JP2557993B2 - Low temperature thin nickel steel plate with excellent weld toughness - Google Patents
Low temperature thin nickel steel plate with excellent weld toughnessInfo
- Publication number
- JP2557993B2 JP2557993B2 JP2013738A JP1373890A JP2557993B2 JP 2557993 B2 JP2557993 B2 JP 2557993B2 JP 2013738 A JP2013738 A JP 2013738A JP 1373890 A JP1373890 A JP 1373890A JP 2557993 B2 JP2557993 B2 JP 2557993B2
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- Prior art keywords
- toughness
- haz
- steel
- region
- steel plate
- 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.)
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/001—Heat treatment of ferrous alloys containing Ni
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Arc Welding In General (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 この発明は、溶接部靱性の優れた低温用薄物ニッケル
鋼板に関し、とくに液化天然ガス（LNG）タンクの底板
や屋根用鋼板、さらには液化天然ガスタンカーの船上タ
ンク用鋼板など−160℃以下のような極低温での使用に
おいて、溶接部靱性が重要な要因となる低温用薄物ニッ
ケル鋼板について、その特性の改善を図ったものであ
る。Description: TECHNICAL FIELD The present invention relates to a low-temperature thin nickel steel plate having excellent weld toughness, and particularly to a bottom plate of a liquefied natural gas (LNG) tank, a roof steel plate, and a liquefied natural steel. It is intended to improve the characteristics of a low temperature thin nickel steel sheet for which weld toughness is an important factor when used at extremely low temperatures such as -160 ° C or less, such as steel sheets for onboard tanks of gas tankers.
（従来の技術） LNGタンク用鋼板としては、代表的なものに９％Ni鋼
があるが、とくにLNGタンクの底板および屋根には大き
な応力が作用しないことから、薄物鋼板が使用される。
この場合、鋼板は−160℃以下のような極低温で使用さ
れるため、低温での高靱性、とくに溶接部における低温
靱性が要求される。(Prior Art) A typical steel sheet for LNG tanks is 9% Ni steel, but thin steel sheets are used because no large stress particularly acts on the bottom plate and roof of the LNG tank.
In this case, since the steel sheet is used at an extremely low temperature of −160 ° C. or lower, high toughness at low temperature, particularly low temperature toughness at the welded portion is required.
一般に、溶接された鋼板の熱影響部は、 （ａ）約1200℃以上の高温に加熱される粗粒域、 （ｂ）1200〜900℃程度に加熱される細粒域、 （ｃ）900〜700℃程度に加熱される二相域および （ｄ）700〜450℃程度に加熱される焼戻し域 に分類される。 Generally, the heat-affected zone of the welded steel sheet includes (a) a coarse grain region heated to a high temperature of about 1200 ° C or higher, (b) a fine grain region heated to about 1200 to 900 ° C, (c) 900 to It is classified into a two-phase region heated to about 700 ° C and (d) a tempered region heated to about 700 to 450 ° C.
かような溶接熱影響部のうち、とくに高温まで加熱さ
れる粗粒域については、その靱性を確保するために、従
来から種々の手立てが講じられている。Among such heat-affected zones of welding, various measures have been conventionally taken in order to secure the toughness of the coarse grain region which is heated to a high temperature.
しかしながら最近、薄物鋼板の溶接継手のうち、二相
域に加熱される領域において、島状マルテンサイトの生
成に起因した靱性の低下（二相域脆化）が明らかとな
り、問題となっている。かかる二相域脆化は、とくにNi
を7.5wt％（以下単に％で示す）以上含む高Ni鋼におい
て顕著であるが、その理由は、Niを7.5％以上含む高Ni
鋼では、二相域のオーステナイトとフェライトにおける
Ｃの分散が異なることから、二相域加熱後の冷却過程に
おいて島状マルテンサイトが生成し易くなるためである
ことが、発明者らの検討により解明された。However, recently, in a region of a welded joint of a thin steel plate, which is heated to a two-phase region, a decrease in toughness due to the formation of island martensite (two-phase region embrittlement) has been revealed, which is a problem. Such two-phase embrittlement is
Is remarkable in the high Ni steel containing 7.5 wt% or more (hereinafter simply referred to as%) because the reason is high Ni containing 7.5% or more Ni.
In steel, the austenite in the two-phase region and the dispersion of C in the ferrite are different, so that island martensite is easily generated in the cooling process after heating in the two-phase region. Was done.
ここに、島状マルテンサイトは焼戻されることによっ
て分解されることが知られており、従って厚物鋼板のよ
うに溶接パス数が多い場合には、一旦生成された島状マ
ルテンサイトが以後の溶接熱サイクル（焼戻し）で分解
されるために二相域脆化は顕著いは現れない。しかしな
がら、板厚が10mm以下程度の薄物鋼板の溶接継手では、
溶接パス数が３パス以下と少ないために島状マルテンサ
イトがそのまま残り、二相域脆化が顕著となることが、
発明者らの研究により明らかとなった。Here, it is known that island martensite is decomposed by being tempered. Therefore, when the number of welding passes is large like a thick steel plate, once the island martensite is generated, Since it is decomposed by the welding heat cycle (tempering), the two-phase zone embrittlement does not appear significantly. However, for thin steel plate welded joints with a plate thickness of 10 mm or less,
Since the number of welding passes is as small as 3 or less, island martensite remains as it is, and the two-phase region embrittlement becomes remarkable.
It became clear by the research of the inventors.
なおかかる現象は、厚物鋼板であっても大入熱溶接継
手のように溶接パス数が少ない場合には現れる。It should be noted that such a phenomenon appears even in the case of a thick steel plate when the number of welding passes is small as in a large heat input welded joint.
そこで上記の問題の解決策として、発明者らは先に、
特開昭63−290246号公報において、Si量とMn量を低減し
た上で、Tiを必須元素として添加し、さらにはMoを選択
元素として添加する方法を提案した。しかしながらさら
に検討を進めた結果、この方法では二相域に加熱される
熱影響部の靱性は改善されるものの、TiさらにはMoを添
加することによって、細粒域に加熱される熱影響部につ
いては、−196℃におけるシャルピー衝撃試験において
脆性破面が現れ、かえって靱性の劣化を招くことが明ら
かとなった。Therefore, as a solution to the above problem, the inventors first
In Japanese Patent Laid-Open No. 63-290246, there has been proposed a method of reducing the amount of Si and Mn, adding Ti as an essential element, and further adding Mo as a selective element. However, as a result of further study, although the toughness of the heat-affected zone heated to the two-phase region is improved by this method, the addition of Ti and Mo to the heat-affected zone to the heat-affected zone It was revealed that in the Charpy impact test at -196 ° C, a brittle fracture surface appeared, which rather deteriorates the toughness.
その他にも類似技術として、特開昭63−128118号公
報、特公昭56−10966号公報および特開昭56−156716号
公報に開示の技術があるが、これらはいずれも母材の低
温靱性の改善のみを目的としたものであり、発明者らの
検討によれば、二相域脆化の防止にはさほど効果がない
ことが確かめられた。Other similar techniques include those disclosed in JP-A-63-128118, JP-B-56-10966 and JP-A-56-156716, all of which have low temperature toughness of the base metal. It is for the purpose of improvement only, and according to the study by the inventors, it was confirmed that it is not so effective in preventing the embrittlement in the two-phase region.
（発明が解決しようとする課題） この発明は、上記の問題を有利に解決するもので、二
相域は勿論のこと、それ以上の温度に加熱される溶接熱
影響部における低温靱性に優れ、必要に応じてASTM規格
（A 553,A 844）およびJIS規格（SL9 N60）に規定され
る強度（降伏強さ≧60kgf/mm2、引張強さ＝70〜85kgf/m
m2）を満足する溶接部靱性の優れた低温用薄物ニッケル
鋼板を提案することを目的とする。(Problems to be Solved by the Invention) The present invention advantageously solves the above problems, and is excellent not only in the two-phase region, but also in low-temperature toughness in a welding heat-affected zone heated to a temperature higher than that, Strength (yield strength ≧ 60 kgf / mm 2 , tensile strength = 70 to 85 kgf / m) specified by ASTM standards (A 553, A 844) and JIS standards (SL9 N60) as required.
It is an object of the present invention to propose a thin nickel steel plate for low temperature, which satisfies m 2 ) and has excellent weld toughness.
（課題を解決するための手段） 上記した目的は、下記の各項に掲げる要旨構成によ
り、有利に実現される。(Means for Solving the Problems) The above-mentioned objects are advantageously realized by the gist constitutions listed in the following items.
（１）C:0.03％以上、 Si:0.02〜0.22％、 Mn:0.05〜0.47％、 P:0.005％以下、 S:0.005％以下、 Ni:7.5〜12.0％および Al:0.01〜0.10％ を、 ３％≦（8Si＋9Mn）≦5.5％ 123C＋（8Si＋9Mn）≦12％ を満足する範囲において含有し、残余は実質的にFeの組
成になる溶接部靱性の優れた低温用薄物ニッケル鋼板
（第１発明）。(1) C: 0.03% or more, Si: 0.02 to 0.22%, Mn: 0.05 to 0.47%, P: 0.005% or less, S: 0.005% or less, Ni: 7.5 to 12.0% and Al: 0.01 to 0.10%, 3% ≤ (8Si + 9Mn) ≤ 5.5% 123C + (8Si + 9Mn) ≤ 12%, with the balance being substantially Fe composition, a thin nickel steel sheet for low temperature use with excellent toughness at the welded portion (first invention) .
（２）Si:0.02〜0.25％、 Mn:0.05〜0.50％、 P:0.005％以下、 S:0.005％以下、 Ni:7.5〜12.0％、 Al:0.01〜0.10％および Nb:0.005〜0.03％ を、 2.2％≦（8Si＋9Mn）≦5.9％ 9.5％≦123C＋（8Si＋9Mn）≦13.5％ を満足する範囲において含有し、残余は実質的にFeの組
成になる溶接部靱性の優れた低温用薄物ニッケル鋼板
（第２発明）。(2) Si: 0.02 to 0.25%, Mn: 0.05 to 0.50%, P: 0.005% or less, S: 0.005% or less, Ni: 7.5 to 12.0%, Al: 0.01 to 0.10% and Nb: 0.005 to 0.03% , 2.2% ≤ (8Si + 9Mn) ≤ 5.9% 9.5% ≤ 123C + (8Si + 9Mn) ≤ 13.5%, and the balance is essentially Fe composition. Second invention).
（３）Si:0.02〜0.25％、 Mn:0.05〜0.50％、 P:0.005％以下、 S:0.005％以下、 Ni:7.5〜12.0％、 Al:0.01〜0.10％、 Nb:0.005〜0.03％および V:0.005〜0.03％ を、 2.2％≦（8Si＋9Mn）≦5.9％ 9.5％≦123C＋（8Si＋9Mn）≦13.5％ を満足する範囲において含有し、残余は実質的にFeの組
成になる溶接部靱性の優れた低温用薄物ニッケル鋼板
（第３発明）。(3) Si: 0.02 to 0.25%, Mn: 0.05 to 0.50%, P: 0.005% or less, S: 0.005% or less, Ni: 7.5 to 12.0%, Al: 0.01 to 0.10%, Nb: 0.005 to 0.03% and V: 0.005 to 0.03% in the range of 2.2% ≤ (8Si + 9Mn) ≤ 5.9% 9.5% ≤ 123C + (8Si + 9Mn) ≤ 13.5%, with the balance being essentially Fe composition. Excellent weld toughness. Low temperature thin nickel steel plate (third invention).
（作用） この発明において、鋼の成分組成を上記の範囲に限定
した理由は次のとおりである。(Function) In the present invention, the reason why the composition of the steel is limited to the above range is as follows.
Siは、この発明における特徴的元素の一つである。そ
れというのは、Siを低減すると二相域に加熱される溶接
熱影響部における島状マルテンサイトの生成量が減少
し、この領域の靱性改善に顕著な効果を示すからであ
る。この効果を有効に発現させるためには、Si含有量に
つき、Nbを添加しない場合は0.22％以下、またNbを添加
した場合は0.25％以下とする必要がある。しかしながら
Nb添加の如何にかかわらずSi量が0.02％に満たないと、
脱酸効果が不十分なだけでなく、溶接時に900〜1200℃
程度の細粒域に加熱される熱影響部において結晶粒が粗
大化し、靱性の低下が顕著となるので、下限は0.02％と
した。Si is one of the characteristic elements in this invention. This is because when Si is reduced, the amount of island martensite produced in the weld heat affected zone heated to the two-phase region is reduced, and the toughness in this region is significantly improved. In order to effectively exhibit this effect, the Si content needs to be 0.22% or less when Nb is not added and 0.25% or less when Nb is added. However
Regardless of whether Nb is added, if the Si content is less than 0.02%,
Not only the deoxidizing effect is insufficient, but also 900 ~ 1200 ℃ during welding
The lower limit was made 0.02% because the crystal grains become coarse in the heat-affected zone which is heated to a fine grain region to a certain extent, and the toughness is markedly reduced.
Mnも、Siと同様、この発明の特徴的元素の一つであ
り、Mnを低減すると、Siの低減と相まって二相域に加熱
される溶接熱影響部における島状マルテンサイトの生成
量が大幅に減少する。そのためには、Mn含有量につき、
Nbを添加しない場合は0.47％以下、またNbを添加した場
合は0.50％以下とする必要がある。しかしながらNb添加
の如何にかかわらずMn量が0.05％に満たないと、母材の
強度および靱性を確保できないだけでなく、細粒域に加
熱される熱影響部の靱性低下が顕著となるので、下限は
0.05％とした。Mn, like Si, is one of the characteristic elements of the present invention, and when Mn is reduced, the amount of island-shaped martensite produced in the weld heat-affected zone, which is heated in the two-phase region in combination with the reduction of Si, is significantly increased. Decrease to. For that, per Mn content,
It should be 0.47% or less when Nb is not added, and 0.50% or less when Nb is added. However, if the amount of Mn is less than 0.05% regardless of the addition of Nb, not only the strength and toughness of the base material cannot be secured, but also the toughness of the heat-affected zone heated to the fine grain region becomes remarkable, The lower limit is
It was set to 0.05%.
この発明によれば、上述の組成限定に加えてさらに、 ｉ）Nbを添加しない場合 ３％≦（8Si＋9Mn）≦5.5％ ii）Nbを添加した場合 2.2％≦（8Si＋9Mn）≦5.9％ なる関係を満足させることが肝要である。 According to the present invention, in addition to the above composition limitation, i) when Nb is not added 3% ≦ (8Si + 9Mn) ≦ 5.5% ii) When Nb is added 2.2% ≦ (8Si + 9Mn) ≦ 5.9% It is essential to satisfy.
というのは、この発明の特徴である溶接時に二相域に
加熱される領域の靱性を改善するには、島状マルテンサ
イトの生成を抑制する必要があるが、島状マルテンサイ
トの生成を抑制するには、SiとMnとを併せて低減するこ
とが極めて有効だからである。しかも細粒域に加熱され
る領域における結晶粒の粗大化による靱性低下も、Siと
Mnの合計量に強い相関がある。This is because it is necessary to suppress the formation of island martensite in order to improve the toughness of the region that is heated to the two-phase region during welding, which is a feature of the present invention, but to suppress the formation of island martensite. This is because it is extremely effective to reduce Si and Mn together. Moreover, the decrease in toughness due to the coarsening of the crystal grains in the region heated to the fine grain region
There is a strong correlation with the total amount of Mn.
すなわち、Nbを添加しない場合には（8Si＋9Mn）≦5.
5％なる関係、またNbを添加した場合には（8Si＋9Mn）
≦5.9％なる関係を満足するSiおよびMn量において、二
相域に加熱される領域の高靱性が実現され、さらにNbを
添加しない場合には３％≦（8Si＋9Mn）なる関係、また
Nbを添加した場合には2.2％≦（8Si＋9Mn）なる関係を
満足するSiおよびMn量において、細粒域に加熱される領
域の高靱性が実現されるからである。That is, when Nb is not added, (8Si + 9Mn) ≦ 5.
5% relationship, and when Nb is added (8Si + 9Mn)
With the amounts of Si and Mn satisfying the relation of ≦ 5.9%, the high toughness of the region heated to the two-phase region is realized, and when the Nb is not added, the relation of 3% ≦ (8Si + 9Mn),
This is because when Nb is added, high toughness in the region heated to the fine grain region is realized with the amounts of Si and Mn satisfying the relationship of 2.2% ≦ (8Si + 9Mn).
P:0.004％,S:0.001％,Ni:8〜11％,Al:0.03％を基本組
成とし、123C＋（8Si＋9Mn）≦12％の範囲内でC,Siおよ
びMn量を種々に変化させて含有させた鋼板を、サブマー
ジアーク溶接したときの溶接部靱性について調査した。
なお溶接部靱性試験における切欠位置はHAZ 4mm位置お
よびHAZ 8mmとしたが、それぞれ細粒域および二相域に
加熱された領域に相当するものである。P: 0.004%, S: 0.001%, Ni: 8-11%, Al: 0.03% as the basic composition, with various amounts of C, Si and Mn contained within 123C + (8Si + 9Mn) ≤ 12% The toughness of the welded portion of the steel sheet thus obtained was examined when submerged arc welding was performed.
The notch positions in the weld toughness test were HAZ 4 mm position and HAZ 8 mm, which correspond to the regions heated to the fine grain region and the two-phase region, respectively.
第１図に、HAZ 4mmにおける靱性と（8Si＋9Mn）との
関係を、また第２図には、HAZ 8mmにおける靱性と（8Si
＋9Mn）との関係を示す。Fig. 1 shows the relationship between toughness at HAZ 4mm and (8Si + 9Mn), and Fig. 2 shows toughness at HAZ 8mm and (8Si + 9Mn).
+ 9Mn).
同図より明らかなように、SiとMnとの合計量が３％≦
（8Si＋9Mn）≦5.5％の範囲を満足する場合に初めてHAZ
4mmおよびHAZ 8mm位置すなわち細粒域および二相域両
者とも優れた低温靱性が得られている。As is clear from the figure, the total amount of Si and Mn is 3% ≦
HAZ for the first time when the range of (8Si + 9Mn) ≤ 5.5% is satisfied
Excellent low temperature toughness is obtained at 4 mm and HAZ 8 mm, that is, in both the fine grain region and the two-phase region.
また同様にP:0.004％,S:0.001％,Ni:8〜11％,Al:0.03
％およびNb:0.005〜0.03％を基本組成とし、123C＋（8S
i＋9Mn）≦13.5％の範囲内でC,SiおよびMn量を種々に変
化させて含有させた鋼板を、サブマージアーク溶接した
ときの溶接部靱性についても調査した。Similarly, P: 0.004%, S: 0.001%, Ni: 8-11%, Al: 0.03
% And Nb: 0.005-0.03% as the basic composition, 123C + (8S
Weld toughness was also investigated when submerged arc welding was performed on steel sheets containing various amounts of C, Si and Mn within the range of i + 9Mn) ≦ 13.5%.
第３図に、HAZ 4mmにおける靱性と（8Si＋9Mn）との
関係を、また第４図には、HAZ 8mmにおける靱性と（8Si
＋9Mn）との関係を示したが、同図より明らかなよう
に、この場合には、SiとMnとの合計量が2.2％≦（8Si＋
9Mn）≦5.9％の範囲を満足する場合において細粒域およ
び二相域両者とも優れた低温靱性が得られている。Fig. 3 shows the relationship between the toughness of HAZ 4mm and (8Si + 9Mn), and Fig. 4 shows the toughness of HAZ 8mm and (8Si + 9Mn).
However, in this case, the total amount of Si and Mn is 2.2% ≦ (8Si +
9Mn) ≤ 5.9%, excellent low temperature toughness is obtained in both the fine grain region and the two-phase region.
Ｃも、SiおよびMn同様、この発明の特徴的元素の一つ
である。Ｃを低減すると、SiおよびMnと同様に二相域に
加熱される領域における島状マルテンサイトの生成量が
減少し、この領域における靱性を改善する。さらに、細
粒域に加熱される領域においても島状マルテンサイトは
生成するが、Ｃの低減は、結晶粒の粗大化を引き起こす
ことなく島状マルテンサイトの生成を減少するのに効果
があるため、この領域の靱性向上にも有効に寄与する。C, like Si and Mn, is one of the characteristic elements of the present invention. When C is reduced, the amount of island martensite formed in the region heated to the two-phase region is reduced like Si and Mn, and the toughness in this region is improved. Further, island martensite is formed even in the region heated to the fine grain region, but the reduction of C is effective in reducing the formation of island martensite without causing coarsening of crystal grains. , Also effectively contributes to the improvement of toughness in this region.
すなわち、Nbを添加しない場合には、123C＋（8Si＋9
Mn）≦12％なる関係、またNbを添加した場合には、123C
＋（8Si＋9Mn）≦13.5％なる関係を満足するＣ量におい
て、二相域および細粒域に加熱される領域の高靱性が実
現されるのである。しかしながら、Nbを添加しない場合
に、Ｃ量が0.03％未満では粗粒域における結晶粒が粗大
化し、この領域における靱性が低下するので、この場合
のＣ量の下限は0.03％とした。またＣは十分な強度を得
るために有用な元素であり、Mnと同様に過度の低減は母
材強度の低下を引き起こす。従ってASTM規格およびJIS
規格に規定される強度を付与するためには、Nb添加と共
に、9.5％≦123C＋（8Si＋9Mn）なる関係を満足するＣ
量が必要である。In other words, when Nb is not added, 123C + (8Si + 9
Mn) ≤ 12%, or 123C when Nb is added
With a C content satisfying the relationship of + (8Si + 9Mn) ≦ 13.5%, the high toughness of the region heated to the two-phase region and the fine grain region is realized. However, when Nb is not added, if the C content is less than 0.03%, the crystal grains in the coarse grain region become coarse and the toughness in this region deteriorates, so the lower limit of the C amount in this case was made 0.03%. C is a useful element for obtaining sufficient strength, and excessive reduction causes a decrease in base material strength, like Mn. Therefore ASTM standard and JIS
In order to give the strength specified in the standard, C satisfying the relation of 9.5% ≦ 123C + (8Si + 9Mn) together with Nb addition.
Quantity is needed.
P:0.004％,S:0.001％,Ni:8〜11％,Al:0.03％を基本組
成とし、３％≦（8Si＋9Mn）≦5.5％の範囲内でC,Siお
よびMn量を種々に変化させて含有させた鋼板を、サブマ
ージアーク溶接したときの溶接部靱性について調査し
た。なお溶接部靱性試験における切欠位置はHAZ 4mm位
置およびHAZ 8mm位置としたが、それぞれ細粒域および
二相域に加熱された領域に相当することは前述したとお
りである。With P: 0.004%, S: 0.001%, Ni: 8-11%, Al: 0.03% as the basic composition, varying the amounts of C, Si and Mn within the range of 3% ≤ (8Si + 9Mn) ≤ 5.5%. The toughness of the welded portion when the submerged arc welding was performed on the steel sheet contained as a material was investigated. The notch positions in the weld toughness test were the HAZ 4 mm position and the HAZ 8 mm position, but as described above, they correspond to the regions heated to the fine grain region and the two-phase region, respectively.
第５図に、HAZ 4mmにおける靱性と123C＋（8Si＋9M
n）との関係を、また第６図には、HAZ 8mmにおける靱性
と123C＋（8Si＋9Mn）との関係を示す。Fig. 5 shows the toughness of HAZ 4mm and 123C + (8Si + 9M
n), and FIG. 6 shows the relationship between 123C + (8Si + 9Mn) and the toughness of HAZ 8 mm.
同図より明らかなように、C,SiおよびMn量が123C＋
（8Si＋9Mn）≦12％の範囲を満足する場合に細粒域およ
び二相域両者とも優れた低温靱性が得られている。As is clear from the figure, the amount of C, Si and Mn is 123C +
When the range of (8Si + 9Mn) ≦ 12% is satisfied, excellent low temperature toughness is obtained in both the fine grain region and the two-phase region.
また同様にP:0.004％,S:0.001％,Ni:8〜11％,Al:0.03
％およびNb:0.005〜0.03％を基本組成とし、2.2％≦（8
Si＋9Mn）≦5.9％の範囲内でC,SiおよびMn量を種々に変
化させて含有させた鋼板を、サブマージアーク溶接した
ときの溶接部靱性についても調査した。Similarly, P: 0.004%, S: 0.001%, Ni: 8-11%, Al: 0.03
% And Nb: 0.005 to 0.03% as the basic composition, and 2.2% ≤ (8
The toughness of welds when submerged arc welding was also investigated for steel sheets containing various amounts of C, Si and Mn within the range of Si + 9Mn) ≦ 5.9%.
第７図に、HAZ 4mmにおける靱性と123C＋（8Si＋9M
n）との関係を、また第８図には、HAZ 8mmにおける靱性
と123C＋（8Si＋9Mn）との関係を示したが、同図より明
らかなように、この場合には、SiとMnとの合計量が123C
＋（8Si＋9Mn）≦13.5％の範囲を満足する場合において
細粒域および二相域両者ともに優れた低温靱性が得られ
ている。Figure 7 shows the toughness of HAZ 4mm and 123C + (8Si + 9M
n), and Fig. 8 shows the relation between the toughness of HAZ 8mm and 123C + (8Si + 9Mn). As is clear from this figure, in this case, the total of Si and Mn is Amount is 123C
When satisfying the range of + (8Si + 9Mn) ≦ 13.5%, excellent low temperature toughness is obtained in both the fine grain region and the two-phase region.
Ｐも、この発明の特徴的元素の一つである。それとい
うのは、Ｐの低減は、母材および溶接部の靱性、とくに
二相域に加熱される領域の靱性向上に極めて有効に寄与
するからである。従ってＰの混入は極力抑制することが
望ましいが、0.005％以下ならば許容できる。P is also one of the characteristic elements of this invention. This is because the reduction of P contributes extremely effectively to the toughness of the base material and the welded part, particularly to the toughness of the region heated to the two-phase region. Therefore, it is desirable to suppress the mixture of P as much as possible, but 0.005% or less is acceptable.
Ｓは、Ｐと同様、母材および溶接部の靱性を害するの
で極力低減することが望ましいが、0.005％以下の範囲
で許容できる。As with P, S impairs the toughness of the base material and the welded portion, so it is desirable to reduce S as much as possible, but S is acceptable within the range of 0.005% or less.
Niは、この発明の低温用鋼において高靱性を与える効
果を有するが、7.5％未満ではその添加効果に乏しく、
一方12％を超えて多量に添加してもその効果は飽和に達
し、また不経済であるので、7.5〜12.0％の範囲に限定
した。Ni has the effect of imparting high toughness in the low temperature steel of the present invention, but if less than 7.5%, its addition effect is poor,
On the other hand, even if added in excess of 12%, the effect reaches saturation and it is uneconomical, so the range was limited to 7.5-12.0%.
Alは、脱酸上必要な元素であるが、0.01％未満ではそ
の効果に乏しく、一方0.10％を超えると清浄性を損なう
ので、0.01〜0.10％の範囲とした。Al is an element necessary for deoxidation, but if it is less than 0.01%, its effect is poor, and if it exceeds 0.10%, detergency is impaired, so Al was made 0.01 to 0.10%.
Nbは、析出強化によって強度を向上させるだけでな
く、結晶粒の微細化によって母材および溶接熱影響部全
体の靱性を向上させる有用元素である。それ故、溶接熱
影響部の高靱性の維持と共に、ASTM規格およびJIS規格
に規定される強度を保証する上からは、Nbの添加は不可
欠である。しかしながら、0.005％未満ではその添加効
果に乏しく、一方0.03％を超えても強度の上昇はなく、
かえって靱性を損なうので、0.005％〜0.03％の範囲で
添加する必要がある。Nb is a useful element that not only improves the strength by precipitation strengthening but also improves the toughness of the base material and the entire weld heat affected zone by refining the crystal grains. Therefore, addition of Nb is indispensable for maintaining high toughness of the heat-affected zone of welding and for guaranteeing the strength defined in ASTM standard and JIS standard. However, if it is less than 0.005%, its effect of addition is poor, while if it exceeds 0.03%, there is no increase in strength,
On the contrary, since toughness is impaired, it is necessary to add it in the range of 0.005% to 0.03%.
Ｖは、析出強化による強度の向上に有効に寄与するの
で、強度向上を目的として添加することができる。しか
しながら、0.005％未満ではその添加効果に乏しく、一
方0.03％を超えるとかえって靱性の劣化を招くので、添
加する場合には0.005〜0.03％の範囲とする必要があ
る。V effectively contributes to the improvement of strength by precipitation strengthening, so V can be added for the purpose of improving strength. However, if less than 0.005%, the effect of addition is poor, and if more than 0.03%, toughness is rather deteriorated. Therefore, when adding, it is necessary to set the content in the range of 0.005 to 0.03%.
そして、上記の成分組成範囲であれば、母材の製造法
は従来公知の方法いずれでも良く、たとえば圧延後再加
熱焼入れ−焼戻し（RQ−Ｔ）、圧延後再加熱焼入れ−二
相域焼入れ−焼戻し（RQ−Ｑ′−Ｔ）、圧延後直接焼入
れ−焼戻し（DQ−Ｔ）および圧延後直接焼入れ−二相域
焼入れ−焼戻し（DQ−Ｑ′−Ｔ）などの方法で良い。Then, as long as it is in the above component composition range, the base material may be produced by any conventionally known method, for example, reheating quenching after rolling-tempering (RQ-T), reheating quenching after rolling-two-phase region quenching- Methods such as tempering (RQ-Q'-T), post-rolling direct quenching-tempering (DQ-T) and post-rolling direct quenching-two-phase region quenching-tempering (DQ-Q'-T) may be used.
（実施例） 実施例１ 表１に示す種々の化学組成（Nb含有せず）になる鋼ス
ラブを、加熱温度:1200℃、圧延仕上げ温度:800℃の条
件で6mm厚まで熱延し、室温まで冷却した後、780℃で30
min加熱後、直ちに水冷する再加熱焼入れを施し、つい
で570℃で45minの焼戻し処理（RQ−Ｔ）を施した。その
後入熱量:20kJ/cm、パス数:2の条件でオーステナイト系
ワイヤーを用いてサブマージアーク溶接を行った。(Example) Example 1 Steel slabs having various chemical compositions (without containing Nb) shown in Table 1 were hot-rolled to a thickness of 6 mm at a heating temperature of 1200 ° C and a rolling finishing temperature of 800 ° C, and then at room temperature. After cooling to 780 ℃, 30
Immediately after the min heating, reheating quenching with water cooling was performed, and then a tempering treatment (RQ-T) was performed at 570 ° C. for 45 min. After that, submerged arc welding was performed using an austenitic wire under the conditions of heat input: 20 kJ / cm and number of passes: 2.
その時の母材強度、靱性および溶接部靱性について調
べた結果を表２に示す。なお溶接部靱性試験における切
欠位置はボンド部、HAZ 4mm位置およびHAZ 8mm位置とし
たが、それぞれ粗粒域、細粒域および二相域に加熱され
た領域に相当する。Table 2 shows the results of an examination of the base metal strength, toughness and weld zone toughness at that time. The notch positions in the weld toughness test were the bond part, the HAZ 4 mm position and the HAZ 8 mm position, which correspond to the coarse grain region, the fine grain region and the two-phase region heated region, respectively.
同表より明らかなように、この発明の適正範囲を満足
する鋼板（鋼No.1〜６）はいずれも、優れた溶接部靱性
が得られている。 As is clear from the table, all of the steel plates (steel Nos. 1 to 6) satisfying the proper range of the present invention have excellent weld zone toughness.
これに対し、（8Si＋9Mn）＜３％の鋼No.7,8ではHAZ
4mmにおける靱性の低下が著しく、一方（8Si＋9Mn）＞
5.5％の鋼No.9,10ではHAZ 8mmにおける靱性の低下が著
しかった。On the other hand, HAZ is used for steel Nos. 7 and 8 with (8Si + 9Mn) <3%.
Significant decrease in toughness at 4 mm, while (8Si + 9Mn)>
In 5.5% steel Nos. 9 and 10, the reduction in toughness at HAZ 8 mm was remarkable.
またSi量とMn量が３％≦（8Si＋9Mn）≦5.5％なる関
係を満足する場合であっても、Si量が0.22％を超えた鋼
板（鋼No.13,14）およびMn量が0.47％を超えた鋼板（鋼
No.15,16）ではHAZ 8mmにおける靱性の低下が著しかっ
た。Even when the Si content and the Mn content satisfy the relationship of 3% ≦ (8Si + 9Mn) ≦ 5.5%, the steel plate with the Si content exceeding 0.22% (Steel No. 13, 14) and the Mn content of 0.47% Steel plate beyond (steel
In Nos. 15 and 16), the decrease in toughness at 8 mm in HAZ was remarkable.
さらに123C＋（8Si＋9Mn）＞12％の鋼No.11,12ではHA
Z 4mmおよびHAZ 8mm両位置において靱性が著しく低下し
ている。Furthermore, 123C + (8Si + 9Mn)> 12% steel No. 11 and 12 HA
The toughness is significantly reduced at both Z 4 mm and HAZ 8 mm positions.
その他、Ｃ量が123C＋（8Si＋9Mn）≦12％なる関係を
満足する場合であっても、0.03％を下回る鋼No.17,18で
はボンド部における靱性が、またＰが上限を超えて多量
に含有された鋼No.19ではHAZ 8mmにおける靱性がそれぞ
れ悪い。In addition, even if the relationship that the C content is 123C + (8Si + 9Mn) ≦ 12% is satisfied, in steel Nos. 17 and 18 below 0.03%, the toughness in the bond part and the P content exceeding the upper limit are contained in large amounts. The toughness of HAZ 8 mm in steel No. 19 was poor.
なお鋼No.20は、前掲特開昭63−128118号公報に開示
の鋼組成であるが、HAZ 4mmおよびHAZ 8mm両位置におけ
る靱性の劣化が著しい。Steel No. 20 has the steel composition disclosed in Japanese Patent Laid-Open No. 63-128118, but the toughness is significantly deteriorated at both HAZ 4 mm and HAZ 8 mm positions.
実施例２ 表３に示す種々の化学組成（Nb含有）になる鋼スラブ
を、加熱温度:1200℃、圧延仕上げ温度:800℃の条件で6
mm厚まで熱延し、室温まで冷却した後、780℃で30min加
熱後、直ちに水冷する再加熱焼入れを施し、ついで570
℃で45minの焼戻し処理（RQ−Ｔ）を施した。その後入
熱量:20kJ/cm、パス数:2の条件でオーステナイト系ワイ
ヤーを用いてサブマージアーク溶接を行った。Example 2 Steel slabs having various chemical compositions (containing Nb) shown in Table 3 were prepared under the conditions of heating temperature: 1200 ° C and rolling finishing temperature: 800 ° C.
After hot rolling to mm thickness, cooling to room temperature, heating at 780 ° C for 30 min, immediately water cooling, reheating and quenching, then 570
A tempering treatment (RQ-T) was performed at 45 ° C for 45 minutes. After that, submerged arc welding was performed using an austenitic wire under the conditions of heat input: 20 kJ / cm and number of passes: 2.
その時の母材強度、靱性および溶接部靱性について調
べた結果を表４に示す。なお溶接部靱性試験における切
欠位置はボンド部、HAZ 4mm位置およびHAZ 8mm位置とし
たが、それぞれ粗粒域、細粒域および二相域に加熱され
た領域に相当する。Table 4 shows the results of an examination of the base metal strength, toughness, and weld toughness at that time. The notch positions in the weld toughness test were the bond part, the HAZ 4 mm position and the HAZ 8 mm position, which correspond to the coarse grain region, the fine grain region and the two-phase region heated region, respectively.
同表より明らかなように、この発明の適正範囲を満足
する鋼板（鋼No.1〜７）はいずれも、優れた溶接部靱性
が得られている。 As is clear from the table, all of the steel sheets (steel Nos. 1 to 7) satisfying the proper range of the present invention have excellent weld zone toughness.
これに対し、（8Si＋9Mn）＜2.2％の鋼No.8,9ではHAZ
4mmにおける靱性の低下が著しく、一方（8Si＋9Mn）＞
5.9％の鋼No.10ではHAZ 8mmにおける靱性の低下が著し
かった。On the other hand, HAZ is used for steel Nos. 8 and 9 with (8Si + 9Mn) <2.2%.
Significant decrease in toughness at 4 mm, while (8Si + 9Mn)>
The decrease in toughness at 8 mm in HAZ was remarkable in 5.9% steel No. 10.
またSi量とMn量が2.2％≦（8Si＋9Mn）≦5.9％なる関
係を満足する場合であっても、Si量が0.25％を超えた鋼
板（鋼No.14）およびMn量が0.50％を超えた鋼板（鋼No.
15）ではHAZ 8mmにおける靱性の低下が著しかった。Even if the Si content and the Mn content satisfy the relationship of 2.2% ≤ (8Si + 9Mn) ≤ 5.9%, the steel sheet with Si content exceeding 0.25% (Steel No. 14) and the Mn content exceeding 0.50% Steel plate (steel No.
In 15), the decrease in toughness at 8 mm in HAZ was remarkable.
さらに123C＋（8Si＋9Mn）＞13.5％の鋼No.12,13では
HAZ 4mmおよびHAZ 8mm両位置において靱性が著しく低下
している。Furthermore, in steel Nos. 12 and 13 with 123C + (8Si + 9Mn)> 13.5%
The toughness is significantly reduced at both HAZ 4 mm and HAZ 8 mm positions.
またさらに123C＋（8Si＋9Mn）＜9.5％では（鋼No.1
1）、ASTM規格およびJIS規格に規定される強度が得られ
ていない。Furthermore, if 123C + (8Si + 9Mn) <9.5% (Steel No. 1
1), the strength specified in ASTM standard and JIS standard is not obtained.
その他、Nb量およびＶ量がこの発明の上限を超える鋼
板（鋼No.16,17）では、母材および溶接部の靱性が低下
している。またＰが上限を超えて多量に含有された鋼N
o.19ではHAZ 8mmにおける靱性が悪い。In addition, the toughness of the base material and the welded portion is reduced in the steel plates (steel Nos. 16 and 17) in which the amounts of Nb and V exceed the upper limits of the present invention. In addition, steel N containing a large amount of P exceeding the upper limit
In o.19, the toughness at HAZ 8 mm is poor.
鋼No.19および20はそれぞれ、特公昭56−10966号公報
および特開昭56−156716号公報に開示の鋼組成である
が、前者はHAZ 4mmおよびHAZ 8mm両位置における靱性
が、また後者はとくにHAZ 8mm位置における靱性が悪
い。Steel Nos. 19 and 20 are steel compositions disclosed in JP-B-56-10966 and JP-A-56-156716, respectively, but the former has toughness at both HAZ 4 mm and HAZ 8 mm positions, and the latter has The toughness is especially poor at the HAZ 8 mm position.
（発明の効果） かくしてこの発明によれば、低温靱性とくに粗粒域、
細粒域および二相域すべての溶接部靱性に優れ、また必
要に応じて高強度を兼備する低温用ニッケル鋼板を容易
に得ることができる。(Effects of the Invention) Thus, according to the present invention, the low temperature toughness, particularly the coarse grain region,
It is possible to easily obtain a low-temperature nickel steel sheet having excellent weld zone toughness in all of the fine grain region and the two-phase region, and having high strength as required.
第１図は、Nb添加のない鋼板溶接継手のHAZ 4mm位置に
おける靱性と8Si＋9Mn（％）との関係を示したグラフ、 第２図は、Nb添加のない鋼板溶接継手のHAZ 8mm位置に
おける靱性と8Si＋9Mn（％）との関係を示したグラフ、 第３図は、Nbを添加した鋼板溶接継手のHAZ 4mm位置に
おける靱性と8Si＋9Mn（％）との関係を示したグラフ、 第４図は、Nbを添加した鋼板溶接継手のHAZ 8mm位置に
おける靱性と8Si＋9Mn（％）との関係を示したグラフ、 第５図は、Nb添加のない鋼板溶接継手のHAZ 4mm位置に
おける靱性と123C＋（8Si＋9Mn）（％）との関係を示し
たグラフ、 第６図は、Nb添加のない鋼板溶接継手のHAZ 8mm位置に
おける靱性と123C＋（8Si＋9Mn）（％）との関係を示し
たグラフ、 第７図は、Nbを添加した鋼板溶接継手のHAZ 4mm位置に
おける靱性と123C＋（8Si＋9Mn）（％）との関係を示し
たグラフ、 第８図は、Nbを添加した鋼板溶接継手のHAZ 8mm位置に
おける靱性と123C＋（8Si＋9Mn）（％）との関係を示し
たグラフである。Fig. 1 is a graph showing the relationship between the toughness of HAZ 4mm position of steel plate welded joint without Nb addition and 8Si + 9Mn (%), and Fig. 2 is the toughness of HAZ 8mm position of steel plate welded joint without Nb addition. A graph showing the relationship with 8Si + 9Mn (%), Fig. 3 is a graph showing the relationship between the toughness at the HAZ 4 mm position of the steel plate welded joint to which Nb is added and 8Si + 9Mn (%), and Fig. 4 shows the relationship between Nb and Fig. 5 is a graph showing the relationship between the toughness of the welded steel plate welded joint at 8mm HAZ and 8Si + 9Mn (%). Fig. 6 is a graph showing the relationship between the toughness of steel plate weld joints without addition of Nb at the HAZ 8 mm position and 123C + (8Si + 9Mn) (%). Fig. 7 is a graph showing the relationship with Nb addition. Of HAZ 4mm position of welded welded steel plate and 123C + (8Si + 9Mn) (%) Graph showing the relationship, FIG. 8 is a graph showing the relationship between the toughness and 123C + (8Si + 9Mn) (%) in the HAZ 8 mm position of the steel plate welded joint with the addition of Nb.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 谷川 治 岡山県倉敷市水島川崎通１丁目（番地な し） 川崎製鉄株式会社水島製鉄所内 (56)参考文献 特開 昭58−217629（ＪＰ，Ａ) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Osamu Tanikawa Osamu Kawasaki, Kurashiki City, Okayama Prefecture 1-chome (no address) Inside Mizushima Works, Kawasaki Steel Co., Ltd. (56) Reference JP-A-58-217629 (JP, A) )
Claims (3)
成になる溶接部靱性の優れた低温用薄物ニッケル鋼板。1. C: 0.03 wt% or more, Si: 0.02 to 0.22 wt%, Mn: 0.05 to 0.47 wt%, P: 0.005 wt% or less, S: 0.005 wt% or less, Ni: 7.5 to 12.0 wt% and Al: 0.01 to 0.10 wt% is contained within the range of 3 wt% ≤ (8Si + 9Mn) ≤ 5.5 wt% 123C + (8Si + 9Mn) ≤ 12 wt% with the balance being substantially Fe composition. Excellent weld toughness. Thin nickel steel plate for low temperature.
成になる溶接部靱性の優れた低温用薄物ニッケル鋼板。2. Si: 0.02 to 0.25 wt%, Mn: 0.05 to 0.50 wt%, P: 0.005 wt% or less, S: 0.005 wt% or less, Ni: 7.5 to 12.0 wt%, Al: 0.01 to 0.10 wt% And Nb: 0.005 to 0.03 wt% within the range of 2.2 wt% ≤ (8Si + 9Mn) ≤ 5.9 wt% 9.5 wt% ≤ 123C + (8Si + 9Mn) ≤ 13.5 wt% with the balance being substantially Fe composition. Low temperature thin nickel steel plate with excellent weld toughness.
成になる溶接部靱性の優れた低温用薄物ニッケル鋼板。3. Si: 0.02 to 0.25 wt%, Mn: 0.05 to 0.50 wt%, P: 0.005 wt% or less, S: 0.005 wt% or less, Ni: 7.5 to 12.0 wt%, Al: 0.01 to 0.10 wt% , Nb: 0.005-0.03wt% and V: 0.005-0.03wt% in the range that satisfies 2.2wt% ≦ (8Si + 9Mn) ≦ 5.9wt% 9.5wt% ≦ 123C + (8Si + 9Mn) ≦ 13.5wt%. Is a low temperature thin nickel steel plate with excellent Fe toughness, which has a substantially Fe composition.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2013738A JP2557993B2 (en) | 1990-01-25 | 1990-01-25 | Low temperature thin nickel steel plate with excellent weld toughness |
| EP91112442A EP0524335B1 (en) | 1990-01-25 | 1991-07-24 | Low-temperature service nickel steel plate with excellent weld toughness |
| US07/946,805 US5266417A (en) | 1990-01-25 | 1992-09-17 | Low-temperature service nickel plate with excellent weld toughness |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2013738A JP2557993B2 (en) | 1990-01-25 | 1990-01-25 | Low temperature thin nickel steel plate with excellent weld toughness |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03223442A JPH03223442A (en) | 1991-10-02 |
| JP2557993B2 true JP2557993B2 (en) | 1996-11-27 |
Family
ID=11841603
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2013738A Expired - Fee Related JP2557993B2 (en) | 1990-01-25 | 1990-01-25 | Low temperature thin nickel steel plate with excellent weld toughness |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0524335B1 (en) |
| JP (1) | JP2557993B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019082326A1 (en) | 2017-10-26 | 2019-05-02 | 新日鐵住金株式会社 | Nickel-containing steel for low-temperature use |
| CN111247262B (en) | 2017-10-26 | 2021-12-21 | 日本制铁株式会社 | Nickel-containing steel for low temperature use |
| JP6852805B2 (en) | 2017-10-26 | 2021-03-31 | 日本製鉄株式会社 | Nickel-containing steel for low temperature |
| US11371127B2 (en) | 2017-10-26 | 2022-06-28 | Nippon Steel Corporation | Nickel-containing steel for low temperature |
| JP6984320B2 (en) * | 2017-10-31 | 2021-12-17 | 日本製鉄株式会社 | Nickel-containing steel sheet for low temperature with excellent toughness and its manufacturing method |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE637650A (en) * | 1962-09-21 | |||
| FR1454534A (en) * | 1965-08-27 | 1966-02-11 | Siderurgie Fse Inst Rech | High-performance alloy |
| JPS58217629A (en) * | 1982-06-12 | 1983-12-17 | Kobe Steel Ltd | Preparation of low temperature steel for welding joint part excellent in toughness |
| JPS61127815A (en) * | 1984-11-26 | 1986-06-16 | Nippon Steel Corp | Production of high arrest steel containing ni |
| JPS63128118A (en) * | 1986-11-18 | 1988-05-31 | Sumitomo Metal Ind Ltd | Manufacture of low temperature steel having superior toughness at low temperature |
| JPS63290246A (en) * | 1987-05-22 | 1988-11-28 | Kawasaki Steel Corp | Steel for low-temperature excellent in toughness in weld zone |
-
1990
- 1990-01-25 JP JP2013738A patent/JP2557993B2/en not_active Expired - Fee Related
-
1991
- 1991-07-24 EP EP91112442A patent/EP0524335B1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03223442A (en) | 1991-10-02 |
| EP0524335B1 (en) | 1996-06-12 |
| EP0524335A1 (en) | 1993-01-27 |
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| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |