JPH08225839A - Production of austenitic stainless steel hot rolled steel strip excellent in surface property - Google Patents
Production of austenitic stainless steel hot rolled steel strip excellent in surface propertyInfo
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- JPH08225839A JPH08225839A JP5678595A JP5678595A JPH08225839A JP H08225839 A JPH08225839 A JP H08225839A JP 5678595 A JP5678595 A JP 5678595A JP 5678595 A JP5678595 A JP 5678595A JP H08225839 A JPH08225839 A JP H08225839A
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- hot
- stainless steel
- austenitic stainless
- slab
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はオーステナイト系ステン
レス鋼熱延鋼帯における表面欠陥（割れ疵、ヘゲ疵）の
発生を防止する方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing the generation of surface defects (cracking defects, bald defects) in an austenitic stainless steel hot rolled steel strip.
【０００２】[0002]
【従来の技術】従来、ステンレス鋼を熱間圧延する際に
問題となる表面欠陥の一つに、ヤヘゲ疵と呼ばれる山形
状のヘゲ疵がある。この欠陥は冷間圧延後も残存し、多
くの場合、熱延鋼帯では発見できない微細なヤヘゲ疵で
も冷間圧延することで顕在化するために大きな問題とな
る。特に表面品質が問題となるオーステナイト系ステン
レス鋼では上記の欠陥は致命的であり、歩留りが低下
し、大幅なコストアップを招いたり、所定の板幅が確保
できない場合もある。このような現象は特に凝固後の時
点でδフェライトを全く含まないオーステナイト単相鋼
に顕著に見られ、熱延鋼帯にヤヘゲが出やすい。2. Description of the Related Art Conventionally, one of the surface defects that has been a problem when hot-rolling stainless steel is a mountain-shaped headdress defect called a yahege defect. This defect remains even after cold rolling, and in many cases, even a fine yahege flaw that cannot be found in a hot-rolled steel strip becomes a serious problem because it becomes apparent by cold rolling. Particularly, in the case of austenitic stainless steel in which the surface quality is a problem, the above defects are fatal, the yield is lowered, the cost is significantly increased, and the predetermined plate width may not be secured in some cases. Such a phenomenon is particularly noticeable in the austenitic single phase steel containing no δ-ferrite at the time of solidification, and the hot-rolled steel strip is apt to be burnt.
【０００３】この表面欠陥はグラインダー等で削除し除
去しても残存することが多く、製品加工後のバレル研磨
程度では除去することができない。また残存した表面疵
は疲労特性、耐食性などの製品特性に悪影響を及ぼすと
ともに、製品歩留りの低下を招くほか、後工程の負荷を
増大させ、コストアップの要因となっている。This surface defect often remains even if it is removed and removed by a grinder or the like, and cannot be removed by barrel polishing after product processing. Further, the remaining surface flaws adversely affect the product characteristics such as fatigue characteristics and corrosion resistance, reduce the product yield, increase the load of the post-process, and cause a cost increase.
【０００４】[0004]
【発明が解決しようとする課題】この熱延後の表面疵を
防止する方法として、特開昭57-127506 公報に記載され
ているように、連鋳時の溶鋼加熱温度(ス-ハ゜-ヒ-ト)ΔＴと
Ｎ（窒素）量の積に応じて熱間圧延時の加熱温度を調整
する方法，特殊成分を添加して熱間強度を向上させる方
法が知られている。しかし、連続鋳造中においては、Δ
ＴおよびＮ量は変化する。また、加熱炉操業において
は、同時に複数のスラブを加熱することから、全スラブ
を対象に熱間圧延時の加熱温度を制御することは困難を
伴う。さらに、特開平5-23703 公報に記載されている連
続鋳造スラブのオッシレ-ションマ-ク の深さを0.2mm 以下とした
り、また、スラブ両側面の厚み中央にスラブ厚の2 〜15
％の深さの窪みをスラブ長手方向に亘って付与する方法
は、工業的に安定して行うことは困難であり、コストア
ップを招く。なお、特開平4-293717公報に示されるよう
な Ni-bal ＝30C ＋0.5Mn ＋Ni＋8.2 ＋1.1(1.5Si ＋Cr
＋Mo＋0.5Nb)で決まるNi-balが1.5 ないし-2.5を満足
し、さらにＳ≦0.001%を満たすように工業的に安定して
溶製することは難しい。これらの方法とヤヘゲ疵との相
関関係は明らかではなく、ヤヘゲ疵を完全に防止するに
は到っていない。本発明は、オーステナイト系ステンレ
ス鋼熱延鋼帯におけるヤヘゲ疵の発生を防止することを
目的とする。As described in JP-A-57-127506, as a method for preventing the surface flaws after the hot rolling, the molten steel heating temperature (super-heat-heat) during continuous casting is used. -G) A method of adjusting the heating temperature during hot rolling according to the product of ΔT and the amount of N (nitrogen), and a method of adding a special component to improve the hot strength are known. However, during continuous casting, Δ
The amount of T and N varies. Further, in the heating furnace operation, since a plurality of slabs are heated at the same time, it is difficult to control the heating temperature during hot rolling for all the slabs. Furthermore, the depth of the oscillation mark of the continuous casting slab described in JP-A-5-23703 is set to 0.2 mm or less, and the slab thickness of 2-15
%, It is difficult to industrially stably perform the method of forming the depressions having the depth of 10% in the longitudinal direction of the slab, which causes an increase in cost. In addition, Ni-bal = 30C + 0.5Mn + Ni +8.2 +1.1 (1.5Si + Cr as shown in Japanese Patent Laid-Open No. 4-293717)
Ni-bal determined by + Mo + 0.5Nb) satisfies 1.5 to -2.5, and it is difficult to industrially stably melt so that S ≦ 0.001% is satisfied. The correlation between these methods and yahege flaws is not clear, and it is not yet possible to completely prevent yahege flaws. It is an object of the present invention to prevent the occurrence of burn marks on an austenitic stainless steel hot rolled steel strip.
【０００５】[0005]
【課題を解決するための手段】上記目的は、（１）式で
定義されるＡγ値が、 Ａγ＝Ｎｉ＋41.2Ｃ＋21.4Ｎ-1.16 （Ｃｒ＋0.26Ｍｎ＋1.85Ｓｉ） … （１） -9.0以上となるオーステナイト系ステンレス鋼におい
て、Ｓ：0.003mass%以下、Ｂ：0.002 〜0.010mass%に成
分調整した連続鋳造スラブを熱間圧延するに際し、該ス
ラブの長辺面に酸化防止剤を膜厚0.2 〜1.0mm 塗布し、
これを1,250 ℃以下の温度域に加熱後、熱間圧延をする
ことにより製造される表面性状に優れたオーステナイト
系ステンレス鋼熱延鋼帯により達成される。[Means for Solving the Problems] The above-mentioned object is that the Aγ value defined by the equation (1) is Aγ = Ni + 41.2C + 21.4N-1.16 (Cr + 0.26Mn + 1.85Si) (1) -9.0 or more In austenitic stainless steel, when hot-rolling a continuously cast slab whose composition is adjusted to S: 0.003 mass% or less and B: 0.002 to 0.010 mass%, an antioxidant is formed on the long side surface of the slab to a film thickness of 0.2 to 1.0. mm application
This is achieved by an austenitic stainless steel hot-rolled steel strip having excellent surface properties, which is produced by heating this to a temperature range of 1,250 ° C or lower and then hot rolling.
【０００６】[0006]
【作用】一般にオーステナイト系ステンレス鋼の代表鋼
種であるSUS304では、凝固−冷却過程でγ＋δ領域を経
るため、凝固後においても数ハ゜-セント程度のδフェライト
を含む。しかしながら、Ｎｉ，Ｃ，Ｎなどのオーステナ
イト生成元素が多くなるとδフェライトの生成が実質的
になくなり、Ｓなどの鋼中の不純物は結晶粒界に偏析
し、粒界の強度が低下する。そこで、オーステナイト系
ステンレス鋼の連続鋳造片を熱間圧延するに当たり、成
分元素と熱延条件の関係を調査、研究した結果、実質的
にδフェライトを含まないオーステナイト単相鋼では、
基本的には熱延時の表面割れがヤヘゲ疵になるが、その
割れの起点となるのはスラブ加熱時の粒界酸化箇所であ
り、さらにこの箇所から粒界酸化されていない粒界へ割
れが伝播していることをつきとめた。従って、ヤヘゲ疵
の発生を完全に防止するには、加熱時のスラブの粒界酸
化の防止と、併せて粒界の割れの伝播を防止するための
粒界の強化を同時に行うことが必要であることを知見し
た。In general, SUS304, which is a typical type of austenitic stainless steel, passes through the γ + δ region during the solidification-cooling process, and therefore contains δ-ferrite in the order of several centigrade after solidification. However, when the amount of austenite-forming elements such as Ni, C, and N increases, the formation of δ-ferrite substantially disappears, and impurities such as S in the steel segregate at the crystal grain boundaries and the strength of the grain boundaries decreases. Therefore, in hot rolling a continuous cast piece of austenitic stainless steel, as a result of investigating and studying the relationship between the constituent elements and hot rolling conditions, as a result, in the austenitic single phase steel containing substantially no δ ferrite,
Basically, surface cracks during hot rolling become burnt defects, but the origins of these cracks are the grain boundary oxidation points during slab heating, and further cracks from this point to grain boundaries that have not been grain boundary oxidized. I found out that it was being propagated. Therefore, in order to completely prevent the occurrence of burnt defects, it is necessary to simultaneously prevent grain boundary oxidation of the slab during heating and strengthen the grain boundaries to prevent the propagation of cracks at the grain boundaries. I found that there is.
【０００７】そこで特定されたステンレス鋼の成分元素
と加熱時の粒界酸化を防止することで、表面疵のないオ
ーステナイト系ステンレス鋼の熱延鋼板および鋼帯さら
には冷延鋼板、鋼帯を歩留り良く製造する方法を見いだ
した。[0007] By preventing the component elements of the specified stainless steel and the grain boundary oxidation during heating, the hot rolled steel sheet and steel strip of austenitic stainless steel without surface flaws, and further cold rolled steel sheet and steel strip yield I have found a way to manufacture well.
【０００８】以下に、本発明のオーステナイト系ステン
レス鋼に含まれる合金元素および含有量を説明する。Ｃ
はオーステナイト相を安定化する元素である。また固溶
効果作用が大きく、且つばね特性の向上に有効である。
しかし、多量のＣ含有量は耐食性を低下させるため、Ｃ
含有量の上限を0.15％に規定した。The alloying elements and contents contained in the austenitic stainless steel of the present invention will be described below. C
Is an element that stabilizes the austenite phase. Further, the solid solution effect is large and it is effective in improving the spring characteristics.
However, since a large amount of C content lowers the corrosion resistance,
The upper limit of the content is specified as 0.15%.
【０００９】Ｓｉは高強度を得る上で有効な元素であ
る。しかし、Ｓｉはフェライト生成元素であり。その含
有量の増加に従い、オーステナイトの安定度が確保でき
なくなる。そのため、Ｓｉ含有量の上限を3.0 mass％と
した。Si is an element effective in obtaining high strength. However, Si is a ferrite forming element. As the content increases, the stability of austenite cannot be ensured. Therefore, the upper limit of the Si content is 3.0 mass%.
【００１０】ＭｎはＮｉと同様にオーステナイト安定元
素である。しかし、多量にＭｎを含有すると、製鋼での
製造性を阻害し、生産コストが上昇する。このためＭｎ
の含有量の上限を5.0 mass％に設定した。Mn, like Ni, is an austenite stable element. However, if Mn is contained in a large amount, the manufacturability in steel making is impaired and the production cost rises. Therefore, Mn
The upper limit of the content of was set to 5.0 mass%.
【００１１】Ｓは熱間加工性を劣化させ熱間圧延中にス
ラブの表面に微小な割れを発生させ、熱間圧延後のコイ
ル表面に山形状の疵やヤヘゲ状の疵を発生させる。これ
らの表面疵の発生原因はγ粒界にＳが偏析し、粒界の割
れ感受性が高くなることによって起こると考えられる。
Ｓ量を低減させればヤヘゲ疵の低減には有効であるが、
本発明のＢを添加し、スラブ加熱時の粒界酸化を防止す
る方法を併用した場合、工業的に安定して製造可能な0.
003 mass％以下のＳ量とすれば、ヤヘゲの発生は防止可
能であることから、その上限を定めた。S deteriorates the hot workability, causes minute cracks on the surface of the slab during hot rolling, and causes mountain-shaped flaws or beard-shaped flaws on the coil surface after hot rolling. It is considered that the cause of these surface defects is caused by the segregation of S in the γ grain boundaries, which increases the crack susceptibility of the grain boundaries.
If the amount of S is reduced, it is effective to reduce the bald spots,
When B of the present invention is added and a method of preventing grain boundary oxidation during heating of a slab is used together, industrially stable production is possible.
If the S content is 003 mass% or less, the occurrence of burns can be prevented, so the upper limit was set.
【００１２】Ｃｒはステンレスの基本成分であり、優れ
た耐食性を得るために16.0mass％以上の含有量が必要で
ある。しかし、多量のＣｒが含有されるとδフェライト
が生成し、オーステナイトの安定性が確保できなくな
る。従って、Ｃｒ含有量を16.0〜26.0mass％の範囲に設
定した。[0012] Cr is a basic component of stainless steel, and its content must be 16.0 mass% or more in order to obtain excellent corrosion resistance. However, if a large amount of Cr is contained, δ ferrite is formed, and the stability of austenite cannot be secured. Therefore, the Cr content is set in the range of 16.0 to 26.0 mass%.
【００１３】Ｎｉはオーステナイト相の安定化に必須の
合金元素である。しかし、多量のＮｉを含有させること
はコスト上昇を招き、安価なオーステナイトステンレス
鋼を提供できなくなることからＮｉ含有量は7.0 〜26.0
mass ％の範囲で選定される。Ni is an alloying element essential for stabilizing the austenite phase. However, the inclusion of a large amount of Ni causes an increase in cost, and it becomes impossible to provide an inexpensive austenitic stainless steel. Therefore, the Ni content is 7.0 to 26.0.
It is selected in the range of mass%.
【００１４】Ｎはオーステナイトステンレス鋼の硬度お
よび強度を高める上で必須成分であるとともに、オース
テナイト相を安定化させる合金元素である。これらの性
能を発揮させるにはＮを0.10mass％以上含有させる必要
がある。しかし、多量に添加するとフ゛ロ-ホ-ル が発生し、
健全な鋼塊が得られないことから上限は0.30mass％とし
た。また下限は特に高強度を必要としない分野も考慮し
てＮ含有量は0.020 〜0.30mass％の範囲に規定した。N is an essential component for enhancing the hardness and strength of austenitic stainless steel, and is an alloying element that stabilizes the austenitic phase. In order to exert these performances, it is necessary to contain N in an amount of 0.10 mass% or more. However, if added in a large amount, blowholes are generated,
The upper limit was set to 0.30 mass% because a sound steel ingot could not be obtained. Further, the lower limit of N content is specified in the range of 0.020 to 0.30 mass% in consideration of the field not requiring particularly high strength.
【００１５】Ｂは熱間加工性に有害なＳを固定し、粒界
強度を向上させることから熱間加工性の改善に効果を有
する元素であるが、0.002 mass％未満の少量添加ではそ
の効果が発揮されない。しかし、多量に含有させると凝
固時に液膜脆化が生じるために連鋳片に内部割れが生じ
たり、非金属介在物が生成し表面欠陥の要因ともなる。
したがって、Ｂ含有量を0.002 〜0.010 mass％の範囲に
設定した。B is an element that fixes S, which is detrimental to hot workability, and improves grain boundary strength, and thus has an effect on hot workability. However, when added in a small amount of less than 0.002 mass%, the effect is obtained. Is not demonstrated. However, when contained in a large amount, liquid film embrittlement occurs during solidification, which causes internal cracks in the continuous cast piece and non-metallic inclusions are generated, which also causes surface defects.
Therefore, the B content is set in the range of 0.002 to 0.010 mass%.
【００１６】Ｍｏは時効処理後の硬さを著しく高める。
また耐食性の改善にも効果的な元素であるが、多量に添
加するとδフェライト生成量が多くなるために上限を5.
5 mass％とした。Mo significantly increases the hardness after aging treatment.
It is also an element effective in improving the corrosion resistance, but if added in a large amount, the amount of δ ferrite produced increases, so the upper limit is 5.
It was set to 5 mass%.
【００１７】Ｃｕはオーステナイト相の安定に寄与する
ものであるが、多量に含有すると溶接時の高温割れ感受
性が高くなるため上限を2.5 mass％とした。Cu contributes to the stability of the austenite phase, but if it is contained in a large amount, the sensitivity to hot cracking during welding increases, so the upper limit was made 2.5 mass%.
【００１８】Ａｌは時効効果の増加に効果的な元素であ
るが、多量に含有すると熱間加工性を著しく低下させる
ことから上限を0.14mass％とした。Al is an element effective for increasing the aging effect, but if it is contained in a large amount, the hot workability is remarkably reduced, so the upper limit was made 0.14 mass%.
【００１９】ＲＥＭは靱性を向上させる作用を有するほ
か、熱間加工性に有害なＳを固定し、粒界強度を向上さ
せるが、多量に含有させると非金属介在物を生成し、表
面欠陥の要因となることから、上限を0.06 mass ％とし
た。REM not only has the effect of improving toughness, but also fixes S, which is detrimental to hot workability, and improves the grain boundary strength. However, if contained in a large amount, non-metallic inclusions are generated and surface defects Since it becomes a factor, the upper limit was made 0.06 mass%.
【００２０】Ａγ：−９以上 （１）式で定義される、Ａγ値は本発明者等による実験
結果から導き出された指標である。図１に示すように、
オーステナイト系ステンレス鋼はＡγ値が-9.0以下にな
るとδフェライトが生成するが、この場合熱延での割れ
は発生しない。しかしながら、-9.0以上では不純物は結
晶粒界に析出し、熱間圧延中にスラブ表面に割れが発生
することから本発明の適用範囲となる。Aγ: -9 or more The Aγ value defined by the equation (1) is an index derived from the experimental results by the present inventors. As shown in Figure 1,
Austenitic stainless steel produces δ ferrite when the Aγ value becomes -9.0 or less, but in this case, cracking in hot rolling does not occur. However, if it is -9.0 or more, the impurities precipitate at the crystal grain boundaries and cracks occur on the surface of the slab during hot rolling, so the present invention is within the applicable range.
【００２１】酸化防止剤は、鋼材用に市販されているも
ので十分に本発明の効果が得られ、その組成等は特に限
定されるものではない。しかしながら、スラブ加熱時に
スラブとの反応性が低く、且つ加熱抽出後の剥離性の良
好なものを用いることが望ましい。酸化防止剤の膜厚の
限定理由は、膜厚が0.2 mm以下では加熱時の粒界酸化効
果が不十分であり、1.0 mmを超えると原単位が悪くな
り、経済的でないことと共に、デスケール後もスラブ表
面に酸化防止剤が残り、熱延による押し込み疵の原因と
なることによる。As the antioxidant, those commercially available for steel products can sufficiently obtain the effects of the present invention, and the composition and the like thereof are not particularly limited. However, it is desirable to use a material that has low reactivity with the slab during heating of the slab and has good peelability after heat extraction. The reason for limiting the film thickness of the antioxidant is that if the film thickness is 0.2 mm or less, the grain boundary oxidation effect during heating is insufficient, and if it exceeds 1.0 mm, the unit consumption deteriorates, which is not economical, and after descaling. This is also because the antioxidant remains on the slab surface and causes indentation defects due to hot rolling.
【００２２】酸化防止剤の塗布方法としては、刷毛によ
る手塗りや機械による吹き付け塗布であってもよい。塗
布はスラブの全面に塗布しても全く問題ないが、ヤヘゲ
疵の発生は熱延コイルの両エッジから250 mm以内の範囲
の圧延面に集中発生することから、より経済的に本発明
の効果を享受するためには、スラブ広面の圧延方向の両
端部から250 mm以内の範囲に塗布することが望ましい。The antioxidant may be applied by hand application with a brush or spray application with a machine. Although there is no problem even if the coating is applied to the entire surface of the slab, the occurrence of burnt marks is concentrated on the rolled surface within a range of 250 mm from both edges of the hot rolled coil, so that the effect of the present invention is more economical. In order to enjoy the above, it is desirable to apply within a range of 250 mm from both ends of the wide surface of the slab in the rolling direction.
【００２３】更に、スラブの加熱温度を1,250 ℃以下に
限定した理由は、1,250 ℃を超えると市販の酸化防止剤
では粒界酸化を抑制することが不可能となるためであ
る。下限温度は所望の熱延コイル板厚を得るための熱延
作業に支障がない範囲であれば、特に限定されるもので
はない。Further, the reason why the heating temperature of the slab is limited to 1,250 ° C. or less is that if it exceeds 1,250 ° C., it becomes impossible to suppress the grain boundary oxidation with the commercially available antioxidant. The lower limit temperature is not particularly limited as long as it does not hinder the hot rolling work for obtaining a desired hot rolled coil plate thickness.
【００２４】[0024]
【実施例１】ＶＯＤ炉において、表１に示す成分のオー
ステナイト系ステンレス鋼を溶製し、連続鋳造にてスラ
ブ（幅：1000mm、厚み：200mm ）を各ヒ-ト ８本製造し
た。ヒ-トNo.Ａ１〜Ａ４はＡγおよびＳ、Ｂ量ともに本発
明の成分規定を満足する鋼である。一方、ヒ-トNo.Ｂ１
は、Ａγが、ヒ-トNo.Ｂ２〜Ｂ４はＳまたはＢ量が本発明
の成分規定を外れる比較鋼である。Example 1 In a VOD furnace, austenitic stainless steel having the components shown in Table 1 was melted and continuously cast to produce 8 heat slabs (width: 1000 mm, thickness: 200 mm). Heat Nos. A1 to A4 are steels satisfying the compositional requirements of the present invention for Aγ and S, B amounts. On the other hand, heat No. B1
Is a comparative steel with Aγ, and heat Nos. B2 to B4 are comparative steels in which the amounts of S or B deviate from the compositional regulations of the present invention.
【００２５】[0025]
【表１】 [Table 1]
【００２６】ヒ-トNo.Ａ１のスラブ７本を用いて酸化防止
剤の塗布条件および加熱温度を変化させて熱間圧延を行
い、得られた熱延コイルの表面疵の評価をした。酸化防
止剤はＳｉＯ2 −Ａｌ2 Ｏ3 −ＺｒＯ2 系の薬剤を有機
溶媒に含有させたものを用いて、スラブに刷毛で塗布し
た。熱延は通常の圧延条件とし、厚さ：6 mm、幅：1000
mmの熱延コイルを製造した。熱延条件と熱延コイルの表
面疵の評価結果を表２に示す。Hot rolling was performed using seven slabs of heat No. A1 while changing the coating conditions of the antioxidant and the heating temperature, and the surface flaws of the obtained hot rolled coil were evaluated. As the antioxidant, a SiO 2 —Al 2 O 3 —ZrO 2 type chemical was used in an organic solvent, and the antioxidant was applied to the slab with a brush. Hot rolling is done under normal rolling conditions, thickness: 6 mm, width: 1000
mm hot rolled coils were manufactured. Table 2 shows the hot rolling conditions and the evaluation results of the surface flaws of the hot rolled coil.
【００２７】[0027]
【表２】 [Table 2]
【００２８】本発明で規定する酸化防止剤の塗布条件お
よびスラブ加熱温度を満足する実験No．１〜３では、熱
延コイルにヤヘゲ疵が全く発生しなかった。一方、本発
明の条件を外れる実験No．４〜６ではコイルの量エッジ
から230 mmの範囲にヤヘゲ疵が多発した。このヤヘゲ疵
はその後の表面研削工程でも除去不可能であり、ヤヘゲ
疵箇所のスリット除去を余儀なくされ、大幅な歩留ロス
を生じた。実験No．７は酸化防止剤の厚みを過剰に塗っ
たケースであるが、粒界酸化は防止されるためにヤヘゲ
疵は発生しなかったが、熱延時に酸化防止剤の押し込み
疵が多発し、後工程での歩留ロスが生じた。Experiment No. satisfying the coating conditions of the antioxidant and the slab heating temperature specified in the present invention. In Nos. 1 to 3, no hot-skin defects occurred on the hot-rolled coil. On the other hand, the experiment No. which deviates from the conditions of the present invention. In Nos. 4 to 6, a lot of bald spots occurred in a range of 230 mm from the coil edge. This yagegure flaw could not be removed even in the subsequent surface grinding step, and the slit of the yagegge flaw was forced to be removed, resulting in a large yield loss. Experiment No. No. 7 is a case in which the thickness of the antioxidant was applied excessively, but no grain burns occurred because grain boundary oxidation was prevented, but indentation of the antioxidant occurred frequently during hot rolling, and Yield loss occurred.
【００２９】ヒ-トNo.Ａ２〜Ａ４のスラブについてもＡ１
と同様なテストを行い、本発明の規定する条件を満足す
る熱延条件のものはヤヘゲ疵が全く生じなかった。The slabs of heat Nos. A2 to A4 are also A1
A similar test was conducted, and the hot rolling conditions satisfying the conditions specified by the present invention did not cause any burnt marks.
【００３０】比較鋼のヒ-トNo.Ｂ１はＡγの値が本発明の
対象外のものであるが、本ヒ-ト のスラブにはδフェライ
トが僅かに認められ、オーステナイト単相組織ではなか
った。本ヒ-ト のスラブは酸化防止剤の塗布無しで熱間圧
延を行ったが、熱延コイルにヤヘゲ疵は全く発生しなか
った。The heat No. B1 of the comparative steel has an Aγ value outside the scope of the present invention, but a slight amount of δ ferrite was observed in the slab of this heat, and it was not an austenite single phase structure. It was The heat-treated slab was hot-rolled without the application of an antioxidant, but no hot-rolled coil was found on the hot-rolled coil.
【００３１】ヒ-トNo.Ｂ２〜Ｂ４はＳ、Ｂ量が本発明の成
分規定を外れるものである。この中でヒ-トNo.Ｂ３のスラ
ブ３本を、本発明で規定する酸化防止剤の塗布条件、ス
ラブ加熱温度で熱延し、熱延コイルの表面疵の評価を行
った。その結果を表３に示す。In Heat Nos. B2 to B4, the amounts of S and B deviate from the component regulations of the present invention. Three heat slabs of heat No. B3 were hot-rolled at the slab heating temperature and the coating conditions of the antioxidant specified in the present invention, and the surface flaws of the hot-rolled coil were evaluated. Table 3 shows the results.
【００３２】[0032]
【表３】 [Table 3]
【００３３】実験No. １〜３ともに、熱延コイルにヤヘ
ゲ疵が多発し、大幅な歩留ロスとなった。同様なテスト
をヒ-トNo.Ｂ２についても行ったが、Ｂ３の場合と全く同
様な結果となった。In Experiment Nos. 1 to 3, the hot-rolled coil frequently suffered from baldness, resulting in a large yield loss. A similar test was conducted for heat No. B2, but the result was exactly the same as that for B3.
【００３４】さらに、ヒ-トNo.Ｂ４は、Ｂ量が本発明の上
限値を上回るものであるが、連鋳スラブに内部割れが発
生し、熱間圧延を行うことが不可能であった。Further, in Heat No. B4, the B content exceeded the upper limit of the present invention, but internal cracking occurred in the continuous casting slab, and hot rolling was impossible. .
【００３５】[0035]
【発明の効果】本発明は、表面性状にすぐれた熱間圧延
材を得ることで、製品歩留を向上させ、さらには後工程
の負荷を低減させるとともに表面性状にすぐれたオース
テナイト系ステンレス鋼を提供することができる。INDUSTRIAL APPLICABILITY The present invention provides an austenitic stainless steel having excellent surface properties by improving the product yield and further reducing the load of the post-process by obtaining a hot rolled material having excellent surface properties. Can be provided.
【図１】オーステナイト系ステンレス鋼中の連鋳材にお
けるδフェライト量とＡγ値の関係を示す。FIG. 1 shows the relationship between the amount of δ ferrite and the Aγ value in a continuous cast material in austenitic stainless steel.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 山内 隆 山口県新南陽市野村南町4976番地 日新製 鋼株式会社鉄鋼研究所内 (72)発明者 廣津 貞雄 山口県新南陽市野村南町4976番地 日新製 鋼株式会社鉄鋼研究所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takashi Yamauchi 4976 Nomura-Minami-cho, Shinnanyo-shi, Yamaguchi Prefecture Steel Research Laboratory, Nisshin Steel Co., Ltd. (72) Sadao Hirotsu 4976 Nomura-Minami-cho, Shinnanyo-shi, Yamaguchi Prefecture Nisshin Steel Research Co., Ltd.
Claims (1)
て、Ｓ：0.003mass%以下、Ｂ：0.002 〜0.010mass%に成
分調整した連続鋳造スラブを熱間圧延するに際し、該ス
ラブの長辺面に酸化防止剤を膜厚0.2 〜1.0mm 塗布し、
これを1,250 ℃以下の温度域に加熱後、熱間圧延をする
ことを特徴とする表面性状に優れたオーステナイト系ス
テンレス鋼熱延鋼帯の製造方法。1. An austenitic stainless steel having an Aγ value defined by the following equation (1): Aγ = Ni + 41.2C + 21.4N-1.16 (Cr + 0.26Mn + 1.85Si) (1) -9.0 or more : 0.003 mass% or less, B: 0.002 to 0.010 mass% When hot-rolling a continuously cast slab whose composition has been adjusted, an antioxidant is applied to the long side surface of the slab in a thickness of 0.2 to 1.0 mm,
A method for producing an austenitic stainless steel hot-rolled steel strip having excellent surface properties, which comprises heating this to a temperature range of 1,250 ° C or lower and then hot rolling.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5678595A JPH08225839A (en) | 1995-02-22 | 1995-02-22 | Production of austenitic stainless steel hot rolled steel strip excellent in surface property |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5678595A JPH08225839A (en) | 1995-02-22 | 1995-02-22 | Production of austenitic stainless steel hot rolled steel strip excellent in surface property |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08225839A true JPH08225839A (en) | 1996-09-03 |
Family
ID=13037080
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5678595A Withdrawn JPH08225839A (en) | 1995-02-22 | 1995-02-22 | Production of austenitic stainless steel hot rolled steel strip excellent in surface property |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08225839A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005281744A (en) * | 2004-03-29 | 2005-10-13 | Nisshin Steel Co Ltd | METHOD FOR MANUFACTURING Cr-Ni-BASED STAINLESS STEEL STRIP |
-
1995
- 1995-02-22 JP JP5678595A patent/JPH08225839A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005281744A (en) * | 2004-03-29 | 2005-10-13 | Nisshin Steel Co Ltd | METHOD FOR MANUFACTURING Cr-Ni-BASED STAINLESS STEEL STRIP |
| JP4591912B2 (en) * | 2004-03-29 | 2010-12-01 | 日新製鋼株式会社 | Method for producing Cr-Ni type stainless steel strip |
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