JPS6254066A - High strength steel excellent in sulfide stress corrosion cracking resistance - Google Patents
High strength steel excellent in sulfide stress corrosion cracking resistanceInfo
- Publication number
- JPS6254066A JPS6254066A JP19344085A JP19344085A JPS6254066A JP S6254066 A JPS6254066 A JP S6254066A JP 19344085 A JP19344085 A JP 19344085A JP 19344085 A JP19344085 A JP 19344085A JP S6254066 A JPS6254066 A JP S6254066A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- stress corrosion
- corrosion cracking
- sulfide stress
- less
- Prior art date
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Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は耐硫化物応力腐食割れ性にすぐれた高張力鋼に
係り、特に高靭性であり、かっ引張強さ60〜80 k
g 17mm2級の耐硫化物応力腐食割れ性のすぐれた
高張力鋼に関し、硫化水素を含む湿潤な環境におけるL
PGや都市ガスを貯蔵するタンクや石油類製品に′接す
る鋼構造物のほか、石油、天然ガス等の油井管、ライン
パイプ等の製造分野に広く利用される。[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a high tensile strength steel with excellent sulfide stress corrosion cracking resistance, particularly high toughness, and a tensile strength of 60 to 80 k.
g Regarding 17mm2 class high tensile steel with excellent sulfide stress corrosion cracking resistance, L in a humid environment containing hydrogen sulfide.
It is widely used in the manufacturing field of tanks for storing PG and city gas, steel structures that come in contact with petroleum products, as well as oil country pipes and line pipes for oil and natural gas.
石油、天然ガスおよびそれらを原料として製造されるL
PG等の石油類製品に接する油井管、う、インパイプ等
の鋼構造物、もしくは原油、LPG等のタンクや石油類
を取扱う化学プラントは、原油中および精製過程で発生
する硫化水素にさらされるために屡々硫化物応力腐食割
れを起すことが知られている。Oil, natural gas, and L produced using them as raw materials
Steel structures such as OCTG, pipes, and in-pipes that come into contact with petroleum products such as PG, tanks for crude oil, LPG, etc., and chemical plants that handle petroleum products are exposed to hydrogen sulfide generated in crude oil and during the refining process. It is known that this often causes sulfide stress corrosion cracking.
耐硫化物応力腐食割れ性は、機械的性質の面からは硬度
と密接な関係があり、高硬度はどその感受性が高いこと
は、「鉄と鋼」第54巻(1968年)第5号に報告さ
れている。従って特開昭55−73848、特開昭58
−107476に開示されているように、溶接構造用鋼
の従来の硫化物応力腐食割れ対策としては、溶接しても
その熱影響部が硬化しにくくすることに向けられ、C当
量を低めた成分組成を採用するのが一般的な方法であっ
た。Resistance to sulfide stress corrosion cracking is closely related to hardness from the perspective of mechanical properties, and the fact that high hardness is more susceptible to cracking is explained in "Tetsu to Hagane" Vol. 54 (1968) No. 5. has been reported. Therefore, JP-A-55-73848, JP-A-58
107476, conventional measures against sulfide stress corrosion cracking of welded structural steel are aimed at making the heat-affected zone difficult to harden even when welded, and using a component with a low C equivalent. The common method was to adopt the composition.
また硫化物応力腐食割れ性は、合金元素の面からは上記
「鉄と鋼」の報告にあるように、特に鋼中のN1の有無
に左右され、Ni1.を耐硫化物応力腐食割れ性を著し
く劣化させろとされているので、Niを無添加もしくは
低減した成分組成が一般に採用されている。In addition, from the perspective of alloying elements, the sulfide stress corrosion cracking resistance is particularly influenced by the presence or absence of N1 in the steel, as reported in the above-mentioned "Iron and Steel", and Ni1. Since the sulfide stress corrosion cracking resistance is expected to be significantly deteriorated, component compositions in which Ni is not added or are reduced are generally employed.
かくの如く、鋼材の硫化物応力腐食割れ性を防止する対
策として従来も多くの研究や開示がされており、これら
の研究や実際の経験からその防止対策として鋼材の硬度
をビッカースケールHvで240〜250以下に規制す
るのが有効であるとされており、従って従来は湿潤硫化
水素環境に適用される溶接構造用鋼材は、溶接による硬
化および組織の不健全性を考慮すると十分にC当量を低
めな成分組成とせざるを得ず、その結果引張強さも60
kg 17mm”以下に制限さぜるを得なかった。As mentioned above, many studies and disclosures have been made in the past as measures to prevent sulfide stress corrosion cracking in steel materials, and based on these studies and actual experience, as a preventive measure, the hardness of steel materials has been increased to 240 on the Vicker scale Hv. It is said that it is effective to limit the C equivalent to ~250 or less, and therefore, welded structural steel materials used in wet hydrogen sulfide environments have been required to have a sufficiently low C equivalent, taking into account the hardening caused by welding and the unsoundness of the structure. As a result, the tensile strength was 60%.
It was unavoidable to limit the weight to 17 mm or less.
またNiは靭性を向上させろ代表的な合金元素の−っで
あるに拘らず、引張強さが60 kg 17mm2級の
ものでも上記理由でN1を無添加もしくは低減した鋼で
ある場合が多く、その結果溶接熱影響部で低靭性となる
ことを避けることができなかった。In addition, although Ni is a typical alloying element that improves toughness, even steels with a tensile strength of 60 kg 17 mm2 are often made with no or reduced N1 added for the above reasons. As a result, low toughness in the weld heat affected zone could not be avoided.
しかしながらLPGや都市ガス等の鋼構造物は、ますま
す大型化傾向にあり、またこれらの鋼構造物の設置に際
しでは高強度鋼はど経済的に有利であるので、最近では
高強度、高靭性を有する耐硫化物応力腐食割れ性のすぐ
れた鋼の開発が切実に望まれているのが実状である。However, steel structures for LPG, city gas, etc. are becoming larger and larger, and high-strength steel is economically advantageous when installing these steel structures. The current situation is that there is an urgent need for the development of a steel with excellent sulfide stress corrosion cracking resistance.
本発明の目的は、耐硫化物応力腐食割れ性鋼の上記従来
技術の問題点を解消し、高靭性を有し、しかも引張強さ
が60〜80kg・17m1112級と最近の要望に応
えることができる耐硫化物応力腐食割れ性にすぐれた溶
接構造用高張力鋼を低合金鋼で提供しようとするもので
ある。The purpose of the present invention is to solve the problems of the above-mentioned conventional techniques of sulfide stress corrosion cracking resistant steel, to have high toughness, and to meet recent demands for tensile strength of 60 to 80 kg/17 m1112 class. The present invention aims to provide a low-alloy high-strength steel for welded structures with excellent resistance to sulfide stress corrosion cracking.
本発明者らは、上記問題点を解決するために先ず硫化物
応力腐食割れの機構を再検討する研究を行った。従来硫
化物応力腐食割れ現象が初めて認識された当時では、水
素脆性説と活性径路割れ(以下APCと称する)説との
両説があった。その後多くの研究により水素脆性説が一
応定説になったのであるが、本発明者らは更に研究を重
ねた結果、次の事実を知見するに到った。すなわち、硫
化水素を含む環境における鋼材の割れ発生機構(よ水素
脆性とAPCのいずれもが作用し、APCは初期に発生
して水素の集積場所を形成する作用を果し、水素脆性を
助長することが明らかになった。更に一般に耐硫化物応
力腐食割れ性を劣化させろといわれている鋼中のNiは
、APCを発生させ易い作用があるのみで、水素脆性に
は無関係であることも併せて明らかにすることができた
。In order to solve the above problems, the present inventors first conducted research to reexamine the mechanism of sulfide stress corrosion cracking. At the time when the sulfide stress corrosion cracking phenomenon was first recognized, there were two theories: the hydrogen embrittlement theory and the active path cracking (hereinafter referred to as APC) theory. After that, many studies made the hydrogen embrittlement theory a common theory, but as a result of further research, the present inventors came to the following fact. In other words, the mechanism by which cracks occur in steel materials in an environment containing hydrogen sulfide (hydrogen embrittlement and APC both act; APC occurs initially and acts to form a place where hydrogen accumulates, promoting hydrogen embrittlement. In addition, Ni in steel, which is generally said to deteriorate sulfide stress corrosion cracking resistance, only has the effect of making APC more likely to occur, and has nothing to do with hydrogen embrittlement. I was able to clarify this.
従って、従来、硫化物応力腐食割れ防止は水素脆化割れ
防止に主眼が置かれていたが、本発明者らの上記知見か
らAPCを防止することも必要であるとの結論に達した
。本発明者らは、この観点から研究を重ねた結果、合金
元素のうちAPCの発生を抑制する元素としてCrが有
効であり、逆にAPCの発生を促進する元素として上記
N1以外にMOがあることが判明した。しかし、とのN
i、M。Therefore, conventionally, prevention of sulfide stress corrosion cracking has focused on preventing hydrogen embrittlement cracking, but based on the above findings of the present inventors, it has been concluded that it is also necessary to prevent APC. As a result of repeated research from this point of view, the present inventors found that among alloying elements, Cr is effective as an element that suppresses the generation of APC, and conversely, MO is an element other than the above-mentioned N1 that promotes the generation of APC. It has been found. However, the N
i, M.
の悪影響は16%以上のCrの添加により抑制できるこ
とを究明し、更に研究を重ねて本発明を完成す、ること
ができた。It was discovered that the adverse effects of Cr can be suppressed by adding 16% or more of Cr, and after further research, the present invention was completed.
上記本発明の目的とする高靭性にして、かつ引張強さ6
0〜80 kg f/mm2級の耐硫化物応力腐食割れ
性高張力鋼は下記要旨の4発明によっていずれも有効に
達成される。The objective of the present invention is to achieve high toughness and tensile strength of 6.
A high tensile strength steel with sulfide stress corrosion cracking resistance of 0 to 80 kg f/mm2 class can be effectively achieved by the following four inventions.
第1発明の要旨とするところは次の如くである。The gist of the first invention is as follows.
すなわち、重量比にて
C:0.05〜015%
Si:0.10〜100%
Mn: 0.10〜1.50%
P:0.010%以下
S:0.005%以下
Ni:0.30〜300%
Cr: 1. 6 0〜3. 0 0%Mo: 00
1〜010%
およびAj’:0.001〜0.10%、T夏:0.0
1〜010%のうちより選ばれた1種または2種を含み
、残部はFeおよび不可避的不純物より成り高靭性を特
徴とする耐硫化物応力腐食割れ性にすぐれた高張力鋼で
ある。That is, in terms of weight ratio, C: 0.05-015% Si: 0.10-100% Mn: 0.10-1.50% P: 0.010% or less S: 0.005% or less Ni: 0. 30-300% Cr: 1. 6 0-3. 0 0% Mo: 00
1-010% and Aj': 0.001-0.10%, T summer: 0.0
It is a high-strength steel that is characterized by high toughness and excellent resistance to sulfide stress corrosion cracking.
第2発明の要旨は、上記第1発明の基本組成のホカニ、
更ニNb: o、 01〜0.10%、V:0.01〜
010%のうちより選ばれた1種または2種を含み、残
部はFeおよび不可避的不純物より成る鋼である。The gist of the second invention is that Hokani having the basic composition of the first invention,
Sarani Nb: o, 01~0.10%, V: 0.01~
The steel contains one or two selected from among 0.010% and the remainder consists of Fe and unavoidable impurities.
第3発明の要旨は、上記第1発明の基本組成のほかにB
:0.0005〜0.0050%を含み、残部はFeお
よび不可避的不純物より成る鋼である。The gist of the third invention is that in addition to the basic composition of the first invention, B
:0.0005 to 0.0050%, with the remainder being Fe and unavoidable impurities.
第4発明の要旨は、上記第1発明の基本組成のほかに、
更ICNb70.01〜0.10%、V:0.01〜0
10%のうちより選ばれた1種または2種およびB:O
,0O05〜0.0050%を同時に含み、残部はFe
および不可避的不純物より成る鋼である。The gist of the fourth invention is that, in addition to the basic composition of the first invention,
Further ICNb70.01~0.10%, V:0.01~0
One or two selected from 10% and B:O
,0O05~0.0050% at the same time, and the remainder is Fe.
and unavoidable impurities.
先ず本発明鋼の基本組成の限定理由について説明する。First, the reason for limiting the basic composition of the steel of the present invention will be explained.
C:
Cは鋼の焼入れ焼もどし性を向上させることにより強度
を確保する作用があり、そのためには少くとも005%
を必要とする。しかし015%を越して過多となると後
記160%以上のCrと共存して溶接熱影響部を硬化さ
せ、ひいては耐硫化物応力腐食割れ性を劣化させるのて
015%を上限とし、005〜015%の範囲に限定し
た。C: C has the effect of ensuring strength by improving the quenching and tempering properties of steel, and for this purpose it must be at least 0.005%
Requires. However, if the amount exceeds 015%, it will coexist with 160% or more of Cr described below, hardening the weld heat affected zone, and eventually deteriorating the sulfide stress corrosion cracking resistance. limited to the range of
S 1:
Siは脱酸のために添加し、かつ強度を高める作ルがあ
るが、この目的のためには少くとも010%を必要とす
る。しかし100%を越して過多となると靭性の劣化を
来たすので上限を1,00%とし、0.10〜100%
の範囲に限定した。S1: Si is added for deoxidation and to increase strength, but for this purpose at least 0.1% is required. However, if the amount exceeds 100%, the toughness will deteriorate, so the upper limit is set at 1,00%, and 0.10 to 100%
limited to the range of
Mn:
MnはSlと同様に脱酸作用があり、かつ強度靭性を高
める作用があるが、010%未満ではこの作用効果が得
られず、また150%を越して過多となると靭性の劣化
を来たすようになるので上限を150%とし、010〜
150%の範囲に限定した。Mn: Like Sl, Mn has a deoxidizing effect and also has the effect of increasing strength and toughness, but if it is less than 10%, this effect cannot be obtained, and if it exceeds 150%, it will cause deterioration of toughness. Therefore, the upper limit is set to 150%, and 010~
It was limited to a range of 150%.
P:
Pは鋼中に不可避的に随伴される不純物であり、少いほ
どよいが、特にその含有量が001096を越すと粒界
に偏析して加工に際し亀裂を生じ易くなり、また焼入れ
時に焼割れを発生するので0010%を上限とした。P: P is an impurity that inevitably accompanies steel, and the less the better, but if the content exceeds 001096, it will segregate at grain boundaries and easily cause cracks during processing. Since cracks may occur, the upper limit was set at 0010%.
S :
SもPと同様に鋼中に不可避的に随伴される不純物であ
り、少いほど良好であるが、特にその含有量が0005
%を越すとMnS系介在物を形成して熱間圧延により延
伸し、割れ発生の起点を誘発する有害成分であるので、
その上限を0005%とした。S: Like P, S is an impurity that inevitably accompanies steel, and the smaller the content, the better.
%, it is a harmful component that forms MnS-based inclusions and stretches during hot rolling, inducing the starting point of cracking.
The upper limit was set at 0005%.
NI:
Ni1.を鋼の焼入れ性を促進し、母材および溶接熱影
響部の靭性向上に寄与する元素であり、そのためには少
くとも0.30%を必要とする。しかし30%を越えて
過多となると効果が飽和するので上限を30%とし、0
30〜30%の範囲に限定した。NI: Ni1. It is an element that promotes the hardenability of steel and contributes to improving the toughness of the base metal and the weld heat affected zone, and for this purpose, at least 0.30% is required. However, if the amount exceeds 30%, the effect will be saturated, so the upper limit is set at 30%, and 0.
It was limited to a range of 30-30%.
Cr:
C「は焼もどし抵抗性を高める作用があるほか、上記の
如<A’PC’の発生を抑制する作用がある。Cr: C' has the effect of increasing the tempering resistance and also has the effect of suppressing the occurrence of <A'PC' as described above.
特にNi、Moの存在下ではこれらの元素のAPC発生
、促進作用を抑制する作用があり、本発明においては重
要な元素の一つである。この作用を効果的ならしめるた
めには少くとも160%を必要とする。しかし30%を
越えて過多となると鋼の靭性劣化をもたらすので上限を
30%とし、160〜30%の範囲に限定した。Particularly in the presence of Ni and Mo, Ni has the effect of suppressing the APC generation and promotion effect of these elements, and is one of the important elements in the present invention. At least 160% is required for this effect to be effective. However, if it exceeds 30%, the toughness of the steel deteriorates, so the upper limit was set at 30%, and the range was limited to 160 to 30%.
MO:
MOは鋼の焼もどし抵抗性を高める作用があり、そのた
めに少くとも0.01%を必要とする。しかし010%
を越えると溶接熱影響部を硬化させ、ひいては耐硫化物
応力腐食割れ性を劣化させるのて上限を0.10%とし
、001〜010%の範囲に限定した。MO: MO has the effect of increasing the tempering resistance of steel, and therefore requires at least 0.01%. But 010%
If it exceeds this amount, the weld heat-affected zone will be hardened, and the sulfide stress corrosion cracking resistance will be deteriorated.
Al:
AIは脱酸作用があり、更に鋼中のNと結合して窒化物
を形成し、B含有鋼の場合はBの作用を有効化する作用
があるが、特に結晶粒を微細化して靭性を高める作用が
大きいので、T1と共に必要に応じいずれか単独もしく
は共存状態で添加される。しかしその含有量は0001
%未満では上記効果を得ることができず、他方010%
を越して過多となると介在物の増加を招き、ひいては靭
性の劣化を来たすので上限を010%とし、0001〜
010%の範囲に限定した。Al: Al has a deoxidizing effect, and also combines with N in steel to form nitrides, and in the case of B-containing steel, it has the effect of activating the effect of B, but it especially has the effect of making crystal grains finer. Since it has a great effect of increasing toughness, it is added together with T1, either alone or in coexistence, if necessary. However, its content is 0001
If it is less than 0.1%, the above effect cannot be obtained; on the other hand, if it is less than 0.10%
If the amount exceeds 0.1%, it will lead to an increase in inclusions, which will eventually lead to deterioration of toughness, so the upper limit is set at 010%, and
It was limited to a range of 0.010%.
T I:
T1はAIと同様に窒化物を形成し結晶粒の微細化に寄
与して靭性を高める作用があり、更にB含有鋼の場合は
Bと共に焼入れ性、焼もどし抵抗性を向上する作用があ
るので、klと共に必要に応しいずれか単独もしくは共
存状態で添加される。T I: Like AI, T1 forms nitrides, contributes to grain refinement, and has the effect of increasing toughness, and in the case of B-containing steels, together with B, it has the effect of improving hardenability and tempering resistance. Therefore, either one of them is added alone or in coexistence with kl as necessary.
しかし、その含有量は0.01%未満では上記効果が得
られず、他方010%を越して過多となると靭性の劣化
を来たすので上限を010%とし、001〜0.10%
の範囲内に限定した。However, if the content is less than 0.01%, the above effects cannot be obtained, while if the content exceeds 0.010%, the toughness will deteriorate, so the upper limit is set at 0.010%, and the content ranges from 0.01 to 0.10%.
limited within the range of
上記組成を本発明鋼の基本組成とするが、更に必要に応
じて下記限定量のNb、Vのいずれか1種または2種お
よびBを別個に添加するか、もしくはNb、Vのいずれ
か1種または2種とBを同時に添加することにより、本
発明の効果を一層向上せしめることができる。これらの
選択添加元素量の限定理由は次の如くである。The above composition is the basic composition of the steel of the present invention, but if necessary, one or two of Nb and V and B may be separately added in the following limited amounts, or one of Nb and V may be added separately. By simultaneously adding one species or two species and B, the effects of the present invention can be further improved. The reasons for limiting the amounts of these selectively added elements are as follows.
Nb、V:
Nb、Vのいずれも鋼の焼もどし抵抗性を向上する作用
があるので必要に応じ単独もしくは複合して添加される
ものであるが、いずれも0.01%未満では上記効果が
得られない。しかし010%を越えるとこれらの作用が
飽和するので両者とも0.01〜0.10%の範囲に限
定した。Nb, V: Both Nb and V have the effect of improving the tempering resistance of steel, so they are added singly or in combination as necessary, but if they are less than 0.01%, the above effects will not be achieved. I can't get it. However, since these effects become saturated if the content exceeds 0.010%, both are limited to a range of 0.01 to 0.10%.
B:
Bは鋼の焼入れ性および焼もどし抵抗性を向上する作用
があるので必要に応じ添加される。しかし上記作用効果
はo、 o o o s%未満では現れず、またo、
o o s o%を越えて添加してもこれらの効果が飽
和するので0.0005〜0.0050%の範囲に限定
した。B: B has the effect of improving the hardenability and tempering resistance of steel, so it is added as necessary. However, the above-mentioned effects do not appear at less than o, o o o s%, and o,
Since these effects will be saturated even if added in excess of 0.0005% to 0.0050%.
次に上記限定組成を有する本発明鋼の製造方法について
説明する。Next, a method for producing the steel of the present invention having the above-mentioned limited composition will be explained.
上記本発明による限定組成を有する本発明鋼の製造方法
は常法によって行えばよいので、特に限定の要はないが
次の如く行うことが望ましい。すなわち、上記成分組成
の鋼を溶製し、脱ガスを十分に行った後、ガス吸収を抑
制して造塊し分塊圧延するか、もしくは連続鋳造により
鋼片とし、次いて熱間圧延により所定の寸法の鋼板とす
る。The method for manufacturing the steel according to the present invention having a limited composition according to the present invention may be carried out by a conventional method, and there is no need for particular limitation, but it is preferable to carry out the method as follows. That is, after melting steel with the above-mentioned composition and sufficiently degassing, it is ingotted and bloomed while suppressing gas absorption, or it is made into steel slabs by continuous casting, and then it is hot-rolled. It shall be a steel plate of specified dimensions.
その後、該鋼板をAc3変態点以上のオーステナイト結
晶粒が粗大化しない範囲の温度に加熱して急冷する焼入
れ処理を行う。この焼入れ処理によって得られた鋼板の
組織は主としてマルテンサイト組織であり、非常に硬く
脆く硫化物応力腐食割れにきわめて敏感であるので、A
C,変態点未満の適正な温度で焼もどしを行うことに
より靭性を与えて前記問題を解消する。この、焼もどし
処理により本発明鋼はいずれも引張強さ60〜80kg
17mm2を得ることができる。後記実施例で示すよ
うに、従来引張強さ60〜80 kg f/mm2級鋼
では低C当社で、かつNi無添加の60 kg f/m
m2級鋼以外は困難とされていた硫化物応力腐食割れの
防止は、本発明鋼では60〜80kg、f/胴2の高強
度鋼で可能となったもので本発明鋼の大きな特徴の−っ
である。Thereafter, a quenching treatment is performed in which the steel plate is heated to a temperature in a range that does not cause coarsening of austenite crystal grains having an Ac3 transformation point or higher, and then rapidly cooled. The structure of the steel sheet obtained by this quenching treatment is mainly a martensitic structure, which is extremely hard and brittle and extremely sensitive to sulfide stress corrosion cracking.
C. Tempering at an appropriate temperature below the transformation temperature imparts toughness and solves the above problem. Through this tempering treatment, the steel of the present invention has a tensile strength of 60 to 80 kg.
17 mm2 can be obtained. As shown in the examples below, conventional steel with a tensile strength of 60 to 80 kg f/mm is 60 kg f/mm, which is low C of our company and without the addition of Ni.
Prevention of sulfide stress corrosion cracking, which was considered difficult with steels other than M2 grade steel, is now possible with the high strength steel of 60 to 80 kg and f/2, which is a major feature of the steel of the present invention. It is.
第1表にて示す如き成分およびC当量を有する本発明鋼
供試材A、B、CSD、E、’F、G、Hおよび比較鋼
供試材1.JXK、L、Mを同一条件で溶製し、脱ガス
処理後、ガス吸収を抑えて分塊圧延し、次いで熱間圧延
により供試材A、B1■およびJは25++nn厚、供
試材C,D、E、F。Invention steel specimens A, B, CSD, E, 'F, G, H and comparative steel specimens 1. having the components and C equivalents shown in Table 1. JXK, L, and M were melted under the same conditions, and after degassing treatment, they were bloomed to suppress gas absorption, and then hot rolled to give specimens A, B1, and J a thickness of 25++ nn, and specimen C. , D, E, F.
G、Hおよびに1L、Mは38mm厚の鋼板とした。G, H, 1L, and M were steel plates with a thickness of 38 mm.
第1表におけるC当量は次式にて表わされるものである
。The C equivalent in Table 1 is expressed by the following formula.
これらの各供試材は第2表に示す条件によって焼入れ、
焼もどしを行った後引張試験およびシャルピー衝撃試験
によって機械的性質を調査した。Each of these test materials was quenched under the conditions shown in Table 2.
After tempering, the mechanical properties were investigated by tensile test and Charpy impact test.
更にこれらの供試材鋼板について、いずれも溶接入熱1
2 kJ/cmの条件にて被覆アーク溶接を行い、その
溶接継手の熱影響部の最高硬さを測定した。Furthermore, for these test steel plates, the welding heat input 1
Covered arc welding was performed under the condition of 2 kJ/cm, and the maximum hardness of the heat affected zone of the welded joint was measured.
この場合の溶接条件は次のとおりである。すなわち、鋼
板表面に開先深さ10關、底部形状5 mm R。The welding conditions in this case are as follows. That is, the groove depth is 10 mm on the surface of the steel plate, and the bottom shape is 5 mm R.
開先角度50度のU型溝切加工を施し、溶接入熱12
J / cmて肉盛溶接を行った。溶接熱影響部の最高
硬さは第2表中に示すとおりである。なお、使用溶接棒
ば供試材A、B、Iについては引張強さ60 kg
f/ nm+2m+2金鋼用、その他については引張強
さ80 kg f/ +nn+”金鋼用のものを使用
した。U-shaped groove cutting with a bevel angle of 50 degrees, welding heat input of 12
Overlay welding was performed at J/cm. The maximum hardness of the weld heat affected zone is as shown in Table 2. In addition, the tensile strength of the welding rods used and test materials A, B, and I is 60 kg.
f/nm+2m+2 for gold steel, and for the others, those with a tensile strength of 80 kg f/+nn+'' for gold steel were used.
次に硫化物応力腐食割れ試験は、上記溶接継手から表面
層1箇を切削して5inmX 18nmw+X 115
mmの試験片を採取し、定本4点曲げ方式で試験片に応
力を付加して行った。この時、溶着金属および溶接熱w
6響部が応力分布の均、−な試験片の中央40mmの部
分に位置するようにして試験を行った。Next, a sulfide stress corrosion cracking test was performed by cutting one surface layer from the welded joint and measuring 5 inm x 18 nmw + x 115
A test piece of mm in diameter was taken, and stress was applied to the test piece using a fixed four-point bending method. At this time, welding metal and welding heat w
The test was conducted so that the 6th sound part was located at the center 40 mm of the test piece where the stress distribution was even and negative.
試験液は十分に脱気した純水もしくは05%酢酸+5%
NaC1水溶液にH2S分圧の異なる混合ガスを吹込む
ことにより調整した。この混合ガスは純度999%のN
2でバランスし全圧1気圧として10ppmから300
0ppmH2Sのio度の異なる水溶液を調整した。応
力骨゛加試験片の浸漬時間は1000時間とし、その期
間中試験槽に混合ガスを吹込み続け、かつ試験水溶液の
温度を(25±1)℃に保持した。この各種濃度のH2
S水溶液中の本発明鋼および比較鋼供試材により応力腐
食割れ試験の結果は第3表に示すとおりである。Test solution is sufficiently degassed pure water or 05% acetic acid + 5%
It was adjusted by blowing mixed gases with different H2S partial pressures into the NaCl aqueous solution. This mixed gas is 999% pure N
Balanced with 2 and assuming a total pressure of 1 atm, 10ppm to 300
Aqueous solutions of 0 ppm H2S with different io degrees were prepared. The immersion time of the stress-strengthened test piece was 1000 hours, during which time the mixed gas was continuously blown into the test tank, and the temperature of the test aqueous solution was maintained at (25±1)°C. These various concentrations of H2
Table 3 shows the results of the stress corrosion cracking test using the steel of the present invention and comparative steel specimens in an S aqueous solution.
第3表の数値は割れ発生時点における母材の降伏強度に
対する負荷応力の割合を%て表示したものである。しか
して試験片の割れは400倍の光学顕微鏡にて観察した
。従って各供試材は第3表にて示す応力比以下では割れ
が発生しなかったことを示している。The values in Table 3 are expressed as a percentage of the load stress relative to the yield strength of the base material at the time of crack occurrence. The cracks in the test piece were observed using an optical microscope with a magnification of 400 times. Therefore, each test material shows that no cracking occurred at stress ratios below the stress ratio shown in Table 3.
第3表より明らかな如く、H2Sa度が100ppm以
下・の低濃度環境では比較鋼供試材Iを除き、最も良好
なものでも応力比が80%を越えると割れるのに対し、
本発明鋼の各供試材は応力比がio。As is clear from Table 3, in a low-concentration environment with a H2Sa degree of 100 ppm or less, even the best specimens, except for comparison steel sample I, crack when the stress ratio exceeds 80%.
Each specimen of the steel of the present invention has a stress ratio of io.
%でも全然割れることがない。また5 00 PpI1
1以上の高濃度硫化水素環境では比較鋼供試材Iを除き
すべての環境で各比較鋼供試材の割れ限界応力比が減少
しているが、本発明鋼は比較fi(こ比し高い割れ限界
応力比を示している。Even if it is %, it will not break at all. Also 500 PpI1
In an environment with a high concentration of hydrogen sulfide of 1 or more, the cracking critical stress ratio of each comparative steel specimen decreases in all environments except for comparative steel specimen I, but the steel of the present invention has a It shows the cracking critical stress ratio.
かくの如く、本発明鋼による各供試材は耐硫化物応力腐
食割れ性にすぐれているほか、第2表に示す如く、その
引張強さは64〜87 kg 17mm2に達し、また
その靭性もシャルピー衝撃試験にょろ破面遷移温度で一
85℃〜−110℃と低く高強度、高靭性であることを
示している。これに対し比較鋼は引張強さおよび靭性は
本発明鋼に比し遜色がないものの、耐硫化物応力腐食割
れ性は供試材Iを除き本発明鋼各供試材に比し著しく劣
る。As described above, each test material made of the steel of the present invention has excellent resistance to sulfide stress corrosion cracking, and as shown in Table 2, its tensile strength reaches 64 to 87 kg 17 mm2, and its toughness also increases. The Nyoro fracture surface transition temperature in the Charpy impact test was as low as -85°C to -110°C, indicating high strength and toughness. On the other hand, although the comparative steels are comparable in tensile strength and toughness to the steels of the present invention, their resistance to sulfide stress corrosion cracking is significantly inferior to that of the steels of the present invention except for sample I.
供試材Iについては、耐硫化物応力腐食割れ性は本発明
鋼に比し遜色なさも、第2表にて示されるように破面遷
移温度で表わされる靭性値は、本発明鋼各供試材に比し
著しく劣る。Regarding specimen I, the sulfide stress corrosion cracking resistance is comparable to that of the steel of the present invention, but as shown in Table 2, the toughness value expressed by the fracture surface transition temperature is lower than that of the steel of the present invention. Significantly inferior to the sample material.
本発明鋼は成分組成を限定し、待にAPCの発生を抑制
する元素としてCr:1.60〜300%を添加し、か
つ従来APCの発生を促進するとされていたN1、MO
の悪影響を16%以上のC「の添加で抑制できることを
見出し、比較的コスト安の低合金鋼で耐硫化物応力腐食
割れ性を確保すると共に、焼入れ、焼もどし後の引張り
強さが60〜80kg「7mm2を確保し、しかも高靭
性の高張力鋼を得ることができ、具体的に次の効果を得
ることができた。The steel of the present invention has a limited composition, and Cr: 1.60 to 300% is added as an element that suppresses the generation of APC, and N1 and MO, which were conventionally thought to promote the generation of APC, are added.
We have discovered that the negative effects of carbon can be suppressed by adding 16% or more of C. We have achieved sulfide stress corrosion cracking resistance with a relatively low-cost low-alloy steel, and the tensile strength after quenching and tempering is 60~60. We were able to secure 80kg of 7mm2 and obtain high tensile strength steel with high toughness, and specifically obtained the following effects.
(イ)100ppm以下の低濃度硫化水素環境下では母
材の降伏強度と同一負荷応力でも割れが発生しない。ま
た5 00 ppm以上の高濃度でも母材の降伏強度の
50%の負荷応力では割れが発生しない。(a) In an environment with a low concentration of hydrogen sulfide of 100 ppm or less, no cracking occurs even if the applied stress is the same as the yield strength of the base material. Further, even at a high concentration of 500 ppm or more, no cracking occurs under a load stress of 50% of the yield strength of the base material.
かくの如〈従来鋼に比し著しく耐硫化物応力腐食割れ性
がすぐれている。As such, it has significantly better resistance to sulfide stress corrosion cracking than conventional steel.
(ロ)焼入れ、焼もどし後の引張強さは確実に60〜8
0 kg f/mm2 であり、従来の同種鋼が溶接に
よる硬化および組織の不健全性から60 kg 17m
m”以下に制限せざるを得なかった問題点を解決するこ
とができた。(b) Tensile strength after quenching and tempering is definitely 60-8
0 kg f/mm2, and conventional steel of the same type is 60 kg 17 m due to hardening due to welding and unsound structure.
We were able to solve the problem that had to be limited to less than m''.
(ハ)シャルピー衝撃試験による破面遷移温度は−85
〜−110℃であって高靭性である。(c) Fracture surface transition temperature by Charpy impact test is -85
~-110°C and has high toughness.
(ニ)上記特性より、本発明鋼は特にLPGや都市ガス
等の低濃度硫化水素環境下で貯蔵容器その他溶接構造物
に使用すれば、十分な安全性を確保しつつ肉厚を薄(°
シて経済的に設立することが可能である。(d) Based on the above characteristics, the steel of the present invention can be used for storage containers and other welded structures in environments with low concentrations of hydrogen sulfide, such as LPG and city gas, while ensuring sufficient safety while reducing wall thickness (°
It is possible to set up economically.
Claims (4)
10〜1.00% Mn:0.10〜1.50% P:0.010%以下 S:0.005%以下 Ni:0.30〜3.00% Cr:1.60〜3.00% Mo:0.01〜0.10% およびAl:0.001〜0.10%、Ti:0.01
〜0.10%のうちより選ばれた1種または2種を含み
、残部はFeおよび不可避的不純物より成り高靭性を特
徴とする耐硫化物応力腐食割れ性にすぐれた高張力鋼。(1) Weight ratio: C: 0.05-0.15% Si: 0.
10-1.00% Mn: 0.10-1.50% P: 0.010% or less S: 0.005% or less Ni: 0.30-3.00% Cr: 1.60-3.00% Mo: 0.01-0.10% and Al: 0.001-0.10%, Ti: 0.01
A high tensile steel containing one or two selected from ~0.10%, the remainder consisting of Fe and unavoidable impurities, characterized by high toughness and excellent sulfide stress corrosion cracking resistance.
10〜1.00% Mn:0.10〜1.50% P:0.010%以下 S:0.005%以下 Ni:0.30〜3.00% Cr:1.60〜3.00% Mo:0.01〜0.10% およびAl:0.001〜0.10%、Ti:0.01
〜0.10%のうちより選ばれた1種または2種を含み
、更にNb:0.01〜0.10%、V:0.01〜0
.10%のうちより選ばれた1種または2種を含み、残
部はFeおよび不可避的不純物より成り高靭性を特徴と
する耐硫化物応力腐食割れ性にすぐれた高張力鋼。(2) Weight ratio: C: 0.05-0.15% Si: 0.
10-1.00% Mn: 0.10-1.50% P: 0.010% or less S: 0.005% or less Ni: 0.30-3.00% Cr: 1.60-3.00% Mo: 0.01-0.10% and Al: 0.001-0.10%, Ti: 0.01
Contains one or two selected from ~0.10%, further Nb: 0.01~0.10%, V: 0.01~0
.. A high-strength steel containing one or two selected from among 10%, the remainder consisting of Fe and unavoidable impurities, and characterized by high toughness and excellent resistance to sulfide stress corrosion cracking.
10〜1.00% Mn:0.10〜1.50% P:0.010%以下 S:0.005%以下 Ni:0.30〜3.00% Cr:1.60〜3.00% Mo:0.01〜0.10% およびAl:0.001〜0.10%、Ti:0.01
〜0.10%のうちより選ばれた1種または2種を含み
、更にB:0.0005〜0.0050%を含み、残部
はFeおよび不可避的不純物より成り高靭性を特徴とす
る耐硫化物応力腐食割れ性にすぐれた高張力鋼。(3) Weight ratio: C: 0.05-0.15% Si: 0.
10-1.00% Mn: 0.10-1.50% P: 0.010% or less S: 0.005% or less Ni: 0.30-3.00% Cr: 1.60-3.00% Mo: 0.01-0.10% and Al: 0.001-0.10%, Ti: 0.01
Contains one or two selected from ~0.10%, further contains B: 0.0005~0.0050%, and the remainder is Fe and unavoidable impurities, and is characterized by high toughness and sulfuration resistance. High tensile strength steel with excellent stress corrosion cracking resistance.
10〜1.00% Mn:0.10〜1.50% P:0.010%以下 S:0.005%以下 Ni:0.30〜3.00% Cr:1.60〜3.00% Mo:0.01〜0.10% およびAl:0.001〜0.10%、Ti:0.01
〜0.10%のうちより選ばれた1種または2種を含み
、更にNb:0.01〜0.10%、V:0.01〜0
.10%のうちより選ばれた1種または2種およびB:
0.0005〜0.0050%を含み、残部はFeおよ
び不可避的不純物より成り高靭性を特徴とする耐硫化物
応力腐食割れ性にすぐれた高張力鋼。(4) C: 0.05-0.15% Si: 0.
10-1.00% Mn: 0.10-1.50% P: 0.010% or less S: 0.005% or less Ni: 0.30-3.00% Cr: 1.60-3.00% Mo: 0.01-0.10% and Al: 0.001-0.10%, Ti: 0.01
Contains one or two selected from ~0.10%, further Nb: 0.01~0.10%, V: 0.01~0
.. One or two selected from 10% and B:
A high-strength steel containing 0.0005 to 0.0050%, the remainder consisting of Fe and unavoidable impurities, and characterized by high toughness and excellent resistance to sulfide stress corrosion cracking.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP19344085A JPS6254066A (en) | 1985-09-02 | 1985-09-02 | High strength steel excellent in sulfide stress corrosion cracking resistance |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP19344085A JPS6254066A (en) | 1985-09-02 | 1985-09-02 | High strength steel excellent in sulfide stress corrosion cracking resistance |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS6254066A true JPS6254066A (en) | 1987-03-09 |
Family
ID=16308021
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP19344085A Pending JPS6254066A (en) | 1985-09-02 | 1985-09-02 | High strength steel excellent in sulfide stress corrosion cracking resistance |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6254066A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102796967A (en) * | 2012-08-31 | 2012-11-28 | 济钢集团有限公司 | 800 MPa economic corrosion-resistance and high-strength steel plate |
-
1985
- 1985-09-02 JP JP19344085A patent/JPS6254066A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102796967A (en) * | 2012-08-31 | 2012-11-28 | 济钢集团有限公司 | 800 MPa economic corrosion-resistance and high-strength steel plate |
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