JP3201711B2 - Age-hardened steel for die casting - Google Patents
Age-hardened steel for die castingInfo
- Publication number
- JP3201711B2 JP3201711B2 JP22708095A JP22708095A JP3201711B2 JP 3201711 B2 JP3201711 B2 JP 3201711B2 JP 22708095 A JP22708095 A JP 22708095A JP 22708095 A JP22708095 A JP 22708095A JP 3201711 B2 JP3201711 B2 JP 3201711B2
- Authority
- JP
- Japan
- Prior art keywords
- die
- age
- casting
- steel
- hardened steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/52—Ferrous alloys, e.g. steel alloys containing chromium with nickel with cobalt
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Molds, Cores, And Manufacturing Methods Thereof (AREA)
- Heat Treatment Of Articles (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】この発明はダイカスト型用時
効硬化鋼に関し、詳しくは対ヒートチェック性に優れ、
且つ時効変寸率の小さいダイカスト型用時効硬化鋼に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an age hardened steel for a die-casting type, and more particularly, to an excellent heat check property.
The present invention also relates to an age-hardened steel for a die-casting type having a small aging change rate.
【０００２】[0002]
【従来の技術及び発明が解決しようとする課題】従来、
ダイカスト型用鋼材としては主に５％Ｃｒ，１〜１．５
％Ｍｏを含む熱間工具鋼が用いられていた。この熱間工
具鋼にてダイカスト型を製造する場合、焼入れ，焼戻し
処理を施して所要の硬さ，強度を発現させる。2. Description of the Related Art
5% Cr, 1 to 1.5% mainly as a steel material for die casting
A hot tool steel containing% Mo was used. When a die-casting die is manufactured from this hot tool steel, quenching and tempering are performed to develop required hardness and strength.
【０００３】ところでこの焼入れ，焼戻し処理を施すと
大きな熱処理歪，変形が生じるため、焼入れ，焼戻し処
理の前に一旦粗加工を行ない、そして焼入れ，焼戻し処
理後に仕上加工を施すこととなる。この場合加工工程数
が多くなり、また金型製造のための所要時間も長くな
る。However, when this quenching and tempering treatment is performed, large heat treatment distortion and deformation occur. Therefore, roughing is performed once before quenching and tempering, and finishing is performed after quenching and tempering. In this case, the number of processing steps increases, and the time required for manufacturing the mold also increases.
【０００４】そこで１８％Ｎｉマルエージング鋼を代表
とする時効硬化鋼のダイカスト型への適用が検討されて
いる。この種時効硬化鋼にてダイカスト型を製造する場
合、上記熱間工具鋼における焼入れ，焼戻し処理と異な
って熱処理時の変形が少なく、従って一部加工工程を省
略することが可能となって製造工程数を短縮できるとと
もに、金型製造のための所要時間を短くすることができ
る。Therefore, application of an age-hardened steel represented by 18% Ni maraging steel to a die-casting type has been studied. When manufacturing a die-casting die using this kind of age-hardened steel, unlike the quenching and tempering treatments of the above-mentioned hot tool steel, there is little deformation during heat treatment, and therefore, it is possible to omit some processing steps, thus making the manufacturing process possible. The number can be reduced, and the time required for mold production can be shortened.
【０００５】しかしながら一般的な時効硬化鋼である１
８％Ｎｉマルエージング鋼の場合、ダイカスト型を構成
した場合において表面部に発生するヒートチェック、即
ち急速な加熱冷却に伴う熱応力の繰返し作用に起因する
クラックの発生に対する耐性が十分でなく、そのために
金型寿命が従来の熱間工具鋼からなるそれに比べて著し
く短寿命となる問題を含んでいる。[0005] However, the general age hardening steel 1
In the case of 8% Ni maraging steel, when a die-casting die is formed, heat resistance generated on a surface portion, that is, resistance to crack generation due to repetitive action of thermal stress accompanying rapid heating / cooling is not sufficient. In addition, there is a problem that the mold life is significantly shorter than that of the conventional hot work tool steel.
【０００６】また従来の熱間工具鋼に較べて熱処理時の
変形は小さいものの、熱処理による等方的収縮は避けら
れず、而してその収縮変形（変寸率）が大きいと、ダイ
カスト型を構成したときの寸法のばらつきが大きくな
り、実際上かかるダイカスト型への適用が困難となる。Although the deformation during heat treatment is smaller than that of conventional hot work tool steel, isotropic shrinkage due to heat treatment is unavoidable. Variations in dimensions when configured make it practically difficult to apply to such a die-casting type.
【０００７】詳述すると、時効硬化鋼にてダイカスト型
を製造する場合、熱処理による収縮を見込んで時効処理
前の金型形状，寸法を定めるが、熱処理による収縮変形
が一定以上に大きいと最終的にダイカスト型の寸法精度
を確保することが困難となる。More specifically, when a die-casting die is manufactured from age-hardened steel, the shape and dimensions of the die before the aging treatment are determined in consideration of shrinkage due to heat treatment. In addition, it is difficult to ensure the dimensional accuracy of the die casting mold.
【０００８】マルエージング鋼の破壊強度を改善する点
については従来種々の技術が提案されている。例えば特
開平６−１５８２２８号公報には、鋼組成をＣｒ：６．
０〜１５％，Ｎｉ：４．０〜１２％，Ｍｏ：０．３〜
３．０％，Ｔｉ：１．０〜３．０％，Ａｌ：０．０１〜
２．００％として、マルエージエージング鋼の耐遅れ破
壊特性を向上させた点が開示されている。Various techniques have been proposed for improving the breaking strength of maraging steel. For example, JP-A-6-158228 discloses that the steel composition is Cr: 6.
0 to 15%, Ni: 4.0 to 12%, Mo: 0.3 to
3.0%, Ti: 1.0 to 3.0%, Al: 0.01 to
2.00% is disclosed to improve the delayed fracture resistance of the maraging steel.
【０００９】しかしながらこの特開平６−１５８２２８
号公報に開示のものはＣｏを含有していないことから、
時効処理の際の硬化が不十分であり、またこのマルエー
ジング鋼は専らボルト，板材等の構造用部材を対象とし
たもので、熱処理時の変寸率が大きく、従ってダイカス
ト型への適用が困難である。However, Japanese Patent Application Laid-Open No. Hei 6-158228 discloses
Because the one disclosed in Japanese Patent Publication No. contains no Co,
Insufficient hardening during aging treatment, and this maraging steel is intended exclusively for structural members such as bolts and plates, and has a large dimensional change during heat treatment. Have difficulty.
【００１０】一方特開平６−２４８３８９号公報には、
ダイカスト金型用マルエージエージング鋼における鋼組
成をＮｉ：１２〜１４％，Ｍｏ：４．５％〜６．０％，
Ｃｏ：７．５〜９．５％，Ｔｉ：０．５〜１．０％，
Ｃ：≦０．０３％，Ｓｉ：≦０．１％，Ｍｎ：≦０．１
％，Ｐ：≦０．０１％，Ｓ：≦０．０１％，Ｃｒ：≦
０．０５％，Ｎ：≦０．０１％，Ａｌ：０．０２〜０．
２０％、残部Ｆｅから成る組成として軟化抵抗を大きく
し、耐ヒートチェック性を改善した点が開示されてい
る。On the other hand, JP-A-6-248389 discloses that
Ni: 12 to 14%, Mo: 4.5% to 6.0% in the maraging aging steel for die casting die,
Co: 7.5 to 9.5%, Ti: 0.5 to 1.0%,
C: ≦ 0.03%, Si: ≦ 0.1%, Mn: ≦ 0.1
%, P: ≦ 0.01%, S: ≦ 0.01%, Cr: ≦
0.05%, N: ≦ 0.01%, Al: 0.02-0.
It discloses that the composition comprising 20% and the balance of Fe increases the softening resistance and improves the heat check resistance.
【００１１】しかしながらこのものはＮｉの含有量が高
めに設定してあることから耐ヒートチェック性の点で十
分でなく、また変寸率の点でも十分でない問題点があ
る。However, since the Ni content is set high, there is a problem in that the heat check resistance is not sufficient and the size reduction ratio is not sufficient.
【００１２】他方、特開昭６３−１４５７５３号公報に
は、鋼組成をＣ：≦０．０３％，Ｓｉ：≦０．１０％，
Ｍｎ：≦０．１０％，Ｃｕ：≦０．１０％，Ｎｉ：７〜
２０％，Ｃｒ：≦０．１０％，Ｍｏ：２〜６％，Ｃｏ：
５〜１８％，Ａｌ：≦０．５０％，Ｔｉ：０．８〜２．
５％，Ｂ：０．０００５〜０．００５％，Ｐ：≦０．０
０２５％，Ｓ：≦０．００２５％，Ｐ＋Ｓ：≦０．００
３０％、残部Ｆｅから成る組成として耐遅れ破壊性を改
善したマルエージング鋼が開示されており、また特開昭
６２−２２８４５５号公報には、鋼組成をＣ：≦０．０
３％，Ｓｉ：≦０．１０％，Ｍｎ：≦０．１０％，Ｃ
ｕ：≦０．１％，Ｎｉ：７〜２０％，Ｃｒ：≦０．１
％，Ｍｏ：１〜１０％，Ｃｏ：≦１８％，Ａｌ：≦１
％，Ｔｉ：≦２．５％，Ｐ：≦０．００２％，Ｓ：≦
０．００１５％，Ｐ＋Ｓ：≦０．００３０％、残部Ｆｅ
から成る組成として疲労特性を改善したマルエージング
鋼がそれぞれ開示されている。On the other hand, Japanese Patent Application Laid-Open No. 63-145,753 discloses that the steel composition is C: ≦ 0.03%, Si: ≦ 0.10%,
Mn: ≦ 0.10%, Cu: ≦ 0.10%, Ni: 7 to
20%, Cr: ≦ 0.10%, Mo: 2 to 6%, Co:
5-18%, Al: 0.50%, Ti: 0.8-2.
5%, B: 0.0005 to 0.005%, P: ≦ 0.0
025%, S: ≦ 0.0025%, P + S: ≦ 0.00
A maraging steel having an improved delayed fracture resistance is disclosed as a composition comprising 30% and the balance of Fe, and Japanese Patent Application Laid-Open No. 62-228455 discloses a steel composition in which C: ≦ 0.0
3%, Si: ≦ 0.10%, Mn: ≦ 0.10%, C
u: ≦ 0.1%, Ni: 7-20%, Cr: ≦ 0.1
%, Mo: 1 to 10%, Co: ≦ 18%, Al: ≦ 1
%, Ti: ≦ 2.5%, P: ≦ 0.002%, S: ≦
0.0015%, P + S: ≤0.0030%, balance Fe
A maraging steel having improved fatigue characteristics as a composition comprising is disclosed.
【００１３】しかしこれらマルエージング鋼もまた熱処
理時の変寸率が十分小さくない問題がある。However, these maraging steels also have a problem that the dimensional change during heat treatment is not sufficiently small.
【００１４】[0014]
【課題を解決するための手段】本願の発明はこのような
課題を解決するためになされたものである。而して本願
の発明はダイカスト型用時効硬化鋼を、重量％でＣ：≦
０．０３％，Ｓｉ：≦０．１０％，Ｍｎ：≦０．１０
％，Ｎｉ：９．０〜１１．０％，Ｃｒ：０．１０〜５．
０％，Ｍｏ：５．０〜８．０％，Ｃｏ：５．０〜８．０
％，Ｔｉ：０．１０〜１．０％，Ａｌ：０．０５〜０．
１５％，且つ３０≦Ｃｏ（％）×Ｍｏ（％）≦５０、残
部実質的にＦｅからなる組成としたことを特徴とする。The invention of the present application has been made to solve such a problem. Thus, the invention of the present application provides an age-hardened steel for die-casting using C: ≦
0.03%, Si: ≦ 0.10%, Mn: ≦ 0.10
%, Ni: 9.0-11.0%, Cr: 0.10-5.
0%, Mo: 5.0 to 8.0%, Co: 5.0 to 8.0
%, Ti: 0.10-1.0%, Al: 0.05-0.
15% and 30 ≦ Co (%) × Mo (%) ≦ 50, with the balance being substantially Fe.
【００１５】本発明者はダイカスト型用時効硬化鋼にお
いて、耐ヒートチェック性を良好とし且つ熱処理時の変
寸率を小さく抑えるための技術手段について研究する中
で、Ｎｉ量の低減、Ｃｒの適量添加が時効処理時の変寸
率の低減に有効であるとの知見を得た。The inventor of the present invention has studied the technical means for improving the heat check resistance and reducing the dimensional change during heat treatment in age-hardened steel for die-casting. It has been found that the addition is effective in reducing the dimensional change during aging treatment.
【００１６】而してＮｉ量の低減はオーステナイト変態
点（Ａｓ点）の上昇をもたらし、耐ヒートチェック性の
向上に寄与する。Ａｓ点の温度が低いと、ダイカスト型
の使用時に溶湯による加熱作用で金型の表層部がマルテ
ンサイト状態からオーステナイト化し易く、これが亀裂
発生を促進するが、Ａｓ点を高くすればこれを防止で
き、耐ヒートチェック性を向上させることができる。Thus, the reduction of the amount of Ni results in an increase in the austenite transformation point (As point), which contributes to an improvement in heat check resistance. When the temperature at the As point is low, the surface layer of the mold is easily transformed from a martensitic state to austenite due to the heating action of the molten metal during use of the die casting mold, and this promotes crack generation, but it can be prevented by increasing the As point. In addition, heat check resistance can be improved.
【００１７】但しＮｉ量の低減は同時に靱性の低下をも
たらす。そこで本発明では、時効硬化処理の際の析出効
果を大きく左右するＣｏ（％）×Ｍｏ（％）量の制御に
よって靱性値を確保するようにした。尚Ｃｒについては
適量添加によって熱処理時の変寸率が小さくなるが、一
方Ｃｒの添加によってＡｓ点が低下し、耐ヒートチェッ
ク性が阻害される恐れがある。そこで本発明ではＣｒの
添加量については一定の値以下に規制するようにした。However, a decrease in the amount of Ni results in a decrease in toughness at the same time. Therefore, in the present invention, the toughness value is ensured by controlling the amount of Co (%) × Mo (%), which largely affects the precipitation effect during the age hardening treatment. The addition of a suitable amount of Cr reduces the dimensional change during the heat treatment, but the addition of Cr lowers the As point and may hinder heat check resistance. Therefore, in the present invention, the amount of Cr added is restricted to a certain value or less.
【００１８】かかる本発明によれば、耐ヒートチェック
性に優れたダイカスト型用時効硬化鋼を得ることがで
き、その耐用寿命を大きく延ばすことができる。また本
発明の時効硬化鋼は熱処理時の変寸率の小さいもので、
ダイカスト型製造時の加工工数を少なくできるとともに
ダイカスト型の寸法精度を良好となすことができる。According to the present invention, it is possible to obtain an age-hardened steel for a die-casting type having excellent heat check resistance, and it is possible to greatly extend its service life. The age hardened steel of the present invention has a small dimensional change during heat treatment,
The number of processing steps during the production of the die casting mold can be reduced, and the dimensional accuracy of the die casting mold can be improved.
【００１９】本発明において、Ｃｒのより望ましい含有
量は０．３０〜１．０％であり（請求項２）、またＮ量
についてはできるだけ少ない方が良い。Ｔｉを含有する
系において、Ｎが増加するとＴｉＮ介在物が析出し、こ
れによりダイカスト型における低サイクル疲労特性が悪
化する。In the present invention, the more preferable content of Cr is 0.30 to 1.0% (claim 2), and the N content is preferably as small as possible. In a system containing Ti, when N increases, TiN inclusions precipitate, which deteriorates the low cycle fatigue characteristics of the die-cast type.
【００２０】ここで低サイクル疲労とは、例えば大きな
型締圧力の下で金型が大割れする現象である。Ｎ量の増
加はまた靱性も劣化させるため、できるだけ少ない方が
望ましいが、極低Ｎ化は製造コストの上昇をもたらすた
め上限を０．００５０％とした（請求項３）。Here, the low cycle fatigue is, for example, a phenomenon in which a mold is largely cracked under a large clamping pressure. Since an increase in the amount of N also deteriorates the toughness, it is desirable that the amount is as small as possible. However, since the extremely low N causes an increase in manufacturing cost, the upper limit is made 0.0050% (claim 3).
【００２１】上記ＴｉＮ介在物はその大きさが１０μｍ
を超えるものが２％より多く含まれると、これが破壊起
点となって低サイクル疲労特性が悪化し、ダイカスト型
の大割れを引き起こすことになる。そこで本発明では１
０μｍを超えるＴｉＮ介在物量が全体の２％以下となる
ようにした（請求項４）。The TiN inclusion has a size of 10 μm.
If more than 2% is contained, this becomes a fracture starting point, deteriorating low cycle fatigue properties, and causing large die-casting cracks. Therefore, in the present invention, 1
The amount of TiN inclusions exceeding 0 μm is set to be 2% or less of the whole (claim 4).
【００２２】次に本発明における各化学成分の限定理由
を詳述する。 Ｃ：≦０．０３％ ＣはＴｉＣ，Ｍｏ2Ｃ等の炭化物を粒界に析出させ、著
しく靱性を低下させるため、上限値を０．０３％とし
た。更に靱性を確保するためには０．０１％以下が望ま
しい。Next, the reasons for limiting each chemical component in the present invention will be described in detail. C: ≦ 0.03% C precipitates carbides such as TiC and Mo 2 C at the grain boundaries and significantly lowers the toughness, so the upper limit was made 0.03%. In order to further secure toughness, 0.01% or less is desirable.
【００２３】Ｓｉ：≦０．１０％ Ｓｉは靱性を劣化させるため０．１０％以下とする必要
がある。 Ｍｎ：≦０．１０％ ＭｎはＳと結び付いてＭｎＳ介在物を生成し、靱性を劣
化させるため０．１０％以下に規制した。Si: ≦ 0.10% Since Si deteriorates toughness, it must be 0.10% or less. Mn: ≦ 0.10% Mn is restricted to 0.10% or less to combine with S to form MnS inclusions and deteriorate toughness.
【００２４】Ｎｉ：９．０〜１１．０％ ＮｉはＦｅに固溶して靱性に富んだマトリックスを形成
する必要不可欠な元素であるが、添加量の増大とともに
析出量が増加するため時効収縮率（変寸率）が増加す
る。また添加量増加とともにオーステナイト変態点Ａｓ
点が低下し、耐ヒートチェック性が低下する。金型表面
は例えば６００〜６５０℃の高温のアルミ溶湯にさらさ
れることからＡｓ点は到達表面温度以上でなければなら
ないが、そのためにはＮｉを１１．０％以下とすること
が必要である。しかし添加量が９．０％より少ないと必
要な靱性を確保することができない。以上の点から本発
明ではＮｉ含有量を９．０〜１１．０％とした。Ni: 9.0-11.0% Ni is an indispensable element that forms a tough matrix in a solid solution with Fe, but the aging shrinkage due to the increase in the amount of precipitation increases with the amount of addition. The rate (size change rate) increases. In addition, the austenite transformation point As increases with the amount added.
And the heat check resistance decreases. Since the mold surface is exposed to a high-temperature molten aluminum of, for example, 600 to 650 ° C., the As point must be equal to or higher than the attained surface temperature. For that purpose, Ni needs to be 11.0% or less. However, if the amount is less than 9.0%, the required toughness cannot be secured. From the above points, in the present invention, the Ni content is set to 9.0 to 11.0%.
【００２５】Ｃｒ：０．１０〜５．０％ Ｃｒを０．１０％以上添加することにより時効変寸率を
低下させることができる。しかし５．０％を超えて過剰
添加した場合、加熱変態点，靱性が低下するため０．１
０〜５．０％とした。Ｃｒのより望ましい範囲は０．３
〜１．０％である。Cr: 0.10 to 5.0% By adding Cr in an amount of 0.10% or more, the aging change rate can be reduced. However, if it is added in excess of 5.0%, the heat transformation point and toughness decrease, so that 0.1% or more is added.
It was set to 0 to 5.0%. A more desirable range of Cr is 0.3
~ 1.0%.
【００２６】Ｍｏ：５．０〜８．０％ ダイカスト型に要求されるＨＲＣ４０以上の時効硬化を
得るためには５％以上が必要である。但し８．０％を超
えると靱性劣化，Ｍｓ点低下が起き、またコスト高とな
る。そのため５．０〜８．０％とした。Mo: 5.0-8.0% In order to obtain the age hardening of HRC 40 or more required for the die-casting type, 5% or more is required. However, if it exceeds 8.0%, toughness and Ms point decrease, and the cost increases. Therefore, it was set to 5.0 to 8.0%.
【００２７】Ｃｏ：５．０〜８．０％ Ｃｏ量増加によりＭｏの固溶度が低下するため時効硬化
性が増す効果がある。但し５％未満ではその効果が小さ
く、Ａｓ点も低下する。８％を超えると靱性が劣化し、
またコスト高となるため５．０〜８．０％の範囲とし
た。Co: 5.0-8.0% The increase in the amount of Co lowers the solid solubility of Mo, which has the effect of increasing age hardening. However, if it is less than 5%, the effect is small, and the As point also decreases. If it exceeds 8%, toughness deteriorates,
Further, in order to increase the cost, the range is set to 5.0 to 8.0%.
【００２８】Ｔｉ：０．１０〜１．０％ ＴｉはＮｉ3Ｔｉを形成し、時効硬化に寄与する硬化元
素であるが、過剰添加するとＴｉＮ介在物が析出し、靱
性及び低サイクル疲労を悪化させる。またＭｓ点低下に
よりＴｉ偏析帯が残留オーステナイトバンドとなり、ま
たオーステナイト変態点を下げることにより耐ヒートチ
ェック性を低下させる。従ってその上限を１．０％とし
た。Ｔｉ量低減に伴って靱性の改善、オーステナイト変
態点の上昇が起きるが、０．１０％未満の場合時効硬化
性が不足するため下限値を０．１０％とした。Ti: 0.10 to 1.0% Ti is a hardening element that forms Ni 3 Ti and contributes to age hardening. However, if added excessively, TiN inclusions precipitate and deteriorate toughness and low cycle fatigue. Let it. Further, the Ti segregation zone becomes a retained austenite band due to the decrease in the Ms point, and the heat check resistance is reduced by decreasing the austenite transformation point. Therefore, the upper limit is set to 1.0%. Although the toughness is improved and the austenite transformation point is increased with a decrease in the amount of Ti, the lower limit is set to 0.10% when the content is less than 0.10% because the age hardening property is insufficient.
【００２９】Ａｌ：０．０５〜０．１５％ Ａｌは脱酸剤として添加されるものであり、Ｔｉととも
に時効硬化にも寄与している。但し０．０５％未満では
時効硬化性が不足し、逆に０．１５％を超えると靱性を
低下させることから本発明では０．０５〜０．１５％と
した。Al: 0.05 to 0.15% Al is added as a deoxidizing agent and contributes to age hardening together with Ti. However, when the content is less than 0.05%, the age hardening property is insufficient. On the contrary, when the content exceeds 0.15%, the toughness is reduced. Therefore, the content is set to 0.05 to 0.15% in the present invention.
【００３０】Ｎ：≦０．００５０％ Ｎ量増加に伴い介在物としてのＴｉＮが析出し、低サイ
クル疲労特性が悪化する。金型の損傷は加熱冷却時の熱
応力によって引き起こされるが、大きな型の場合、大割
れに到る低サイクル疲労が問題となる。また靱性も悪化
させるためＮ量はできる限り低くしたいが、極低Ｎ化は
製造コストの上昇につながるため上限を０．００５０％
とした。N: ≦ 0.0050% As the amount of N increases, TiN as an inclusion precipitates and the low cycle fatigue characteristics deteriorate. Damage to the mold is caused by thermal stress during heating and cooling. In the case of a large mold, low cycle fatigue leading to large cracks becomes a problem. In addition, the N content is desired to be as low as possible to deteriorate the toughness.
And
【００３１】円相当径で１０μｍを超えるＴｉＮ介在物
が全体の２％以下 素材中の介在物においてその大きさが１０μｍを超える
ものがあると、型締力や注湯応力や熱応力が作用する個
所で破壊起点となり、低サイクル疲労特性を低下させ、
金型の大割れを引き起こすこととなるため、１０μｍを
超えるＴｉＮ介在物粒子が全体の２％以下であるように
する必要がある。2% or less of TiN inclusions having a circle equivalent diameter of more than 10 μm If there are inclusions in the material having a size of more than 10 μm, mold clamping force, pouring stress and thermal stress act. It becomes the starting point of fracture at each location, lowering low cycle fatigue characteristics,
To cause a large crack in the mold, it is necessary to make the TiN inclusion particles exceeding 10 μm to be 2% or less of the whole.
【００３２】３０≦Ｃｏ（％）×Ｍｏ（％）≦５０ Ｃｏ（％）×Ｍｏ（％）の溶解度積は時効硬化性を示す
ものであり、これを低減すると時効硬さも低下する。結
果としてＮｉ量低減によってもたらされた靱性の低下を
押しとどめ、靱性を確保することとなる。そこでこの値
の上限値を５０とした。一方Ｃｏ（％）×Ｍｏ（％）が
３０未満であると高温での軟化抵抗性が十分でなく、耐
ヒートチェック性が急激に悪化するため、下限値を３０
とした。The solubility product of 30 ≦ Co (%) × Mo (%) ≦ 50 Co (%) × Mo (%) indicates age hardening, and when this is reduced, the aging hardness also decreases. As a result, the reduction in toughness caused by the reduction in the amount of Ni is suppressed, and the toughness is secured. Therefore, the upper limit of this value was set to 50. On the other hand, if Co (%) × Mo (%) is less than 30, the softening resistance at a high temperature is not sufficient, and the heat check resistance rapidly deteriorates.
And
【００３３】[0033]
【実施例】次に本発明の実施例を以下に詳述する。表１
に示す化学組成の時効硬化鋼を大気誘導溶解及び造塊し
（３５０ｍｍφ）、これを９３０〜１１３０℃に保持後
水冷、更に８８０〜９８０℃に保持後空冷し、１／２Ｒ
（半径）部Ｔ方向（圧延方向と直角方向）からＪＩＳ３
号シャルピー衝撃試験片，１５ｍｍφ（直径）×５ｍｍ
ｔ（厚み）のヒートチェック試験片及び低サイクル疲労
試験片を採取し、シャルピー衝撃試験，ヒートチェック
試験，低サイクル疲労試験を行なった。また中心部から
２１０Ｌ（長さ）×１３０Ｗ（幅）×４５ｍｍｔ（厚
み）のブロック材を採取して寸法測定→時効処理→寸法
測定を行ない変寸率を測定した。Next, embodiments of the present invention will be described in detail. Table 1
Age-hardened steel having the chemical composition shown in (1) was melted and agglomerated by air induction (350 mmφ), kept at 930 to 1130 ° C, then cooled with water, further kept at 880 to 980 ° C, and then air-cooled to obtain 1 / 2R.
(Radius) JIS3 from T direction (direction perpendicular to rolling direction)
No. Charpy impact test specimen, 15mmφ (diameter) × 5mm
A heat check test piece and a low cycle fatigue test piece of t (thickness) were collected and subjected to a Charpy impact test, a heat check test, and a low cycle fatigue test. Further, a block material of 210 L (length) × 130 W (width) × 45 mmt (thickness) was sampled from the center portion, and the dimensions were measured, then the aging treatment was performed, and the dimensions were measured to measure the size reduction ratio.
【００３４】尚、時効処理，耐ヒートチェック試験，シ
ャルピー衝撃試験の各条件はそれぞれ下記の条件とし
た。 時効処理：５２０℃×５ｈｒ，ＡＣ(ピーク時効条件) 耐ヒートチェック試験：高周波加熱６５０℃×４秒及び
水冷３秒の繰り返し、繰返数１０００回 シャルピー衝撃試験：２ｍｍＵノッチ試験片，Ｔ方向採
取 室温試験The conditions for the aging treatment, the heat check test, and the Charpy impact test were as follows. Aging treatment: 520 ° C. × 5 hr, AC (peak aging condition) Heat check test: Repeating high frequency heating at 650 ° C. × 4 seconds and water cooling for 3 seconds, repeating 1000 times Charpy impact test: 2 mm U notch test specimen, T direction sampling Room temperature test
【００３５】また時効変寸率の測定は、２１０Ｌ×１３
０Ｗ×４５ｍｍｔブロック試験片について長さ（Ｌ）方
向及び幅（Ｔ）方向のそれぞれについて行なった。更に
低サイクル疲労試験は、最大応力１２３ｋｇｆ／ｍｍ2
の１軸の片振引張を繰り返し作用させて破断に到る繰返
回数を求めることにより行なった。これらの結果が表２
に示してある。The aging change rate was measured as 210 L × 13
The test was performed on the 0 W × 45 mmt block test piece in each of the length (L) direction and the width (T) direction. Further, the low cycle fatigue test shows that the maximum stress is 123 kgf / mm 2
And the number of repetitions leading to fracture was determined by repeatedly applying uniaxial pulsating tension. Table 2 shows these results.
It is shown in
【００３６】[0036]
【表１】 [Table 1]
【００３７】[0037]
【表２】 [Table 2]
【００３８】表２の結果において、Ｎｉの含有量が本発
明の範囲から外れている比較例１８のものはＡｓ点が低
く、耐ヒートチェック性が劣っており、またＮｉを１８
％含有する比較例１９のものは、シャルピー衝撃値は良
好な値を示しているもののＡｓ点が大幅に低く、耐ヒー
トチェック性も大きく劣っている。According to the results shown in Table 2, those of Comparative Example 18 in which the content of Ni is out of the range of the present invention have a low As point, are inferior in heat check resistance, and have an Ni content of 18%.
In Comparative Example 19 containing 0.1%, although the Charpy impact value showed a good value, the As point was significantly lower, and the heat check resistance was also significantly inferior.
【００３９】またＣｏとＭｏの溶解度積Ｃｏ（％）×Ｍ
ｏ（％）の値が本発明の範囲より低い比較例２０と２１
については耐ヒートチェック性が悪く、逆に本発明の範
囲より高い比較例２２と２３についてはシャルピー衝撃
値が劣っているのに対し、本発明例のものは何れも良好
な値を示している。The solubility product of Co and Mo, Co (%) × M
Comparative Examples 20 and 21 where the value of o (%) is lower than the range of the present invention
Is poor in heat check resistance, and conversely, Comparative Examples 22 and 23, which are higher than the range of the present invention, have inferior Charpy impact values, while those of the present invention show good values. .
【００４０】尚、本例において時効変寸率（Ｌ方向）、
Ａｓ点、耐ヒートチェック性における平均長さ，最大長
さ、シャルピー衝撃値のそれぞれの良否判定の基準とな
る目標値は、変寸率（絶対値）：≦０．０７０％，Ａｓ
点：≧６５０℃，耐ヒートチェック性における平均長
さ：≦７．５μｍ，最大長さ：≦５５μｍ，シャルピー
衝撃値：≧２０Ｊ／ｃｍ2とした。In this example, the aging dimensional change (L direction),
The target values serving as criteria for the quality judgment of the As point, the average length, the maximum length in the heat check resistance, and the Charpy impact value are as follows: Displacement ratio (absolute value): 0.070%, As
Points: ≧ 650 ° C., average length in heat check resistance: ≦ 7.5 μm, maximum length: ≦ 55 μm, Charpy impact value: ≧ 20 J / cm 2 .
【００４１】次に図１（Ａ），（Ｂ）は表２の結果に基
づいてＣｏ及びＭｏの溶解度積と耐ヒートチェック性及
びシャルピー衝撃値との関係を求めたもので、この図か
らＣｏとＭｏとの溶解度積を３０〜５０の範囲内に制御
することによって、耐ヒートチェック性及びシャルピー
衝撃値ともに良好な値が得られることが分かる。FIGS. 1A and 1B show the relationship between the solubility product of Co and Mo, the heat check resistance and the Charpy impact value based on the results shown in Table 2, and FIG. It can be understood that by controlling the solubility product of Mo and Mo within the range of 30 to 50, good values can be obtained for both the heat check resistance and the Charpy impact value.
【００４２】以上本発明の実施例を詳述したがこれはあ
くまで一例示であり、本発明はその主旨を逸脱しない範
囲において種々変更を加えた態様で実施可能である。Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention can be carried out in various modified forms without departing from the gist thereof.
【００４３】[0043]
【発明の効果】本発明によれば、耐ヒートチェック性に
優れたダイカスト用時効硬化鋼を得ることができ、その
耐用寿命を大きく延ばすことができる。また本発明の時
効硬化鋼は熱処理時の変寸率の小さいもので、ダイカス
ト型製造時の加工工数を少なくできるとともに、ダイカ
スト型の寸法精度を良好となすことができる。According to the present invention, an age-hardened steel for die casting having excellent heat check resistance can be obtained, and the service life thereof can be greatly extended. Further, the age-hardened steel of the present invention has a small dimensional change rate during the heat treatment, so that the number of processing steps in the production of the die-casting die can be reduced and the dimensional accuracy of the die-casting die can be improved.
【図１】本発明の実施例において得られたＣｏ（％）と
Ｍｏ（％）の溶解度積と耐ヒートチェック性及びシャル
ピー衝撃値との関係を表わした図である。FIG. 1 is a diagram showing the relationship between the solubility product of Co (%) and Mo (%) obtained in Examples of the present invention, heat check resistance, and Charpy impact value.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平６−248389（ＪＰ，Ａ) 特公 昭51−61（ＪＰ，Ｂ１) 特公 昭51−10171（ＪＰ，Ｂ１) (58)調査した分野(Int.Cl.7，ＤＢ名) C22C 38/00 302 B22D 17/22 C22C 38/52 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-248389 (JP, A) JP-B-51-61 (JP, B1) JP-B-51-10171 (JP, B1) (58) Field (Int. Cl. 7 , DB name) C22C 38/00 302 B22D 17/22 C22C 38/52
Claims (4)
変寸率に優れたダイカスト型用時効硬化鋼。C .: 0.03% Si: 0.10% Mn: 0.10% Ni: 9.0-11.0% Cr: 0.10-5.0% by weight% Mo: 5.0 to 8.0% Co: 5.0 to 8.0% Ti: 0.10 to 1.0% Al: 0.05 to 0.15% and 30 ≦ Co (%) × Mo ( %) ≦ 50 Aging-hardened steel for die-casting with excellent heat check resistance and aging dimensional change essentially composed of the balance of Fe.
１．０％であることを特徴とする耐ヒートチェック性及
び時効変寸率に優れたダイカスト型用時効硬化鋼。2. The method according to claim 1, wherein Cr: 0.30 to 0.30.
An age-hardened steel for die-casting, which is excellent in heat check resistance and aging dimensional change characterized by being 1.0%.
０５０％に規制されていることを特徴とする耐ヒートチ
ェック性及び時効変寸率に優れたダイカスト型用時効硬
化鋼。3. The method according to claim 1, wherein N: ≦ 0.0.
An age-hardened steel for die-casting, which is excellent in heat check resistance and age dimensional change, characterized by being regulated to 050%.
相当径で１０μｍを超えるＴｉＮ介在物が鋼全体の２％
以下であることを特徴とする耐ヒートチェック性，時効
変寸率及び低サイクル疲労に優れたダイカスト型用時効
硬化鋼。4. The steel according to claim 1, wherein TiN inclusions having a circle equivalent diameter exceeding 10 μm account for 2% of the entire steel.
An age-hardened steel for die-casting type having excellent heat check resistance, aging reduction ratio and low cycle fatigue, characterized by the following.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22708095A JP3201711B2 (en) | 1995-08-10 | 1995-08-10 | Age-hardened steel for die casting |
| EP19960112457 EP0767251B1 (en) | 1995-08-10 | 1996-08-01 | Age-hardening steel for die-casting dies |
| DE1996600831 DE69600831T2 (en) | 1995-08-10 | 1996-08-01 | Hardenable steel for molds |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22708095A JP3201711B2 (en) | 1995-08-10 | 1995-08-10 | Age-hardened steel for die casting |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0949057A JPH0949057A (en) | 1997-02-18 |
| JP3201711B2 true JP3201711B2 (en) | 2001-08-27 |
Family
ID=16855203
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22708095A Expired - Fee Related JP3201711B2 (en) | 1995-08-10 | 1995-08-10 | Age-hardened steel for die casting |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0767251B1 (en) |
| JP (1) | JP3201711B2 (en) |
| DE (1) | DE69600831T2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI107269B (en) * | 1998-12-02 | 2001-06-29 | Metso Powdermet Oy | shape Steel |
| DE60043526D1 (en) † | 1999-03-19 | 2010-01-28 | Honda Motor Co Ltd | MARTENSITAUSHÄRTENDER STEEL WITH OUTSTANDING TEMPERING CHARACTERISTICS AND METHOD FOR THE PRODUCTION THEREOF |
| PL2250293T3 (en) * | 2008-02-20 | 2012-04-30 | Questek Innovations Llc | Lower-cost, ultra-high-strength, high-toughness steel |
| CN104087859A (en) * | 2014-07-02 | 2014-10-08 | 钢铁研究总院 | Molybdenum-strengthened 10Ni7Co secondary hardened ultrahigh-strength steel and preparation method thereof |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5161B1 (en) * | 1967-09-18 | 1976-01-05 | ||
| AT374846B (en) * | 1982-09-15 | 1984-06-12 | Voest Alpine Ag | HEART PIECE, IN PARTICULAR HEART PIECE TIP, FOR RAIL CROSSINGS OR SWITCHES, AND METHOD FOR THE PRODUCTION THEREOF |
| JPS60255959A (en) * | 1984-05-28 | 1985-12-17 | Japan Steel Works Ltd:The | High hardness alloy steel having high saturation magnetic flux density |
| JPS61190050A (en) * | 1985-02-20 | 1986-08-23 | Hitachi Metals Ltd | Marageing steel combining high strength, high value of electric resistance, and soft magnetic property |
-
1995
- 1995-08-10 JP JP22708095A patent/JP3201711B2/en not_active Expired - Fee Related
-
1996
- 1996-08-01 EP EP19960112457 patent/EP0767251B1/en not_active Revoked
- 1996-08-01 DE DE1996600831 patent/DE69600831T2/en not_active Revoked
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0949057A (en) | 1997-02-18 |
| EP0767251B1 (en) | 1998-10-21 |
| DE69600831T2 (en) | 1999-04-08 |
| EP0767251A1 (en) | 1997-04-09 |
| DE69600831D1 (en) | 1998-11-26 |
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