JPH02153044A - Duplex stainless steel having high cracking resistance - Google Patents
Duplex stainless steel having high cracking resistanceInfo
- Publication number
- JPH02153044A JPH02153044A JP30666388A JP30666388A JPH02153044A JP H02153044 A JPH02153044 A JP H02153044A JP 30666388 A JP30666388 A JP 30666388A JP 30666388 A JP30666388 A JP 30666388A JP H02153044 A JPH02153044 A JP H02153044A
- Authority
- JP
- Japan
- Prior art keywords
- stainless steel
- duplex stainless
- steel
- resistance
- cracking resistance
- 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
Links
- 229910001039 duplex stainless steel Inorganic materials 0.000 title claims abstract description 15
- 238000005336 cracking Methods 0.000 title claims abstract description 9
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 4
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 4
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 3
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 230000007797 corrosion Effects 0.000 abstract description 21
- 238000005260 corrosion Methods 0.000 abstract description 21
- 229910000831 Steel Inorganic materials 0.000 abstract description 19
- 239000010959 steel Substances 0.000 abstract description 19
- 229910001220 stainless steel Inorganic materials 0.000 abstract description 5
- 229910052759 nickel Inorganic materials 0.000 abstract description 3
- 239000010935 stainless steel Substances 0.000 abstract description 3
- 239000000203 mixture Substances 0.000 abstract description 2
- 238000001556 precipitation Methods 0.000 abstract description 2
- 229910003296 Ni-Mo Inorganic materials 0.000 abstract 1
- 239000006104 solid solution Substances 0.000 abstract 1
- 238000005728 strengthening Methods 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 7
- 230000007547 defect Effects 0.000 description 6
- 229910001566 austenite Inorganic materials 0.000 description 4
- 230000000977 initiatory effect Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 201000004569 Blindness Diseases 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000000875 corresponding effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Paper (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、例えば製紙ＩＲ械におけるサクションロール
等に使用される二相ステンレス鋼の改良に関し、より具
体的には、亀裂が発生しにくい特性を備えた二相ステン
レス鋼に関する。Detailed Description of the Invention (Field of Industrial Application) The present invention relates to the improvement of duplex stainless steel used, for example, in suction rolls in paper manufacturing IR machines, and more specifically, the invention relates to improvement of duplex stainless steel that is used for suction rolls, etc. in paper manufacturing IR machines, and more specifically, to improve the property of preventing cracking. Regarding duplex stainless steel with.
（１足来技術とその問題点）
例えば製紙工業におけるサクションロールは、白水環境
で使用されるため、ロール用材料はすぐれた耐食性、高
い腐食疲労強度等を具備することが要請される。従来、
この種の用途には、種々の二相ステンレス鋼が使用され
ている。(Last technology and its problems) For example, suction rolls in the paper industry are used in white water environments, so the roll materials are required to have excellent corrosion resistance, high corrosion fatigue strength, and the like. Conventionally,
A variety of duplex stainless steels are used for this type of application.
しかしながら、近年、耐食性にすぐれかつ腐食疲労強度
が高い材料を使用しているにも拘わらず、ロールの早期
折損事故が相次いで発生した。事故品を調査した結果、
ロールの内部に鋳造欠陥、介在物等が存在する場きには
、その欠陥部を起点にして亀裂が発生し、その亀裂が進
展して折損に至っていることがわかった。However, in recent years, despite the use of materials with excellent corrosion resistance and high corrosion fatigue strength, early breakage accidents of rolls have occurred one after another. As a result of investigating the accident product,
It was found that when casting defects, inclusions, etc. were present inside the roll, cracks were generated starting from the defects, and the cracks propagated to lead to breakage.
ロールの折損品を調べた結果、下限界応力拡大係数値が
小さいもの程、早期に折損事故に至っていることがわか
った５
本発明は下限界応力拡大係数値が大きい、即ち、亀裂発
生抵抗の高い二相ステンレス鋼を提供するものである。As a result of examining broken rolls, it was found that the smaller the lower limit stress intensity factor value, the earlier the breakage accident occurred5. It provides high duplex stainless steel.
（技術的手段及び作用）
本発明にがかる二相ステンレス鋼は、重量％にて、Ｃ：
０．０５％以下、Ｓ ｉ：２．０％以下、Ｍｎ：２．０
％以下、Ｃｒ：２０〜２５％、Ｎｉ：３〜８％、Ｍｏ：
１．５〜３．５％、Ｎ：Ｑ、１〜０．３％を含有し、残
部実質的にＦｅからなる。(Technical means and effects) The duplex stainless steel according to the present invention has C:
0.05% or less, Si: 2.0% or less, Mn: 2.0
% or less, Cr: 20-25%, Ni: 3-8%, Mo:
1.5 to 3.5%, N:Q, and 1 to 0.3%, with the balance essentially consisting of Fe.
本発明の二相ステンレス鋼は、少なくとも従来鋼と同程
度の耐食性及び腐食疲労強度を具備すると共に、亀裂発
生抵抗性にすぐれている。The duplex stainless steel of the present invention has at least the same corrosion resistance and corrosion fatigue strength as conventional steel, and has excellent cracking resistance.
本発明の二相ステンレス鋼の成分限定理由が次の通りで
ある。The reasons for limiting the components of the duplex stainless steel of the present invention are as follows.
Ｃ：Ｏ、ｏ ５％以下
Ｃはオーステナイト生成元素であると共に、オーステナ
イト相に固溶された素地を強１ヒする動きを有する。し
かし、含有量が多くなるとＣ「炭化者を形成し、耐食性
に有効なＣ「が消費されることによって局部腐食に対す
る抵抗性が低下する。C: O, o 5% or less C is an austenite-forming element, and has the ability to strongly damage the matrix dissolved in the austenite phase. However, when the content increases, C "forms carbonizers and C" which is effective for corrosion resistance is consumed, resulting in a decrease in resistance to local corrosion.
このため、上限は０．０５％とする。Therefore, the upper limit is set to 0.05%.
Ｓｉ：２．０％以下
Ｓｉは溶鋼の脱酸及び良好な鋳造性の確保のために必要
な元素である。しかし、多量に含むと脱化等の材料特性
の劣化を招くので上限は２．０％とする。Si: 2.0% or less Si is an element necessary for deoxidizing molten steel and ensuring good castability. However, the upper limit is set at 2.0% since containing a large amount causes deterioration of material properties such as deoxidization.
Ｍ ｎ ： ２．０ ％以下
Ｍ ｎは上記Ｓｉと同様に脱酸剤として作用する他、溶
製中のイオウ（Ｓ）を固定する役割を有する。しか腰多
量に含まれると耐食性が低下するので上限は２８０％と
する。Mn: 2.0% or less Mn acts as a deoxidizing agent like the above-mentioned Si, and also has the role of fixing sulfur (S) during melting. However, if a large amount is included, the corrosion resistance will decrease, so the upper limit is set at 280%.
Ｃｒ：２０〜２５％ Ｃｒは耐食性及び耐応力腐食割れ性の向上に寄与する。Cr: 20-25% Cr contributes to improving corrosion resistance and stress corrosion cracking resistance.
また、Ｃｒはフェライト生成元素であり、二相組織にお
けるフェライト相の形成にとって強度が高められる。こ
のため、少なくとも２０％を要する。し劣化、あまりに
多く含有すると鋼の靭性低下を招くばかりか鋳造時にお
ける脆弱なシグマ相が生成する。促って、上限は２５％
に規定する。Further, Cr is a ferrite-forming element, and the strength is increased due to the formation of a ferrite phase in a two-phase structure. Therefore, at least 20% is required. Containing too much will not only lead to a decrease in the toughness of the steel, but also the formation of a brittle sigma phase during casting. The upper limit is 25%.
stipulates.
Ｎｉ：３〜８％
Ｎｉはオーステナイト相を安定化する元素である、鋼の
靭性の向上に寄与する。又、耐食性の確保の点からも重
要な元素である。含有量が３％に満たないとこれらの効
果が十分に発揮できな０゜一方、多量に含有してもそれ
に対応する効果が得られず、経済的に不利である。更に
又、二相組織におけるオーステナイト相が過剰となり、
二相組織の量的均衡を失う。このため、８％を上限とす
る。Ni: 3-8% Ni is an element that stabilizes the austenite phase and contributes to improving the toughness of steel. It is also an important element from the viewpoint of ensuring corrosion resistance. If the content is less than 3%, these effects cannot be fully exhibited, whereas if the content is in a large amount, the corresponding effects cannot be obtained, which is economically disadvantageous. Furthermore, the austenite phase in the two-phase structure becomes excessive,
The quantitative balance of the two-phase structure is lost. Therefore, the upper limit is set at 8%.
Ｍｏ：１．５〜３．５％ Ｍｏはステンレス鋼の耐食性の向上に寄与する。Mo: 1.5-3.5% Mo contributes to improving the corrosion resistance of stainless steel.
このため、少なくとら１．５％の含有を要する。Therefore, it is necessary to contain at least 1.5%.
しかし、多量に加えても耐食性の改善効果は飽和するだ
けでなく、ｊｉ７ｉ３″ａ時にシグマ相が析出しやすく
なり脆化が著しくなるので上限は３．５％とする。However, even if added in a large amount, the effect of improving corrosion resistance not only becomes saturated, but also the sigma phase tends to precipitate at ji7i3''a, resulting in significant embrittlement, so the upper limit is set at 3.5%.
Ｎ：０．１〜０．３％
Ｎは本発明の二相ステンレス鋼を特徴づける重要な元素
である。オーステナイト相を固溶性１ヒすると共にフェ
ライト相内におけるシグマ相の析出を抑制する作用があ
り、下限界応力拡大係数値を大きくし、部材の亀裂発生
抵抗を高める。これらの効果を発揮するためには少なく
とも０．１％以上倉有する必要がある。なお、Ｎは通常
の大気溶解において不可避的に含まれるが、その含有量
は０．１％に満たないため、積極的に添加する必要があ
る。Ｎ量の増加に伴ってこれらの効果も増すが、０．３
％を超えるとＣｒｚＮ等の窒化物を析出しやすく、耐食
性を低下させる。このため、上限は０，３％とする。N: 0.1-0.3% N is an important element that characterizes the duplex stainless steel of the present invention. It has the effect of increasing the solid solubility of the austenite phase and suppressing the precipitation of the sigma phase within the ferrite phase, increasing the lower limit stress intensity factor value and increasing the cracking resistance of the member. In order to exhibit these effects, it is necessary to have a content of at least 0.1% or more. Note that although N is inevitably included in normal atmospheric dissolution, its content is less than 0.1%, so it is necessary to actively add it. These effects increase as the amount of N increases, but 0.3
%, nitrides such as CrzN tend to precipitate, reducing corrosion resistance. Therefore, the upper limit is set at 0.3%.
本発明のステンレス鋼は上記成分元素を含有し、残部は
不可避的に混入する不純物元素及びＦｅからなる。The stainless steel of the present invention contains the above-mentioned component elements, and the remainder consists of unavoidably mixed impurity elements and Fe.
次に実施例を挙げて本発明の二相ステンレス鋼の亀裂発
生抵抗の改善結果を具体的に説明する。Next, the results of improving the cracking resistance of the duplex stainless steel of the present invention will be specifically explained with reference to Examples.
（実施例）
第１表に示す成分組成を有する供試鋼について機械的性
質及び亀裂発生抵抗を調べた。(Example) The mechanical properties and crack initiation resistance of test steels having the compositions shown in Table 1 were investigated.
供試Ｗ４Ｎｏ、１及びＮＯ１２は本発明の二相ステンル
・ス鋼、供試鋼Ｎ０１３は従来鋼である。なお、各供試
鋼はすべて１０５０℃にて、肉厚１インチ当たり２時間
保持した後、空冷した。Samples W4 No. 1 and No. 12 are duplex stainless steels of the present invention, and sample steel No. 013 is a conventional steel. Each steel sample was kept at 1050° C. for 2 hours per inch of wall thickness, and then cooled in air.
第２表に機械的性質の試験結果を示す。Table 2 shows the mechanical property test results.
第１図に応力拡大係数と亀裂の進展速度との関係を示す
、この試験は、＾ＳＴＭ ％４７に準拠して行ない、１
インチ角の試験片を用いた。また、試験は５０℃、ＣＣ
ｌ−１０００ｐｐ、 ｐＨ３，５の腐食溶液中で行なっ
た。Figure 1 shows the relationship between stress intensity factor and crack growth rate. This test was conducted in accordance with ^STM %47, and 1
An inch square test piece was used. In addition, the test was conducted at 50℃, CC
The test was carried out in a corrosive solution of l-1000pp, pH 3.5.
第２表に示すように、機械的性質については、本発明の
Ｎ含有鋼と、従来のＮを含有しない鋼との間に特に大き
な相違は認められなかった。As shown in Table 2, no significant difference in mechanical properties was observed between the N-containing steel of the present invention and conventional N-free steel.
ところで、下限界応力拡大係数値とは、それよりも小さ
い応力を縁り退し加えても亀裂が発生しないときの値を
いい、ΔＫＬｂ＝σ／ｉ７’−（△Ｋｔｂ：下限界応力
拡大係数値、σ：応力、ａ：許容欠陥の大きさ）で表わ
される。ΔＫｔｌ＋が大きければ、σを同じとしたとき
ａが大きいものまで許容される。By the way, the lower limit stress intensity factor value is the value at which no crack occurs even if a smaller stress is applied, ΔKLb=σ/i7'−(△Ktb: lower limit stress intensity factor It is expressed as a numerical value, σ: stress, a: allowable defect size). If ΔKtl+ is large, even large values of a are allowed when σ is the same.
換言すれば、大きな内部欠陥が存在しても亀裂が発生し
ないことになり、部材の亀裂発生抵抗は内向上すること
がわかる。In other words, it can be seen that even if a large internal defect exists, no crack occurs, and the resistance to crack occurrence of the member is improved.
なお、＾ＳＴＭ Ｅ６４７によれば、応力拡大係数値は
１０−’ｍ／サイクル（３，９４に１０−１インチ／サ
イクル）以上の進展速度での測定と規定されている。従
って、第１図を参照しながら供試鋼Ｎｏ、１乃至Ｎｏ、
３の下限界応力拡大係数値へＫｔｌ＋を求めると、Ｎｏ
、１は約１２ｋｓｉ、／”’ＴＭ、Ｎｏ、２は約１０．
５ｋｓｉｒ盲、及びＮｏ、３は約９ｋｓ■］丁と判定さ
れる。このように本発明鋼は従来鋼よりも下限界応力拡
大係数値が大きい。According to STM E647, the stress intensity factor value is specified to be measured at a growth rate of 10-' m/cycle (3,94 to 10-1 inch/cycle) or more. Therefore, with reference to FIG. 1, test steel No. 1 to No.
When determining Ktl+ to the lower limit stress intensity factor value of 3, No.
, 1 is about 12ksi, /"'TM, No. 2 is about 10.
5ksir blindness, and No. 3 is determined to be about 9ks. As described above, the steel of the present invention has a higher lower limit stress intensity factor value than the conventional steel.
ところで実際の操業時にロールに作用する応力を５ ｋ
ｇ／ａｎ”（３２２５ｋｇ／１１１２）と仮定した場合
、前述の△Ｋｔｌ＋＝σ５下の式から、許容されうる欠
陥の大きさａを求めると、供試鋼Ｎｏ、１は約２３ｍｍ
、供試ＪＩＮｏ、２は約１８１、供試ｊｌｌＮｏ、３
は約１３ｆ１となる。By the way, the stress that acts on the roll during actual operation is 5 k.
g/an” (3225 kg/1112), the allowable defect size a is determined from the above formula △Ktl+=σ5, and test steel No. 1 is approximately 23 mm.
, sample JI No. 2 is approximately 181, sample jll No. 3
is approximately 13f1.
この値が大きい程、大きな欠陥が存在しても亀裂が発生
しないこと、即ち亀裂発生抵抗にすぐれていることを意
味しており、本発明鋼は従来鋼よりも亀裂発生抵抗にす
ぐれているといえる。The larger this value is, the less cracks will occur even in the presence of large defects, which means that the steel of the present invention has better crack initiation resistance than conventional steel. I can say that.
（発明の効果）
本発明の二相ステンレス渭は、少なくとも従来鋼と同程
度の耐食性及び腐食疲労強度を具備すると共に、従来鋼
よりもはるかにすぐれた亀裂発生抵抗性を備えている。(Effects of the Invention) The duplex stainless steel according to the present invention has corrosion resistance and corrosion fatigue strength at least comparable to conventional steel, and has far superior crack initiation resistance than conventional steel.
従って、腐食環境の繰返し応力の作用する条件下で使用
される製紙機械のロール部材として好適である。Therefore, it is suitable as a roll member of a paper manufacturing machine used under conditions where repeated stress is applied in a corrosive environment.
第１図は応力拡大係数値と亀裂の進展速度との関係を示
すグラフである。
（インチ／号イクル）
応力拡大係数値Δｋ（ｋｓｉ龜）FIG. 1 is a graph showing the relationship between stress intensity factor value and crack growth rate. (inch/cycle) Stress intensity factor value Δk (ksi)
Claims (1)
％以下、Ｍｎ：２．０％以下、Ｃｒ：２０〜２５％、Ｎ
ｉ：３〜８％、Ｍｏ：１．５〜３．５％、Ｎ：０．１〜
０．３％を含有し、残部実質的にＦｅからなる亀裂発生
抵抗の高い二相ステンレス鋼。(1) In weight%, C: 0.05% or less, Si: 2.0
% or less, Mn: 2.0% or less, Cr: 20-25%, N
i: 3~8%, Mo: 1.5~3.5%, N: 0.1~
Duplex stainless steel with high resistance to cracking, containing 0.3% Fe and the remainder substantially consisting of Fe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30666388A JPH02153044A (en) | 1988-12-02 | 1988-12-02 | Duplex stainless steel having high cracking resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30666388A JPH02153044A (en) | 1988-12-02 | 1988-12-02 | Duplex stainless steel having high cracking resistance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02153044A true JPH02153044A (en) | 1990-06-12 |
Family
ID=17959825
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30666388A Pending JPH02153044A (en) | 1988-12-02 | 1988-12-02 | Duplex stainless steel having high cracking resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02153044A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003100277A1 (en) * | 2002-05-23 | 2003-12-04 | Ntn Corporation | Rolling part and power transmission part |
| CN104451414A (en) * | 2013-09-19 | 2015-03-25 | 精工电子有限公司 | Two-phase stainless steel, thin sheet material and diaphragm using two-phase stainless steel |
| CN106756604A (en) * | 2016-11-16 | 2017-05-31 | 重庆大学 | Nonstandard stainless steel of a kind of improved corrosion based on PSO SVR and preparation method thereof |
| CN110088323A (en) * | 2016-12-21 | 2019-08-02 | 山特维克知识产权股份有限公司 | Product and application thereof comprising two phase stainless steel |
-
1988
- 1988-12-02 JP JP30666388A patent/JPH02153044A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003100277A1 (en) * | 2002-05-23 | 2003-12-04 | Ntn Corporation | Rolling part and power transmission part |
| US7237963B2 (en) | 2002-05-23 | 2007-07-03 | Ntn Corporation | Rolling part and power transmission part |
| CN104451414A (en) * | 2013-09-19 | 2015-03-25 | 精工电子有限公司 | Two-phase stainless steel, thin sheet material and diaphragm using two-phase stainless steel |
| CN106756604A (en) * | 2016-11-16 | 2017-05-31 | 重庆大学 | Nonstandard stainless steel of a kind of improved corrosion based on PSO SVR and preparation method thereof |
| CN110088323A (en) * | 2016-12-21 | 2019-08-02 | 山特维克知识产权股份有限公司 | Product and application thereof comprising two phase stainless steel |
| CN110088323B (en) * | 2016-12-21 | 2022-03-22 | 山特维克知识产权股份有限公司 | Article comprising a duplex stainless steel and use thereof |
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