JPS645098B2 - - Google Patents
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- Publication number
- JPS645098B2 JPS645098B2 JP11343782A JP11343782A JPS645098B2 JP S645098 B2 JPS645098 B2 JP S645098B2 JP 11343782 A JP11343782 A JP 11343782A JP 11343782 A JP11343782 A JP 11343782A JP S645098 B2 JPS645098 B2 JP S645098B2
- Authority
- JP
- Japan
- Prior art keywords
- steel
- ultra
- content
- strength
- high tensile
- 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
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- 229910000831 Steel Inorganic materials 0.000 claims description 31
- 239000010959 steel Substances 0.000 claims description 31
- 229910052782 aluminium Inorganic materials 0.000 claims description 7
- 229910052719 titanium Inorganic materials 0.000 claims description 7
- 229910052759 nickel Inorganic materials 0.000 description 21
- 229910001240 Maraging steel Inorganic materials 0.000 description 14
- 230000000694 effects Effects 0.000 description 12
- 238000001556 precipitation Methods 0.000 description 10
- 238000005728 strengthening Methods 0.000 description 9
- 238000001816 cooling Methods 0.000 description 8
- 230000032683 aging Effects 0.000 description 7
- 229910000734 martensite Inorganic materials 0.000 description 7
- 229910052750 molybdenum Inorganic materials 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 5
- 239000002244 precipitate Substances 0.000 description 5
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 4
- 229910001566 austenite Inorganic materials 0.000 description 4
- 229910000765 intermetallic Inorganic materials 0.000 description 4
- 238000010583 slow cooling Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 230000001376 precipitating effect Effects 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 230000035882 stress Effects 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 235000015842 Hesperis Nutrition 0.000 description 1
- 235000012633 Iberis amara Nutrition 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000004512 die casting Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000004881 precipitation hardening Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
Description
本発明は超高張力鋼に関し、さらに詳しくは、
航空機用部材、ロケツト、ミサイルのチヤンバ
ー、マンドレル、ステム、ダイキヤスト、或い
は、プラスチツクの金型等の工具、圧力容器、
板、線等のバネ、ボルト、フアスナー等に適用し
て好適な超高張力鋼に関するものである。
一般に、従来より使用され、又、提案されてい
る超高張力鋼として代表的な鋼種とその問題点に
ついて説明する。
(1) 焼入焼戻し鋼（例えば、SNCM439、
SKD61）
この鋼はＣ含有量が高いために、超高強度レ
ベルで靭性が低く、溶接性に問題があり、質量
効果が大きく極厚製品の品質が劣り、熱処理歪
が大きく、かつ、冷間加工性が悪いという問題
点がある。
(2) 析出硬化型ステンレス鋼（例えば、17―
4PHステンレス鋼）
この鋼は超高張力鋼としては強度と靭性が不
足しており、熱処理が複雑で、かつ、溶接性に
問題がある。
(3) 18％Niマルエージング鋼
この鋼は超高強度レベルで優れた靭性を有
し、(1)、(2)で説明した鋼の問題点は解消された
が、Co、Moを多量に含有するためコスト高と
なり省資源からも問題がある。また、TiC、
TiNによる粒界脆化の問題から大型製品の場
合に問題が生じる。
(4) 20％Ni、25％Niマルエージング鋼
この鋼は強度に優れているが、時効処理時に
粗大なNi3（Ti、Al）が結晶粒界に析出し、こ
のため靭性が著しく劣化するという問題があ
る。
(5) 20％Ni、25％Niマルエージング鋼改良型
（特願昭46−9371号）
この鋼は20％Ni、25％Niマルエージング鋼
にMoを添加してNi3（Ti、Al）の結晶粒界への
析出を阻止し、靭性を改善したマルエージング
鋼であるが、18％Niマルエージング鋼と同様
に、冷却速度が遅い場合の脆化や低い疲労強度
の問題が残されている。
本発明が上記に説明した従来における超高張力
鋼の種々の問題点に鑑みなされたものであり、優
れた靭性や強度を有する超高張力鋼を提供するも
のである。
本発明に係る優れた靭性、強度を有する超高張
力鋼は、(1)Ｃ≦0.05％、Ni10〜25％、Mo0.2〜
4.0％、Ti0.1〜5.0％、Al0.01〜3.0％、B0.0005〜
0.1％を含有し、残部実質的にFeであることを特
徴とする超高張力鋼を第１の発明とし、(2)Ｃ≦
0.05％、Ni10〜25％、Mo0.2〜4.0％、Ti0.1〜5.0
％、Al0.01〜3.0％、B0.0005〜0.1％、Co2％以下
を含有し、残部実質的にFeであることを特徴と
する超高張力鋼を第２の発明とする２つの発明よ
りなるものである。
本発明に係る超高張力鋼は、上記の構成を有し
ているものであるが、以下説明することが基本と
なつているのである。
(1) 強靭化には、18％Niマルエージング鋼と同
様に、金属間化合物の析出による強化を利用す
るが、Co、Moの含有量を少なくして、Ti、
Alの含有量を増加させて析出強化を図る。即
ち、Fe―（10〜25）％Niで靭性の優れたマル
テンサイト母相を形成し、析出強化元素として
Ti、Alを含有させ、時効処理によつてマルテ
ンサイト母相中に金属間化合物を析出させて強
靭化し、超高強度レベルでの靭性を確保するた
め、Ｃ含有量は極力低くするとともに、Ｐ、Ｓ
も不純物元素として極力低く抑制する。
(2) 18％Niマルエージング鋼のCo含有量７〜14
％、Mo4〜６％とあるのを、Coは含有させな
かつたり、含有させても２％以下、また、Mo
は0.2〜４％と低い含有量とし、このため、強
度低下を補い、かつ、超高強度レベルでの靭性
を確保するためにTi、Alを複合含有させるの
である。
(3) 18％Niマルエージング鋼の問題点である徐
冷時の脆化を防ぎ、疲労強度を向上させるため
に、Ｂを含有させるのであり、即ち、18％Ni
マルエージング鋼、20％Ni、25％Niマルエー
ジング改良鋼は、オーステナイト化処理後、冷
却速度が小さい場合、TiC、TiNがオーステナ
イト粒界に析出して粒界脆化することが知られ
ており、このような徐冷時の脆化を防止するた
めにはＢを含有させるのが効果的であり、Ｂを
0.0005〜0.1％の範囲に含有させると徐冷脆化
現象がなく、このことは、オーステナイト化処
理中にＢがオーステナイト粒界に偏析し、それ
によつてTiC、TiNの粒界上への析出が抑制さ
れるためと考えられる。また、18％Niマルエ
ージング鋼、20％Ni、25％Niマルエージング
改良鋼は極低炭素鋼で侵入型固溶元素を含んで
いないので、これがマルエージング鋼の疲労強
度が低い原因の一つと考えられ、一部侵入型に
固溶するＢを含有させて疲労強度の向上を図つ
ている。
(4) 20％Ni、25％Niマルエージング改良鋼では、
時として深冷処理を必要とするが、深冷処理を
施さなくても室温にてマルテンサイト相になる
ように成分調整をする。
次に熱処理については、Af温度以上でオース
テナイト化し、常温まで冷却（冷却速度は問わな
い。）して、マルテンサイト相を得、次いで、300
〜650℃×（0.5〜100）hr時効処理して析出強化さ
せるのである。
次に、本発明に係る超高張力鋼の含有成分、お
よび、成分割合について詳細に説明する。
Ｃは強度を高める作用をするが、強化にＣを使
用した場合従来の焼入焼戻し超高張力鋼のように
靭性が低くなり、溶接性に問題があり、熱処理歪
が大きく、また、冷間加工性が悪くなるという問
題が生じるので、本発明に係る超高張力鋼では、
Ｃは不純物元素と考え強化には金属間化合物の析
出を利用するので、Ｃ含有量は、0.05％以下とす
る。
Niはマルテンサイト母相を形成する重要な元
素であり、靭性の優れた高強度ラスマルテンサイ
ト相を生成させるためには、Ni含有量が10％未
満ではこの効果が得られず、また、25％を越えて
含有されるとオーステナイト相が安定化して室温
で100％マルテンサイト相にならない。よつて、
Ni含有量は、10〜25％とする。また、Niは時効
処理によりTi、Al、Cu、Moと金属間化合物を
形成して強度を上昇させる作用がある。
Moは超高強度レベルでの粒界脆化を防止する
元素で、含有量が0.2％未満ではこの効果は少な
く、また、時効処理によりNi3Mo、Fe2Moとし
て析出し強化に寄与するが、含有量が多くなると
経済的でないので4.0％を越えて含有させない。
よつて、Mo含有量は0.2〜4.0％とする。
Tiは強度を付与する重要な元素で、時効処理
によりNi3Tiが析出して著しく強化するが、含有
量が0.1％未満では析出強化にあまり期待ができ
ず、また、多量に含有すると脆化するので5.0％
を越えて含有させる必要はない。よつて、Ti含
有量は0.1〜5.0％とする。
Alは強化に大きな影響を与える元素であり、
時効処理によりNi3Alを析出し強度を上昇させる
が、含有量が0.01％未満ではこの効果が少なく、
また、3.0％を越えて多量に含有されると脆化す
る。よつて、Al含有量は0.01〜3.0％とする。
Ｂはオーステナイト化処理中に、オーステナイ
ト粒界に偏析し、これにより冷却速度が小さい場
合でも、TiC、TiNの粒界上への析出を抑制する
ため徐冷脆化を防止する効果があり、また、一部
侵入型に固溶して疲労強度を向上させるのであ
る。このような効果を得るには、Ｂ含有量は
0.0005〜0.1％とする。
CoはMoの固溶度を低下させ、Ni3Moなどの析
出を促進する作用があるといわれているが、本発
明に係る超高張力鋼ではむしろTi、Alによる析
出効果が主であり、Co含有の効果は少ない。ま
た、Coは高価であることもあつて、Co含有量は
２％以下とする。
Si、Mn、Ｐ、Ｓは不純物元素とみなされるの
で、できる限り低く抑える必要があり、含有量と
しては、Si≦0.3％、Mn≦0.3％、Ｐ≦0.05％、お
よび、Ｓ≦0.05％とするのが望ましい。
本発明に係る超高張力鋼の実施例について比較
例とともに説明する。
実施例
第１表に示す含有成分、および、成分割合とな
るように、各鋼種を通常の溶製法により溶製して
鋳造した。その後、加工して試料を調整した。第
２表に熱処理条件と機械的性質について示す。
また、第１図にＢ含有のNo.７、No.８の本発明に
係る超高張力鋼と、No.15、No.16の比較鋼との絞り
と冷却速度について示してある。
第２図はＢ含有鋼Ａと比較鋼Ｂの応力振幅と繰
り返し数について示してある。
The present invention relates to ultra-high tensile strength steel, and more particularly:
Aircraft parts, rockets, missile chambers, mandrels, stems, tools such as die casting or plastic molds, pressure vessels,
The present invention relates to ultra-high tensile strength steel suitable for use in springs, bolts, fasteners, etc. such as plates and wires. In general, typical types of ultra-high tensile strength steels that have been conventionally used or proposed and their problems will be explained. (1) Quenched and tempered steel (e.g. SNCM439,
SKD61) This steel has a high C content, so it has ultra-high strength, low toughness, weldability problems, large mass effect, poor quality of extremely thick products, large heat treatment distortion, and cold There is a problem of poor workability. (2) Precipitation hardening stainless steel (e.g. 17-
4PH stainless steel) This steel lacks the strength and toughness of ultra-high tensile strength steel, requires complicated heat treatment, and has problems with weldability. (3) 18% Ni maraging steel This steel has ultra-high strength and excellent toughness, and the problems of steel explained in (1) and (2) have been solved, but it contains a large amount of Co and Mo. Because of the presence of carbon dioxide, the cost is high and there are also problems in terms of resource conservation. Also, TiC,
Problems arise in large products due to grain boundary embrittlement caused by TiN. (4) 20%Ni, 25%Ni maraging steel This steel has excellent strength, but coarse Ni 3 (Ti, Al) precipitates at grain boundaries during aging treatment, which significantly deteriorates toughness. There is a problem. (5) Improved 20% Ni, 25% Ni maraging steel (Patent Application No. 1971-9371) This steel is a 20% Ni, 25% Ni maraging steel with the addition of Mo and Ni 3 (Ti, Al). This maraging steel has improved toughness by preventing Ni from precipitating at grain boundaries, but like the 18% Ni maraging steel, it still suffers from embrittlement and low fatigue strength when the cooling rate is slow. There is. The present invention has been made in view of the various problems of conventional ultra-high tensile strength steels explained above, and provides ultra-high tensile strength steels having excellent toughness and strength. The ultra-high tensile steel having excellent toughness and strength according to the present invention has (1) C≦0.05%, Ni10-25%, Mo0.2-
4.0%, Ti0.1~5.0%, Al0.01~3.0%, B0.0005~
The first invention is an ultra-high tensile strength steel characterized by containing 0.1% Fe and the remainder being substantially Fe, and (2) C≦
0.05%, Ni10~25%, Mo0.2~4.0%, Ti0.1~5.0
%, Al0.01-3.0%, B0.0005-0.1%, Co2% or less, and the balance is substantially Fe. It is what it is. The ultra-high tensile strength steel according to the present invention has the above-mentioned structure, but the following is the basic principle. (1) For toughening, similar to 18%Ni maraging steel, strengthening by precipitation of intermetallic compounds is used, but the content of Co and Mo is reduced, and Ti,
Aiming at precipitation strengthening by increasing the Al content. In other words, Fe-(10~25)%Ni forms a martensitic matrix with excellent toughness and is used as a precipitation strengthening element.
In order to contain Ti and Al and precipitate intermetallic compounds in the martensite matrix through aging treatment to make it tougher and ensure toughness at an ultra-high strength level, the C content is kept as low as possible, and P , S
Also, as an impurity element, it is suppressed as low as possible. (2) Co content of 18% Ni maraging steel 7-14
%, Mo4 to 6%, but Co is not included, or even if it is included, it is less than 2%, and Mo
The content is as low as 0.2 to 4%, and therefore Ti and Al are contained in a composite manner to compensate for the decrease in strength and to ensure toughness at an ultra-high strength level. (3) In order to prevent embrittlement during slow cooling, which is a problem with 18% Ni maraging steel, and to improve fatigue strength, B is included, that is, 18% Ni
Maraging steel, 20% Ni, 25% Ni improved maraging steel is known to cause grain boundary embrittlement due to TiC and TiN precipitating at austenite grain boundaries if the cooling rate is slow after austenitizing treatment. In order to prevent such embrittlement during slow cooling, it is effective to include B.
When B is contained in the range of 0.0005 to 0.1%, there is no slow cooling embrittlement phenomenon, which means that B segregates at the austenite grain boundaries during the austenitization process, thereby preventing the precipitation of TiC and TiN on the grain boundaries. This is thought to be because it is suppressed. In addition, 18% Ni maraging steel, 20% Ni, and 25% Ni improved maraging steel are ultra-low carbon steels that do not contain interstitial solid solution elements, which is one of the reasons why the fatigue strength of maraging steel is low. Therefore, the fatigue strength is improved by partially incorporating B as a solid solution in the interstitial form. (4) For 20% Ni and 25% Ni maraging improved steels,
Although deep cooling treatment is sometimes required, the components are adjusted so that the martensite phase can be obtained at room temperature even without deep cooling treatment. Next, regarding heat treatment, it is austenitized at a temperature higher than Af temperature, cooled to room temperature (the cooling rate does not matter) to obtain a martensitic phase, and then
It is subjected to aging treatment at ~650°C x (0.5~100) hours to strengthen it by precipitation. Next, the components contained in the ultra-high tensile strength steel according to the present invention and the component ratios will be explained in detail. C has the effect of increasing strength, but when C is used for strengthening, the toughness is lower than that of conventional quenched and tempered ultra-high tensile strength steel, there are problems with weldability, large heat treatment distortions, and cold Since the problem of poor workability arises, in the ultra-high tensile steel according to the present invention,
Since C is considered to be an impurity element and the precipitation of intermetallic compounds is used for strengthening, the C content is set to 0.05% or less. Ni is an important element that forms the martensite matrix, and in order to generate a high-strength lath martensite phase with excellent toughness, this effect cannot be obtained if the Ni content is less than 10%. If the content exceeds %, the austenite phase will be stabilized and will not become 100% martensite at room temperature. Then,
The Ni content is 10 to 25%. Furthermore, Ni has the effect of increasing strength by forming intermetallic compounds with Ti, Al, Cu, and Mo through aging treatment. Mo is an element that prevents grain boundary embrittlement at ultra-high strength levels, and if the content is less than 0.2%, this effect is small, and when aging treatment, it precipitates as Ni 3 Mo and Fe 2 Mo, contributing to strengthening. , since it is not economical if the content increases, the content should not exceed 4.0%.
Therefore, the Mo content is set to 0.2 to 4.0%. Ti is an important element that imparts strength, and Ni 3 Ti precipitates during aging treatment, significantly strengthening it. However, if the content is less than 0.1%, precipitation strengthening cannot be expected, and if it is contained in a large amount, it will become brittle. Therefore, 5.0%
It is not necessary to contain more than Therefore, the Ti content is set to 0.1 to 5.0%. Al is an element that has a great effect on strengthening.
Aging treatment precipitates Ni 3 Al to increase the strength, but if the content is less than 0.01%, this effect is small;
Moreover, if it is contained in a large amount exceeding 3.0%, it becomes brittle. Therefore, the Al content is set to 0.01 to 3.0%. B segregates at the austenite grain boundaries during the austenitization process, and even when the cooling rate is slow, it suppresses the precipitation of TiC and TiN on the grain boundaries, which has the effect of preventing slow cooling embrittlement. , partially interstitial solid solution improves fatigue strength. To obtain this effect, the B content must be
Set to 0.0005-0.1%. It is said that Co has the effect of reducing the solid solubility of Mo and promoting the precipitation of Ni 3 Mo, etc., but in the ultra-high tensile steel according to the present invention, the precipitation effect is mainly caused by Ti and Al. Co content has little effect. Furthermore, since Co is expensive, the Co content should be 2% or less. Since Si, Mn, P, and S are considered impurity elements, they must be kept as low as possible.The content should be Si≦0.3%, Mn≦0.3%, P≦0.05%, and S≦0.05%. It is desirable to do so. Examples of ultra-high tensile strength steel according to the present invention will be described together with comparative examples. Examples Each type of steel was melted and cast using a normal melting method so as to have the components and ratios shown in Table 1. Thereafter, the sample was prepared by processing. Table 2 shows the heat treatment conditions and mechanical properties. Further, FIG. 1 shows the reduction of area and cooling rate of B-containing ultra-high tensile strength steels No. 7 and No. 8 according to the present invention and comparative steels No. 15 and No. 16. FIG. 2 shows the stress amplitude and number of repetitions for B-containing steel A and comparative steel B.
【表】【table】
【表】【table】
【表】
以上説明したように、本発明に係る超高張力鋼
は上記の構成を有しているものであるから、引張
性質、絞り等の機械的性質は極めて優れたもので
あつて、従来のものに比して勝るとも劣らない良
好な超高張力鋼である。[Table] As explained above, since the ultra-high tensile strength steel according to the present invention has the above-mentioned structure, it has extremely superior mechanical properties such as tensile properties and reduction of area. This ultra-high tensile strength steel is as good as any other.
第１図は絞りと冷却速度を示す図、第２図は応
力振幅と繰返し数を示す図である。
FIG. 1 is a diagram showing the aperture and cooling rate, and FIG. 2 is a diagram showing the stress amplitude and the number of repetitions.
Claims (1)
Ti0.1〜5.0％、Al0.01〜3.0％、B0.0005〜0.1％を
含有し、残部実質的にFeであることを特徴とす
る超高張力鋼。 ２ Ｃ≦0.05％、Ni10〜25％、Mo0.2〜4.0％、
Ti0.1〜5.0％、Al0.01〜3.0％、B0.0005〜0.1％、
Co2％以下を含有し、残部実質的にFeであること
を特徴とする超高張力鋼。[Claims] 1 C≦0.05%, Ni10-25%, Mo0.2-4.0%,
An ultra-high tensile steel containing 0.1-5.0% Ti, 0.01-3.0% Al, and 0.0005-0.1% B, with the remainder being substantially Fe. 2 C≦0.05%, Ni10~25%, Mo0.2~4.0%,
Ti0.1~5.0%, Al0.01~3.0%, B0.0005~0.1%,
An ultra-high tensile steel characterized by containing 2% or less of Co, with the remainder being essentially Fe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11343782A JPS596356A (en) | 1982-06-30 | 1982-06-30 | Ultra-high tensile steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11343782A JPS596356A (en) | 1982-06-30 | 1982-06-30 | Ultra-high tensile steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS596356A JPS596356A (en) | 1984-01-13 |
| JPS645098B2 true JPS645098B2 (en) | 1989-01-27 |
Family
ID=14612195
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11343782A Granted JPS596356A (en) | 1982-06-30 | 1982-06-30 | Ultra-high tensile steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS596356A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0436597U (en) * | 1990-07-24 | 1992-03-26 | ||
| MX2007011392A (en) * | 2005-08-30 | 2007-11-09 | Ati Properties Inc | Steel compositions, methods of forming the same, and articles formed therefrom. |
| US8444776B1 (en) | 2007-08-01 | 2013-05-21 | Ati Properties, Inc. | High hardness, high toughness iron-base alloys and methods for making same |
| KR101873582B1 (en) | 2007-08-01 | 2018-08-02 | 에이티아이 프로퍼티즈 엘엘씨 | High hardness, high toughness iron-base alloys and methods for making same |
| US9182196B2 (en) | 2011-01-07 | 2015-11-10 | Ati Properties, Inc. | Dual hardness steel article |
-
1982
- 1982-06-30 JP JP11343782A patent/JPS596356A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS596356A (en) | 1984-01-13 |
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