JPH10237604A - Martensitic stainless steel excellent in hot workability and sulfide stress cracking resistance, method of blooming therefor, seamless steel tube using same, and its production - Google Patents
Martensitic stainless steel excellent in hot workability and sulfide stress cracking resistance, method of blooming therefor, seamless steel tube using same, and its productionInfo
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- JPH10237604A JPH10237604A JP30444197A JP30444197A JPH10237604A JP H10237604 A JPH10237604 A JP H10237604A JP 30444197 A JP30444197 A JP 30444197A JP 30444197 A JP30444197 A JP 30444197A JP H10237604 A JPH10237604 A JP H10237604A
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、熱間加工性及び耐硫化
物応力割れ性に優れたマルテンサイト系ステンレス鋼に
関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a martensitic stainless steel excellent in hot workability and sulfide stress cracking resistance.
【０００２】[0002]
【従来の技術】マルテンサイト系ステンレス鋼は、ＡＩ
ＳＩ４２０鋼に代表されるように、強度、耐ＣＯ2 腐食
性に優れ比較的安価であることから１９８０年頃より油
井管として適用されてきたが、近年では、高温かつ多量
のＣＯ2 やそれに加えてＨ2 Ｓを含む油井環境にも適応
しうるために、４２０鋼より優れた耐食性を有する、特
開平３−１２０３３７号公報などに見られるような、低
Ｃ−Ｎｉ−Ｍｏ添加鋼、あるいは、特開平２−２４７３
６０号公報などに見られるような、低Ｃ−Ｃｕ−Ｎｉ−
Ｍｏ添加鋼といった鋼種（いわゆるModified 13Cr 鋼と
称される鋼種）が開発されてきている。一般に、合金量
が多くなると、耐食性は向上する反面、加工性が悪化す
る。従って、これらの鋼の開発においては、加工性を大
幅に低下させない範囲で、耐食性を究極まで高めようと
する努力がなされてきた。2. Description of the Related Art Martensitic stainless steel has been developed using AI.
As typified by SI420 steel, strength, have been applied as oil country tubular goods from 1980 because it is excellent relatively inexpensive resistance to CO 2 corrosion resistance, in recent years, high temperature and a large amount of CO 2 and in addition to Since it can be adapted to an oil well environment containing H 2 S, it has a higher corrosion resistance than 420 steel, such as low-C-Ni-Mo-added steel as disclosed in JP-A-3-120337 or the like. Kaihei 2-2473
No. 60, etc., low C-Cu-Ni-
Steel grades such as Mo-added steels (steel grades called so-called Modified 13Cr steels) have been developed. Generally, as the amount of alloy increases, corrosion resistance improves, but workability deteriorates. Therefore, in the development of these steels, efforts have been made to increase the corrosion resistance to the ultimate extent without significantly reducing the workability.
【０００３】上記鋼の油井管はマンネスマン方式の圧延
法によって継目無管に製管されるのが通例である。従来
マンネスマン圧延は、熱間加工方法の中でも最も苛酷な
加工方法として知られており、これらの鋼は、Ｃｒ，Ｎ
ｉ，Ｍｏ，Ｃｕといった合金元素を多量に含むため、マ
ンネスマン方式の圧延法によって製管する際、圧延疵が
発生することがあった。このような圧延中の割れ問題に
対して、特開平５−２６３１３８号公報などに見られる
ように熱間加工温度域での組織をオーステナイト単相に
制御するためにＣｒ，Ｎｉ，Ｍｏ，Ｃｕ，Ｃ，Ｎ等の主
要合金元素添加量バランスを調整する方法や、特公平３
−６０９０４号公報などに見られるようにＳに代表され
る熱間加工性に有害な不純物の含有量を特に低く制限す
る技術が提示されてきている。しかしながら、これらの
策をとってもなお、熱間加工に伴う疵の問題は解決でき
ていないのが現状である。[0003] Generally, the above-mentioned steel oil country tubular goods are produced seamlessly by the rolling method of the Mannesmann system. Conventionally, Mannesmann rolling is known as the most severe working method among hot working methods, and these steels are made of Cr, N
Since it contains a large amount of alloy elements such as i, Mo, and Cu, rolling defects may occur when pipes are manufactured by the Mannesmann rolling method. In order to control the microstructure in the hot working temperature range to a single austenite phase as disclosed in Japanese Patent Application Laid-Open No. 5-263138, Cr, Ni, Mo, Cu, The method of adjusting the balance of the addition amount of the main alloying elements such as C, N, etc.
As disclosed in, for example, Japanese Patent Application Laid-Open No. -60904, a technique has been proposed in which the content of impurities harmful to hot workability typified by S is particularly limited. However, even with these measures, the problem of flaws associated with hot working has not been solved at present.
【０００４】上記鋼をマンネスマン方式の圧延法によっ
て継目無管に製管する場合、製管の前工程として、大断
面のスラブまたはブルーム形状の鋳片を小断面の製管用
素材（矩形断面ブルームまたは丸断面ビレット、以下、
管材と称す）に分塊圧延するのが通例である。近年の生
産性向上要請から、鋳片サイズは大断面化する傾向にあ
り、これに伴い分塊圧延は大圧下、低仕上温度化してき
ており、上記鋼のような難加工材では分塊圧延中に割れ
が発生するという問題が最近生じてきた。When the above steel is formed into a seamless pipe by the Mannesmann rolling method, a large-section slab or bloom-shaped slab is cast into a small-section pipe-forming material (bloom with rectangular cross-section or Round section billet, below,
It is customary to carry out slab rolling to a tube material. Due to recent demands for productivity improvement, the slab size tends to increase in cross section, and with this, slab rolling has been under large pressure and low finishing temperature. A recent problem has been that cracking has occurred.
【０００５】上述の如く、マンネスマン圧延法は熱間加
工方法の中で最も苛酷な圧延法とみなされてきたが、上
記難加工鋼種に関しては大圧下、低温仕上げの分塊圧延
の方がより苛酷である。これは、第一に、被圧延材の組
織によるものである。すなわち、製管加工前あるいは加
工時の管材は、圧延再結晶組織を呈しているのが通例で
あり、加えて加熱時に不純物の拡散が起きているため、
割れ抵抗性が大きい。一方、分塊圧延前の鋳片はミクロ
偏析を伴う上、粒度も粗く、割れ感受性が高い。また、
第二に、マンネスマン圧延法における最大圧下ミルであ
るピアサー、エロンゲータにおける被圧延材の温度は、
大断面分塊する場合の最終仕上温度に比べて遥かに高
く、疵や割れに対して有利なためである。これによっ
て、上記鋼の継目無管製造全体の高能率生産を阻害して
いるのが実状である。このように、従来提示されてきた
技術では、上記鋼の分塊圧延時に発生する割れの問題を
解決することができなかった。As described above, the Mannesmann rolling method has been regarded as the most severe rolling method among the hot working methods. However, with respect to the above difficult-to-work steel types, large-pressure, low-temperature finishing slab rolling is more severe. It is. This is primarily due to the structure of the material to be rolled. That is, the pipe material before or at the time of pipe forming usually has a rolled recrystallization structure, and in addition, diffusion of impurities occurs during heating,
High crack resistance. On the other hand, the slab before the slab rolling involves micro-segregation, has a coarse grain size, and has high cracking susceptibility. Also,
Secondly, the temperature of the material to be rolled in the piercer, elongator, which is the maximum rolling mill in the Mannesmann rolling method,
This is because it is much higher than the final finishing temperature when a large cross section is agglomerated, and is advantageous for flaws and cracks. As a result, the fact is that high efficiency production of the entire seamless pipe manufacturing of the steel is hindered. As described above, the techniques presented heretofore have not been able to solve the problem of cracking that occurs during slab rolling of the steel.
【０００６】一方、上記従来鋼では、前記したように熱
間加工温度域での組織をオーステナイト単相に制御する
ためにＣｒ，Ｎｉ，Ｍｏ，Ｃｕ，Ｃ，Ｎ等の主要合金元
素添加量バランスを調整する方法が採られてきたが、こ
の制約によって、耐食性に有効なＣｒ，Ｍｏ等の合金添
加量が制限されたが故に、油井管としての機能が頭打ち
となっており、市場ニーズに応えるには新たなシーズ展
開が必要となってきた。On the other hand, in the conventional steel, as described above, in order to control the structure in the hot working temperature range to a single phase of austenite, the amount of addition of the main alloying elements such as Cr, Ni, Mo, Cu, C, and N is balanced. Has been adopted, but due to this limitation, the amount of alloys such as Cr and Mo effective for corrosion resistance has been limited, so that the function as an oil well tube has reached a plateau, and it meets market needs. Needs a new seed development.
【０００７】[0007]
【発明が解決しようとする課題】本発明は、上記したよ
うな問題点を解決しようとするものであって、分塊圧延
時の割れを防止するとともに、従来のModified 13Cr 鋼
より優れた耐硫化物応力割れ性を有するマルテンサイト
系ステンレス鋼を提供することを目的とする。DISCLOSURE OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and it is intended to prevent cracking during slab rolling, and to provide a sulfurization resistance superior to conventional Modified 13Cr steel. An object of the present invention is to provide a martensitic stainless steel having a material stress cracking property.
【０００８】[0008]
【課題を解決するための手段】本発明者らは、成分の異
なる種々の素材に対して熱間加工性と耐硫化物応力腐食
割れ性について研究を重ねた結果、本鋼種においてはＳ
を０．００２％以下にし、かつ分塊圧延条件を制限すれ
ば割れを起こさず大断面鋳片の大圧下分塊圧延が可能で
あること、Ａｌを０．０６％を超えて０．３％以下添加
することにより耐硫化物応力割れ性が向上すること、を
知見した。Means for Solving the Problems The present inventors have repeatedly studied on hot workability and sulfide stress corrosion cracking resistance of various materials having different components.
Is not more than 0.002%, and if the conditions of slab rolling are restricted, it is possible to perform slab rolling under large pressure of a large-section slab without cracking. It has been found that the sulfide stress cracking resistance is improved by the following addition.
【０００９】本発明はこのような知見に基づいて構成し
たものであって、その要旨は以下の通りである。 （１）重量％で、 Ｃ ：０．０５％以下、 Ｓｉ：０．５％以下、 Ｍｎ：１．５％以下、 Ｐ ：０．０３％以下、 Ｓ ：０．００２％以下、 Ｃｒ：１０〜１４％、 Ｎｉ：４．０〜７．０％、 Ａｌ：０．０６％を超え
て０．３％以下、 Ｎ ：０．０８％以下、 Ｍｏ：１．０〜３．０
％、Ｃｕ：１．０〜２．０％を含有し、さらに必要に応
じて、Ｃａ：０．００１〜０．０１％、 Ｔｉ：０．５
Ｓ〜０．０５％の１種または２種を含有し、残部がＦｅ
及び不可避的不純物からなることを特徴とする熱間加工
性及び耐硫化物応力割れ性に優れたマルテンサイト系ス
テンレス鋼。The present invention has been made based on such knowledge, and the gist is as follows. (1) By weight%, C: 0.05% or less, Si: 0.5% or less, Mn: 1.5% or less, P: 0.03% or less, S: 0.002% or less, Cr: 10 １４14%, Ni: 4.0 to 7.0%, Al: more than 0.06% to 0.3% or less, N: 0.08% or less, Mo: 1.0 to 3.0
%, Cu: 1.0 to 2.0%, and if necessary, Ca: 0.001 to 0.01%, Ti: 0.5
S-0.05%, one or two types, the balance being Fe
And martensitic stainless steel excellent in hot workability and sulfide stress cracking resistance, characterized by being composed of unavoidable impurities.
【００１０】（２）重量％で、 Ｃ ：０．０５％以下、 Ｓｉ：０．５％以下、 Ｍｎ：１．５％以下、 Ｐ ：０．０３％以下、 Ｓ ：０．００２％以下、 Ｃｒ：１０〜１４％、 Ｎｉ：４．０〜７．０％、 Ａｌ：０．０６％を超え
て０．３％以下、 Ｎ ：０．０８％以下、 Ｍｏ：１．０〜３．０
％、Ｃｕ：１．０〜２．０％を含有し、さらに必要に応
じて、Ｃａ：０．００１〜０．１％、 Ｔｉ：０．
５Ｓ〜０．０５％を含有し、残部がＦｅ及び不可避的不
純物からなるマルテンサイト系ステンレス鋼の連続鋳造
鋳片を分塊圧延して矩形断面ブルームまたは丸断面ビレ
ットを製造する方法であって、分塊圧延中の鋳片温度を
１０００℃以上１３００℃以下とすることを特徴とする
熱間加工性及び耐硫化物応力割れ性に優れたマルテンサ
イト系ステンレス鋼の分塊圧延方法。(2) By weight%, C: 0.05% or less, Si: 0.5% or less, Mn: 1.5% or less, P: 0.03% or less, S: 0.002% or less, Cr: 10 to 14%, Ni: 4.0 to 7.0%, Al: more than 0.06% to 0.3% or less, N: 0.08% or less, Mo: 1.0 to 3.0
%, Cu: 1.0 to 2.0%, and if necessary, Ca: 0.001 to 0.1%;
A method for producing a rectangular cross-section bloom or a round cross-section billet by subjecting a continuously cast slab of martensitic stainless steel containing 5S to 0.05%, with the balance being Fe and inevitable impurities, to a rectangular cross-section bloom or a round cross-section billet, A method for bulk-rolling martensitic stainless steel having excellent hot workability and sulfide stress cracking resistance, wherein the slab temperature during bulk-rolling is 1000 ° C. or more and 1300 ° C. or less.
【００１１】（３）前記（１）記載の熱間加工性及び耐
硫化物応力割れ性に優れたマルテンサイト系ステンレス
鋼よりなることを特徴とする継目無鋼管。(3) A seamless steel pipe comprising a martensitic stainless steel excellent in hot workability and sulfide stress cracking resistance as described in (1) above.
【００１２】（４）前記（２）記載の方法により得られ
た矩形断面ブルーム又は丸断面ビレットを、マンネスマ
ン方式の熱間圧延に供して継目無鋼管に製管することを
特徴とする熱間加工性及び耐硫化物応力割れ性に優れた
マルテンサイト系ステンレス鋼管の製造方法。(4) Hot working characterized in that the rectangular cross-section bloom or the round cross-section billet obtained by the method described in the above (2) is subjected to Mannesmann hot rolling to produce a seamless steel pipe. For producing martensitic stainless steel pipes having excellent resistance and sulfide stress cracking resistance.
【００１３】[0013]
【発明の実施の形態】以下、本発明について詳細に説明
する。Modified 13Cr 鋼（0.02C-0.02N-1.5Cu-12.2Cr-
5.8Ni-2.0Mo）の鋳造まま材及び圧延材の熱間加工性に
及ぼす変形温度の影響を図１に示す。鋳造まま材と圧延
材は全く同じ成分であり、Ｓを０．００２９％含有し、
組織のみが異なっている。これらの素材を用いて、図２
に示した条件で熱間引張試験を行った。すなわち、１２
５０℃に加熱し１分保定後、変形温度（Ｔ１℃）まで１
０℃／sec で冷却し、その温度で１分間保定後、１．４
／sec の歪み速度で引張試験を行った。試験後の破断部
の断面積を試験前の断面積で割った値を絞り値と定義す
る。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. Modified 13Cr steel (0.02C-0.02N-1.5Cu-12.2Cr-
The effect of deformation temperature on the hot workability of as-cast and rolled 5.8Ni-2.0Mo) materials is shown in FIG. The as-cast material and the rolled material have exactly the same components, contain 0.0029% of S,
Only the organization is different. Using these materials, Figure 2
A hot tensile test was performed under the conditions shown in (1). That is, 12
After heating to 50 ° C and holding for 1 minute, until the deformation temperature (T1 ° C)
After cooling at 0 ° C./sec and holding at that temperature for 1 minute, 1.4
The tensile test was performed at a strain rate of / sec. The value obtained by dividing the sectional area of the fractured part after the test by the sectional area before the test is defined as the aperture value.
【００１４】図１の縦軸と横軸はそれぞれ、絞り値と変
形温度Ｔ１を示している。絞り値が高いほど熱間加工性
は良好である。図１中には分塊圧延の加工温度域もあわ
せて示す。これまでの知見から、絞り値が７５％以上あ
ればその温度で良好な熱間加工性を示すことが分かって
いる。図１より、鋳造まま材の熱間加工性は圧延材より
も大幅に悪く、Ｓが０．００３％以下でも分塊圧延の加
工温度域で良好な熱間加工性を示さないことがわかる。The ordinate and the abscissa of FIG. 1 indicate the aperture value and the deformation temperature T1, respectively. The higher the aperture value, the better the hot workability. FIG. 1 also shows the processing temperature range of slab rolling. From the findings so far, it has been found that if the aperture value is 75% or more, good hot workability is exhibited at that temperature. From FIG. 1, it is understood that the hot workability of the as-cast material is significantly worse than that of the rolled material, and that even when S is 0.003% or less, good hot workability is not exhibited in the working temperature range of slab rolling.
【００１５】次に、分塊圧延時の最大割れ深さに及ぼす
Ｓ含有量の影響を図３に示す。図３中の各データに付さ
れた数字は後述する実施例中の鋼の符号を意味する。図
３のデータはベース成分がほぼ同じでＳ含有量のみ異な
る組成の２５０mm×６５０mm断面の連続鋳造スラブを２
１７mm×２１７mm断面のブルームに分塊圧延し、圧延終
了後、ブルーム表面の割れを目視観察した結果である。
図３より、Ｓを０．００２％以下に制限しなければ分塊
圧延時の割れは防止できないことがわかる。Next, FIG. 3 shows the effect of the S content on the maximum crack depth during slab rolling. The numbers attached to the respective data in FIG. 3 mean the symbols of steel in the examples described later. The data in FIG. 3 shows that a continuous cast slab having a cross section of 250 mm × 650 mm having a composition that is substantially the same as the base component but differs only in the S content is 2
It is a result of slab-rolling into a bloom having a cross section of 17 mm x 217 mm, and visually observing cracks on the surface of the bloom after rolling.
From FIG. 3, it can be seen that unless S is limited to 0.002% or less, cracking during slab rolling cannot be prevented.
【００１６】さらに、発明者らは極低硫鋼に於いて残存
する固溶Ｓを固定すれば熱間加工性がさらに良くなるこ
とを知見し、研究を重ねた結果、ＣａとＴｉを単独又は
複合添加すれば熱間加工性が飛躍的に改善されることを
知見した。ただし、Ｔｉの添加量については重量％でＳ
の添加量の０．５倍未満ではその効果が発現されず、
０．０５％を超えて添加してもその効果は飽和し、逆に
粗大な窒化物を析出して靱性を低下させるため０．０５
％以下とした。また、Ｃａの添加量については、０．０
０１％未満ではその効果が発現されず、０．０１％を超
えて添加するとＣａ系介在物が増加して耐硫化物応力割
れ性が劣化するので、最適添加量を０．００１％〜０．
０１％とした。Further, the inventors have found that fixing the remaining solid solution S in the ultra-low sulfur steel further improves the hot workability, and as a result of repeated studies, Ca and Ti can be used alone or separately. It has been found that the hot workability is drastically improved by adding a composite. However, the addition amount of Ti is expressed in terms of% by weight.
If the amount is less than 0.5 times the effect is not exhibited,
Even if added over 0.05%, the effect is saturated, and conversely, coarse nitrides are precipitated and the toughness is lowered, so that 0.05% is added.
% Or less. The amount of Ca added was 0.0
When the content is less than 0.01%, the effect is not exhibited. When the content exceeds 0.01%, Ca-based inclusions increase and the resistance to sulfide stress cracking deteriorates.
01%.
【００１７】次に、望ましい分塊圧延条件について説明
する。Modified 13Cr 鋼（0.02C-0,02N-1.5Cu-12.2Cr-
5.8Ni-2.0Mo) の鋳造まま材の熱間加工性に及ぼす加熱
温度の影響を図４に示す。Ｓ含有量が0.0020％である素
材を用いて、図５に示す条件で加熱温度Ｔ２と変形温度
Ｔ１を変化させて熱間引張試験を行った。加熱温度が１
３００℃を超えると急激に熱間加工性が低下することが
わかる。これは、１３００℃を超える温度になるとＭｎ
Ｓの溶解が促進され、それによって生じる固溶Ｓが温度
低下に伴なって粒界に偏析するために粒界が脆化するた
めである。従って、より良好な熱間加工性を得るために
は圧延中の素材温度が１３００℃以下になるように素材
温度をコントロールすることが望ましい。Next, desirable bulk rolling conditions will be described. Modified 13Cr steel (0.02C-0,02N-1.5Cu-12.2Cr-
The effect of the heating temperature on the hot workability of the as-cast material (5.8Ni-2.0Mo) is shown in FIG. Using a material having an S content of 0.0020%, a hot tensile test was performed under the conditions shown in FIG. 5 while changing the heating temperature T2 and the deformation temperature T1. Heating temperature is 1
It can be seen that when the temperature exceeds 300 ° C., the hot workability rapidly decreases. This is because when the temperature exceeds 1300 ° C., Mn
This is because the dissolution of S is promoted, and the resulting solid solution S segregates at the grain boundaries with a decrease in temperature, so that the grain boundaries are embrittled. Therefore, in order to obtain better hot workability, it is desirable to control the material temperature so that the material temperature during rolling is 1300 ° C. or less.
【００１８】そこで、２５０mm×６５０mm断面のModifi
ed 13Cr 鋼（0.02C-0,02N-1.5Cu-12.2Cr-5.8Ni-2.0Mo)
連続鋳造スラブを２１７mm×２１７mm断面のブルームに
分塊圧延する場合における素材温度を有限要素法解析に
より計算した。ただし、素材温度はロールの温度により
大きく影響を受けるので、ロールに冷却水をかけない場
合とかける場合の両方について解析した。その結果、素
材には加工発熱による温度上昇が見られ、特に表面近傍
が高温になることがわかった。これは、変形が均一に起
こらず中心側よりに歪みが集中するためである。Therefore, a 250 mm x 650 mm section of Modifi
ed 13Cr steel (0.02C-0,02N-1.5Cu-12.2Cr-5.8Ni-2.0Mo)
The raw material temperature in the case where the continuously cast slab was subjected to slab rolling to a bloom having a section of 217 mm x 217 mm was calculated by a finite element method analysis. However, since the material temperature is greatly affected by the temperature of the roll, the analysis was performed both when the cooling water was not applied to the roll and when the cooling water was applied. As a result, it was found that the temperature of the raw material increased due to the heat generated during processing, and particularly the temperature near the surface became high. This is because the deformation does not occur uniformly and the distortion concentrates on the center side.
【００１９】計算結果によれば、ロールに冷却水をかけ
ない場合には、素材表層部の温度は加熱温度に比べて約
１００℃も上昇することがわかった。一方、ロールに冷
却水をかける場合には、ロールによる抜熱により素材表
層部の温度上昇は抑制され、加工発熱による温度上昇は
約５０℃に低減できることがわかった。したがって、素
材の最高到達温度を１３００℃以下にするためには、ロ
ールに冷却水をかけない場合には加熱温度を１２００℃
以下、ロールに冷却水をかける場合には加熱温度を１２
５０℃以下に制限すればよい。また、加熱温度の下限に
ついては特に規定するものではないが、圧延仕上温度確
保のため１１００℃以上が望ましい。According to the calculation results, it was found that when no cooling water was applied to the roll, the temperature of the surface layer of the material was increased by about 100 ° C. as compared with the heating temperature. On the other hand, when cooling water was applied to the roll, it was found that the temperature rise in the surface layer of the material was suppressed by the heat removal by the roll, and the temperature rise due to the heat generated during processing could be reduced to about 50 ° C. Therefore, in order to reduce the maximum temperature of the material to 1300 ° C. or less, the heating temperature is set to 1200 ° C. unless cooling water is applied to the roll.
Hereinafter, when cooling water is applied to the roll, the heating temperature is set to 12
What is necessary is just to limit it to 50 degreeC or less. The lower limit of the heating temperature is not particularly specified, but is preferably 1100 ° C. or higher in order to secure the finishing temperature of the rolling.
【００２０】一方、図４より、良好な熱間加工性を得る
ためには圧延仕上温度を１０００℃以上に制限する必要
がある。従って、圧延仕上温度の下限を１０００℃とし
た。圧延仕上温度の上限については特に規定するもので
はなく、１３００℃以下であれば問題はない。On the other hand, from FIG. 4, it is necessary to limit the rolling finishing temperature to 1000 ° C. or higher in order to obtain good hot workability. Therefore, the lower limit of the rolling finishing temperature was set to 1000 ° C. There is no particular limitation on the upper limit of the rolling finishing temperature, and there is no problem as long as it is 1300 ° C. or less.
【００２１】次に、耐硫化物応力割れ性について説明す
る。ベース成分がほぼ同じでＡｌ含有量のみ異なる組成
の２５０mm×６５０mm断面の連続鋳造スラブを２１７mm
×２１７mm断面のブルームに分塊圧延し、さらに継目無
管に製管し、同一の強度レベルになるように調質した
後、硫化物応力割れが発生し得る代表的な腐食環境
（０．０１ＭＰａ Ｈ2 Ｓ，ｐＨ＝３．０，５％ＮａＣ
ｌ，付加応力σap＝降伏強度ＹＳの９０％，７２０ｈ
ｒ，２４℃）で定荷重ＳＳＣ（Sulfide Stress Crackin
g ）試験を行ったときの破断時間に及ぼすＡｌ含有量の
影響を図６に示す。○印は７２０時間たっても破断しな
かったものを示し、●印は７２０時間以内に破断したこ
とを示す。図６中の各データに付された数字は後述する
実施例中の鋼の符号を意味する。Next, the sulfide stress cracking resistance will be described. A 217 mm continuous cast slab with a 250 mm x 650 mm cross section with a composition that has almost the same base components but different Al content
After slab-rolling into a bloom having a cross section of 217 mm, producing a seamless pipe, and tempering to the same strength level, a typical corrosion environment (0.01 MPa) where sulfide stress cracking can occur H 2 S, pH = 3.0, 5% NaC
1, additional stress σap = 90% of yield strength YS, 720h
r, 24 ° C) and constant load SSC (Sulfide Stress Crackin)
g) The effect of the Al content on the rupture time during the test is shown in FIG. Open circles indicate that they did not break even after 720 hours, and open circles indicate that they broke within 720 hours. Numerals given to the respective data in FIG. 6 mean the symbols of steel in Examples described later.
【００２２】図６から、Ａｌ添加量を０．０６％を超え
て０．３％以下とすることで耐硫化物応力割れ性が向上
することは明らかである。Ａｌを０．０６％を超えて添
加すると耐硫化物応力割れ性が向上する理由は、不動態
皮膜が強化され耐孔食性が向上するためである。また、
Ａｌを０．３％を超えて添加すると耐硫化物応力割れ性
が劣化するのは粗大なＡｌ系介在物が生じてそれが孔食
の起点あるいは割れ伝播経路となるため耐ＳＳＣ性が劣
化するためである。It is apparent from FIG. 6 that the sulfide stress cracking resistance is improved by setting the Al addition amount to more than 0.06% and 0.3% or less. The reason why the sulfide stress cracking resistance is improved when Al is added in excess of 0.06% is that the passive film is strengthened and the pitting corrosion resistance is improved. Also,
When Al is added in excess of 0.3%, the sulfide stress cracking resistance is deteriorated because coarse Al-based inclusions are formed and serve as a starting point of pitting corrosion or a crack propagation path, thereby deteriorating SSC resistance. That's why.
【００２３】また、高Ａｌ化は製鋼段階における脱硫効
率向上にも有効であり、良好な熱間加工性を維持するた
めの極低硫鋼を安定的かつ経済的に工業生産可能とする
副次効果をも奏する。以上のことから、Ａｌの添加量を
０．０６％を超えて０．３％以下とすることで、耐硫化
物応力割れ性を向上させることができるうえに、高効
率、低コストで極低硫化することが可能である。Further, the high Al content is also effective for improving the desulfurization efficiency in the steelmaking stage, and makes it possible to stably and economically industrially produce extremely low sulfur steel for maintaining good hot workability. It also has an effect. From the above, it is possible to improve the resistance to sulfide stress cracking by setting the addition amount of Al to more than 0.06% and 0.3% or less, and to achieve high efficiency, low cost and extremely low cost. It is possible to sulfide.
【００２４】本発明におけるマルテンサイト系ステンレ
ス鋼の成分限定理由は以下の通りである。 Ｃ：ＣはＣｒ炭化物などを形成し耐食性を劣化させる元
素である。また、強度を増大させ、油井管として使用さ
れるときに必要とされる耐硫化物割れ性の劣化をまねく
ため、０．０５％以下とした。The reasons for limiting the components of the martensitic stainless steel in the present invention are as follows. C: C is an element that forms a Cr carbide or the like and deteriorates corrosion resistance. Further, in order to increase the strength and to deteriorate the sulfide crack resistance required when used as an oil country tubular good, the content is set to 0.05% or less.
【００２５】Ｓｉ：Ｓｉは製鋼工程において脱炭剤とし
て添加されるものである。０．５％を超えて含有される
と靱性が劣化することから、０．５％以下とした。Si: Si is added as a decarburizing agent in the steel making process. If the content exceeds 0.5%, the toughness deteriorates, so the content is set to 0.5% or less.
【００２６】Ｍｎ：Ｍｎはオーステナイト安定化元素で
あり、熱間加工時にδ相の析出を抑制することにより圧
延疵防止に有効であるが、１．５％を超えて添加すると
粒界強度を低下させ靭性が劣化するので１．５％以下と
した。Mn: Mn is an austenite stabilizing element and is effective in preventing rolling flaws by suppressing the precipitation of the δ phase during hot working, but when added in excess of 1.5%, the grain boundary strength decreases. Therefore, the toughness is deteriorated, so that the content is set to 1.5% or less.
【００２７】Ｐ：Ｐは粒界に偏析して粒界強度を低下さ
せ、靭性を劣化させる不純物元素であり、可及的低レベ
ルが望ましいが、現状精錬技術の到達可能レベルとコス
トを考慮して、０．０３％以下とした。P: P is an impurity element that segregates at the grain boundaries to lower the grain boundary strength and degrades the toughness, and it is desirable that the level be as low as possible. To 0.03% or less.
【００２８】Ｓ：Ｓは熱間加工性を劣化させる不純物元
素であり、０．００２％を超えると分塊圧延時に割れが
発生するため、０．００２％以下とした。S: S is an impurity element that degrades hot workability, and if it exceeds 0.002%, cracks occur during slab rolling, so S is set to 0.002% or less.
【００２９】Ｃｒ：Ｃｒは耐食性向上の基本元素であ
り、十分な耐食性を得るには１０％以上の添加が必要で
あるが、フェライト安定化元素でもあり、多すぎると熱
間加工時にδ相が析出して熱間加工性及び耐硫化物応力
割れ性を劣化するため、１４％以下とした。Cr: Cr is a basic element for improving corrosion resistance, and it is necessary to add 10% or more to obtain sufficient corrosion resistance. However, it is also a ferrite stabilizing element. Since it precipitates and deteriorates hot workability and sulfide stress cracking resistance, it is set to 14% or less.
【００３０】Ｎｉ：Ｎｉは耐腐食性向上及び靱性向上に
有効である。また、オーステナイト安定化元素であり、
圧延疵につながるδ相の生成を抑止する。これらの効果
は添加量４％未満では小さいため、４％以上とした。ま
た、７％を超えて添加しても効果が飽和するとともにＡ
ｃ1 変態点を低下させ強度調質を困難にすることから、
７％以下とした。Ni: Ni is effective in improving corrosion resistance and toughness. It is also an austenite stabilizing element,
Suppress formation of δ phase leading to rolling flaws. Since these effects are small when the added amount is less than 4%, the effect is set to 4% or more. In addition, even if it exceeds 7%, the effect is saturated and
c 1 lowering the transformation point and making strength tempering difficult,
7% or less.
【００３１】Ａｌ：耐硫化物応力割れ性を向上させると
ともに脱酸及び脱硫を促進させるために添加される。耐
硫化物応力割れ性の向上効果は０．０６％以下では発現
されず、０．３％を超えて添加すると、逆に粗大なＡｌ
系介在物が生じてそれが孔食の起点あるいは割れ伝播経
路となるため耐硫化物応力割れ性が劣化することから、
最適添加範囲を０．０６％を超えて０．３％以下とし
た。また、この添加範囲であれば、十分な脱酸及び脱硫
が可能である。Al: Added to improve sulfide stress cracking resistance and promote deoxidation and desulfurization. The effect of improving the sulfide stress cracking resistance is not exhibited at 0.06% or less.
Since sulfide stress cracking resistance is deteriorated because system inclusions are formed and serve as starting points of pitting corrosion or crack propagation paths,
The optimum addition range is more than 0.06% and 0.3% or less. In addition, sufficient deoxidation and desulfurization are possible within this addition range.
【００３２】Ｎ：ＮはＭｎ、Ｎｉと同様に強力なオース
テナイト安定化元素であり、圧延疵防止に有効である
が、Ｃと同様に強度を増大させ、油井管として使用され
るときに必要とされる耐応力腐食割れ性の劣化をまねく
ため、０．０８％以下とした。下限は低いほど良い。N: N is a strong austenite stabilizing element like Mn and Ni, and is effective in preventing rolling flaws. However, it increases the strength similarly to C and is necessary when used as an oil country tubular good. 0.08% or less in order to cause deterioration of the stress corrosion cracking resistance. The lower the lower limit, the better.
【００３３】Ｍｏ：Ｍｏは耐孔食性、耐硫化物応力腐食
割れ性を向上させるのに必須の元素である。これらの効
果は１．０％未満の添加では改善効果が小さいため１．
０％以上とした。また、強力なフェライト安定化元素で
あり、３％を超える添加によりδ相を生成しやすくなる
ことから３．０％以下とした。Mo: Mo is an essential element for improving pitting corrosion resistance and sulfide stress corrosion cracking resistance. These effects are small when the addition is less than 1.0%.
0% or more. Further, it is a strong ferrite stabilizing element, and when added in an amount exceeding 3%, the δ phase is easily formed, so that the content is set to 3.0% or less.
【００３４】Ｃｕ：ＣｕはＮｉと同様に耐腐食性向上に
有効な元素であるとともに、オーステナイト安定化元素
であり、δ相の生成を抑止し圧延疵防止に有効であるた
め添加するが、１．０％未満ではこれらの効果が十分に
得られないため、１．０％以上とした。また、２．０％
を超えて添加すると粒界に過剰に偏析して粒界強度を低
下させるため熱間加工性が著しく劣化するため、２．０
％以下とした。Cu: Like Ni, Cu is an element effective in improving corrosion resistance and is an austenite stabilizing element. Cu is added because it is effective in suppressing the formation of the δ phase and preventing rolling scratches. If the content is less than 0.0%, these effects cannot be sufficiently obtained, so the content is set to 1.0% or more. 2.0%
If added in excess of the above, excessive segregation at the grain boundaries lowers the grain boundary strength, so that hot workability is significantly deteriorated.
% Or less.
【００３５】Ｔｉ：ＴｉはＳによる熱間加工性劣化を抑
制するものであり、必要に応じて添加するが、重量％で
Ｓの添加量の０．５倍未満ではその効果が発現されず、
０．０５％を超えて添加してもその効果は飽和し、逆に
粗大な窒化物を析出して靱性を低下させるため、最適添
加範囲をＳの添加量の０．５倍以上、０．０５％以下と
した。Ti: Ti suppresses the deterioration of hot workability due to S, and is added as necessary. However, if the addition amount of S is less than 0.5 times the addition amount of S in weight%, the effect is not exhibited.
Even if it is added in excess of 0.05%, the effect is saturated, and conversely, coarse nitrides are precipitated and the toughness is lowered. 05% or less.
【００３６】Ｃａ：ＣａはＳによる熱間加工性劣化を抑
制するものであり、必要に応じて添加するが、０．００
１％未満ではその効果が発現されず、０．０１％を超え
て添加するとＣａ系介在物が増加して耐硫化物応力割れ
性が劣化するので、最適添加量を０．００１％以上、
０．０１％以下とした。Ca: Ca suppresses deterioration of hot workability due to S, and is added as necessary.
If the content is less than 1%, the effect is not exhibited. If the content exceeds 0.01%, Ca-based inclusions increase and the sulfide stress cracking resistance deteriorates.
It was set to 0.01% or less.
【００３７】本発明鋼は、主にマンネスマン方式の熱間
圧延によって継目無管に造管される。ここでいうマンネ
スマン方式の圧延法とは、通常の継目無鋼管製造のため
の熱間圧延法で、矩形断面もしくは丸断面の管材を用
い、プレスロール穿孔法あるいはマンネスマン穿孔法に
よって穿孔した後、必要に応じて傾斜圧延機（エロンゲ
ーター）により延伸し、さらにプラグミルあるいはマン
ドレルミルで肉厚調整、摩管を行い、最終仕上圧延機
（サイザーミル）で真円度を調整することにより造管し
ていく一連のプロセスである。The steel of the present invention is formed into a seamless pipe mainly by hot rolling of the Mannesmann system. The rolling method of the Mannesmann method here is a normal hot rolling method for manufacturing a seamless steel pipe, using a tubular material having a rectangular cross section or a round cross section, and punching by a press roll drilling method or a Mannesmann drilling method. The pipe is stretched by an inclined rolling mill (Elongator) according to the requirements, and the wall thickness is adjusted and tubed by a plug mill or mandrel mill, and the roundness is adjusted by a final finishing mill (Sizer mill) to form a pipe. It is a series of processes.
【００３８】[0038]
【実施例】表１に示す組成の２５０mm×６５０mm断面の
連続鋳造スラブを２１７mm×２１７mm断面のブルームに
分塊圧延した。分塊圧延の際の素材の最高到達温度と仕
上温度とを表１に併せて示す。本発明例の１〜１１は成
分、分塊圧延条件とも本発明の範囲である。一方、本発
明例の２３〜３３は、それぞれ本発明例の１〜１１と成
分が同じであるが、分塊圧延条件は本発明の範囲を外れ
ている。表１には、これらの分塊圧延終了後にブルーム
表面の割れを目視観察により調査した結果を示す。EXAMPLE A continuous cast slab having a composition shown in Table 1 having a cross section of 250 mm × 650 mm was slab-rolled into a bloom having a cross section of 217 mm × 217 mm. Table 1 also shows the maximum attainable temperature and the finishing temperature of the material at the time of slab rolling. The components 1 to 11 of the present invention are both within the scope of the present invention in terms of the components and the bulk rolling conditions. On the other hand, the components 23 to 33 of the present invention have the same components as the components 1 to 11 of the present invention, respectively, but the slab rolling conditions are out of the scope of the present invention. Table 1 shows the results of a visual inspection of cracks on the bloom surface after the completion of the bulk rolling.
【００３９】[0039]
【表１】 [Table 1]
【００４０】ベース成分がほぼ同じでＳ含有量のみ異な
る鋼（No. １，２，３，１２，１３，１４）に着目し
て、分塊圧延時の最大割れ深さに及ぼすＳ含有量の影響
を示した図が前出の図３である。本発明例（No. １，
２，３）では分塊圧延時の割れは発生していない。一
方、Ｓ含有量が本発明の成分限定範囲を超えている比較
例（No. １２，１３，１４）では分塊圧延時の割れが発
生しており、Ｓ含有量の増加に伴い最大割れ深さは増大
している。Focusing on steels (Nos. 1, 2, 3, 12, 13 and 14) having substantially the same base components but different S contents, the effect of the S content on the maximum crack depth during slab rolling was considered. FIG. 3 shows the influence. Example of the present invention (No. 1,
In (2) and (3), no cracks occurred during slab rolling. On the other hand, in Comparative Examples (Nos. 12, 13, and 14) in which the S content exceeds the component limitation range of the present invention, cracks occurred during slab rolling, and the maximum crack depth was increased with the increase in the S content. It is growing.
【００４１】また、本発明例の２３〜３３ではほとんど
割れが生じておらず、分塊圧延は十分可能である。しか
しながら、分塊圧延条件が最敵条件ではないために、微
小な割れが生じることがある。一方、本発明例の１〜１
１では成分に加えて分塊圧延条件も最適条件としている
ため、分塊圧延時の割れを完全に防止することができ、
製造の安定性の観点からはより好ましい。In Examples 23 to 33 of the present invention, almost no cracks were generated, and slab rolling is sufficiently possible. However, since the slab rolling conditions are not the most enemy conditions, minute cracks may occur. On the other hand, 1-1 of the present invention examples
In the case of No. 1, since the slab rolling conditions are also set to the optimum conditions in addition to the components, it is possible to completely prevent cracking during slab rolling.
It is more preferable from the viewpoint of production stability.
【００４２】また、上記ブルームを継目無管に圧延し、
同一の強度レベルになるように調質した後、硫化物応力
割れ（ＳＳＣ）が発生し得る代表的な腐食環境で定荷重
ＳＳＣ試験を行った。試験条件については、表１に示し
た鋼をベース成分の違いにより２つのグループに分け、
グループ１（No. １〜６，１２〜１９，２３〜２８）の
鋼は条件Ａ（０．０１ＭＰａ Ｈ2 Ｓ，ｐＨ＝３．０，
５％ＮａＣｌ，付加応力σap＝降伏応力ＹＳの９０％，
７２０ｈｒ，２４℃）とし、グループＢ（No.７〜１
１，２０〜２２，２９〜３３）の鋼は条件Ｂ（０．００
３ＭＰａ Ｈ2 Ｓ，ｐＨ＝３．２，５％ＮａＣｌ，付加
応力σap＝降伏応力ＹＳの９０％，７２０ｈｒ，２４
℃）で定荷重ＳＳＣ試験を行った。結果を表１に併せて
示す。Further, the bloom is rolled into a seamless pipe,
After tempering to the same strength level, a constant load SSC test was performed in a typical corrosive environment where sulfide stress cracking (SSC) could occur. Regarding the test conditions, the steels shown in Table 1 were divided into two groups according to the difference in base components.
Group 1 (No. 1~6,12~19,23~28) steel condition A (0.01MPa H 2 S in, pH = 3.0,
5% NaCl, additional stress σap = 90% of yield stress YS,
720 hours, 24 ° C.) and Group B (Nos. 7-1)
1,20 to 22,29 to 33) steels are in condition B (0.00
3 MPa H 2 S, pH = 3.2, 5% NaCl, additional stress σap = 90% of yield stress YS, 720 hr, 24
C) at a constant load. The results are shown in Table 1.
【００４３】ベース成分がほぼ同じでＡｌ含有量のみ異
なる鋼（No. １，４，５，６，１５，１６，１７）に着
目して、定荷重ＳＳＣ試験における破断時間に及ぼすＡ
ｌ含有量の影響を示したのが前出の図６である。本発明
例（No. １，４，５，６）では上記試験条件では７２０
時間経過後も硫化物応力割れは発生していない。一方、
Ａｌ含有量が本発明の成分限定範囲を超えている比較例
（No. １５，１６，１７）では硫化物応力割れが発生し
ている。Focusing on steels (Nos. 1, 4, 5, 6, 15, 16, and 17) having substantially the same base components but different Al contents, the effect of A on the fracture time in the constant load SSC test was examined.
FIG. 6 shows the effect of the l content. In the present invention examples (Nos. 1, 4, 5, and 6), 720 under the above test conditions.
No sulfide stress cracking occurred even after the lapse of time. on the other hand,
In Comparative Examples (Nos. 15, 16, and 17) in which the Al content exceeds the component limitation range of the present invention, sulfide stress cracking occurred.
【００４４】表１、図３、図６より、Ｓ含有量とＡｌ含
有量が本発明の限定範囲内であれば、分塊圧延時に割れ
が発生せず、かつ、良好な耐硫化物応力割れ性が得られ
ることが明らかである。As can be seen from Table 1, FIGS. 3 and 6, when the S content and the Al content are within the limits of the present invention, no cracking occurs during slab rolling and good sulfide stress cracking resistance. It is clear that the property is obtained.
【００４５】[0045]
【発明の効果】以上のように本発明によれば、分塊圧延
時に割れが発生しない、熱間加工性及び耐硫化物応力割
れ性に優れたマルテンサイト系ステンレス鋼をが得られ
る。As described above, according to the present invention, it is possible to obtain a martensitic stainless steel which is excellent in hot workability and sulfide stress cracking resistance without cracking during slab rolling.
【図１】Modified 13Cr 鋼（低C-低N-1.5Cu-12.2Cr-5.8
Ni-2.0Mo）の鋳造まま材及び圧延材の熱間加工性に及ぼ
す変形温度の影響を示す図表である。[Fig. 1] Modified 13Cr steel (low C-low N-1.5Cu-12.2Cr-5.8
4 is a chart showing the effect of deformation temperature on the hot workability of as-cast and rolled (Ni-2.0Mo) materials.
【図２】熱間引張試験の条件を示す図表である。FIG. 2 is a table showing conditions of a hot tensile test.
【図３】分塊圧延時の最大割れ深さに及ぼすＳ含有量の
影響を示す図表である。FIG. 3 is a table showing the effect of the S content on the maximum crack depth during slab rolling.
【図４】Modified 13Cr 鋼（0.02C-0.02N-1.5Cu-12.2Cr
-5.8Ni-2.0Mo）の鋳造まま材の熱間加工性に及ぼす加熱
温度の影響を示す図表である。[Fig. 4] Modified 13Cr steel (0.02C-0.02N-1.5Cu-12.2Cr)
5 is a chart showing the effect of heating temperature on the hot workability of the as-cast material (-5.8Ni-2.0Mo).
【図５】熱間引張試験の条件を示す図表である。FIG. 5 is a table showing conditions of a hot tensile test.
【図６】硫化物応力割れが発生する代表的な腐食環境で
定荷重ＳＳＣ試験を行ったときの破断時間とＡｌ含有量
の関係を示す図表である。FIG. 6 is a table showing the relationship between the fracture time and the Al content when a constant load SSC test is performed in a typical corrosive environment in which sulfide stress cracking occurs.
フロントページの続き (72)発明者 佐藤 直治 福岡県北九州市戸畑区飛幡町１番１号 新 日本製鐵株式会社八幡製鐵所内 (72)発明者 永吉 治之 福岡県北九州市戸畑区飛幡町１番１号 新 日本製鐵株式会社八幡製鐵所内Continued on the front page (72) Inventor Naoji Sato 1-1-1, Tobata-cho, Tobata-ku, Kitakyushu-shi, Fukuoka Prefecture New Nippon Steel Corporation Yawata Works (72) Inventor Haruyuki Nagayoshi 1st Tobihata-cho, Tobata-ku, Kitakyushu-shi, Fukuoka No. 1 New Nippon Steel Corporation Yawata Works
Claims (6)
を特徴とする熱間加工性及び耐硫化物応力割れ性に優れ
たマルテンサイト系ステンレス鋼。1. In weight%, C: 0.05% or less, Si: 0.5% or less, Mn: 1.5% or less, P: 0.03% or less, S: 0.002% or less, Cr : 10 to 14%, Ni: 4.0 to 7.0%, Al: more than 0.06% to 0.3% or less, N: 0.08% or less, Mo: 1.0 to 3.0% , Cu: 1.0 to 2.0%, with the balance being Fe and unavoidable impurities, characterized by having excellent hot workability and sulfide stress cracking resistance.
純物からなることを特徴とする熱間加工性及び耐硫化物
応力割れ性に優れたマルテンサイト系ステンレス鋼。2. In% by weight, C: 0.05% or less, Si: 0.5% or less, Mn: 1.5% or less, P: 0.03% or less, S: 0.002% or less, Cr : 10 to 14%, Ni: 4.0 to 7.0%, Al: more than 0.06% to 0.3% or less, N: 0.08% or less, Mo: 1.0 to 3.0% , Cu: 1.0 to 2.0%, further contains one or two of Ca: 0.001 to 0.01%, Ti: 0.5S to 0.05%, and the balance Is a martensitic stainless steel excellent in hot workability and sulfide stress cracking resistance, characterized by comprising Fe and unavoidable impurities.
テンサイト系ステンレス鋼の連続鋳造鋳片を分塊圧延し
て矩形断面ブルームまたは丸断面ビレットを製造する方
法であって、分塊圧延中の鋳片温度を１０００℃以上１
３００℃以下とすることを特徴とする熱間加工性及び耐
硫化物応力割れ性に優れたマルテンサイト系ステンレス
鋼の分塊圧延方法。3. In% by weight, C: 0.05% or less, Si: 0.5% or less, Mn: 1.5% or less, P: 0.03% or less, S: 0.002% or less, Cr : 10 to 14%, Ni: 4.0 to 7.0%, Al: more than 0.06% to 0.3% or less, N: 0.08% or less, Mo: 1.0 to 3.0% , Cu: 1.0 to 2.0%, and the remaining cast iron of martensitic stainless steel consisting of Fe and unavoidable impurities is subjected to bulk-rolling to produce a bloom with a rectangular cross section or a billet with a round cross section. A method wherein the slab temperature during slab rolling is 1000 ° C. or higher and 1
A method for bulk rolling martensitic stainless steel having excellent hot workability and sulfide stress cracking resistance, wherein the temperature is 300 ° C. or lower.
テンサイト系ステンレス鋼の連続鋳造鋳片を分塊圧延し
て矩形断面ブルーム又は丸断面ビレットを製造する方法
であって、分塊圧延中の鋳片温度を１０００℃以上１３
００℃以下とすることを特徴とする熱間加工性及び耐硫
化物応力割れ性に優れたマルテンサイト系ステンレス鋼
の分塊圧延方法。4. In% by weight, C: 0.05% or less, Si: 0.5% or less, Mn: 1.5% or less, P: 0.03% or less, S: 0.002% or less, Cr : 10 to 14%, Ni: 4.0 to 7.0%, Al: more than 0.06% to 0.3% or less, N: 0.08% or less, Mo: 1.0 to 3.0% , Cu: 1.0-2.0%, Ca: 0.001-0.1%, Ti: 0.5S-0.05%, with the balance being Fe and unavoidable impurities A continuous cast slab of the following martensitic stainless steel to produce a bloom with a rectangular cross section or a billet with a round cross section.
A method for bulk rolling martensitic stainless steel having excellent hot workability and resistance to sulfide stress cracking, wherein the temperature is not higher than 00 ° C.
硫化物応力割れ性に優れたマルテンサイト系ステンレス
鋼よりなることを特徴とする継目無鋼管。5. A seamless steel pipe comprising a martensitic stainless steel excellent in hot workability and sulfide stress cracking resistance according to claim 1 or 2.
た矩形断面ブルーム又は丸断面ビレットを、マンネスマ
ン方式の熱間圧延に供して継目無鋼管に製管することを
特徴とする熱間加工性及び耐硫化物応力割れ性に優れた
マルテンサイト系ステンレス鋼管の製造方法。6. Hot working characterized by subjecting a bloom of a rectangular cross section or a billet of a round cross section obtained by the method according to claim 3 to hot rolling in a Mannesmann system to produce a seamless steel pipe. For producing martensitic stainless steel pipes having excellent resistance and sulfide stress cracking resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30444197A JP3598771B2 (en) | 1996-12-19 | 1997-11-06 | Martensitic stainless steel excellent in hot workability and sulfide stress cracking resistance, method of bulk rolling thereof, seamless steel pipe using these, and method of manufacturing the same |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8-340235 | 1996-12-19 | ||
| JP34023596 | 1996-12-19 | ||
| JP30444197A JP3598771B2 (en) | 1996-12-19 | 1997-11-06 | Martensitic stainless steel excellent in hot workability and sulfide stress cracking resistance, method of bulk rolling thereof, seamless steel pipe using these, and method of manufacturing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10237604A true JPH10237604A (en) | 1998-09-08 |
| JP3598771B2 JP3598771B2 (en) | 2004-12-08 |
Family
ID=26563908
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30444197A Expired - Fee Related JP3598771B2 (en) | 1996-12-19 | 1997-11-06 | Martensitic stainless steel excellent in hot workability and sulfide stress cracking resistance, method of bulk rolling thereof, seamless steel pipe using these, and method of manufacturing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3598771B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000328201A (en) * | 1999-05-17 | 2000-11-28 | Nippon Steel Corp | Martensitic stainless steel excellent in hot workability |
| WO2022075406A1 (en) * | 2020-10-08 | 2022-04-14 | 日本製鉄株式会社 | Martensitic stainless steel material |
| EP3862451A4 (en) * | 2018-10-02 | 2022-06-15 | Nippon Steel Corporation | Martensite-based stainless steel seamless pipe |
| EP3859031A4 (en) * | 2018-09-27 | 2022-06-15 | Nippon Steel Corporation | Martensitic stainless steel material |
| EP4130317A4 (en) * | 2020-04-01 | 2023-05-17 | Nippon Steel Corporation | Steel material |
-
1997
- 1997-11-06 JP JP30444197A patent/JP3598771B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000328201A (en) * | 1999-05-17 | 2000-11-28 | Nippon Steel Corp | Martensitic stainless steel excellent in hot workability |
| EP3859031A4 (en) * | 2018-09-27 | 2022-06-15 | Nippon Steel Corporation | Martensitic stainless steel material |
| EP3862451A4 (en) * | 2018-10-02 | 2022-06-15 | Nippon Steel Corporation | Martensite-based stainless steel seamless pipe |
| EP4130317A4 (en) * | 2020-04-01 | 2023-05-17 | Nippon Steel Corporation | Steel material |
| WO2022075406A1 (en) * | 2020-10-08 | 2022-04-14 | 日本製鉄株式会社 | Martensitic stainless steel material |
| JPWO2022075406A1 (en) * | 2020-10-08 | 2022-04-14 |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3598771B2 (en) | 2004-12-08 |
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