JP3416503B2 - Hypereutectic Al-Si alloy die casting member and method of manufacturing the same - Google Patents
Hypereutectic Al-Si alloy die casting member and method of manufacturing the sameInfo
- Publication number
- JP3416503B2 JP3416503B2 JP03154898A JP3154898A JP3416503B2 JP 3416503 B2 JP3416503 B2 JP 3416503B2 JP 03154898 A JP03154898 A JP 03154898A JP 3154898 A JP3154898 A JP 3154898A JP 3416503 B2 JP3416503 B2 JP 3416503B2
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- Prior art keywords
- alloy
- hypereutectic
- sleeve
- primary crystal
- temperature
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- Cylinder Crankcases Of Internal Combustion Engines (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、耐摩耗性に優れた過共
晶Ａｌ−Ｓｉ合金ダイカスト部材及びその製造方法に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hypereutectic Al-Si alloy die casting member having excellent wear resistance and a method for producing the same.
【０００２】[0002]
【従来の技術】過共晶Ａｌ−Ｓｉ合金のダイカスト鋳造
に際しては、溶湯保持温度及び射出温度を可能な限り高
温にし、且つスリーブ内充填率も可能な限り高く設定す
ることにより、スリーブ内で凝固が始まらないうちにダ
イカスト鋳造する方法が一般的である。この方法による
とき、溶湯の全量が金型キャビティ内で急速凝固するた
め、初晶Ｓｉ粒も含めて極めて微細な鋳造組織となる。
微細な組織は、加工性，機械強度等に対しては有効であ
るが、耐摩耗性を低下させる傾向を示す。過共晶Ａｌ−
Ｓｉ合金部材に高い耐摩耗性を付与するためには、適度
な粒径をもつ初晶Ｓｉを十分な密度で分散させることが
要求される。そのため、たとえば高い耐摩耗性が必要と
されるダイカスト部材では、１８重量％ＳｉのようにＳ
ｉ含有量が非常に高い材料が使用されている。また、加
工性や強度特性を確保する上から比較的低いＳｉ含有量
の材料を使用する場合、初晶Ｓｉを成長させるため、ダ
イカスト鋳造に比較して凝固速度の遅い金型鋳造や低圧
鋳造が余儀なくされていた。2. Description of the Related Art In die casting of hypereutectic Al-Si alloy, the temperature of molten metal holding and injection is set as high as possible and the filling rate in the sleeve is set as high as possible to solidify in the sleeve. The method of die casting before the start of the process is common. According to this method, the entire amount of the molten metal is rapidly solidified in the mold cavity, so that an extremely fine cast structure including primary crystal Si grains is formed.
A fine structure is effective for workability, mechanical strength, etc., but tends to reduce wear resistance. Hypereutectic Al-
In order to impart high wear resistance to a Si alloy member, it is necessary to disperse primary crystal Si having an appropriate grain size at a sufficient density. Therefore, for example, in a die cast member that requires high wear resistance, S
A material with a very high i content is used. Also, when using a material with a relatively low Si content in order to secure workability and strength characteristics, in order to grow primary crystal Si, die casting or low pressure casting with a slower solidification rate compared to die casting can be used. Had to be forced.
【０００３】[0003]
【発明が解決しようとする課題】過共晶Ａｌ−Ｓｉ合金
の融点は、Ｓｉ含有量に応じて高くなり、たとえばＳｉ
含有量１８重量％で６５８℃となる。このように融点の
高い過共晶Ａｌ−Ｓｉ合金をダイカスト鋳造で使用する
とき必然的に溶湯温度が高くなり、エネルギ消費量が多
くなるばかりでなく、金型等の設備寿命が著しく低下
し、メンテナンスに要するコストも嵩んでしまう。しか
も、初晶Ｓｉの粒径を所定範囲にコントロールすること
が難しく、材料に含まれているＳｉ量の極く一部が耐摩
耗性に有効な粒径になるに過ぎないため、材料が潜在的
にもつ耐摩耗特性を十分に引き出されていない。他方、
凝固速度の遅い金型鋳造や低圧鋳造では、初晶Ｓｉ粒の
成長及び粒径コントロールが容易であるため、Ｓｉ含有
量が比較的低い材料に対しても良好な耐摩耗性が付与さ
れる。しかし、凝固速度の遅い金型鋳造や低圧鋳造は、
ダイカスト鋳造に比較して生産性が低く、得られた製品
のコストがその分だけ高くなる。本発明は、このような
問題を解消すべく案出されたものであり、ダイカストス
リーブ内で初晶Ｓｉ粒が晶出・成長する条件に過共晶Ａ
ｌ−Ｓｉ合金溶湯を保持することにより、Ｓｉ含有量が
比較的低い過共晶Ａｌ−Ｓｉ合金であってもダイカスト
鋳造法で耐摩耗性に有効なサイズの初晶Ｓｉ粒を晶出さ
せ、耐摩耗性に優れた過共晶Ａｌ−Ｓｉ合金ダイカスト
部材を得ることを目的とする。The melting point of a hypereutectic Al-Si alloy increases with the Si content.
It becomes 658 ° C. when the content is 18% by weight. When using a hypereutectic Al-Si alloy with a high melting point in this way in die casting, the melt temperature inevitably rises, not only the energy consumption increases, but also the equipment life of the mold and the like significantly decreases, The cost required for maintenance also increases. Moreover, it is difficult to control the grain size of the primary crystal Si within a predetermined range, and only a small part of the Si amount contained in the material has a grain size effective for wear resistance. The wear resistance characteristic of conventional materials is not fully exploited. On the other hand,
In die casting or low pressure casting with a slow solidification rate, it is easy to grow and control the grain size of primary Si grains, so that good wear resistance can be imparted even to a material having a relatively low Si content. However, die casting and low pressure casting with slow solidification rate
The productivity is lower than that of die casting, and the cost of the obtained product is correspondingly higher. The present invention has been devised to solve such a problem, and the hypereutectic crystal A is formed under the condition that primary crystal Si grains crystallize and grow in the die casting sleeve.
By holding the 1-Si alloy molten metal, even the hypereutectic Al-Si alloy having a relatively low Si content crystallizes primary crystal Si particles of a size effective for wear resistance by the die casting method, It is an object to obtain a hypereutectic Al-Si alloy die-cast member having excellent wear resistance.
【０００４】[0004]
【課題を解決するための手段】本発明の製造方法は、そ
の目的を達成するため、１４〜１７重量％のＳｉを含有
するアルミニウム合金溶湯を充填率２０〜４０体積％で
ダイカストスリーブに注湯し、次いでダイカストスリー
ブ内でアルミニウム合金溶湯を初晶Ｓｉ晶出温度と共晶
温度との間の温度範囲で２〜５秒保持して初晶Ｓｉを晶
出・成長させた後、アルミニウム合金溶湯を射出成形す
ることにより鋳造組織に晶出した初晶Ｓｉの平均粒径を
７〜１５μｍの範囲に調整することを特徴とする。使用
するアルミニウム合金は、初晶Ｓｉの晶出を促進させる
ため更に０．００１〜０．０２重量％のＰを含むことが
できる。In order to achieve the object, the manufacturing method of the present invention is to pour a molten aluminum alloy containing 14 to 17% by weight of Si into a die casting sleeve at a filling rate of 20 to 40% by volume. Then, the aluminum alloy melt is held in the die casting sleeve in the temperature range between the primary crystal Si crystallization temperature and the eutectic temperature for 2 to 5 seconds to crystallize and grow the primary crystal Si. Is injection-molded to adjust the average grain size of the primary crystal Si crystallized in the cast structure to a range of 7 to 15 μm. The aluminum alloy used may further contain 0.001 to 0.02% by weight of P in order to promote crystallization of primary Si.
【０００５】[0005]
【実施の形態】本発明が対象とする過共晶Ａｌ−Ｓｉ合
金は、１４〜１７重量％のＳｉを含んでいる。１４重量
％以上のＳｉ含有量は、初晶Ｓｉとして晶出するＳｉ量
を確保するために必要である。Ｓｉ含有量が１４重量％
未満では、初晶Ｓｉの晶出に必要なＳｉ量が不足し、耐
摩耗性の改善に有効なサイズ及び分布密度で初晶Ｓｉを
晶出させることができない。逆に、１７重量％を超える
過剰のＳｉが含まれると、加工性及び疲労強度が劣化す
るため、得られたダイカスト部材の実用性が低下する。
この過共晶Ａｌ−Ｓｉ合金に、０．００１〜０．０２重
量％のＰを更に含ませても良い。Ｐは、初晶Ｓｉが晶出
するときのシードとなる異質核を合金溶湯中に生成し、
初晶Ｓｉの晶出を促進させる。このような効果は、０．
００１重量％以上のＰ含有で顕著になる。Ｐ添加の効果
は０．０２重量％で飽和し、それ以上添加しても増量に
見合った効果が得られない。BEST MODE FOR CARRYING OUT THE INVENTION The hypereutectic Al-Si alloy targeted by the present invention contains 14 to 17% by weight of Si. The Si content of 14% by weight or more is necessary to secure the amount of Si crystallized as primary crystal Si. Si content 14% by weight
If the amount is less than the range, the amount of Si required for crystallization of primary crystal Si is insufficient, and primary crystal Si cannot be crystallized with a size and distribution density effective for improving wear resistance. On the other hand, if Si is contained in excess of 17% by weight, the workability and the fatigue strength are deteriorated and the practicality of the obtained die cast member is reduced.
The hypereutectic Al-Si alloy may further contain 0.001 to 0.02% by weight of P. P forms a heterogeneous nucleus in the molten alloy that serves as a seed when the primary crystal Si crystallizes,
Promotes crystallization of primary Si. Such an effect is 0.
It becomes remarkable when the P content is 001% by weight or more. The effect of P addition is saturated at 0.02% by weight, and even if it is added more, the effect corresponding to the increase in amount cannot be obtained.
【０００６】過共晶Ａｌ−Ｓｉ合金溶湯は、図１に示す
ように手元炉からレードル１を経てダイカスト鋳造機の
スリーブ２に注湯された後、プランジャ３によって金型
４内に射出される。金型４の内部には、製品形状に対応
したキャビティ５が設けられている。キャビティ５に充
填された過共晶Ａｌ−Ｓｉ合金溶湯が金型４の内面形状
を倣って凝固することにより、目標形状をもつ製品とな
る。スリーブ２に注湯された過共晶Ａｌ−Ｓｉ合金溶湯
は、初晶Ｓｉ晶出温度と共晶温度との間の温度範囲で２
〜５秒保持される。初晶Ｓｉ晶出温度は、図２に示すよ
うに溶湯のＳｉ含有量に応じて基本的に定まる。他の合
金成分によっても多少変動するが、この場合には合金成
分によって定まる初晶Ｓｉ晶出温度と合金成分によって
はほとんど変化しない共晶温度（約５７７℃）との関係
を考慮しながら、初晶Ｓｉ晶出温度と共晶温度との間に
保持温度を設定する。As shown in FIG. 1, a hypereutectic Al-Si alloy melt is poured from a hand furnace through a ladle 1 into a sleeve 2 of a die casting machine, and then injected into a mold 4 by a plunger 3. . A cavity 5 corresponding to the product shape is provided inside the mold 4. The hypereutectic Al—Si alloy molten metal filled in the cavity 5 is solidified by following the inner surface shape of the mold 4 to obtain a product having a target shape. The hypereutectic Al-Si alloy melt poured into the sleeve 2 has a temperature range of between the primary crystal Si crystallization temperature and the eutectic temperature.
Hold for ~ 5 seconds. The primary crystal Si crystallization temperature is basically determined according to the Si content of the molten metal as shown in FIG. Although it may fluctuate to some extent depending on other alloy components, in this case, considering the relationship between the primary crystallized Si crystallization temperature determined by the alloy component and the eutectic temperature (about 577 ° C) that hardly changes depending on the alloy component, A holding temperature is set between the crystallizing Si crystallization temperature and the eutectic temperature.
【０００７】過共晶Ａｌ−Ｓｉ合金溶湯を初晶Ｓｉ晶出
温度以下に維持するとき、スリーブ２内にある過共晶Ａ
ｌ−Ｓｉ合金溶湯に初晶Ｓｉが晶出し始める。この状態
を２〜５秒継続させることによって、晶出した初晶Ｓｉ
が耐摩耗性の改善に有効な適正粒径に成長する。晶出し
た初晶Ｓｉの粒径や量は、スリーブ２内で保持される過
共晶Ａｌ−Ｓｉ合金溶湯の温度及び保持時間によって調
整される。２秒に満たない保持時間では、平均粒径７μ
ｍ以上の初晶Ｓｉが少なく、得られるダイカスト部材に
十分な耐摩耗性を付与できない。逆に５秒を超える保持
時間では、平均粒径が１５μｍを超え、粗大な初晶Ｓｉ
粒が多くなり、結果として摺動時に割れて耐摩耗性に悪
影響を与え、或いは切削加工時等に切欠き発生等の欠陥
を発生させ、またダイカスト部材の強度を低下させるこ
とになる。また、５秒を超える保持時間では、スリーブ
２の入口近傍にある合金溶湯が共晶温度付近まで低下
し、スリーブ２の内壁面にα−Ａｌが凝固し易く、操業
ができなくなる虞れがある。When the hypereutectic Al-Si alloy melt is maintained below the primary Si crystallization temperature, the hypereutectic A in the sleeve 2 is kept.
Primary crystal Si begins to crystallize in the molten 1-Si alloy. By continuing this state for 2 to 5 seconds, crystallized primary crystal Si
Grows to an appropriate grain size effective for improving wear resistance. The grain size and amount of the crystallized primary crystal Si are adjusted by the temperature and holding time of the hypereutectic Al—Si alloy molten metal held in the sleeve 2. If the holding time is less than 2 seconds, the average particle size is 7μ
Since the amount of primary crystal Si of m or more is small, sufficient wear resistance cannot be imparted to the obtained die cast member. On the contrary, when the holding time exceeds 5 seconds, the average grain size exceeds 15 μm, and coarse primary crystal Si
The number of grains increases, resulting in cracking during sliding, which adversely affects wear resistance, or causes defects such as the occurrence of notches during cutting, etc., and also reduces the strength of the die casting member. Further, if the holding time exceeds 5 seconds, the molten alloy in the vicinity of the inlet of the sleeve 2 is lowered to near the eutectic temperature, and α-Al is likely to be solidified on the inner wall surface of the sleeve 2, which may make the operation impossible. .
【０００８】Ｓｉ含有量が１４〜１７重量％と比較的低
い過共晶Ａｌ−Ｓｉ合金であっても、図２に示すように
比較的高い温度から初晶Ｓｉの晶出が始まるため、初晶
Ｓｉ晶出温度と共晶温度との間に過共晶Ａｌ−Ｓｉ合金
溶湯をスリーブ２内で保持するとき、初晶Ｓｉが十分に
晶出・成長する。ただし、スリーブ２内で凝固が始まら
ないように、過共晶Ａｌ−Ｓｉ合金溶湯を共晶温度以上
の温度に維持することが必要である。スリーブ２に対す
る過共晶Ａｌ−Ｓｉ合金溶湯の充填率は、共晶凝固を起
こすことなく初晶Ｓｉを晶出・成長させるために２０〜
４０体積％の範囲で選定することが必要である。Even in a hypereutectic Al--Si alloy having a relatively low Si content of 14 to 17% by weight, crystallization of primary Si begins at a relatively high temperature as shown in FIG. When the hypereutectic Al—Si alloy molten metal is held in the sleeve 2 between the crystal Si crystallization temperature and the eutectic temperature, the primary crystal Si crystallizes and grows sufficiently. However, it is necessary to maintain the hypereutectic Al-Si alloy melt at a temperature equal to or higher than the eutectic temperature so that solidification does not start in the sleeve 2. The filling rate of the hypereutectic Al-Si alloy melt with respect to the sleeve 2 is 20 to 20 in order to crystallize and grow primary Si without causing eutectic solidification.
It is necessary to select in the range of 40% by volume.
【０００９】スリーブ２に充填された過共晶Ａｌ−Ｓｉ
合金溶湯６は、図３に示すようにスリーブ２の側壁を介
した熱放散によって冷却され、スリーブ２の内面に近い
ほど大きな冷却効果を受ける。そのため、高い充填率で
充填された合金溶湯６では中心部とスリーブ２の近傍と
の温度差が大きくなり、スリーブ２近傍では初晶Ｓｉが
晶出・成長するが、中心部では初晶Ｓｉの晶出がない状
態となる。このような合金溶湯６を金型４に射出して鋳
造すると、得られたダイカスト部材は微細Ｓｉ粒及び粗
大Ｓｉ粒が混在した鋳造組織をもち、耐摩耗性の改善に
有効な粒径，分布密度のＳｉ粒が得られない。Hypereutectic Al-Si filled in the sleeve 2
The molten alloy 6 is cooled by heat dissipation through the side wall of the sleeve 2 as shown in FIG. 3, and the greater the cooling effect is, the closer the inner surface of the sleeve 2 is. Therefore, in the molten alloy 6 filled with a high filling rate, the temperature difference between the central portion and the vicinity of the sleeve 2 becomes large, and primary crystal Si crystallizes and grows near the sleeve 2, but the primary crystal Si does not grow. There is no crystallization. When such a molten alloy 6 is injected into the die 4 and cast, the die-cast member obtained has a casting structure in which fine Si particles and coarse Si particles are mixed, and the particle size and distribution effective in improving wear resistance are obtained. Si particles of high density cannot be obtained.
【００１０】この点、スリーブ２に対する合金溶湯６の
充填率を４０体積％以下にするとき、合金溶湯６内部の
温度差が小さくなり、初晶Ｓｉの晶出・成長が合金溶湯
６の全域に渡って均一化される。また、４０体積％を超
える充填率でスリーブ２に合金溶湯６を注湯する場合、
注湯温度を下げてスリーブ２内にある合金溶湯６の全量
を初晶晶出温度以下に冷却しようとすると、スリーブ２
に接している部分の溶湯温度が共晶温度以下になり易
く、初晶Ｓｉ晶出温度〜共晶温度の温度域に合金溶湯６
を維持することが困難になる。部分的にも共晶温度以下
になった合金溶湯６を金型４に射出すると、健全なダイ
カスト部材が得られない。逆に２０体積％に満たない充
填率で合金溶湯６をスリーブ２に充填する場合、合金溶
湯６が持つ熱量が不足し、スリーブ２に注湯された合金
溶湯６がスリーブ２内で共晶凝固することなく初晶Ｓｉ
を合金溶湯６に晶出させることが困難になる。その結
果、得られたダイカスト部材の強度が低下する。In this respect, when the filling rate of the molten alloy 6 in the sleeve 2 is set to 40% by volume or less, the temperature difference inside the molten alloy 6 becomes small, and the crystallization / growth of the primary crystal Si spreads throughout the molten alloy 6. Is homogenized across. When pouring the molten alloy 6 into the sleeve 2 at a filling rate of more than 40% by volume,
If it is attempted to lower the pouring temperature to cool the total amount of the molten alloy 6 in the sleeve 2 to below the primary crystallization temperature, the sleeve 2
The temperature of the molten metal in the portion in contact with the eutectic temperature is likely to be lower than the eutectic temperature, and the molten alloy 6 falls within the temperature range from the primary crystal crystallization temperature to the eutectic temperature.
Becomes difficult to maintain. If the molten alloy 6 which is partially below the eutectic temperature is injected into the die 4, a sound die casting member cannot be obtained. Conversely, when the sleeve 2 is filled with the molten alloy 6 at a filling rate of less than 20% by volume, the amount of heat of the molten alloy 6 is insufficient, and the molten alloy 6 poured into the sleeve 2 is eutectic solidified in the sleeve 2. Without primary crystal Si
It becomes difficult to crystallize the molten alloy 6 into the molten alloy 6. As a result, the strength of the obtained die casting member is reduced.
【００１１】[0011]
【実施例】本実施例で使用した過共晶Ａｌ−Ｓｉ合金の
組成を表１に示す。合金番号１は本発明で規定したＳｉ
含有量の下限近傍の量でＳｉを含む材料であり、合金番
号３はダイカスト鋳造で初晶Ｓｉの晶出によって耐摩耗
性の改善が図られる従来材の下限近傍に当る量のＳｉを
含む材料である。EXAMPLES Table 1 shows the composition of the hypereutectic Al-Si alloy used in this example. Alloy No. 1 is Si specified in the present invention
A material containing Si in an amount near the lower limit of the content, and Alloy No. 3 is a material containing Si in an amount close to the lower limit of the conventional material in which wear resistance is improved by crystallization of primary crystal Si in die casting. Is.
【００１２】 [0012]
【００１３】合金番号１〜３の各溶湯を用意し、表２の
鋳造条件でダイカスト部材を製造した。鋳造条件１及び
２は、本発明で規定したスリーブ２に対する合金溶湯６
の充填率の上限及び下限近傍に充填率を設定した例であ
る。鋳造条件３は、本発明で規定した充填率を超える充
填率で合金溶湯６をスリーブ２に充填し、従来の鋳造条
件に従って鋳造した例である。Molten alloys Nos. 1 to 3 were prepared and die-cast members were manufactured under the casting conditions shown in Table 2. The casting conditions 1 and 2 are the molten alloy 6 for the sleeve 2 defined in the present invention.
In this example, the filling rate is set near the upper and lower limits of the filling rate. Casting condition 3 is an example of filling the sleeve 2 with the molten alloy 6 at a filling rate exceeding the filling rate specified in the present invention, and casting according to the conventional casting conditions.
【００１４】 [0014]
【００１５】合金番号２の過共晶Ａｌ−Ｓｉ合金溶湯を
鋳造条件２に従って鋳造したときの溶湯温度の変化を図
４に示す。なお、図１に示すように下部壁から１０ｍｍ
の高さでスリーブ２内の測定点Ｔ1 ，Ｔ2 に配置された
複数の温度計でスリーブ２に充填された合金溶湯６を温
度測定することにより、スリーブ２中心部及び入口部の
溶湯温度を求めた。溶湯温度の変化を示す図４から明ら
かなように、スリーブ２に合金溶湯６を注湯した直後か
ら溶湯中心部（測定点Ｔ2 ）で初晶Ｓｉの晶出が開始さ
れ、注湯後２秒経過した時点ではスリーブ２の入口付近
（測定点Ｔ1 ）でも初晶Ｓｉの晶出が開始され、スリー
ブ２内にある合金溶湯６の全域に渡って初晶Ｓｉが晶出
した。この場合、スリーブ２の中心部（測定点Ｔ2 ）に
おける溶湯温度が初晶Ｓｉ晶出温度以下になった時点か
ら射出時間までを保持時間とし、図４の例では合金溶湯
６をスリーブ２内で３秒間保持した。鋳造条件１では、
保持時間を２秒に設定し、晶出温度以下になった合金溶
湯６を金型４に射出した。鋳造条件３では、実質的な保
持時間を取ることなく、スリーブ２に注湯した合金溶湯
６を直ちに金型４に射出した。このようにして鋳造され
たダイカスト部材について、光学顕微鏡を備えた画像解
析装置を用い初晶Ｓｉの平均粒径を測定した。FIG. 4 shows changes in the melt temperature when the hypereutectic Al--Si alloy melt of Alloy No. 2 was cast under the casting conditions 2. In addition, as shown in FIG. 1, 10 mm from the lower wall
Measurement point T 1 of the sleeve 2 at the height of, by temperature measuring molten alloy 6 which are filled into the sleeve 2 by a plurality of thermometers disposed in T 2, the melt temperature of the second central portion and the inlet portion the sleeve I asked. As is clear from FIG. 4 showing the change in the melt temperature, crystallization of primary crystal Si starts at the center of the melt (measurement point T 2 ) immediately after pouring the alloy melt 6 into the sleeve 2 and after pouring 2 After a lapse of seconds, crystallization of primary crystal Si was started even near the inlet of the sleeve 2 (measurement point T 1 ), and primary crystal Si was crystallized over the entire area of the molten alloy 6 in the sleeve 2. In this case, the holding time is from the time when the temperature of the molten metal at the central portion (measurement point T 2 ) of the sleeve 2 becomes equal to or lower than the primary crystal crystallization temperature to the injection time, and in the example of FIG. Held for 3 seconds. In casting condition 1,
The holding time was set to 2 seconds, and the molten alloy 6 having a crystallization temperature or lower was injected into the mold 4. Under casting condition 3, the alloy melt 6 poured into the sleeve 2 was immediately injected into the mold 4 without taking a substantial holding time. With respect to the die-cast member thus cast, the average grain size of primary crystal Si was measured by using an image analyzer equipped with an optical microscope.
【００１６】 [0016]
【００１７】表３から明らかなように、合金成分及び鋳
造条件が本発明で規定した条件を満足するものでは、何
れも平均粒径が７〜１５μｍの範囲にある初晶Ｓｉが晶
出した鋳造組織になっていた。これに対し、スリーブ２
に注湯した合金溶湯６を直ちに金型４に射出する鋳造条
件３では、金型４内で合金溶湯６が急冷凝固されるた
め、平均粒径４〜６μｍの微細な初晶Ｓｉが晶出した。
また、Ｓｉ含有量の多い合金番号３の過共晶Ａｌ−Ｓｉ
合金をスリーブ２内で初晶Ｓｉ晶出温度と共晶温度との
間に２秒間保持したところ、平均粒径が１６μｍと初晶
Ｓｉが大きく成長した。As is apparent from Table 3, when the alloy components and the casting conditions satisfy the conditions specified in the present invention, casting in which primary crystal Si having an average grain size in the range of 7 to 15 μm is crystallized It was an organization. On the other hand, the sleeve 2
In casting condition 3 in which the molten alloy 6 poured into the mold is immediately injected into the mold 4, the molten alloy 6 is rapidly solidified in the mold 4, so that fine primary crystal Si having an average particle size of 4 to 6 μm is crystallized. did.
Further, the hypereutectic Al-Si alloy No. 3 having a high Si content is used.
When the alloy was held in the sleeve 2 between the crystallization temperature of primary Si and the eutectic temperature for 2 seconds, the average grain size was 16 μm and primary Si grew greatly.
【００１８】次いで、鋳造条件１，２で鋳造された各ダ
イカスト部材をプレート状に加工し、リング・オン・プ
レート式の摩擦摩耗試験に供した。摩擦摩耗試験では、
相手材としてリング状のクロム鋼を用い、プレート状試
験片を面圧１８ＭＰａで相手材に押し付けて滑り速度
０．２５ｍ／秒，油温８０℃の条件下で摩擦させ、１時
間経過後にプレート状試験片の摩耗量を測定した。合金
番号１の過共晶Ａｌ−Ｓｉ合金を鋳造条件１で鋳造して
得られたダイカスト部材の摩耗量を基準値１とし、他の
ダイカスト部材の摩耗量の基準値に対する比を求めた。
摩耗量比が少ないほど、耐摩耗性に優れた材料であると
いえる。表４の測定結果にみられるように、本発明に従
った合金組成１，２及び鋳造条件１，２で得られたダイ
カスト部材は、何れも良好な耐摩耗性を示した。これに
対し、スリーブ２に注湯した合金溶湯６を直ちに金型４
に射出させること（鋳造条件３）により得られたダイカ
スト部材は、初晶Ｓｉの平均粒径が小さすぎるため本発
明品に比較して摩耗量が著しく大きく、耐摩耗性の改善
に有効な平均粒径に初晶Ｓｉの粒径が調整されていない
ことが判る。また、合金番号３の過共晶Ａｌ−Ｓｉ合金
を鋳造条件１で鋳造したダイカスト部材は、初晶Ｓｉの
平均粒径が大きいため、本発明例に比較して耐摩耗性が
悪く、また切削加工に支障を来した。これは、粗大な初
晶Ｓｉが割れて悪影響を及ぼしたものと考えられる。Next, each die-cast member cast under the casting conditions 1 and 2 was processed into a plate shape and subjected to a ring-on-plate type friction and wear test. In the friction and wear test,
A ring-shaped chrome steel was used as the mating material, and a plate-shaped test piece was pressed against the mating material with a surface pressure of 18 MPa and rubbed under the conditions of a sliding speed of 0.25 m / sec and an oil temperature of 80 ° C. The amount of wear of the test piece was measured. The wear amount of the die-cast member obtained by casting the hypereutectic Al—Si alloy of Alloy No. 1 under the casting condition 1 was used as the reference value 1, and the ratio of the wear amount of the other die-cast members to the reference value was determined.
It can be said that the smaller the wear amount ratio, the more excellent the wear resistance of the material. As can be seen from the measurement results in Table 4, the die-cast members obtained under the alloy compositions 1 and 2 and the casting conditions 1 and 2 according to the present invention all showed good wear resistance. On the other hand, the molten alloy 6 poured into the sleeve 2 is immediately fed to the die 4
In the die-cast member obtained by injecting into the casting (casting condition 3), the average grain size of the primary crystal Si is too small, so the wear amount is remarkably large as compared with the product of the present invention, and the average value effective for improving wear resistance is high. It can be seen that the grain size of the primary crystal Si is not adjusted to the grain size. Further, the die-cast member produced by casting the hypereutectic Al—Si alloy of Alloy No. 3 under the casting condition 1 has a large average grain size of primary crystal Si, so that it has poor wear resistance as compared with the examples of the present invention, and the cutting Processing has been hindered. It is considered that this is because coarse primary crystal Si was cracked and had an adverse effect.
【００１９】 [0019]
【００２０】本発明で規定した合金組成及び鋳造条件
は、比較的低温になった過共晶Ａｌ−Ｓｉ合金溶湯６を
金型４に射出することから、金型４が受ける熱衝撃が少
なくなり、金型の寿命を長くする上でも有効である。た
とえば、合金番号１の過共晶Ａｌ−Ｓｉ合金を鋳造条件
１で鋳造した場合と、合金番号３の過共晶Ａｌ−Ｓｉ合
金を鋳造条件３で鋳造した場合の金型寿命を表５に比較
する。なお、金型寿命は、金型４に割れが発生するまで
の鋳造回数で評価した。表５から明らかなように、本発
明に従った鋳造法では、従来に比較して金型寿命が１．
５倍に改善されており、その分だけ製造コストが低減さ
れることが判る。According to the alloy composition and casting conditions specified in the present invention, the hypereutectic Al--Si alloy melt 6 having a relatively low temperature is injected into the mold 4, so that the thermal shock to the mold 4 is reduced. It is also effective in extending the life of the mold. For example, Table 5 shows the die lives when a hypereutectic Al-Si alloy of alloy number 1 is cast under casting conditions 1 and a hypereutectic Al-Si alloy of alloy number 3 is cast under casting conditions 3. Compare. The mold life was evaluated by the number of castings until the mold 4 cracked. As is clear from Table 5, in the casting method according to the present invention, the mold life is 1.
It has been improved five times, and it can be seen that the manufacturing cost is reduced accordingly.
【００２１】 [0021]
【００２２】以上の結果から、合金組成及び鋳造条件を
本発明で特定した条件下で組み合わせることによって、
加工性や強度を損なうことなく、比較的Ｓｉ含有量の低
い過共晶Ａｌ−Ｓｉ合金であっても、耐摩耗性に有効な
粒径及び分布密度で初晶Ｓｉが晶出することが確認され
る。From the above results, by combining the alloy composition and casting conditions under the conditions specified in the present invention,
It was confirmed that primary crystal Si crystallizes with a grain size and distribution density effective for wear resistance, even with a hypereutectic Al-Si alloy having a relatively low Si content, without impairing workability and strength. To be done.
【００２３】[0023]
【発明の効果】以上に説明したように、本発明において
は、充填率２０〜４０体積％でダイカストスリーブに注
湯された過共晶Ａｌ−Ｓｉ合金を初晶Ｓｉ晶出温度〜共
晶温度の温度域に所定時間保持して初晶Ｓｉをスリーブ
内で晶出・成長させた後、スリーブから金型に合金溶湯
を射出している。そのため、得られたダイカスト部材
は、Ｓｉ含有量が１４〜１７重量％と比較的低いにも拘
らず、耐摩耗性の改善に好適な粒径及び分布密度で初晶
Ｓｉが分散した鋳造組織をもつ。このダイカスト部材
は、粗大な初晶Ｓｉが成長していないため加工性や強度
も良好である。しかも、金型が受ける熱衝撃が緩和され
ることから、金型の繰返し使用回数も多くなり、その分
だけ製造コストが節減される。As described above, in the present invention, the hypereutectic Al-Si alloy poured in the die casting sleeve at the filling rate of 20 to 40% by volume is used as the primary crystal Si crystallization temperature to the eutectic temperature. After keeping the temperature range of 1 for a predetermined time to crystallize and grow the primary crystal Si in the sleeve, the molten alloy is injected from the sleeve into the mold. Therefore, the obtained die cast member has a cast structure in which primary crystal Si is dispersed in a grain size and a distribution density suitable for improving wear resistance, even though the Si content is relatively low at 14 to 17% by weight. Hold. This die cast member has good workability and strength because coarse primary crystal Si has not grown. Moreover, since the thermal shock applied to the mold is alleviated, the number of times the mold is used repeatedly increases, and the manufacturing cost is reduced accordingly.
【図１】 本発明に従ったダイカスト鋳造の説明図FIG. 1 is an explanatory view of die casting according to the present invention.
【図２】 初晶Ｓｉの晶出温度とＳｉ含有量との関係を
示したグラフFIG. 2 is a graph showing the relationship between the crystallization temperature of primary Si and the Si content.
【図３】 所定の充填率でダイカストスリーブに充填さ
れた合金溶湯[Fig. 3] Molten metal alloy filled in a die casting sleeve at a predetermined filling rate.
【図４】 本発明に従った鋳造条件で鋳造される過共晶
Ａｌ−Ｓｉ合金溶湯の温度変化を示すグラフFIG. 4 is a graph showing changes in temperature of a hypereutectic Al—Si alloy melt cast under the casting conditions according to the present invention.
１：レードル ２：ダイカストスリーブ ３：プラ
ンジャ ４：金型
５：キャビティ ６：過共晶Ａｌ−Ｓｉ合金溶湯
Ｔ1 ，Ｔ2 ：温度測定点1: Ladle 2: Die casting sleeve 3: Plunger 4: Mold 5: Cavity 6: Hypereutectic Al-Si alloy melt
T 1 , T 2 : Temperature measurement points
───────────────────────────────────────────────────── フロントページの続き (72)発明者 猪狩 隆彰 静岡県庵原郡蒲原町蒲原１丁目34番１号 日本軽金属株式会社 グループ技術セ ンター内 (72)発明者 倉増 幸雄 静岡県庵原郡蒲原町蒲原１丁目34番１号 日本軽金属株式会社 グループ技術セ ンター内 (72)発明者 志賀 英俊 神奈川県横浜市神奈川区宝町２番地 日 産自動車株式会社内 (56)参考文献 特開 平９−87768（ＪＰ，Ａ) 特開 平９−157781（ＪＰ，Ａ) 特開 平５−78770（ＪＰ，Ａ) 特開 平８−49035（ＪＰ，Ａ) 特開 平10−298690（ＪＰ，Ａ) 特開 平11−222636（ＪＰ，Ａ) 特開 平６−292961（ＪＰ，Ａ) 特開 平10−296422（ＪＰ，Ａ) 特開 平10−152731（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B22D 21/04 B22D 17/00 C22C 1/02 C22C 21/02 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Takaaki Inokari 1-34-1, Kambara, Kambara-cho, Awara-gun, Shizuoka Nippon Light Metal Co., Ltd. Group Technology Center (72) Inventor Yukio Kuramasu Kambara-cho, Anbara-gun, Shizuoka 1-34 Kambara Nippon Light Metal Co., Ltd. In the Group Technology Center (72) Inventor Hidetoshi Shiga 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (56) Reference JP-A-9-87768 ( JP, A) JP 9-157781 (JP, A) JP 5-78770 (JP, A) JP 8-49035 (JP, A) JP 10-298690 (JP, A) JP 11-222636 (JP, A) JP 6-292961 (JP, A) JP 10-296422 (JP, A) JP 10-152731 (JP, A) (58) Fields investigated (Int .Cl. 7 , DB name) B22D 21/04 B22D 17/00 C22C 1/02 C22C 21/02
Claims (3)
ミニウム合金溶湯を充填率２０〜４０体積％でダイカス
トスリーブに注湯し、次いでダイカストスリーブ内でア
ルミニウム合金溶湯を初晶Ｓｉ晶出温度と共晶温度との
間の温度範囲で２〜５秒保持して初晶Ｓｉを晶出・成長
させた後、アルミニウム合金溶湯を射出成形することに
より鋳造組織に晶出した初晶Ｓｉの平均粒径を７〜１５
μｍの範囲に調整することを特徴とする過共晶Ａｌ−Ｓ
ｉ合金ダイカスト部材の製造方法。1. An aluminum alloy melt containing 14 to 17% by weight of Si is poured into a die casting sleeve at a filling rate of 20 to 40% by volume , and then the aluminum alloy melt is added to the primary crystal Si in the die casting sleeve. After maintaining the temperature range between the crystallization temperature and the eutectic temperature for 2 to 5 seconds to crystallize and grow the primary crystal Si, the molten aluminum alloy is injection-molded to crystallize into the cast structure. The average particle size of Si is 7 to 15
Hypereutectic Al-S characterized by adjusting to the range of μm
Method for manufacturing i-alloy die-cast member.
含むアルミニウム合金溶湯を使用する請求項１に記載の
過共晶Ａｌ−Ｓｉ合金ダイカスト部材の製造方法。2. Further, 0.001 to 0.02% by weight of P is added.
The method for producing a hypereutectic Al-Si alloy die casting member according to claim 1, wherein an aluminum alloy melt containing the same is used .
れ、初晶Ｓｉの平均粒径が７〜１５μｍの範囲にある鋳
造組織をもつ過共晶Ａｌ−Ｓｉ合金ダイカスト部材。 3. Manufactured by the method according to claim 1 or 2.
Casting in which the average grain size of primary crystal Si is in the range of 7 to 15 μm
A hypereutectic Al-Si alloy die-cast member having a structure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03154898A JP3416503B2 (en) | 1998-02-13 | 1998-02-13 | Hypereutectic Al-Si alloy die casting member and method of manufacturing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03154898A JP3416503B2 (en) | 1998-02-13 | 1998-02-13 | Hypereutectic Al-Si alloy die casting member and method of manufacturing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11226723A JPH11226723A (en) | 1999-08-24 |
| JP3416503B2 true JP3416503B2 (en) | 2003-06-16 |
Family
ID=12334253
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03154898A Expired - Lifetime JP3416503B2 (en) | 1998-02-13 | 1998-02-13 | Hypereutectic Al-Si alloy die casting member and method of manufacturing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3416503B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011097479A2 (en) * | 2010-02-05 | 2011-08-11 | Thixomat, Inc. | Method and apparatus of forming a wrought material having a refined grain structure |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10006269A1 (en) | 2000-02-12 | 2001-08-16 | Bayerische Motoren Werke Ag | Method for producing a metal component for a drive unit, in particular an internal combustion engine, which interacts with a friction partner via a sliding surface |
| WO2013039247A1 (en) * | 2011-09-15 | 2013-03-21 | 国立大学法人東北大学 | Die-casting method, die-casting device, and die-cast article |
| EP2905351B1 (en) * | 2012-09-25 | 2017-11-01 | Josho Gakuen Educational Foundation | Hypereutectic aluminum/silicon alloy die-cast member and process for producing same |
| JP6393008B1 (en) | 2017-04-27 | 2018-09-19 | 株式会社コイワイ | High-strength aluminum alloy laminated molded body and method for producing the same |
-
1998
- 1998-02-13 JP JP03154898A patent/JP3416503B2/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011097479A2 (en) * | 2010-02-05 | 2011-08-11 | Thixomat, Inc. | Method and apparatus of forming a wrought material having a refined grain structure |
| WO2011097479A3 (en) * | 2010-02-05 | 2011-09-29 | Thixomat, Inc. | Method and apparatus of forming a wrought material having a refined grain structure |
| GB2490467A (en) * | 2010-02-05 | 2012-10-31 | Thixomat Inc | Method and apparatus of forming a wrought material having a refined grain structure |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH11226723A (en) | 1999-08-24 |
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