JP3948825B2 - Method for producing austenitic stainless steel sheet free from wrinkles during hot rolling - Google Patents
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Description
【０００１】
【発明の属する技術分野】
本発明はオーステナイト系ステンレス鋼板を製造するに際し、熱間圧延時に疵が発生しない製造方法に関するものである。
【０００２】
【従来の技術】
オーステナイト系ステンレス鋼は高合金であるために、熱間加工性が悪く、熱間圧延時に割れが発生し、これを防止するためにさまざまな研究がなされてきた。特に、耳割れといわれる熱延板エッジに発生する大きな割れは製造可否に関わる場合が生じたり歩留まりを大幅に低下させるなど製造上の大きな問題点であった。
これらの熱延過程で発生する耳割れのような大きな割れについては、今日では成分の適正化等によって製造不可となることは少なくなってきている。
【０００３】
一方で、このような製造可否に関わるような大きな割れとは別に、熱延鋼板のエッジから２００mm程度の部分にヘゲ疵と言われるような疵が発生し、発生部分を製品化できずに歩留り落ちとなる場合がある。
【０００４】
特に、オーステナイトが安定で凝固初期にオーステナイトが晶出するようなＳＵＳ３１６ＬＮ鋼のような高Ｍｏ、高Ｎ鋼の場合、一旦鋳片を加熱して所定の厚みまで圧延（ブレークダウン）し、表面手入れ及び疵部除去を行い、再度加熱して圧延を実施する方法いわゆる２ヒート法を実施したり、また疵発生を見込んで製造サイズを決定する等が行われている。
【０００５】
これに対して、従来技術として、例えば、へげ疵は熱延工程での微小な割れであるとして割れを防止する観点から、特開昭５７−１６１５３号公報では、鋼組成のＣｒ当量、Ｎｉ当量を規制し、δ(cal) ＝３（Ｃｒ＋Ｍｏ＋１．５Ｓｉ＋０．５Ｎｂ）−２．８（Ｎｉ＋０．５Ｍｎ＋０．５Ｃｕ）−８４（Ｃ＋Ｎ）−１９．８で決まるδ(cal) を４以下にすることで熱間加工性を確保する技術を開示している。
【０００６】
またスラブ組織の観点から、特開昭５７−１２７５５４号公報では、鋳造段階でオーステナイト系ステンレス鋼のＮ量と鋳造時のタンディシュ温度（△Ｔ）の関係を制御し、結晶粒の粗大化を防止して熱間加工性を高める技術を開示している。
【０００７】
さらに、表層の組織改善の観点から、特公平２−９６５１号公報では、オーステナイト系ステンレス鋼のＳｉ含有量を規制したスラブに加熱炉挿入前にショットブラストを行うことで表層に加工層を導入し、加熱時に再結晶させスラブ表層の結晶粒を微細化させて割れを防止する技術を開示している。
【０００８】
しかし、上述の技術だけでは、発生率は低下するものの完全に防止するには至っていないのが実状であり、コストアップの大きな原因となっている。
【０００９】
【発明が解決しようとする課題】
本発明は、上述したＭｏ及びＮを含有するオーステナイト系ステンレス鋼の熱間圧延時に発生する微小な割れやヘゲ疵といわれる疵を改善するにあたり、疵防止のための工程負荷増なく疵発生を防止する、オーステナイト系ステンレス鋼板を提供することを目的とする。
【００１０】
【課題を解決するための手段】
本発明者らは、Ｍｏ及びＮを多量に含有するオーステナイト系ステンレス鋼の連続鋳造鋳片を圧延する際の疵と熱延条件の関係を詳細に調査した。その結果、疵は圧延初期の圧下率、パス間時間と圧延温度によって大きく変化することを知見した。本発明はかかる知見に基づくものであって、以下の構成を要旨とする。
すなわち、質量％で、
Ｃ ：０．０３％以下、 Ｓｉ：０．１〜２．０％、
Ｍｎ：０．５〜２．０％、 Ｐ ：０．０４％以下、
Ｓ ：０．００３０％以下、 Ｃｒ：１６．０〜２５．０％、
Ｎｉ：１１．０〜２０．０％、 Ｍｏ：２．０〜７．０％、
Ｃｕ：１．０％以下、 Ａｌ：０．０１〜０．０５％、
Ｏ ：０．００５％以下、 Ｃａ：０．００１０〜０．００５０％、
Ｎ ：０．１５〜０．３０％
を含有し、残部がＦｅと不可避的不純物からなり、下式で示されるδcal が０未満であるオーステナイト系ステンレス鋼の連続鋳造鋳片を熱間圧延するに際し、１１５０℃以上で加熱を行い、圧延開始から３パス以上を圧下率３％以下でかつパス間時間１５秒以上として１０５０℃以上で圧延し、次いで累積圧下率５０％まではパス間時間を１０秒以上として１０００℃以上で圧延することを特徴とする熱間圧延時に疵の発生しないオーステナイト系ステンレス鋼板の製造方法である。
δcal ＝３（Ｃｒ＋１．５Ｓｉ＋Ｍｏ）−２．８（Ｎｉ＋０．５Ｍｎ
＋０．５Ｃｕ）−８４（Ｃ＋Ｎ）−１９．８
【００１１】
【発明の実施の形態】
本発明者らは、１８％Ｃｒ−１２％Ｎｉ−３％Ｍｏ−０．１７％Ｎを含有するＳＵＳ３１６ＬＮの１９０mm連続鋳造鋳片を用いて熱間圧延実験を行い、熱間圧延後の割れと熱延条件の関係を詳細に検討し、加熱条件、熱延条件を制御することで割れを防止する方法を確認した。
【００１２】
以下に本発明を詳細に説明する。
加熱温度を１１５０℃以上としたのは、これより低い加熱温度では、熱間圧延中に温度が下がり熱間加工性の点から不利になるからであり、本発明では加熱温度は高いほど望ましい。加熱温度の上限は特に定めないが、本発明のような、δcal が０未満であるようながオ−ステナイト系ステンレス鋼の連続鋳造鋳片の表層部は粗大なオ−ステナイトの柱状晶が存在し、オ−ステナイト粒も著しく大きくなっており、１３００℃を超えて加熱するとオ−ステナイト粒の粗大化が生じ本発明によっても割れが防止できなくなり、また異常スケ−ルによる表面不良が発生するので、１３００℃が上限と考えられる。
【００１３】
また圧延開始から３パス以上を３％以下の軽圧下率で１５秒以上のパス間時間を取り、かつ１０５０℃以上で圧延することが必要である。
これは圧延初期を軽圧下とすることで割れ感受性の高い粗大な柱状晶粒界での歪みの集中を回避し、かつパス間時間を１５秒以上とすることで回復による軟化及び再結晶を生じさせ、これを３パス以上繰り返すことにより粗大な柱状晶粒界の移動や再結晶による粗大な柱状晶粒界の消失により、圧延初期の割れ発生が防止できるものと考えられる。
【００１４】
圧延初期に圧下率３％を超えるような圧下率では、表層部の粗大粒の粒界で割れが発生し、またパス間時間を１５秒未満では、累積歪効果により軽圧下を繰り返しても高圧下率圧延と同様になり粗大粒の粒界で割れが発生する。
【００１５】
本発明で、初期軽圧下に続く圧延での割れ防止するためには、鋳片厚みの半分まで（累積圧下率で５０％）までを、１０００℃以上で圧延しパス間時間１０秒以上とすることが必要である。この場合の圧下率は軽圧下率である必要はなく、通常のパススケジュールでよいが、温度が低いと割れが発生しやすくなるため１０００℃以上とし、累積歪効果を防止する観点からパス間時間は１０秒以上必要である。
【００１６】
上記の関係について、成分範囲を広げて検討した結果、本発明は下記の成分系で成り立つことが判明した。
すなわち、本発明のオーステナイト系ステンレス鋼は、質量％で、
Ｃ ：０．０３％以下、 Ｓｉ：０．１〜２．０％、
Ｍｎ：０．５〜２．０％、 Ｐ ：０．０４％以下、
Ｓ ：０．００３０％以下、 Ｃｒ：１６．０〜２５．０％、
Ｎｉ：１１．０〜２０．０％、 Ｍｏ：２．０〜７．０％、
Ｃｕ：１．０％以下、 Ａｌ：０．０１〜０．０５％、
Ｏ ：０．００５％以下、 Ｃａ：０．００１０〜０．００５０％、
Ｎ ：０．１５〜０．３０％
で、かつ下式のδcal が０未満であるオーステナイト系ステンレス鋼である。
δcal ＝３（Ｃｒ＋１．５Ｓｉ＋Ｍｏ）−２．８（Ｎｉ＋０．５Ｍｎ
＋０．５Ｃｕ）−８４（Ｃ＋Ｎ）−１９．８
【００１７】
以下に成分の限定理由を述べる。
Ｃ：Ｃはステンレス鋼の耐食性に有害であり、０．０３％以下とした。これを超えて添加すると耐食性が劣化する。
【００１８】
Ｓｉ：Ｓｉはステンレス鋼の脱酸元素として使用され０．１％以上で効果がみられる。２．０％を超えて添加しても脱酸効果は飽和し、また熱間加工性を劣化させ、疵発生の頻度を増加させるので、０．１〜２．０％とする。
【００１９】
Ｍｎ：Ｍｎは脱酸効果があり、０．５％以上で効果が見られる。また２．０％を超えて添加してもその効果は飽和するため、０．５〜２．０％で添加する。
【００２０】
Ｐ：Ｐは耐食性及び熱間加工性の観点から有害な元素であり、極力低減することが望ましく、その成分範囲を０．０４％以下とする。
【００２１】
Ｓ：Ｓは耐食性及び熱間加工性に対して有害な元素であり、熱間加工性に大きく影響するため含有量は低いほどが望ましく、０．００３０％以下とした。
【００２２】
Ｃｒ：Ｃｒはステンレス鋼の基本成分であり、耐食性の点から１６．０％以上の添加が必要である。しかし、２５．０％を超えて添加しても耐食性は飽和し、さらに熱間加工性の点において金属間化合物の析出を促進させるため、１６．０〜２５．０％とした。
【００２３】
Ｎｉ：ＮｉはＣｒとともにステンレス鋼の基本成分であり、本発明ではＣｒ量との関係から１１．０％以上添加し、また上限は２０．０％で十分であり、これを超えて添加してもコストも高くなるため、上限を２０％とした。
【００２４】
Ｍｏ：Ｍｏは耐食性を確保するための重要な添加元素であり、２．０％以上の添加で効果が見られる。また、７％を超えても耐食性は飽和し、さらに金属間化合物の析出を促進させるため熱間加工性を劣化し、本発明の方法によっても疵を防止できなくなるので、上限を７％とした。
【００２５】
Ｃｕ：Ｃｕはステンレス鋼の耐食性を向上さるため、１．０％以下で添加する。これを超えて添加しても効果は飽和する。
【００２６】
Ａｌ：Ａｌは強力な脱酸剤として、０．０１％以上で添加する。しかし、０．０５％を超えて添加をしてもその効果は飽和し、さらにＡｌの酸化物による表面疵が発生しやすくなるため、その添加量を０．０５％以下とした。
【００２７】
Ｏ：Ｏは熱間加工性に著しく有害な元素であり、その含有量は極力低減することが望ましいために、その含有量を０．００５％以下とした。
【００２８】
Ｃａ：Ｃａは強力な脱酸、脱硫剤であり熱間加工性を改善するのに有効な元素であり、０．００１０％以上で効果が著しい。また０．００５０％を超えて添加しても効果は飽和するため、０．００１０〜０．００５０％とした。
【００２９】
Ｎ：Ｎはγ相安定化、耐食性、強度の観点から添加する元素であり、０．１５％以上で添加する。また０．３％を超えて添加すると熱間加工性を劣化させるため上限を０．３％とした。
【００３０】
【実施例】
表１に示す成分を含有するオーステナイト系ステンレス鋼（溶鋼）連続鋳造して得られたスラブを用いて、表２に示す条件で熱間圧延して鋼板を製造した。スラブ厚１９０mmのＡ鋼については２０mmの鋼板を、またスラブ厚み１４０mmのＢ鋼は１０mmの鋼板を製造し、割れ発生状況を観察した。その結果、本発明によって製造した鋼板は割れの発生も見られなかったのに対し、本発明の熱間圧延の条件を満たしていない比較例では、割れの発生が認められた。
【００３１】
【表１】
【表２】
【発明の効果】
本発明によれば、割れが発生しやすいＭｏ、Ｎを多量に含有したオーステナイト系ステンレス鋼の熱間圧延時のオーステナイト粒界割れに起因する疵を防止できるため、歩留りの向上が達成でき、安価なオーステナイト系ステンレス鋼板の生産に大きく寄与する。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a production method in which wrinkles are not generated during hot rolling when producing an austenitic stainless steel sheet.
[0002]
[Prior art]
Since austenitic stainless steel is a high alloy, hot workability is poor, and cracks occur during hot rolling, and various studies have been conducted to prevent this. In particular, large cracks that occur at the hot-rolled plate edge, which are called ear cracks, are serious problems in manufacturing, such as cases that are related to whether or not manufacturing is possible, and that the yield is greatly reduced.
With regard to large cracks such as ear cracks generated in the hot rolling process, it is becoming less likely that production is impossible due to optimization of components and the like today.
[0003]
On the other hand, apart from such large cracks related to the availability of production, wrinkles such as hege wrinkles occur in the portion of about 200 mm from the edge of the hot-rolled steel sheet, and the generated portion cannot be commercialized. Yield may be lost.
[0004]
In particular, in the case of a high Mo and high N steel such as SUS316LN steel in which austenite is stable and austenite crystallizes in the early stage of solidification, the slab is once heated and rolled (breakdown) to a predetermined thickness, and the surface is cleaned. In addition, a so-called two-heat method is performed in which the heel portion is removed and heated again to perform rolling, or the production size is determined in consideration of the occurrence of wrinkles.
[0005]
On the other hand, as a conventional technique, for example, from the viewpoint of preventing cracks because heels are small cracks in the hot rolling process, Japanese Patent Application Laid-Open No. 57-16153 discloses Cr equivalent of steel composition, Ni Equivalent amount is regulated, and δ (cal) = 3 (Cr + Mo + 1.5Si + 0.5Nb) −2.8 (Ni + 0.5Mn + 0.5Cu) −84 (C + N) −19.8 is set to 4 or less. Discloses a technique for ensuring hot workability.
[0006]
From the viewpoint of the slab structure, Japanese Patent Application Laid-Open No. 57-127554 controls the relationship between the N content of austenitic stainless steel and the tundish temperature (ΔT) during casting to prevent crystal grains from becoming coarse. Thus, a technique for improving hot workability is disclosed.
[0007]
Furthermore, from the viewpoint of improving the structure of the surface layer, Japanese Examined Patent Publication No. 2-9651 introduces a processing layer to the surface layer by performing shot blasting before inserting the heating furnace into the slab in which the Si content of the austenitic stainless steel is regulated. Discloses a technique for preventing cracking by recrystallizing during heating to refine the crystal grains of the slab surface layer.
[0008]
However, with the above-described technology alone, although the occurrence rate is reduced, it has not yet been completely prevented, which is a major cause of cost increase.
[0009]
[Problems to be solved by the invention]
The present invention improves the generation of wrinkles without increasing the process load for preventing wrinkles in order to improve the fine cracks and the wrinkles that are caused by hot rolling of the austenitic stainless steel containing Mo and N described above. It aims at providing the austenitic stainless steel plate which prevents.
[0010]
[Means for Solving the Problems]
The present inventors investigated in detail the relationship between the hot rolling conditions and the wrinkles when rolling a continuous cast slab of austenitic stainless steel containing a large amount of Mo and N. As a result, it was found that the drought greatly changes depending on the rolling reduction, the time between passes and the rolling temperature at the beginning of rolling. The present invention is based on such knowledge and has the following configuration.
That is, in mass %,
C: 0.03% or less, Si: 0.1-2.0%,
Mn: 0.5 to 2.0%, P: 0.04% or less,
S: 0.0030% or less, Cr: 16.0-25.0%,
Ni: 11.0-20.0%, Mo: 2.0-7.0%,
Cu: 1.0% or less, Al: 0.01 to 0.05%,
O: 0.005% or less, Ca: 0.0010 to 0.0050%,
N: 0.15-0.30%
In the case of hot rolling a continuous cast slab of austenitic stainless steel, the balance of which is Fe and inevitable impurities, and δcal represented by the following formula is less than 0, heating is performed at 1150 ° C. or more, rolling Rolling at 1050 ° C or more with a reduction rate of 3% or less and a time between passes of 15 seconds or more from the start, and then rolling at 1000 ° C or more with a time between passes of 10 seconds or more until the cumulative reduction rate of 50% Is a method for producing an austenitic stainless steel sheet free from wrinkles during hot rolling.
δcal = 3 (Cr + 1.5Si + Mo) −2.8 (Ni + 0.5Mn
+ 0.5Cu) -84 (C + N) -19.8
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The present inventors conducted a hot rolling experiment using a 190 mm continuous cast slab of SUS316LN containing 18% Cr-12% Ni-3% Mo-0.17% N, and The relationship between hot rolling conditions was examined in detail, and a method for preventing cracking by controlling heating conditions and hot rolling conditions was confirmed.
[0012]
The present invention is described in detail below.
The reason why the heating temperature is set to 1150 ° C. or higher is that at a heating temperature lower than this, the temperature decreases during hot rolling, which is disadvantageous from the viewpoint of hot workability. In the present invention, the higher the heating temperature, the more desirable. The upper limit of the heating temperature is not particularly defined, but the surface layer portion of the continuous cast slab of austenitic stainless steel has coarse austenite columnar crystals as in the present invention, where δcal is less than 0. However, the austenite grains are remarkably large, and when heated above 1300 ° C., the austenite grains become coarse and cracks cannot be prevented by the present invention, and surface defects due to abnormal scale occur. Therefore, 1300 ° C. is considered the upper limit.
[0013]
In addition, it is necessary to perform rolling at 1050 ° C. or more after taking 3 seconds or more from the start of rolling at a light reduction rate of 3% or less with a time between passes of 15 seconds or more.
This is due to light rolling at the beginning of rolling to avoid strain concentration at coarse columnar grain boundaries with high cracking sensitivity, and to soften and recrystallize by recovery by setting the time between passes to 15 seconds or more. By repeating this three or more passes, it is considered that the occurrence of cracks at the initial stage of rolling can be prevented due to the movement of coarse columnar grain boundaries and the disappearance of coarse columnar grain boundaries due to recrystallization.
[0014]
When the rolling reduction ratio exceeds 3% at the beginning of rolling, cracks occur at the grain boundaries of the coarse grains in the surface layer portion, and when the time between passes is less than 15 seconds, high pressure is maintained even if light rolling is repeated due to the cumulative strain effect. Cracks occur at the grain boundaries of coarse grains in the same manner as the rolling at lower rate.
[0015]
In the present invention, in order to prevent cracking in rolling following the initial light reduction, up to half of the slab thickness (50% in cumulative reduction ratio) is rolled at 1000 ° C. or more and the time between passes is 10 seconds or more. It is necessary. The reduction ratio in this case does not need to be a light reduction ratio, and a normal pass schedule may be used. However, cracking is likely to occur at a low temperature, so that the temperature is set to 1000 ° C. or higher, and the time between passes from the viewpoint of preventing the cumulative strain effect. Requires more than 10 seconds.
[0016]
As a result of expanding the component range and examining the above relationship, it has been found that the present invention is composed of the following component systems.
That is, the austenitic stainless steel of the present invention is in mass %,
C: 0.03% or less, Si: 0.1-2.0%,
Mn: 0.5 to 2.0%, P: 0.04% or less,
S: 0.0030% or less, Cr: 16.0-25.0%,
Ni: 11.0-20.0%, Mo: 2.0-7.0%,
Cu: 1.0% or less, Al: 0.01 to 0.05%,
O: 0.005% or less, Ca: 0.0010 to 0.0050%,
N: 0.15-0.30%
And an austenitic stainless steel having a δcal of less than 0 in the following formula.
δcal = 3 (Cr + 1.5Si + Mo) −2.8 (Ni + 0.5Mn
+ 0.5Cu) -84 (C + N) -19.8
[0017]
The reasons for limiting the components are described below.
C: C is harmful to the corrosion resistance of stainless steel, and is set to 0.03% or less. If it is added in excess of this, the corrosion resistance deteriorates.
[0018]
Si: Si is used as a deoxidizing element for stainless steel and is effective at 0.1% or more. Even if it is added over 2.0%, the deoxidation effect is saturated, the hot workability is deteriorated, and the frequency of soot generation is increased.
[0019]
Mn: Mn has a deoxidizing effect, and an effect is seen at 0.5% or more. Moreover, since the effect is saturated even if it adds exceeding 2.0%, it adds at 0.5 to 2.0%.
[0020]
P: P is a harmful element from the viewpoint of corrosion resistance and hot workability, and it is desirable to reduce it as much as possible, and its component range is 0.04% or less.
[0021]
S: S is an element harmful to corrosion resistance and hot workability, and since it greatly affects hot workability, the lower the content, the better. The content was made 0.0030% or less.
[0022]
Cr: Cr is a basic component of stainless steel and needs to be added in an amount of 16.0% or more from the viewpoint of corrosion resistance. However, even if added over 25.0%, the corrosion resistance is saturated, and further in order to promote precipitation of intermetallic compounds in terms of hot workability, the content was made 16.0 to 25.0%.
[0023]
Ni: Ni is a basic component of stainless steel together with Cr. In the present invention, 11.0% or more is added from the relationship with the amount of Cr, and the upper limit is 20.0%. However, the upper limit is set to 20%.
[0024]
Mo: Mo is an important additive element for ensuring corrosion resistance, and an effect is seen with addition of 2.0% or more. Further, even if it exceeds 7%, the corrosion resistance is saturated, and further, the hot workability is deteriorated to promote the precipitation of intermetallic compounds, and wrinkles cannot be prevented even by the method of the present invention, so the upper limit was made 7%. .
[0025]
Cu: Cu is added at 1.0% or less in order to improve the corrosion resistance of stainless steel. Even if it is added in excess of this, the effect is saturated.
[0026]
Al: Al is added as a strong deoxidizer at 0.01% or more. However, even if added over 0.05%, the effect is saturated, and surface flaws due to Al oxides are more likely to occur, so the added amount was made 0.05% or less.
[0027]
O: O is an element that is extremely harmful to hot workability, and it is desirable to reduce its content as much as possible. Therefore, its content is set to 0.005% or less.
[0028]
Ca: Ca is a powerful deoxidizing and desulfurizing agent and an element effective for improving hot workability, and the effect is remarkable at 0.0010% or more. Further, even if added over 0.0050%, the effect is saturated, so 0.0010 to 0.0050% was set.
[0029]
N: N is an element added from the viewpoint of γ phase stabilization, corrosion resistance, and strength, and is added at 0.15% or more. Further, if added over 0.3%, the hot workability deteriorates, so the upper limit was made 0.3%.
[0030]
【Example】
Using a slab obtained by continuous casting of austenitic stainless steel (molten steel) containing the components shown in Table 1, it was hot-rolled under the conditions shown in Table 2 to produce a steel plate. A 20 mm steel plate was manufactured for steel A having a slab thickness of 190 mm, and a 10 mm steel plate was manufactured for steel B having a slab thickness of 140 mm, and the occurrence of cracks was observed. As a result, the steel sheet produced according to the present invention did not show any cracks, whereas cracks were observed in the comparative examples that did not satisfy the hot rolling conditions of the present invention.
[0031]
[Table 1]
[Table 2]
【The invention's effect】
According to the present invention, it is possible to prevent defects caused by austenite grain boundary cracking during hot rolling of austenitic stainless steel containing a large amount of Mo and N which are prone to cracking. This greatly contributes to the production of austenitic stainless steel sheets.
Claims (1)
Ｃ ：０．０３％以下、
Ｓｉ：０．１〜２．０％、
Ｍｎ：０．５〜２．０％、
Ｐ ：０．０４％以下、
Ｓ ：０．００３０％以下、
Ｃｒ：１６．０〜２５．０％、
Ｎｉ：１１．０〜２０．０％、
Ｍｏ：２．０〜７．０％、
Ｃｕ：１．０％以下、
Ａｌ：０．０１〜０．０５％、
Ｏ ：０．００５％以下、
Ｃａ：０．００１０〜０．００５０％、
Ｎ ：０．１５〜０．３０％
を含有し、残部がＦｅと不可避的不純物からなり、下式で示されるδcal が０未満であるオーステナイト系ステンレス鋼の連続鋳造鋳片を熱間圧延するに際し、１１５０℃以上で加熱を行い、圧延開始から３パス以上を圧下率３％以下で、かつパス間時間１５秒以上として１０５０℃以上で圧延し、次いで累積圧下率５０％まではパス間時間を１０秒以上として１０００℃以上で圧延することを特徴とする熱間圧延時に疵の発生しないオーステナイト系ステンレス鋼板の製造方法。
δcal ＝３（Ｃｒ＋１．５Ｓｉ＋Ｍｏ）−２．８（Ｎｉ＋０．５Ｍｎ
＋０．５Ｃｕ）−８４（Ｃ＋Ｎ）−１９．８ % By mass
C: 0.03% or less,
Si: 0.1 to 2.0%,
Mn: 0.5 to 2.0%
P: 0.04% or less,
S: 0.0030% or less,
Cr: 16.0 to 25.0%,
Ni: 11.0-20.0%,
Mo: 2.0-7.0%,
Cu: 1.0% or less,
Al: 0.01 to 0.05%,
O: 0.005% or less,
Ca: 0.0010 to 0.0050%,
N: 0.15-0.30%
In the case of hot rolling a continuous cast slab of austenitic stainless steel, the balance of which is Fe and inevitable impurities, and δcal represented by the following formula is less than 0, heating is performed at 1150 ° C. or more, rolling From the start, rolling is performed at 1050 ° C. or more with a reduction rate of 3% or less at a reduction rate of 3% or less, and then, at a cumulative reduction rate of 50%, rolling is performed at 1000 ° C. or more with a time between passes of 10 seconds or more. A method for producing an austenitic stainless steel sheet free from wrinkles during hot rolling.
δcal = 3 (Cr + 1.5Si + Mo) −2.8 (Ni + 0.5Mn
+ 0.5Cu) -84 (C + N) -19.8
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12892698A JP3948825B2 (en) | 1998-05-12 | 1998-05-12 | Method for producing austenitic stainless steel sheet free from wrinkles during hot rolling |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12892698A JP3948825B2 (en) | 1998-05-12 | 1998-05-12 | Method for producing austenitic stainless steel sheet free from wrinkles during hot rolling |
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| Publication Number | Publication Date |
|---|---|
| JPH11319910A JPH11319910A (en) | 1999-11-24 |
| JP3948825B2 true JP3948825B2 (en) | 2007-07-25 |
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| JP5801647B2 (en) * | 2011-03-17 | 2015-10-28 | 新日鐵住金ステンレス株式会社 | High N content stainless steel having excellent surface resistance and method for producing the same |
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