JP2934089B2 - Manufacturing method of maraging steel - Google Patents
Manufacturing method of maraging steelInfo
- Publication number
- JP2934089B2 JP2934089B2 JP3344199A JP34419991A JP2934089B2 JP 2934089 B2 JP2934089 B2 JP 2934089B2 JP 3344199 A JP3344199 A JP 3344199A JP 34419991 A JP34419991 A JP 34419991A JP 2934089 B2 JP2934089 B2 JP 2934089B2
- Authority
- JP
- Japan
- Prior art keywords
- steel
- maraging steel
- delayed fracture
- tensile strength
- less
- 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
- 229910001240 Maraging steel Inorganic materials 0.000 title claims description 33
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- 230000003111 delayed effect Effects 0.000 claims description 30
- 238000005482 strain hardening Methods 0.000 claims description 16
- 238000003483 aging Methods 0.000 claims description 12
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 claims description 5
- 238000000034 method Methods 0.000 claims description 5
- 229910052799 carbon Inorganic materials 0.000 claims description 4
- 229910000831 Steel Inorganic materials 0.000 description 34
- 239000010959 steel Substances 0.000 description 34
- 230000000052 comparative effect Effects 0.000 description 16
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 13
- 229910000040 hydrogen fluoride Inorganic materials 0.000 description 13
- 239000007789 gas Substances 0.000 description 11
- SANRKQGLYCLAFE-UHFFFAOYSA-H uranium hexafluoride Chemical compound F[U](F)(F)(F)(F)F SANRKQGLYCLAFE-UHFFFAOYSA-H 0.000 description 11
- 239000000463 material Substances 0.000 description 8
- 230000007423 decrease Effects 0.000 description 5
- 238000009864 tensile test Methods 0.000 description 5
- 230000007797 corrosion Effects 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 4
- 239000013078 crystal Substances 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- 229910052770 Uranium Inorganic materials 0.000 description 2
- 230000032683 aging Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 230000035882 stress Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- JFALSRSLKYAFGM-UHFFFAOYSA-N uranium(0) Chemical compound [U] JFALSRSLKYAFGM-UHFFFAOYSA-N 0.000 description 2
- 238000003723 Smelting Methods 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 150000002222 fluorine compounds Chemical class 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 229910000765 intermetallic Inorganic materials 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000011257 shell material Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、圧力容器外殻材、宇宙
航空用部品、原子力用部材のような高強度、高靭性、耐
蝕性及び耐遅れ破壊性が要求される分野で使用するのに
適したマルエージング鋼の製造方法に関し、特に、フッ
化物系ガス雰囲気で使用しても優れた耐遅れ破壊性を有
するマルエージング鋼の製造方法に関するものである。The present invention is used in fields requiring high strength, high toughness, corrosion resistance and delayed fracture resistance, such as pressure vessel shell materials, aerospace parts, and nuclear power parts. More particularly, the present invention relates to a method for producing a maraging steel having excellent delayed fracture resistance even when used in a fluoride gas atmosphere.
【０００２】[0002]
【従来の技術】マルエージング鋼は極低炭素の高Ｎｉマ
ルテンサイト鋼を時効硬化処理し、Ｎｉ3 Ｔｉ、Ｎｉ3
Ｍｏ等の微細な金属間化合物を析出させた強靭鋼であ
る。なかでも１８％Ｎｉ系マルエージング鋼は比較的に
強度と靭性とを兼ね備えており、加工熱処理やサブゼロ
処理等の複雑な熱処理を必要とせず、合金元素の添加量
を変化させることにより、冷間加工を加えない状態で引
張強さ１４０〜２８０Ｋｇ／ｍｍ2 程度のものが得られ
る。さらに冷間加工性及び溶接性にも優れることから量
産品の材料として適したものである。2. Description of the Related Art Maraging steel is a low-carbon high-Ni martensitic steel which is subjected to age hardening treatment to obtain Ni 3 Ti, Ni 3
This is a tough steel in which fine intermetallic compounds such as Mo are precipitated. Above all, 18% Ni-based maraging steel has relatively high strength and toughness, does not require complicated heat treatment such as working heat treatment or sub-zero treatment, and can be cold-worked by changing the amount of alloying elements added. A tensile strength of about 140 to 280 kg / mm 2 can be obtained without any processing. Further, since it is excellent in cold workability and weldability, it is suitable as a material for mass production.
【０００３】[0003]
【発明が解決しようとする課題】一般に高強度鋼におい
ては降伏応力よりも低い負荷条件においても環境との相
互作用の結果、遅れ破壊に到ることがあり、その使用に
あたっては応力及び環境条件に十分な注意を払う必要が
ある。１８％Ｎｉ系マルエージング鋼もこの例外ではな
く、六フッ化ウランガスやフッ化水素のような腐蝕性の
強いガス中で負荷を行うと容易に遅れ破壊を生じ、その
性能が十分に発揮されない。この傾向は引張強さが２６
０Ｋｇ／ｍｍ2 を超えるとより顕著となる。また、六フ
ッ化ウランガスは前述のように遅れ破壊を引き起こす原
因となるとともにマルエージング鋼を腐食させ、このと
きに生じるウランの低次フッ化物がマルエージング鋼の
表面に付着する現象を生起する。従って例えばマルエー
ジング鋼により回転体構造物を構築した場合、ウランの
低次フッ化物の付着物が回転体のアンバランスを引き起
こし、回転が不可となる。Generally, in high-strength steel, even under a load condition lower than the yield stress, delayed fracture may occur as a result of interaction with the environment. Great care must be taken. 18% Ni-based maraging steel is no exception to this. When a load is applied in a highly corrosive gas such as uranium hexafluoride gas or hydrogen fluoride, delayed fracture easily occurs, and its performance is not sufficiently exhibited. This tendency indicates that the tensile strength is 26
When it exceeds 0 Kg / mm 2 , it becomes more remarkable. Further, uranium hexafluoride gas causes delayed fracture as described above and corrodes the maraging steel, causing a phenomenon in which low-order fluorides of uranium generated at this time adhere to the surface of the maraging steel. Therefore, for example, when a rotating body structure is constructed by maraging steel, the deposit of uranium with a lower fluoride causes imbalance of the rotating body, and rotation becomes impossible.
【０００４】そこで本発明は、２６０Ｋｇ／ｍｍ2 以上
の高い強度を有し、しかも六フッ化ウランガスのごとき
フッ化物ガス中での耐遅れ破壊性及び耐蝕性に優れる１
８％Ｎｉ系マルエージング鋼の製造方法を提供すること
を目的とする。[0004] Therefore, the present invention is intended to provide high strength of 260 kg / mm 2 or more, and excellent resistance to delayed fracture and corrosion in a fluoride gas such as uranium hexafluoride gas.
An object of the present invention is to provide a method for producing an 8% Ni-based maraging steel.
【０００５】[0005]
【課題を解決するための手段】すなわち本発明によるマ
ルエージング鋼の製造方法は、重量百分率でＮｉが１７
〜１９％、Ｃｏが１１．７〜１２．７％、Ｍｏが３．８
〜４．５％、Ｔｉが１．４５〜１．５５％、Ａｌが０．
３％以下、Ｃが０．０３％以下、Ｓｉが０．１％以下、
Ｍｎが０．１％以下、Ｐが０．００１％以下、Ｓが０．
００１％以下、残部がＦｅからなるマルエージング鋼を
断面減少率で５０％以上の冷間加工を施し８２０〜８３
０℃で１時間溶体化処理後、断面減少率で６５〜７０％
の冷間加工を施し、次いで５１０〜５２０℃で１〜１０
時間時効硬化処理することを特徴とするものである。That is, the method for producing a maraging steel according to the present invention comprises the steps of:
~ 19%, Co is 11.7 ~ 12.7%, Mo is 3.8
４4.5%, Ti 1.45５1.55%, Al 0. 4%.
3% or less, C is 0.03% or less, Si is 0.1% or less,
Mn is 0.1% or less, P is 0.001% or less, and S is 0.1% or less.
001% or less, the remainder is made of a maraging steel made of Fe and subjected to cold working at a cross-sectional reduction rate of 50% or more.
After solution treatment at 0 ° C for 1 hour, the cross-sectional reduction rate is 65-70%
And then cold working at 510-520 ° C. for 1-10
It is characterized by being subjected to a time-age hardening treatment.
【０００６】本発明の製造工程を理解しやく図示すると
図１のようになる。以下に本発明におけるマルエージン
グ鋼の組成および製造条件の設定理由を説明する。なお
成分を示す％はいずれも重量百分率を表わす。FIG. 1 shows the manufacturing process of the present invention for easy understanding. Hereinafter, the reasons for setting the composition of the maraging steel and the manufacturing conditions in the present invention will be described. In addition, each% which shows a component represents a weight percentage.
【０００７】化学成分 Ｎｉは材料の靭性を改善する効果があるが、オーステナ
イト安定化元素であり過剰に添加すると高強度が得られ
ないことから、引張強さ２６０Ｋｇ／ｍｍ2 以上を有す
る１８％Ｎｉ系マルエージング鋼中のＮｉ量は自ずと規
定されその範囲は１７％〜１９％である。Although the chemical component Ni has the effect of improving the toughness of the material, it is an austenite stabilizing element, and if it is added excessively, high strength cannot be obtained. Therefore, 18% Ni having a tensile strength of 260 kg / mm 2 or more is used. The amount of Ni in the system maraging steel is naturally defined, and its range is 17% to 19%.
【０００８】Ｍｏは析出強化元素であり、通常３〜６％
の範囲で添加される。しかしながら図２に示すようにＭ
ｏ量の多いマルエージング鋼ではウランフッ化物の付着
量が増加し、六フッ化ウランガスに耐する耐蝕性が低下
することがわかる。また、添加量が少ないと所望の強度
が得られないことから、Ｍｏ量は３．８〜４．５％と規
定する。[0008] Mo is a precipitation strengthening element, usually 3-6%
Is added within the range. However, as shown in FIG.
It can be seen that in a maraging steel having a large o content, the amount of uranium fluoride attached increases, and the corrosion resistance to uranium hexafluoride gas decreases. In addition, since the desired strength cannot be obtained if the amount is small, the Mo amount is specified to be 3.8 to 4.5%.
【０００９】Ｔｉは同じく析出強化元素であるが、多量
の添加は靭性を低下させる。第３図にマルエージング鋼
中のＴｉ量を変化させフッ化水素中で低ひずみ速度引張
試験を行った結果を示す。低ひずみ速度引張試験は一定
の環境下において毎分１μｍの非常にゆっくりとした引
張速度で試験片を破断に到らしめ、このときの破断強度
の大小により材料の遅れ破壊感受性を評価するものであ
る。図３の縦軸はフッ化水素中での引張強さσを大気中
での引張強さσ0 で除した値の百分率であり、材料の耐
遅れ破壊性を表わしている。Ｔｉ量の増加とともに遅れ
破壊感受性が増大することがわかる。このためＴｉ量は
できるだけ低くすることが望ましいが、前述のようにＭ
ｏ量を定めたことから２６０Ｋｇ／ｍｍ2 以上の強度を
確保するためにＴｉ量は１．４５〜１．５５％と規定す
る。[0009] Ti is also a precipitation strengthening element, but the addition of a large amount lowers the toughness. FIG. 3 shows the results of performing a low strain rate tensile test in hydrogen fluoride while changing the amount of Ti in the maraging steel. The low-strain-rate tensile test involves breaking a test piece at a very slow tensile speed of 1 μm per minute under a constant environment, and evaluating the delayed fracture susceptibility of the material based on the magnitude of the breaking strength at this time. is there. The vertical axis in FIG. 3 is the percentage of the value obtained by dividing the tensile strength σ in hydrogen fluoride by the tensile strength σ 0 in the atmosphere, and represents the delayed fracture resistance of the material. It can be seen that delayed fracture susceptibility increases with an increase in the amount of Ti. For this reason, it is desirable to reduce the Ti content as much as possible.
Since the amount of o is determined, the amount of Ti is specified to be 1.45 to 1.55% in order to secure a strength of 260 kg / mm 2 or more.
【００１０】ＣｏはＭｏ含有鋼の時効硬化を促進させる
が過剰に添加すると靭性を低下させるため、通常７〜１
２．５％としている。しかしながら強化に寄与する合金
元素であるＭｏ及びＴｉ量を前述のように定めたことか
ら２６０Ｋｇ／ｍｍ2 以上の強度を確保するために、上
限値をやや高めとし１１．７〜１２．７％とする。[0010] Co promotes age hardening of the Mo-containing steel, but if added excessively, lowers the toughness.
2.5%. However, since the amounts of Mo and Ti, which are alloy elements contributing to strengthening, are determined as described above, the upper limit is set to a slightly higher value of 11.7 to 12.7% to secure a strength of 260 kg / mm 2 or more. I do.
【００１１】ＰおよびＳはマルエージング鋼の粒界に偏
析し粒界強度を弱め、材料の耐遅れ破壊性を低下させ
る。したがってＰおよびＳ量は可能な限り低くする必要
があるが、製錬、製鋼上の制約からともに０．００１％
以下と規定する。P and S segregate at the grain boundaries of the maraging steel, weakening the grain boundary strength and reducing the delayed fracture resistance of the material. Therefore, the contents of P and S need to be as low as possible, but are limited to 0.001% for both smelting and steelmaking.
It is specified as follows.
【００１２】その他の不純物元素であるＣ、Ｓｉ、Ｍｎ
及びＡｌの量については通常のマルエージング鋼と同等
である。Other impurity elements such as C, Si and Mn
And the amount of Al is equivalent to that of ordinary maraging steel.
【００１３】溶体化処理温度 図４に示すように同じＭｏ含有量であってもＭｏの未固
溶析出物が残留する温度で溶体化処理を行ったマルエー
ジング鋼はウランフッ化物の付着量が増加する。したが
って溶体化処理温度の下限はＭｏを完全に固溶させ六フ
ッ化ウランガスに対する耐蝕性を向上させるために８２
０℃以上と規定する。また、マルエージング鋼の遅れ破
壊感受性を低下させるためには結晶粒を微細化させる必
要がある。結晶粒径は溶体化処理前の冷間加工率と溶体
化処理温度との組合せによって決まり、５０％以上の冷
間加工を施した後８３０℃以下で溶体化処理を行えばＡ
ＳＴＭ Ｎｏ．９以上の結晶粒が得られ、耐遅れ破壊性
に優れるマルエージング鋼とすることができる。以上の
ことから溶体化処理温度は８２０〜８３０℃と定める。
なお、処理時間は１時間とする。 Solution treatment temperature As shown in FIG. 4, the maraging steel subjected to solution treatment at a temperature at which undissolved Mo precipitates remain even with the same Mo content has an increased amount of uranium fluoride attached. I do. Accordingly, the lower limit of the solution treatment temperature is set to 82 in order to completely dissolve Mo and improve the corrosion resistance to uranium hexafluoride gas.
Defined as 0 ° C or higher. Further, in order to reduce the delayed fracture susceptibility of maraging steel, it is necessary to refine crystal grains. The crystal grain size is determined by the combination of the cold working ratio before the solution treatment and the solution treatment temperature. If the solution treatment is performed at 830 ° C. or less after performing the cold working of 50% or more, A
STM No. Nine or more crystal grains are obtained, and a maraging steel having excellent delayed fracture resistance can be obtained. From the above, the solution treatment temperature is determined to be 820 to 830 ° C.
The processing time is one hour.
【００１４】冷間加工率 図５に１８％Ｎｉ系マルエージング鋼の溶体化処理後の
冷間加工率を変化させたものを時効硬化処理後、フッ化
水素中で低ひずみ速度引張試験を行った結果を示す。冷
間加工率を増加させるとフッ化水素中での引張強さは増
大し、遅れ破壊感受性が低下することがわかる。一方図
６に示すように通常の大気中での引張強さは冷間加工率
を増加させると加工方向、加工直角方向とも漸増する。
しかしながら図７に示すように切欠引張強さは冷間加工
率が断面減少率で７０％を超えると急激に低下し、靭性
が著しく損なわれ耐遅れ破壊性が低下する傾向にあるこ
とがわかる。したがって冷間加工率は７０％を超えない
範囲でできるだけ高めることが望まく、本発明では６５
〜７０％と規定する。また、溶体化処理前の冷間加工率
については前述のように５０％以上とする。[0014] performed after age hardening processes that alter the cold working ratio after the solution treatment of cold working ratio diagram 5 to 18% Ni-based maraging steel, a low strain rate tensile test in hydrogen fluoride The results are shown below. It can be seen that increasing the cold work rate increases the tensile strength in hydrogen fluoride and decreases the delayed fracture susceptibility. On the other hand, as shown in FIG. 6, the tensile strength in the normal atmosphere gradually increases in the processing direction and the direction perpendicular to the processing when the cold working ratio is increased.
However, as shown in FIG. 7, it can be seen that the notch tensile strength rapidly decreases when the cold working ratio exceeds 70% in terms of the cross-sectional reduction rate, and the toughness is significantly impaired, and the delayed fracture resistance tends to decrease. Therefore, it is desirable to increase the cold working ratio as much as possible within a range not exceeding 70%.
７０70%. Further, the cold working rate before the solution treatment is 50% or more as described above.
【００１５】時効硬化処理温度 図８に１８％Ｎｉ系マルエージング鋼の時効硬化処理温
度を変化させてフッ化水素中で低ひずみ速度引張試験を
行った結果を示す。この図の縦軸はフッ化水素中での引
張り強さσを大気中での引張強さσ0 で除した値の百分
率であり、材料の耐遅れ破壊性を表わしている。最高強
度の得られる５１０〜５２０℃で時効硬化処理を行った
とき最も耐遅れ破壊性が良好であることがわかる。した
がって時効硬化処理は５１０〜５２０℃で１〜１０時間
行うことと定める。 Aging Hardening Temperature FIG. 8 shows the results of a low strain rate tensile test in hydrogen fluoride by changing the age hardening temperature of an 18% Ni maraging steel. The vertical axis in this figure is the percentage of the value obtained by dividing the tensile strength σ in hydrogen fluoride by the tensile strength σ 0 in the atmosphere, and represents the delayed fracture resistance of the material. It can be seen that when the age hardening treatment is performed at 510 to 520 ° C. where the highest strength is obtained, the delayed fracture resistance is the best. Therefore, it is determined that the age hardening treatment is performed at 510 to 520 ° C. for 1 to 10 hours.
【００１６】[0016]
【実施例】以下に本発明を実施例および比較例を挙げて
詳述する。表１に遅れ破壊特性を調べるために用いた本
発明鋼及び比較鋼の化学組成を示す。また、表２に各鋼
の溶体化処理条件、時効硬化処理条件及び大気中での通
常の引張強さを示す。The present invention will be described in detail below with reference to examples and comparative examples. Table 1 shows the chemical compositions of the steel of the present invention and the comparative steel used for examining the delayed fracture characteristics. Table 2 shows the solution treatment conditions, the age hardening conditions, and the normal tensile strength in the air of each steel.
【００１７】 [0017]
【００１８】 表 ２ 溶体化処理条件 時効硬化処理条件 引張強さ(Kg/mm2 ) 本発明鋼 ８２５℃×１時間 ５１５℃× 4.5時間 ２７８．１ 比較鋼Ａ ８２０℃×１時間 ５１５℃×４時間 ２６７．６ 比較鋼Ｂ ８２０℃×１時間 ５１０℃×４時間 ２６５．７ 比較鋼Ｃ ８２０℃×１時間 ５１０℃×４時間 ２９４．１ 比較鋼Ｄ ８２０℃×１時間 ５１０℃×４時間 ２７６．８ 比較鋼Ｅ ８２０℃×３時間 ５１０℃×５時間 ２８１．５ 比較鋼Ｆ ８２０℃×１時間 ５００℃×５時間 ２６５．０ Table 2 Solution treatment condition Age hardening condition Tensile strength (Kg / mm 2 ) Invention steel 825 ° C. × 1 hour 515 ° C. × 4.5 hours 278.1 Comparative steel A 820 ° C. × 1 hour 515 ° C. × 4 Time 267.6 Comparative steel B 820 ° C × 1 hour 510 ° C × 4 hours 265.7 Comparative steel C 820 ° C × 1 hour 510 ° C × 4 hours 294.1 Comparative steel D 820 ° C × 1 hour 510 ° C × 4 hours 276 .8 Comparative steel E 820 ° C × 3 hours 510 ° C × 5 hours 281.5 Comparative steel F 820 ° C × 1 hour 500 ° C × 5 hours 265.0
【００１９】表２に示すように各鋼はいずれも２６０Ｋ
ｇ／ｍｍ2 以上の強度を有している。比較鋼はいずれも
Ｐ量が本発明で規定する範囲を超えて含有されている。
比較鋼Ｂ、Ｃ、Ｄ、Ｅ及びＦはＣｏ、Ｍｏ、Ｔｉ量のい
ずれかが本発明で規定する範囲を超えて含有されてい
る。比較鋼Ｄは時効硬化処理前の冷間加工率は５０％で
あり、その他の鋼の時効硬化処理前の冷間加工率は６０
〜７０％の範囲にある。なお、いずれの鋼についても溶
体化処理前の冷間加工率は５０％以上であり、また、図
１に示す製造工程以外の工程は通常のマルエージング鋼
のそれと同様のものである。As shown in Table 2, each steel was 260K
g / mm 2 or more. In all of the comparative steels, the P content exceeds the range specified in the present invention.
Comparative steels B, C, D, E, and F contain Co, Mo, or Ti in amounts exceeding the ranges specified in the present invention. Comparative steel D had a cold working rate of 50% before the age hardening treatment, and other steels had a cold working rate of 60% before the age hardening treatment.
７０70%. In addition, the cold working ratio before the solution treatment is 50% or more for all steels, and the processes other than the manufacturing process shown in FIG. 1 are the same as those of the normal maraging steel.
【００２０】図９に各鋼についてフッ化水素中で低ひず
み速度引張試験を行った結果を示す。図の縦軸は各鋼の
フッ化水素中での引張強さσを大気中での引張強さσ0
で除した値の百分率であり、この値が低いほど遅れ破壊
感受性が高いことを表わしている。比較鋼においてはい
ずれもフッ化水素圧力の増大とともに遅れ破壊感受性が
より顕著に現れている。それに対して本発明鋼では高フ
ッ化水素圧力においても引張強さの低下はほとんどな
く、本発明鋼の耐遅れ破壊性が優れていることが明らか
である。FIG. 9 shows the results of a low strain rate tensile test performed on each steel in hydrogen fluoride. The vertical axis of the figure indicates the tensile strength σ of each steel in hydrogen fluoride as the tensile strength σ 0 in the atmosphere.
The lower the value, the higher the delayed fracture susceptibility. In all the comparative steels, the delayed fracture susceptibility appears more remarkably as the hydrogen fluoride pressure increases. On the other hand, in the steel of the present invention, the tensile strength hardly decreases even at a high hydrogen fluoride pressure, and it is clear that the steel of the present invention has excellent delayed fracture resistance.
【００２１】表３は本発明鋼及び比較鋼Ｅ、Ｆについて
各鋼の大気中引張強さの約７０％の応力を負荷し、六フ
ッ化ウランガス中（６０℃、１００Ｔｏｒｒ）で遅れ破
壊試験を行った結果である。本発明鋼の耐遅れ破壊性が
優れていることが明らかである。Table 3 shows that the steel of the present invention and the comparative steels E and F were subjected to a delayed fracture test in a uranium hexafluoride gas (60 ° C., 100 Torr) by applying a stress of about 70% of the tensile strength in the atmosphere of each steel. It is the result of having performed. It is clear that the steel of the present invention has excellent delayed fracture resistance.
【００２２】表 ３六フッ化ウランガス中遅れ破壊試験結果 本発明鋼： ３００００時間を経過し健全 比較鋼Ｅ： １３０００時間で遅れ破壊比較鋼Ｆ： １３０００時間で遅れ破壊 Table 3 Results of delayed fracture test in uranium hexafluoride gas Steel of the present invention: Healthy after passing 30000 hours Comparative steel E: Delayed fracture after 13000 hours Comparative steel F: Delayed fracture after 13000 hours
【００２３】[0023]
【発明の効果】以上の説明からわかるように、本発明の
方法によれば、従来のマルエージング鋼と同様に引張強
さ２６０Ｋｇ／ｍｍ2 以上の高強度を有し、しかも六フ
ッ化ウランガス中での耐遅れ破壊性に優れていることか
ら、特にフッ化物系ガス雰囲気で使用するのに好適なマ
ルエージング鋼を製造することができる。As can be seen from the above description, according to the method of the present invention, as in the case of the conventional maraging steel, it has a high tensile strength of 260 kg / mm 2 or more, and has a high In particular, it is possible to manufacture a maraging steel suitable for use in a fluoride-based gas atmosphere because of its excellent delayed fracture resistance.
【図１】本発明の製造方法を示す工程図。FIG. 1 is a process chart showing a manufacturing method of the present invention.
【図２】１８％Ｎｉ系マルエージング鋼におけるＭｏ量
とウランフッ化物付着量との関係を示すグラフ。FIG. 2 is a graph showing the relationship between the amount of Mo and the amount of uranium fluoride attached to 18% Ni-based maraging steel.
【図３】１８％Ｎｉ系マルエージング鋼におけるＴｉ量
と耐遅れ破壊性との関係を示すグラフ。FIG. 3 is a graph showing the relationship between Ti content and delayed fracture resistance in 18% Ni-based maraging steel.
【図４】完全溶体化処理材および不完全溶体化処理材に
おけるウランフッ化物付着量の相違を示すグラフ。FIG. 4 is a graph showing a difference in the amount of uranium fluoride attached between a complete solution treatment material and an incomplete solution treatment material.
【図５】１８％Ｎｉ系マルエージング鋼の溶体化処理後
の冷間加工率とフッ化水素中引張強さとの関係を示すグ
ラフ。FIG. 5 is a graph showing the relationship between the cold work rate after solution treatment of 18% Ni-based maraging steel and tensile strength in hydrogen fluoride.
【図６】１８％Ｎｉ系マルエージング鋼の溶体化処理後
の冷間加工率と大気中引張強さとの関係を示すグラフ。FIG. 6 is a graph showing the relationship between the cold working ratio after solution treatment of 18% Ni-based maraging steel and tensile strength in air.
【図７】１８％Ｎｉ系マルエージング鋼の溶体化処理後
の冷間加工率と切欠引張強さとの関係を示すグラフ。FIG. 7 is a graph showing the relationship between the cold work rate after the solution treatment of 18% Ni-based maraging steel and the notch tensile strength.
【図８】１８％Ｎｉ系マルエージング鋼の時効温度と耐
遅れ破壊性との関係を示すグラフ。FIG. 8 is a graph showing the relationship between aging temperature and delayed fracture resistance of 18% Ni-based maraging steel.
【図９】本発明鋼および比較鋼についてのフッ化水素圧
力と耐遅れ破壊性との関係を示すグラフ。FIG. 9 is a graph showing the relationship between the hydrogen fluoride pressure and the delayed fracture resistance of the steel of the present invention and the comparative steel.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 上原 典文 茨城県那珂郡東海村大字村松４番地33 動力炉・核燃料開発事業団 東海事業所 内 (56)参考文献 特開 昭62−228455（ＪＰ，Ａ) 特開 昭51−27164（ＪＰ，Ａ) 特開 昭59−219414（ＪＰ，Ａ) ──────────────────────────────────────────────────続 き Continuing on the front page (72) Norifumi Uehara, Inventor, No.4, Muramatsu, Oji, Tokai-mura, Naka-gun, Ibaraki Pref. JP-A-51-27164 (JP, A) JP-A-59-219414 (JP, A)
Claims (1)
が１１．７〜１２．７％、Ｍｏが３．８〜４．５％、Ｔ
ｉが１．４５〜１．５５％、Ａｌが０．３％以下、Ｃが
０．０３％以下、Ｓｉが０．１％以下、Ｍｎが０．１％
以下、Ｐが０．００１％以下、Ｓが０．００１％以下、
残部がＦｅからなるマルエージング鋼を断面減少率で５
０％以上の冷間加工を施し８２０〜８３０℃で１時間溶
体化処理後、断面減少率で６５〜７０％の冷間加工を施
し、次いで５１０〜５２０℃で１〜１０時間時効硬化処
理することを特徴とする、フッ化物ガス中での耐遅れ破
壊性に優れた引張強さ２６０Ｋｇ／ｍｍ 2 以上のマルエ
ージング鋼の製造方法。1. The method according to claim 1, wherein the content of Ni is 17 to 19% by weight,
Is 11.7 to 12.7%, Mo is 3.8 to 4.5%, T
i is 1.45 to 1.55%, Al is 0.3% or less, C is 0.03% or less, Si is 0.1% or less, and Mn is 0.1%.
Hereinafter, P is 0.001% or less, S is 0.001% or less,
The maraging steel consisting of Fe as the balance is reduced in cross section by 5%.
After cold working of 0% or more and solution treatment at 820 to 830 ° C. for 1 hour, cold working of 65 to 70% in cross-sectional reduction rate is performed, and then age hardening at 510 to 520 ° C. for 1 to 10 hours. Characterized by delayed rupture in fluoride gas
A method for producing a maraging steel having a tensile strength of 260 kg / mm 2 or more, which is excellent in fragility .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3344199A JP2934089B2 (en) | 1991-12-26 | 1991-12-26 | Manufacturing method of maraging steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3344199A JP2934089B2 (en) | 1991-12-26 | 1991-12-26 | Manufacturing method of maraging steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05171269A JPH05171269A (en) | 1993-07-09 |
| JP2934089B2 true JP2934089B2 (en) | 1999-08-16 |
Family
ID=18367402
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3344199A Expired - Fee Related JP2934089B2 (en) | 1991-12-26 | 1991-12-26 | Manufacturing method of maraging steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2934089B2 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5127164A (en) * | 1974-08-28 | 1976-03-06 | Hitachi Ltd | URANNOSHUKUENSHINBUNRIKYOKYODOKAITENDO NO SEIZOHO |
| JPS59219414A (en) * | 1983-05-24 | 1984-12-10 | Toyota Motor Corp | Improvement of strength of thin maraging steel hoop |
| JPS62228455A (en) * | 1985-12-05 | 1987-10-07 | Kobe Steel Ltd | Maraging steel excellent in fatigue characteristic |
-
1991
- 1991-12-26 JP JP3344199A patent/JP2934089B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05171269A (en) | 1993-07-09 |
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