JPH0762219B2 - Ultra-high vacuum stainless steel - Google Patents
Ultra-high vacuum stainless steelInfo
- Publication number
- JPH0762219B2 JPH0762219B2 JP1165432A JP16543289A JPH0762219B2 JP H0762219 B2 JPH0762219 B2 JP H0762219B2 JP 1165432 A JP1165432 A JP 1165432A JP 16543289 A JP16543289 A JP 16543289A JP H0762219 B2 JPH0762219 B2 JP H0762219B2
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- Prior art keywords
- steel
- stainless steel
- metallic inclusions
- hydrogen
- ultra
- Prior art date
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- Treatment Of Steel In Its Molten State (AREA)
- Manufacture And Refinement Of Metals (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 この発明は粒子加速器、理化学機器、半導体製造用、或
いは医療機器用等に用いられている極高真空（Ｐ＜10-7
Pa）〜極高真空（Ｐ＜10-10Pa）装置を構成するチャン
バ・配管・バルブ・フランジ・ベローズ・エルボ等の構
造部材として用いられているステンレス鋼に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an extremely high vacuum (P <10 −7 ) used for particle accelerators, physics and chemistry equipment, semiconductor manufacturing, medical equipment and the like.
Pa) to ultra-high vacuum (P <10 -10 Pa) The present invention relates to stainless steel used as structural members such as chambers, pipes, valves, flanges, bellows, and elbows.
超LSI等の半導体製造に用いられる製造装置や電子顕微
鏡・粒子加速器等の理化学機器等における真空装置を構
成するチャンバ・配管・バルブ・フランジ・ベローズ・
エルボ・容器等には、SUS316L、SUS304等のステンレス
鋼若しくはアルミニウム合金等の非鉄金属が用いられて
いる。例えば、超LSI製造技術において反応チャンバ表
面の耐食性及び耐イオン衝撃性を高めた超高真空装置に
接続した超クリーンガス供給用配管には、SUS316Lステ
ンレス鋼が用いられている。このガス供給系や反応チャ
ンバ内面からの放出ガスを極小にするために、接ガス部
表面を電解研磨することにより、加工変質層を伴わない
鏡面に仕上げている。また最近では材料内の吸蔵ガス自
体を減少させるために、２度真空溶解を行なったSUS316
Lステンレス鋼が用いられている。Chambers, pipes, valves, flanges, bellows, etc. that make up vacuum equipment for manufacturing equipment used for semiconductor manufacturing such as VLSI and electron microscopes, particle accelerators and other physics and chemistry equipment, etc.
For the elbow, container, etc., stainless steel such as SUS316L and SUS304, or non-ferrous metal such as aluminum alloy is used. For example, SUS316L stainless steel is used for an ultra-clean gas supply pipe connected to an ultra-high vacuum device in which the corrosion resistance and the ion impact resistance of the reaction chamber surface are increased in the VLSI manufacturing technology. In order to minimize the gas released from the gas supply system and the inner surface of the reaction chamber, the surface of the gas contacting portion is electrolytically polished to a mirror surface without a work-affected layer. Recently, SUS316 has been vacuum-melted twice in order to reduce the stored gas itself in the material.
L stainless steel is used.
従来の超高真空装置に用いられている構造材料は、上述
のように、ステンレス鋼とアルミニウム合金であるが、
半導体製造装置、核融合装置等の各種先端技術関係の真
空装置は、このような構造材料から放出されるガスの種
類・量・放出率によって大きな影響を受ける。従って材
料のガス放出については多くの研究がなされてきた。こ
れまでの研究から、超高真空領域（圧力Ｐ＜10-7Pa）以
下の圧力を構成する真空機器においては、材料から放出
されるガスの主役は水素であることがわかっており、そ
の結果、現状の真空装置に用いられる材料としては、
（ａ）表面吸着の制御のために、接ガス部表面を電解研
磨若しくは電解複合研磨を行なって接ガス面積を小さく
し、（ｂ）200℃以上の高温でプレベーキングした後、
（ｃ）接ガス部表面を酸化皮膜処理を行なう等の表面処
理を行なったステンレス鋼が用いられている。The structural materials used in the conventional ultra-high vacuum apparatus are stainless steel and aluminum alloy as described above,
Vacuum devices related to various advanced technologies such as semiconductor manufacturing devices and fusion devices are greatly affected by the type, amount, and release rate of gas released from such structural materials. Therefore, much research has been done on outgassing of materials. From the research conducted so far, it has been known that the main role of the gas released from the material is hydrogen in the vacuum equipment that configures the pressure below the ultra-high vacuum region (pressure P <10 -7 Pa). The materials used for the current vacuum equipment are:
(A) In order to control surface adsorption, the surface of the gas contact portion is subjected to electrolytic polishing or electrolytic composite polishing to reduce the gas contact area, and (b) after prebaking at a high temperature of 200 ° C. or higher,
(C) Stainless steel is used which has been subjected to a surface treatment such as an oxide film treatment on the surface of the gas contacting portion.
しかし、装置の形状によっては高温プレベーキングが難
しい場合もあり、また表面処理を接ガス部全面に均一に
行なうことが難しいため、必ずしも最良の条件を満たす
ことはできない。更に、プレベーキング・表面処理とい
った作業は特別な装置を必要とし、コストが上昇すると
共に時間もかかるという問題点があった。However, high temperature pre-baking may be difficult depending on the shape of the apparatus, and it is difficult to uniformly perform the surface treatment on the entire surface of the gas-contacting portion. Therefore, the best condition cannot always be satisfied. Further, the work such as pre-baking and surface treatment requires a special device, which raises the cost and time.
一方、特願昭62−282252号では、（ア）鋼中の非金属介
在物は電解研磨により脱落してピンホールとなるという
ことや、（イ）非金属介在物の周囲に水素原子がトラッ
プされ、見掛け上の水素固溶度が低くなっても局部的な
水素の滞り場が形成され、拡散も速いということが明ら
かにされ、これらのことから鋼中の非金属介在物は水素
ガス放出に深く関っており、該非金属介在物を低減させ
てやることにより、材料からの放出ガスの減少速度が速
くなるということが見い出されている。On the other hand, in Japanese Patent Application No. 62-282252, (a) non-metallic inclusions in steel fall off by electrolytic polishing to form pinholes, and (b) hydrogen atoms are trapped around non-metallic inclusions. It was clarified that even if the apparent solid solubility of hydrogen was low, a local hydrogen trap was formed and the diffusion was fast, and from these facts, nonmetallic inclusions in steel released hydrogen gas. It has been found that the reduction rate of the gas released from the material is increased by reducing the non-metallic inclusions.
しかし、鋼中の非金属介在物を“ゼロ”にすることはで
きず、また極端に低減することは製鋼コストの上昇を招
くと共に、生産上の管理も困難である、という問題点が
ある。However, there is a problem that the non-metallic inclusions in the steel cannot be made "zero", and that extremely reducing them causes an increase in steelmaking cost and is difficult to control in production.
本発明は以上のような問題に鑑み創案されたもので、こ
れまでのプレベーキング・表面処理等を行なわなくて
も、或いは非金属介在物の極端な低減を図らなくても、
水素ガスの放出率を低く抑えることができるステンレス
鋼を開発し、極高真空機器用の構造材料として提供せん
とするものである。The present invention was devised in view of the above problems, without performing pre-baking, surface treatment, etc., up to now, or without extreme reduction of non-metallic inclusions,
It aims to develop stainless steel that can keep the release rate of hydrogen gas low and to provide it as a structural material for ultra-high vacuum equipment.
本発明の創案に当っては、水素ガス放出の原因を次のよ
うに仮定し、これを本発明の開発のベースとした。In devising the present invention, the cause of hydrogen gas release was assumed as follows, and this was the basis for the development of the present invention.
第２図に模式的に示されるように、接ガス部表面に散
在している非金属介在物（１）は、電解研磨加工とか電
解複合研磨等の表面処理を受けることにより脱落する。
そのため、微細なピンホール（２）があとに残り、吸着
ガスの滞り場となる。又、材料内部の非金属介在物
（１）は水素原子（３）をトラップするため、非金属介
在物（１）周囲の水素濃度が高く拡散も速くなる。従っ
て材料に固溶している水素原子（３）とこれらトラツプ
されている水素原子（３）とが材料り水素ガス放出率を
決める要素となる。As schematically shown in FIG. 2, the non-metallic inclusions (1) scattered on the surface of the gas contacting portion are removed by being subjected to a surface treatment such as electrolytic polishing processing or electrolytic composite polishing.
Therefore, minute pinholes (2) remain behind, which becomes a trapping place for adsorbed gas. Further, since the non-metallic inclusions (1) inside the material trap the hydrogen atoms (3), the hydrogen concentration around the non-metallic inclusions (1) is high and the diffusion becomes faster. Therefore, the hydrogen atoms (3) solid-dissolved in the material and the trapped hydrogen atoms (3) are factors that determine the hydrogen gas release rate of the material.
本発明者らは、このような推測から、その周りに水素原
子をトラップする鋼中の非金属介在物の量と鋼中の水素
含有量とが水素ガスの放出に何らかの関連性があると考
え、次のような実験を行なってこれらの関連性を明らか
にした。From such speculation, the present inventors believe that the amount of non-metallic inclusions in the steel that trap hydrogen atoms around it and the hydrogen content in the steel have some relation to the release of hydrogen gas. , The following experiments were conducted to clarify these relationships.
即ち、本発明者らの行なった実験は、種々の溶解方法を
用いて、鋼中の非金属介在物量と鋼中の水素含有量とが
異なるステンレス鋼の水素ガス放出率を測定するという
ものである。その結果、ステンレス鋼からの水素ガス放
出率は、鋼中の非金属介在物と水素含有量とから推定で
きることが判明した。That is, the experiments conducted by the inventors of the present invention are to measure the hydrogen gas release rate of stainless steels having different amounts of non-metallic inclusions in steel and hydrogen content in steel by using various melting methods. is there. As a result, it was found that the hydrogen gas release rate from stainless steel can be estimated from the nonmetallic inclusions and hydrogen content in the steel.
従って、ステンレス鋼中の水素含有量と、該ステンレス
鋼の非金属介在物とを制御することができれば、水素ガ
ス放出率を著しく低減することができるであろうとの推
測がなされ、更に、上記の実験結果から、極高真空機器
用の構造材料として望ましい水素ガス放出率まで低減化
せしめるために必要な上記水素含有量と非金属介在物の
制御条件が求められた。Therefore, it is presumed that if the hydrogen content in the stainless steel and the non-metallic inclusions in the stainless steel can be controlled, the hydrogen gas release rate can be significantly reduced. From the experimental results, the above hydrogen content and the control conditions of non-metallic inclusions required to reduce the hydrogen gas release rate, which is desirable as a structural material for extremely high vacuum equipment, were obtained.
本発明はこのような制御条件の究明から得られたもの
で、次のような構成を有している。The present invention is obtained from the investigation of such control conditions, and has the following configuration.
即ち、本発明のステンレス鋼は、鋼中の水素含有量
〔Ｈ〕（単位:ppm）と、鋼中の非金属介在物量〔Ｉ〕
（単位：個/mm2）とが次式を満足する成分組成を有する
ことを特徴としている。That is, the stainless steel of the present invention has a hydrogen content [H] (unit: ppm) in the steel and the amount of non-metallic inclusions [I] in the steel.
(Unit: piece / mm 2 ) is characterized by having a composition that satisfies the following equation.
１＞α〔Ｈ〕＋β〔Ｉ〕 α＝2.16×10-2（1/ppm） β＝3.76×10-2（mm2/個） ここで非金属介在物量は、ステンレス鋼部材の圧延方向
断面において、400倍の光学顕微鏡にて少なくとも10mm2
以上の面積に観察された非金属介在物の個数の単位面積
当りの個数をいう。1> α [H] + β [I] α = 2.16 × 10 -2 (1 / ppm) β = 3.76 × 10 -2 (mm 2 / piece) where the amount of non-metallic inclusions is the cross section of the stainless steel member in the rolling direction. At least 10 mm 2 with a 400x optical microscope at
The number of non-metallic inclusions observed in the above area is the number per unit area.
尚、上述した鋼中の水素含有量を制御する方法には、真
空溶解時の原料選別・操作条件制御等によるものや、鋼
塊若しくは圧延鋼材において熱処理する方法がある。
又、鋼中の非金属介在物量を制御する方法には、鋼中の
不純物元素の低減・ガス成分の低減を図るものや、溶解
及び鋳造時の雰囲気制御を行なう方法がある。In addition, as a method of controlling the hydrogen content in the above-mentioned steel, there are a method of selecting raw materials at the time of vacuum melting and controlling operating conditions, and a method of heat-treating a steel ingot or a rolled steel material.
In addition, as a method of controlling the amount of non-metallic inclusions in steel, there are a method of reducing impurity elements and gas components in steel, and a method of controlling an atmosphere during melting and casting.
以下、実施例について説明するが、本発明は以下の実施
例に限定されるものではなく、前後の趣旨に照らして適
宜設計変更をなすことは本発明の技術的範囲に含まれる
ものである。Examples will be described below, but the present invention is not limited to the following examples, and it is within the technical scope of the present invention to make appropriate design changes in light of the preceding and following points.
以下、本発明の具体的実施例につき説明する。 Hereinafter, specific examples of the present invention will be described.
下記第１表に示す組成の鋼を大気溶解炉・真空溶解炉・
真空アーク炉等を用いて溶解した。Steel with the composition shown in Table 1 below is used in an atmospheric melting furnace, a vacuum melting furnace,
It was melted using a vacuum arc furnace or the like.
そして造塊−熱間圧延により10mm厚さの熱延板とした。
その後冷間圧延により3mm厚さの冷延板とし、固溶化処
理を施した。肉厚中央部より化学成分分析用サンプルを
採取して、水素含有量を分析した。又、圧延方向と平行
断面の非金属介在物測定用サンプルを採取した。非金属
介在物測定は、400倍の光学顕微鏡を用いて、10mm2以上
の面積について実際に非金属介在物を大きさ毎にカウン
トし、総数を1mm2当りの個数で平均するカウント法によ
って行なった。この測定中に観察された比較鋼サンプル
の非金属介在物の状態から、鋼内部の非金属介在物
（３）は丁度前記第２図に示されたような状態であろう
と考えられる。一方、本発明鋼サンプルで観察された非
金属介在物の状態から推測すると、第１図に示されるよ
うに、極めて径の小さな非金属介在物（３）がその周り
に微量の水素原子（１）をトラップした状態に鋼中に疎
らに存在しているものと思われる。 Then, ingot-hot rolling was performed to obtain a hot-rolled sheet having a thickness of 10 mm.
After that, it was cold-rolled into a cold-rolled sheet having a thickness of 3 mm and subjected to solution treatment. A sample for chemical component analysis was taken from the central portion of the wall thickness, and the hydrogen content was analyzed. A sample for measuring non-metallic inclusions having a cross section parallel to the rolling direction was taken. The measurement of non-metallic inclusions is performed by a counting method using an optical microscope with a magnification of 400, by actually counting non-metallic inclusions by size for an area of 10 mm 2 or more, and averaging the total number by the number per 1 mm 2. It was From the state of the non-metallic inclusions of the comparative steel sample observed during this measurement, it is considered that the non-metallic inclusions (3) inside the steel may be exactly in the state shown in FIG. On the other hand, inferring from the state of the non-metallic inclusions observed in the steel sample of the present invention, as shown in FIG. 1, the non-metallic inclusions (3) having an extremely small diameter are surrounded by a small amount of hydrogen atoms (1 ) Is considered to be sparsely present in the steel in a trapped state.
一方、冷延板より10×10×１（mm）の平板を採取し、全
表面を電解研磨加工により鏡面仕上げとし、水素ガス放
出率測定サンプルとした。On the other hand, a flat plate of 10 × 10 × 1 (mm) was sampled from the cold-rolled sheet, and the entire surface was subjected to electrolytic polishing to obtain a mirror-finished surface, which was used as a hydrogen gas release rate measurement sample.
最も重要な特性である水素ガス放出率測定は、以下の手
法で行なった。前述のサンプルを１×10-10torrの圧力
に保たれている測定室中に導入したのち、1000℃に加熱
均熱し、表面に吸着している炭素、酸素、水蒸気等の吸
着分子を除去する。その後、室温に冷却し、その時点に
おける水素ガス分圧を四重極質量分析計にて計測する。
一方、試料室表面から放出される水素ガス分圧を、バッ
クグラウンドとしてサンプルを装入せずに同一の履歴に
て測定し、補正を行なう。四重極質量分析計にて求まる
Intensity（電流値：単位Ａ…アンペア）に、四重極質
量分析計の水素ガスに対する感度係数Ｒ（単位:torr/
A）と排気系の水素ガスに対する排気速度Ｓ（単位：/
sec）を乗じたのち、サンプルの表面積（単位:cm2）で
除してやることにより、水素ガスの放出率（単位:torr
・/sec・cm2）が求まる。The hydrogen gas release rate, which is the most important characteristic, was measured by the following method. After introducing the above-mentioned sample into the measuring chamber kept at a pressure of 1 × 10 -10 torr, it is heated and soaked at 1000 ° C to remove the adsorbed molecules such as carbon, oxygen and water vapor adsorbed on the surface. . Then, it is cooled to room temperature, and the hydrogen gas partial pressure at that time is measured by a quadrupole mass spectrometer.
On the other hand, the partial pressure of hydrogen gas released from the surface of the sample chamber is measured and corrected in the same history without loading the sample as the background. Obtained with quadrupole mass spectrometer
Intensity (current value: unit A ... Amperes), sensitivity coefficient R (unit: torr / of quadrupole mass spectrometer for hydrogen gas)
A) and the exhaust speed S for the hydrogen gas in the exhaust system (unit: /
sec) and then divide by the surface area of the sample (unit: cm 2 ) to release the hydrogen gas (unit: torr
・ / Sec ・ cm 2 ) can be obtained.
以上のようにして求めた結果を下記第２表及び第３図に
示す。第２表は、本発明鋼及び比較鋼の各々の水素ガス
放出率と比較鋼Ｂの水素ガス放出率を１とした場合の放
出率比を示しており、又第３図はｘ軸座標にα〔Ｈ〕＋
β〔Ｉ〕を、ｙ軸座標に前記放出率比を採ってグラフ化
したものである。The results obtained as described above are shown in Table 2 and FIG. 3 below. Table 2 shows the hydrogen gas release rate of each of the present invention steel and the comparative steel and the release rate ratio when the hydrogen gas release rate of the comparative steel B is 1, and FIG. 3 shows the x-axis coordinate. α [H] +
β [I] is a graph in which the release rate ratio is taken on the y-axis coordinate.
以上の第２表と第３図から、本発明鋼は比較鋼に比べて
水素ガス放出率が低く、放出ガス特性が極めて優れてい
ることが判る。 From the above Table 2 and FIG. 3, it can be seen that the steel of the present invention has a lower hydrogen gas release rate and is extremely excellent in the released gas characteristics as compared with the comparative steel.
以上述べた本発明の極高真空機器用ステンレス鋼を用い
て、真空装置を構成すれば、鋼中から放出される水素ガ
スを極めて低減化することが可能となり、真空装置の性
能を著しく向上させることができる。このような利点に
加え、ガス放出率の低減化の予測が可能となり、プレベ
ーキング条件を緩和することができること、及び装置を
構成する材料の品質管理ができること等から、製作コス
トも低くすることができる。更には、ベーキングを制約
される形状の部品の性能も向上せしめることができるた
め、真空系全体の性能向上が期待できることになる。If a vacuum device is constructed using the above-described stainless steel for extremely high vacuum equipment of the present invention, hydrogen gas released from the steel can be extremely reduced, and the performance of the vacuum device is significantly improved. be able to. In addition to these advantages, it is possible to predict a reduction in the gas release rate, the pre-baking conditions can be relaxed, and the quality of the materials that make up the device can be controlled. it can. Furthermore, since the performance of parts having a shape in which baking is restricted can be improved, it is expected that the performance of the entire vacuum system will be improved.
第１図は本発明のステンレス鋼内部における非金属介在
物の状態を模式的に示す説明図、第２図は従来のステン
レス鋼内部における非金属介在物の状態を同じく模式的
に示す説明図、第３図は本発明の実施例における水素ガ
ス放出率測定結果を示すグラフ図である。FIG. 1 is an explanatory view schematically showing the state of non-metallic inclusions inside the stainless steel of the present invention, and FIG. 2 is an explanatory view schematically showing the state of non-metallic inclusions inside the conventional stainless steel, FIG. 3 is a graph showing the measurement results of hydrogen gas release rate in the example of the present invention.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 山田 武海 東京都千代田区丸の内１丁目１番２号 日 本鋼管株式会社内 (72)発明者 滝沢 広保 東京都千代田区丸の内１丁目１番２号 日 本鋼管株式会社内 (56)参考文献 特開 昭63−161145（ＪＰ，Ａ) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takemi Yamada 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Hiroyasu Takizawa 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (56) References JP-A-63-161145 (JP, A)
Claims (1)
位:ppm）と、同じくステンレス鋼中の非金属介在物量
〔Ｉ〕（単位：個/mm2）とが次式を満足する成分組成を
有することを特徴とする極高真空機器用ステンレス鋼。 １＞α〔Ｈ〕＋β〔Ｉ〕 α＝2.16×10-2（1/ppm） β＝3.76×10-2（mm2/個）1. A composition in which the hydrogen content [H] (unit: ppm) in stainless steel and the amount of nonmetallic inclusions [I] (unit: pieces / mm 2 ) in the stainless steel also satisfy the following formula. Ultra-high vacuum equipment stainless steel characterized by having a composition. 1> α [H] + β [I] α = 2.16 × 10 -2 (1 / ppm) β = 3.76 × 10 -2 (mm 2 / piece)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1165432A JPH0762219B2 (en) | 1989-06-29 | 1989-06-29 | Ultra-high vacuum stainless steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1165432A JPH0762219B2 (en) | 1989-06-29 | 1989-06-29 | Ultra-high vacuum stainless steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0331451A JPH0331451A (en) | 1991-02-12 |
| JPH0762219B2 true JPH0762219B2 (en) | 1995-07-05 |
Family
ID=15812318
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1165432A Expired - Fee Related JPH0762219B2 (en) | 1989-06-29 | 1989-06-29 | Ultra-high vacuum stainless steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0762219B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5478524A (en) * | 1992-08-24 | 1995-12-26 | Nissan Motor Co., Ltd. | Super high vacuum vessel |
| JP6139119B2 (en) | 2012-01-13 | 2017-05-31 | 東芝メディカルシステムズ株式会社 | Magnetic resonance imaging system |
| JP7050989B1 (en) | 2021-03-12 | 2022-04-08 | 日本冶金工業株式会社 | Fe-Ni alloy with excellent outgas characteristics and its manufacturing method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63161145A (en) * | 1986-12-25 | 1988-07-04 | Nkk Corp | Steel pipe for clean room |
-
1989
- 1989-06-29 JP JP1165432A patent/JPH0762219B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0331451A (en) | 1991-02-12 |
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| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |