶湯酸化が激しくなり、鋳造性が著しく悪くな
る。
Alは電気伝導率を小さくすることを目的とし
てまた高温伸びを改善する目的で添加されるが、
電気伝導率を所望する30〜15%IACSにするため
には添加量が2.0%以下ではその効果が小さく、
また5.0%以上では添加量の割には電気伝導率が
15%IACSより小さくならないばかりか、かえつ
て高温脆性を生じる欠点がある。
上記本発明組成の銅合金材料を鍛造後に、960
±20℃×0.5Hr水冷で溶体化処理、および500±
50℃×2Hr空冷で時効処理したものは、30〜15%
IACSの低い電気伝導率を示し、さらに従来のク
ロム銅よりも優れた高強度・高温靭性を示した。
従つて本発明材料は、電磁撹拌装置を設置した鋼
等の連続鋳造用鋳型材料としては好適なものであ
る。
次に、本発明組成をもつ銅合金材料の実施例を
挙げ、同時に従来の析出硬化型材料であるクロム
銅を比較例として挙げ、それぞれについて900℃
で鍛造後、960℃×0.5Hr水冷で溶体化処理し、
500℃×2Hr空冷で時効処理したものの電気伝導
率(%IACS)について試験した。その結果は次
の表に示す通りである。
The present invention relates to a novel copper alloy material having various properties suitable as a material for a mold used in continuous casting of steel or the like equipped with an electromagnetic stirring device. In recent years, the electromagnetic stirring method has been widely adopted as a continuous casting method for steel, making it possible to improve the quality of ingots and to continuously cast high-grade steel. However, the mold material used in the conventional continuous casting method for steel etc. has a high electrical conductivity of 100-80%, so when an electromagnetic stirring device is installed, the high electrical conductivity causes eddy current loss. Therefore, there was a drawback that the magnetic force was greatly attenuated and the stirring effect acting on the molten steel in the mold was reduced. For this reason, in the continuous casting of steel and other materials equipped with an electromagnetic stirring device, it has been possible to achieve high-temperature strength and high-temperature elongation, which are the characteristics required for conventional mold materials, and also to have an electrical conductivity of 30 to 30, depending on the usage conditions. 15%
IACS low electrical conductivity mold material may be required. In view of these circumstances, the present inventors specified the electrical conductivity to be as low as 30 to 15% IACS, and
He is conducting intensive research to develop a mold material with high toughness that has superior high-temperature strength and elongation when compared to chromium copper, a conventional precipitation-hardening material. And this type of mold material (patent application 1986--
182371 invention) chemical composition range (Cr: 0.2 to 1.0
%, Zr: 0.1 to 0.3%, Al: 2.0 to 4.0%, remaining Cu and unavoidable impurities). That is, Cr: 0.3-1.5%, Zr: 0.03-0.6 in weight ratio
%, Al: 2.0 to 5.0% and the balance is Cu, and this copper alloy material is subjected to solution heat treatment and aging to have an electrical conductivity of 30 to 15%.
%IACS, which has a low electrical conductivity, and has high toughness with excellent high temperature strength and elongation compared to chromium copper, which is a conventional precipitation hardening material. Therefore, the mold material of the present invention is outside the composition range of the preceding mold material, and has a weight ratio of Cr: 1.1 to 1.5.
%, Zr: 0.03-0.6%, Al: 2.0-5.0% and balance
Its gist is a copper alloy material composed of Cu, with a low electrical conductivity of 30 to 15% IACS, high strength and high temperature toughness, and a precipitation hardening mold material for continuous casting. It is something. Among the compositional components of the material of the present invention, Cr is added for the purpose of increasing high-temperature strength, and if it is less than 0.3%, the effect is small, and if it is more than 1.5%, the effect of increasing high-temperature strength is small, and vice versa. The molten metal oxidizes violently and deteriorates castability. Zr is added to refine recrystallized grains, increase high-temperature strength, and improve high-temperature elongation, but 0.03
If it is less than 0.6%, the effect will be small, and if it is more than 0.6%, the effect will not improve much compared to the amount added, and the oxidation of the molten metal will become severe, resulting in significantly poor castability. Al is added for the purpose of reducing electrical conductivity and improving high temperature elongation, but
In order to achieve the desired electrical conductivity of 30 to 15% IACS, the effect will be small if the amount added is less than 2.0%.
In addition, if it exceeds 5.0%, the electrical conductivity will be low compared to the amount added.
Not only is it not smaller than 15% IACS, it also has the disadvantage of causing high-temperature brittleness. After forging the above-mentioned copper alloy material having the composition of the present invention, 960
±20℃×0.5Hr water cooling solution treatment and 500±
30-15% for those aged at 50℃ x 2 hours air cooling
It exhibited low electrical conductivity of IACS, and also exhibited high strength and high temperature toughness superior to conventional chromium copper.
Therefore, the material of the present invention is suitable as a mold material for continuous casting of steel or the like equipped with an electromagnetic stirring device. Next, examples of copper alloy materials having the composition of the present invention are listed, and at the same time, chromium copper, which is a conventional precipitation hardening type material, is listed as a comparative example.
After forging at 960℃ x 0.5Hr water cooling,
The electrical conductivity (%IACS) of the material that had been aged at 500°C and air-cooled for 2 hours was tested. The results are shown in the table below.
【表】
また、上記実施例,,および比較例の常
温から500℃における高温引張強さ,高温耐力,
高温伸びの試験結果は、第1図ないし第3図に示
す通りであつた。
上記表および第1図ないし第3図から明らかな
ように、本願発明銅合金材料は従来のクロム銅に
比べ、電気伝導率が所望する低電気伝導率30〜15
%IACSにまで小さくなるのみならず、常温から
500℃までの高温でクロム銅よりもさらに強度が
大きくかつ高い伸びを備えた靭性の高い材料であ
ることがわかる。[Table] In addition, the high temperature tensile strength, high temperature yield strength, and
The high temperature elongation test results were as shown in Figures 1 to 3. As is clear from the above table and FIGS. 1 to 3, the copper alloy material of the present invention has a desired low electrical conductivity of 30 to 15, compared to conventional chromium copper.
%IACS, but also from room temperature.
It can be seen that it is a highly tough material with greater strength and elongation than chromium copper at high temperatures up to 500℃.
【図面の簡単な説明】[Brief explanation of the drawing]
第1図ないし第3図はそれぞれ実施例,,
と比較例の常温から500℃における高温引張強
さ,高温耐力,高温伸びの試験結果を示す図。
Figures 1 to 3 are examples, respectively.
A diagram showing the test results of high-temperature tensile strength, high-temperature yield strength, and high-temperature elongation from room temperature to 500°C for Comparative Example.