JPH07243002A - Maraging steel excellent in high temperature strength and heat check resistance - Google Patents

Maraging steel excellent in high temperature strength and heat check resistance

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Publication number
JPH07243002A
JPH07243002A JP6032097A JP3209794A JPH07243002A JP H07243002 A JPH07243002 A JP H07243002A JP 6032097 A JP6032097 A JP 6032097A JP 3209794 A JP3209794 A JP 3209794A JP H07243002 A JPH07243002 A JP H07243002A
Authority
JP
Japan
Prior art keywords
steel
less
high temperature
heat check
maraging 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.)
Pending
Application number
JP6032097A
Other languages
Japanese (ja)
Inventor
Kunio Kondo
邦夫 近藤
Yasutaka Okada
康孝 岡田
Mitsuo Miyahara
光雄 宮原
Masahide Unno
正英 海野
Atsuo Dazai
敦夫 太宰
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
Original Assignee
Sumitomo Metal Industries Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sumitomo Metal Industries Ltd filed Critical Sumitomo Metal Industries Ltd
Priority to JP6032097A priority Critical patent/JPH07243002A/en
Publication of JPH07243002A publication Critical patent/JPH07243002A/en
Pending legal-status Critical Current

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  • Heat Treatment Of Steel (AREA)

Abstract

PURPOSE:To obtain a maraging steel increased in high temp. strength and excellent in heat check resistance by specifying respective contents of Ni, Co, Mo, Ti, Al, C, Si, Mn, P, S, Cr, and N. CONSTITUTION:This steel is a maraging steel having a composition which consists of, by weight, 8-<12% Ni, 5-15% Co, with impurities 2-9% Mo, 0.1-1.5% Ti, 0.02-0.5% sol.Al, and the balance Fe with impurities and satisfies 732-6.7Ni+3.7Co-2Mo+4.3Ti>=675 and 111 which the amounts of C, Si, Mn, P, S, Cr, and N as the impurities are limited to <=0.03%, <=0.1%, <=0.1%, <=0.01%, <=0.01%, <=0.1%, and <=0.01%, respectively. In this maraging steel, high temp. strength is improved while maintaining the superior balance between strength and toughness and also heat check resistance is improved.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は、高温強度が高く、耐ヒ
ートチェック性に優れ、例えばダイカスト用金型の材料
としてきわめて有用なマルエージング鋼に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a maraging steel which has high strength at high temperature and excellent heat check resistance and is extremely useful as a material for a die casting die, for example.

【0002】[0002]

【従来の技術】マルエージング鋼は極低炭素マルテンサ
イトを時効析出によって強化した鋼であり、その優れた
強靱性ゆえに、工具、圧力容器をはじめ航空宇宙産業用
機器等の材料として広く使用されている。かかるマルエ
ージング鋼の期待される用途の一つに、表面が溶融金属
にさらされ、はげしい加熱・冷却が繰り返されるダイカ
スト用金型がある。
2. Description of the Related Art Maraging steel is a steel obtained by strengthening ultra-low carbon martensite by aging precipitation, and due to its excellent toughness, it is widely used as a material for tools, pressure vessels and other equipment for the aerospace industry. There is. One of the expected applications of such maraging steel is a die casting mold in which the surface is exposed to molten metal and vigorous heating and cooling are repeated.

【0003】従来、アルミニウム、銅、亜鉛等をダイカ
ストする金型としては、JIS G 4404に SKD 61 として規
定されている合金工具鋼が使用されてきた。
Conventionally, an alloy tool steel defined by JIS G 4404 as SKD 61 has been used as a die for die-casting aluminum, copper, zinc or the like.

【0004】ダイカスト金型は、その表面で急速高温加
熱と急冷却が繰り返される過酷な条件下で使用されるた
め、その寿命が短いことが問題となっている。ダイカス
ト金型に発生する損傷の主なものは、熱塑性歪みによる
亀裂(ヒートチェック)、溶湯と金型表面が化学反応す
ることによって発生する溶損、および鋳造の際の溶湯圧
力に起因する成形応力による亀裂の進展と大割れであ
る。このうち、特にヒートチェックは、金型自体の寿命
を著しく短縮するのみならず、成形品 (鋳物製品) への
亀裂転写、製品と鋳型の離型性の悪化などの障害を惹起
する。従って、金型用材料に対しては特に耐ヒートチェ
ック性の向上が望まれている。
Since the die casting mold is used under severe conditions in which rapid high temperature heating and rapid cooling are repeated on its surface, its life is short. The main damages that occur in die casting dies are cracks due to thermoplastic strain (heat check), melting loss caused by the chemical reaction between the molten metal and the die surface, and molding stress caused by the molten metal pressure during casting. It is a crack and a large crack caused by. Among them, the heat check not only shortens the life of the mold itself significantly, but also causes problems such as crack transfer to a molded product (cast product) and deterioration of mold release property between the product and the mold. Therefore, it is particularly desired to improve the heat check resistance of the mold material.

【0005】前記のJIS SKD 61鋼については、その材質
改善、製造技術の改善、表面処理による改善が試みられ
ている (例えば、特開53−80318 号公報)。しかし、こ
れらの対策では、未だ満足すべき耐ヒートチェック性は
得られていない。
With respect to the JIS SKD 61 steel described above, attempts have been made to improve its material, manufacturing technology, and surface treatment (for example, Japanese Patent Laid-Open No. 53-80318). However, these measures have not yet obtained satisfactory heat check resistance.

【0006】JIS SKD 61鋼に替えて、強度、靱性バラン
スに優れる18%Ni系マルエージングの使用も検討されて
いる。マルエージング鋼は、溶体化のままでは低強度で
加工しやすく、寸法変化が小さい低温の時効硬化処理で
強靱化できるので、SKD 61鋼のように、高硬度材を切削
加工するというコストのかかる工程が省略できる利点が
ある。さらに、マルエージング鋼は、溶接性が良好なの
で肉盛り補修が容易である等の長所も有する。
In place of JIS SKD 61 steel, the use of 18% Ni-based maraging, which has an excellent balance of strength and toughness, is also under consideration. Maraging steel is easy to work with low strength as it is in solution form, and can be toughened by low temperature age hardening treatment with small dimensional change, so it costs a lot to cut high hardness material like SKD 61 steel. There is an advantage that steps can be omitted. Further, the maraging steel has advantages such as easy overlay repair since it has good weldability.

【0007】しかしながら、上記18%Ni系マルエージン
グ鋼をはじめとして、これまでに知られているマルエー
ジング鋼は、いずれもダイカスト金型用材料として十分
に満足できる高温強度と耐ヒートチェック性を備えてい
ない。
However, all the known maraging steels such as the above 18% Ni-based maraging steel have high temperature strength and heat check resistance which are sufficiently satisfactory as materials for die casting molds. Not not.

【0008】例えば、特開平5−154635号公報には、金
型の表面層のみを時効硬化させて性能向上を図る発明が
開示されているが、その対象としているのは18%Ni系マ
ルエージング鋼であり、複雑な熱処理を行うにしては十
分な耐ヒートチェック性は得られない。
For example, Japanese Unexamined Patent Publication (Kokai) No. 5-154635 discloses an invention in which only the surface layer of a mold is age-hardened to improve the performance. The object of the invention is 18% Ni-based maraging. Since it is steel, sufficient heat check resistance cannot be obtained even if complicated heat treatment is performed.

【0009】[0009]

【発明が解決しようとする課題】本発明の目的は、マル
エージング鋼の優れた強度と靱性のバランスを維持した
まま、その高温強度を向上させると共に耐ヒートチェッ
ク性を改善し、特にダイカスト金型用として用いたとき
にその使用寿命を大きく延長することができるマルエー
ジング鋼を提供することにある。
SUMMARY OF THE INVENTION The object of the present invention is to improve the high temperature strength and heat check resistance of a maraging steel while maintaining the excellent balance between strength and toughness. An object of the present invention is to provide a maraging steel capable of greatly extending its service life when used as an application.

【0010】[0010]

【課題を解決するための手段】本発明は、下記のマルエ
ージング鋼をその要旨とする。
DISCLOSURE OF THE INVENTION The gist of the present invention is the following maraging steel.

【0011】重量%で、Ni:8%から12%未満、Co:5
〜15%、Mo:2〜9%、Ti: 0.1〜1.5 %、sol.Al:0.
02〜0.5 %を含有し、残部はFeおよび不純物からなり、
不純物としてのCは0.03%以下、Siは 0.1%以下、Mnは
0.1%以下、Pは0.01%以下、Sは0.01%以下、Crは
0.1%以下、Nは0.01%以下であり、かつ、Ni、Co、Mo
およびTiの含有量は下記の式を満足することを特徴と
する高温強度が高く、耐ヒートチェック性に優れたマル
エージング鋼。
% By weight, Ni: 8% to less than 12%, Co: 5
~ 15%, Mo: 2-9%, Ti: 0.1-1.5%, sol.Al: 0.
02-0.5%, the balance Fe and impurities,
C as an impurity is 0.03% or less, Si is 0.1% or less, and Mn is
0.1% or less, P is 0.01% or less, S is 0.01% or less, Cr is
0.1% or less, N 0.01% or less, and Ni, Co, Mo
Maraging steel with high strength at high temperature and excellent heat check resistance, characterized in that the contents of Ti and Ti satisfy the following formula.

【0012】732− 6.7×(%Ni) + 3.7×(%Co) −2×
(%Mo) + 4.3×(%Ti) ≧ 675・・・
732−6.7 × (% Ni) + 3.7 × (% Co) −2 ×
(% Mo) + 4.3 × (% Ti) ≧ 675 ・ ・ ・

【0013】[0013]

【作用】本発明は、マルエージング鋼に関する多大な試
験研究によって得られた下記の新しい知見に基づいて完
成したものである。
The present invention has been completed on the basis of the following new findings obtained through a great deal of experimental research on maraging steel.

【0014】(1) ダイカスト用金型のように、表面が 6
50℃程度の高温に繰り返し曝される条件下では、通常の
18%Ni系マルエージング鋼を使用するとA1変態点が 650
℃より低いために、熱膨張率の大きいオーステナイトが
使用中に析出して、高温強度が著しく低下するととも
に、ヒートチェックの発生を促進する。
(1) The surface of the die is 6
Under conditions of repeated exposure to high temperatures of about 50 ° C, normal
When using 18% Ni-based maraging steel, A 1 transformation point is 650
Since the temperature is lower than 0 ° C, austenite having a large thermal expansion coefficient is precipitated during use, the high temperature strength is significantly reduced, and the occurrence of heat check is promoted.

【0015】(2) 従って、鋼のA1変態点を高温側へ移行
させることが、高温強度の向上と耐ヒートチェック性の
改善に極めて有効である。
(2) Therefore, shifting the A 1 transformation point of steel to the high temperature side is extremely effective for improving high temperature strength and heat check resistance.

【0016】(3) 本発明者らの行った多数の実験結果に
よれば、マルエージング鋼のA1変態点は下記の式で表す
ことができ、この式で表される値が 675(℃)以上であ
れば、耐ヒートチェック性が大幅に改善される。
(3) According to the results of a number of experiments conducted by the present inventors, the A 1 transformation point of maraging steel can be expressed by the following formula, and the value expressed by this formula is 675 (° C. ) Above, the heat check resistance is greatly improved.

【0017】A1-cal =732 − 6.7×(%Ni) + 3.7×(%C
o) −2×(%Mo) + 4.3×(%Ti) (4) 合金成分としてMoとTiを複合添加することによっ
て、高温強度が著しく上昇し、耐ヒートチェック性が改
善される。
A 1 -cal = 732−6.7 × (% Ni) + 3.7 × (% C
o) -2 x (% Mo) + 4.3 x (% Ti) (4) By adding Mo and Ti as alloy components in combination, the high temperature strength is significantly increased and the heat check resistance is improved.

【0018】上記の基本的な知見、ならびにマルエージ
ング鋼を構成する各種の合金成分および不純物元素に関
する詳細な検討結果を総合してなされたのが本発明であ
る。
The present invention has been made by synthesizing the above-mentioned basic knowledge and the detailed examination results regarding various alloy components and impurity elements constituting the maraging steel.

【0019】以下、各合金成分および不純物の含有量の
限定理由を説明する。なお、含有量に関する%は重量%
を意味する。
The reasons for limiting the content of each alloy component and impurities will be described below. In addition,% related to content is% by weight
Means

【0020】Ni:Niは靱性の高い母相組織を形成させる
ためには不可欠の元素であり、そのためには8%以上の
含有量が必要である。しかし、Niが12%以上になると変
態点が低下し、特にダイカスト金型のような使用条件下
では、軟化抵抗が小さくなるのでその含有量の上限を12
%未満とした。
Ni: Ni is an indispensable element for forming a matrix structure having high toughness, and for this purpose, its content must be 8% or more. However, when Ni is 12% or more, the transformation point decreases, and especially under use conditions such as die casting dies, the softening resistance decreases, so the upper limit of the content is set to 12
It was less than%.

【0021】Co:Coは、下記の Fe2Mo、Ni3Mo のような
Moを含む金属間化合物の析出を促進して鋼を強化し、ま
た、変態点の上昇に有効な元素であるが、含有量が15%
を超えると靱性を低下させる。一方、その含有量が5%
未満では強化が不十分となるので、その含有量を5〜15
%とした。
Co: Co is such as Fe 2 Mo and Ni 3 Mo described below.
It is an element that promotes the precipitation of intermetallic compounds containing Mo, strengthens the steel, and is effective in raising the transformation point, but its content is 15%.
If it exceeds, toughness is reduced. On the other hand, its content is 5%
If the content is less than 5%, the strengthening will be insufficient.
%.

【0022】Mo:Moは時効処理によって Fe2Mo、Ni3Mo
を析出し、鋼の引張強さの向上に有効な元素である。し
かし、その含有量が2%未満では強化が不十分となり、
9%を超えると鋼中のミクロ偏析が増大し、靱性を低下
させるので、2〜9%とした。
Mo: Mo is Fe 2 Mo, Ni 3 Mo by aging treatment.
Is an element effective in improving the tensile strength of steel. However, if the content is less than 2%, strengthening becomes insufficient,
If it exceeds 9%, the microsegregation in the steel increases and the toughness decreases, so the content was made 2-9%.

【0023】Ti:Tiは時効処理によって Ni3Ti、NiTiを
析出してMoと同様に鋼の引張強さの向上に寄与する。ま
た、前記Moの金属間化合物の析出温度域を高温側にシフ
トさせてフェライトの高温軟化抵抗を増して高温強度を
増大させる働きがある。更に、Tiは、鋼の変態点を上昇
させる作用によって高温強度を上げ、耐ヒートチェック
性を向上させる。しかし、その含有量が 0.1%未満では
上記の作用効果が不十分である。一方、Tiが 1.5%を超
えるとミクロ偏析の増大が顕著となり、靱性が低下す
る。
Ti: Ti precipitates Ni 3 Ti and NiTi by the aging treatment and contributes to the improvement of the tensile strength of steel similarly to Mo. It also has a function of shifting the precipitation temperature range of the intermetallic compound of Mo to the high temperature side to increase the high temperature softening resistance of ferrite and increase the high temperature strength. Further, Ti increases the high temperature strength by the action of increasing the transformation point of steel, and improves the heat check resistance. However, if the content is less than 0.1%, the above-mentioned effects are insufficient. On the other hand, when Ti exceeds 1.5%, the increase in microsegregation becomes remarkable and the toughness decreases.

【0024】sol.Al:Alは溶鋼の脱酸に必須の成分であ
り、その効果を得るためには、sol.Alとして0.02%以上
の含有量を必要とする。しかし、sol.Alとしての含有量
が 0.5%を超えると Ti3Alを析出し、靱性を低下させる
ことを考慮して、本発明ではその含有量を0.02〜0.5 %
とした。
Sol.Al: Al is an essential component for deoxidizing molten steel, and in order to obtain its effect, a content of sol.Al of 0.02% or more is required. However, considering that when the content as sol.Al exceeds 0.5%, Ti 3 Al precipitates and the toughness is reduced, in the present invention, the content is 0.02 to 0.5%.
And

【0025】以上が本発明のマルエージング鋼の必須成
分であり、その残部はFeと不純物である。ただし、不純
物のうち、特に下記の元素はその含有量をそれぞれの上
限値以下のできるだけ低い値に抑える必要がある。
The above are the essential components of the maraging steel of the present invention, with the balance being Fe and impurities. However, among the impurities, it is necessary to suppress the content of the following elements, in particular, to the lowest possible values below the respective upper limits.

【0026】C:CはTiと結合してTiCを析出する。こ
のTiCは、それ自体が鋼の靱性を低下させるが、一方で
はTiCの析出により前記の Ni3Ti、NiTiとして析出すべ
きTiを減少させ、強度、靱性を低下させる。かかる弊害
を避けるため、Cの含有量は0.03%以下とすべきであ
る。0.01%以下に抑えるのがさらに望ましい。
C: C combines with Ti to precipitate TiC. This TiC itself lowers the toughness of the steel, but on the other hand, the precipitation of TiC reduces the Ti that should be precipitated as the above Ni 3 Ti and NiTi, and lowers the strength and toughness. In order to avoid such adverse effects, the content of C should be 0.03% or less. It is more desirable to suppress it to 0.01% or less.

【0027】Si:Siは鋼中の介在物を増加させ、鋼の靱
性を低下させるので、本発明ではその含有量を 0.1%以
下とした。なお、Si含有量は0.05%以下が望ましい。
Si: Si increases the inclusions in the steel and reduces the toughness of the steel, so the content of Si is set to 0.1% or less in the present invention. The Si content is preferably 0.05% or less.

【0028】Mn:MnはSiと同様に介在物を増加させ、靱
性を低下させるので、本発明ではその含有量を 0.1%以
下とした。なお、Mn含有量は0.05%以下が望ましい。
Mn: Mn increases inclusions and lowers toughness similarly to Si. Therefore, the content of Mn is set to 0.1% or less in the present invention. The Mn content is preferably 0.05% or less.

【0029】P:Pは溶鋼が凝固する際のミクロ偏析に
より、鋼の靱性を低下させるので、本発明ではその含有
量を0.01%以下とした。なお、P含有量は 0.005%以下
が望ましい。
P: P reduces the toughness of the steel due to micro-segregation when the molten steel is solidified, so the content of P is set to 0.01% or less in the present invention. The P content is preferably 0.005% or less.

【0030】S:Sは硫化物を生成し、鋼の靱性を低下
させるので、本発明ではその含有量を0.01%以下とし
た。なお、S含有量は 0.003%以下が望ましい。
S: S forms sulfides and reduces the toughness of steel, so the content of S is set to 0.01% or less in the present invention. The S content is preferably 0.003% or less.

【0031】N:NはTiNを析出し、前記のCと同様に
析出に有効なTiを減少させる。また、TiNは、鍛造方向
に点列状に分布する傾向があり、金型等に加工したとき
にその表面性状を劣化させる。また、靱性も低下させる
ので、本発明ではその含有量を0.01%以下とした。な
お、N含有量は 0.005%以下が望ましい。
N: N precipitates TiN, and reduces Ti effective for precipitation, like C mentioned above. In addition, TiN tends to be distributed in a dot array in the forging direction, and deteriorates the surface quality when processed into a mold or the like. Further, since toughness is also reduced, the content is set to 0.01% or less in the present invention. The N content is preferably 0.005% or less.

【0032】Cr:Crは変態点を低下させ残留オーステナ
イトを増加させるので、鋼の強度を低下させる。従っ
て、本発明ではその含有量を 0.1%以下とした。なお、
Cr含有量は0.03%以下が望ましい。
Cr: Cr lowers the transformation point and increases the retained austenite, thus lowering the strength of the steel. Therefore, in the present invention, the content is set to 0.1% or less. In addition,
Cr content is preferably 0.03% or less.

【0033】以上が本発明のマルエージング鋼の合金成
分および不純物元素の個々の作用および含有量の限定理
由である。本発明のマルエージング鋼は、さらに必須合
金成分のうちのNi、Co、MoおよびTiの含有量が前記式
の関係を満たすことを特徴としている。
The above is the reasons for limiting the individual actions and contents of the alloying components and impurity elements of the maraging steel of the present invention. The maraging steel of the present invention is further characterized in that the contents of Ni, Co, Mo and Ti among the essential alloy components satisfy the relation of the above formula.

【0034】前述のように、本発明者らは、マルエージ
ング鋼のA1変態点が、主に、Ni、Co、Mo、Tiの4元素の
含有量によって大きく変化することを見いだし、そのA1
変態点は式の左辺で表されることを突き止めた。更
に、上記式の左辺の値が 675(℃) 以上であれば、そ
の鋼の耐ヒートチェック性が著しく向上することを確認
した。
As described above, the present inventors have found that the A 1 transformation point of the maraging steel largely changes mainly depending on the contents of the four elements of Ni, Co, Mo and Ti. 1
We have found that the transformation point is represented by the left side of the formula. Further, it was confirmed that if the value on the left side of the above formula is 675 (° C) or more, the heat check resistance of the steel is remarkably improved.

【0035】以下、実施例によって本発明の効果を具体
的に説明する。
The effects of the present invention will be specifically described below with reference to examples.

【0036】[0036]

【実施例】表1に示す化学組成の鋼を真空溶解し、20kg
の鋼塊とした後、熱間鍛造によって40mmφの丸棒に仕上
げた。その後 850℃で溶体化処理を施し、550 ℃で4時
間の時効処理を行った。
[Example] 20 kg of steel having the chemical composition shown in Table 1 was vacuum melted.
After making the steel ingot, it was hot forged into a 40 mmφ round bar. After that, solution treatment was performed at 850 ° C., and aging treatment was performed at 550 ° C. for 4 hours.

【0037】時効処理後の鋼から各種試験片を採取して
常温のロックウェルC硬度、600 ℃の高温強度(引張強
さ)、および耐ヒートチェック性を調査した。
Various test pieces were taken from the steel after the aging treatment, and the Rockwell C hardness at room temperature, the high temperature strength (tensile strength) at 600 ° C., and the heat check resistance were investigated.

【0038】耐ヒートチェック性の試験は、図1に示す
形状の試験片1を図2に示すように、高周波誘導加熱装
置(200 kHz の高周波コイル)2により表面温度が 650
℃(表面から4mmの深さの位置では約400 ℃) になるよ
うに急速加熱し、ただちに30℃の水槽3に浸漬して水冷
するサイクルを1000回繰り返した後、試験片の表面に発
生する亀裂を横断面のミクロ観察で検査し、平均の亀裂
深さを測定した。
In the heat check resistance test, the surface temperature of the test piece 1 having the shape shown in FIG.
Rapidly heats up to ℃ (about 400 ℃ at a depth of 4 mm from the surface), immediately immerses it in a water tank 3 at 30 ℃ and repeats water cooling 1000 times. The cracks were inspected by microscopic observation of the cross section and the average crack depth was measured.

【0039】表1中のNo.1〜10の鋼は本発明の実施例に
相当するものであり、No. 11〜14の鋼は、個々の成分含
有量は本発明で定める範囲内にあるが、前記式の条件
を満たしていない鋼である。No.15 および16の鋼は式
は満足するが、前者はTiを含まず、後者はMoが過少なも
のである。 No.17と18の鋼は従来の18%Ni系 250 ksi級
のマルエージング鋼である。
Steels Nos. 1 to 10 in Table 1 correspond to the examples of the present invention, and steels Nos. 11 to 14 have individual component contents within the range defined by the present invention. Is a steel that does not satisfy the conditions of the above formula. The steels of Nos. 15 and 16 satisfy the formula, but the former does not contain Ti, and the latter has an excessively small amount of Mo. Steel Nos. 17 and 18 are conventional 18% Ni-based 250 ksi grade maraging steels.

【0040】表2に常温のロックウェルC硬度、 600℃
の高温引張強さ、および耐ヒートチェック性の試験結果
を示す。常温の硬度は本発明鋼、比較鋼、従来鋼ともに
ほぼ同水準であるが、耐ヒートチェック性と高温強度に
おいては本発明鋼が格段に優れることが明らかである。
なお、比較鋼のうちNo.15 および16の鋼は、前記のとお
り式を満足するものであるが、それぞれTiを含まず、
Moの含有量が適正でないために、高温強度も耐ヒートチ
ェック性も本発明鋼に劣る。これによって、MoとTiとを
適正範囲で複合添加することが重要であることがわか
る。
Table 2 shows the Rockwell C hardness at room temperature, 600 ° C.
The high temperature tensile strength and the heat check resistance test results are shown. Although the hardness of the present invention, the comparative steel, and the conventional steel are almost the same level at room temperature, it is clear that the present invention is remarkably excellent in heat check resistance and high temperature strength.
Note that, among the comparative steels, No. 15 and 16 steels satisfy the formula as described above, but each does not contain Ti,
Since the Mo content is not appropriate, the high temperature strength and heat check resistance are inferior to those of the steel of the present invention. This shows that it is important to add Mo and Ti together in an appropriate range.

【0041】[0041]

【表1】 [Table 1]

【0042】[0042]

【表2】 [Table 2]

【0043】[0043]

【発明の効果】実施例にも示したとおり、本発明のマル
エージング鋼は高温強度が高く、耐ヒートチェック性に
きわめて優れている。このような特性をもつ鋼は、特に
高温加熱と冷却の繰り返しにさらされるダイカスト金型
の素材として用いれば金型の使用寿命の大幅な延長を可
能にし、ダイカスト製品の生産コストの低減に寄与す
る。また、本発明のマルエージング鋼は、18%Ni系に較
べてNi含有量が低いため安価であり、しかも強度、靱性
においても従来のマルエージング鋼に較べて何ら遜色な
いものであるから、従来のマルエージング鋼の各種用途
にも広く使用できるものである。
As shown in the examples, the maraging steel of the present invention has high high temperature strength and extremely excellent heat check resistance. Steels with such characteristics can significantly extend the service life of the die, if used as a material for die casting that is exposed to repeated high temperature heating and cooling, and contribute to the reduction of production cost of die casting products. . Further, the maraging steel of the present invention is inexpensive because the Ni content is lower than that of the 18% Ni system, and the strength and toughness of the maraging steel are not inferior to those of the conventional maraging steel. It can be widely used in various applications of the maraging steel of.

【図面の簡単な説明】[Brief description of drawings]

【図1】耐ヒートチェック性の調査に使用した試験片形
状を示す図で、 (a)は平面図、(b) は側面図 (単位はm
m) である。
FIG. 1 is a diagram showing the shape of a test piece used for the heat check resistance investigation. (A) is a plan view, (b) is a side view (unit: m
m).

【図2】耐ヒートチェック性を調査するための実験方法
の概略を示す図である。
FIG. 2 is a diagram showing an outline of an experimental method for investigating heat check resistance.

【符号の説明】[Explanation of symbols]

1…試験片、 2…誘導加熱装置、 3…水槽 1 ... Test piece, 2 ... Induction heating device, 3 ... Water tank

フロントページの続き (72)発明者 海野 正英 大阪府大阪市此花区島屋5丁目1番109号 住友金属工業株式会社製鋼所内 (72)発明者 太宰 敦夫 大阪府大阪市此花区島屋5丁目1番109号 住友金属工業株式会社製鋼所内(72) Inventor Masahide Unno 5-1-1109 Shimaya, Konohana-ku, Osaka City, Osaka Prefecture Sumitomo Metal Industries, Ltd. Steel Works (72) Inventor Atsuo Dazai 5-109 Shimaya, Konohana-ku, Osaka City, Osaka Prefecture No. Sumitomo Metal Industries, Ltd. Steel Works

Claims (1)

【特許請求の範囲】[Claims] 【請求項1】重量%で、Ni:8%から12%未満、Co:5
〜15%、Mo:2〜9%、Ti: 0.1〜1.5 %、sol.Al:0.
02〜0.5 %を含有し、残部はFeおよび不純物からなり、
不純物としてのCは0.03%以下、Siは 0.1%以下、Mnは
0.1%以下、Pは0.01%以下、Sは0.01%以下、Crは
0.1%以下、Nは0.01%以下であり、かつ、Ni、Co、Mo
およびTiの含有量は下記の式を満足することを特徴と
する高温強度が高く、耐ヒートチェック性に優れたマル
エージング鋼。 732− 6.7×(%Ni) + 3.7×(%Co) −2×(%Mo) + 4.3
×(%Ti) ≧ 675・・・
1. By weight%, Ni: 8% to less than 12%, Co: 5
~ 15%, Mo: 2-9%, Ti: 0.1-1.5%, sol.Al: 0.
02-0.5%, the balance Fe and impurities,
C as an impurity is 0.03% or less, Si is 0.1% or less, and Mn is
0.1% or less, P is 0.01% or less, S is 0.01% or less, Cr is
0.1% or less, N 0.01% or less, and Ni, Co, Mo
Maraging steel with high strength at high temperature and excellent heat check resistance, characterized in that the contents of Ti and Ti satisfy the following formula. 732- 6.7 x (% Ni) + 3.7 x (% Co) -2 x (% Mo) + 4.3
× (% Ti) ≧ 675 ・ ・ ・
JP6032097A 1994-03-02 1994-03-02 Maraging steel excellent in high temperature strength and heat check resistance Pending JPH07243002A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6032097A JPH07243002A (en) 1994-03-02 1994-03-02 Maraging steel excellent in high temperature strength and heat check resistance

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6032097A JPH07243002A (en) 1994-03-02 1994-03-02 Maraging steel excellent in high temperature strength and heat check resistance

Publications (1)

Publication Number Publication Date
JPH07243002A true JPH07243002A (en) 1995-09-19

Family

ID=12349398

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6032097A Pending JPH07243002A (en) 1994-03-02 1994-03-02 Maraging steel excellent in high temperature strength and heat check resistance

Country Status (1)

Country Link
JP (1) JPH07243002A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006096684A1 (en) * 2005-03-07 2006-09-14 Thixomat, Inc. Semisolid metal injection molding machine components of intermetallic hardened steel alloys
EP3255171A1 (en) * 2016-06-08 2017-12-13 Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) Maraging steel
WO2018159219A1 (en) * 2017-03-02 2018-09-07 株式会社神戸製鋼所 Maraging steel and method for manufacturing same
EP3578678A4 (en) * 2017-03-02 2020-07-22 Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) Maraging steel and method for manufacturing same

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006096684A1 (en) * 2005-03-07 2006-09-14 Thixomat, Inc. Semisolid metal injection molding machine components of intermetallic hardened steel alloys
EP3255171A1 (en) * 2016-06-08 2017-12-13 Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) Maraging steel
WO2018159219A1 (en) * 2017-03-02 2018-09-07 株式会社神戸製鋼所 Maraging steel and method for manufacturing same
EP3578678A4 (en) * 2017-03-02 2020-07-22 Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) Maraging steel and method for manufacturing same

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