JPH06241B2 - Hot rolling method for stainless steel - Google Patents
Hot rolling method for stainless steelInfo
- Publication number
- JPH06241B2 JPH06241B2 JP62226400A JP22640087A JPH06241B2 JP H06241 B2 JPH06241 B2 JP H06241B2 JP 62226400 A JP62226400 A JP 62226400A JP 22640087 A JP22640087 A JP 22640087A JP H06241 B2 JPH06241 B2 JP H06241B2
- Authority
- JP
- Japan
- Prior art keywords
- rolling
- width
- rolled
- stainless steel
- pass
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Description
【発明の詳細な説明】 〈産業上の利用分野〉 本発明は、ステンレス鋼の熱間圧延方法に係り、特に被
圧延材の側端部に発生する表面疵を防止する方法に関す
る。Description: TECHNICAL FIELD The present invention relates to a hot rolling method for stainless steel, and more particularly to a method for preventing surface flaws generated at the side edges of a material to be rolled.
〈従来の技術〉 近年、ステンレス鋼板の表面性状に対する需要家の要求
はますます厳しくなってきている。また、圧延された鋼
板の幅精度も向上してきており、被圧延材側端部の表面
疵が非常に大きな問題としてクローズアップされてい
る。特に、第1図に示すような被圧延材1の側端部2近
傍の表裏面に見られる線状疵(以下、エッジシームと称
す)3に対しては効果的な防止策が見当たらない。この
エッジシーム3の発生原因としては、粗圧延工程におい
て被圧延材の側端部に発生した疵が水平圧延時の、幅拡
がりによって表裏面にまわり込み残存することが一般に
知られている。<Prior Art> In recent years, the demands of consumers for the surface properties of stainless steel sheets have become more and more strict. In addition, the width accuracy of the rolled steel sheet has been improved, and the surface flaw on the side end of the rolled material has been highlighted as a very serious problem. In particular, no effective preventive measure is found for the linear flaws (hereinafter, referred to as edge seams) 3 that are seen on the front and back surfaces near the side end portions 2 of the material 1 to be rolled as shown in FIG. It is generally known that a cause of the edge seam 3 is that a flaw generated at a side end portion of a material to be rolled in a rough rolling step wraps around and remains on the front and back surfaces due to width expansion during horizontal rolling.
従来からこのようなエッジシームを防止する方法として
は、例えば特公昭50−14632号や特開昭56−6
707号、特開昭53−28542号などの公報による
方法が公知である。Conventional methods for preventing such edge seams include, for example, Japanese Patent Publication No. 50-14632 and Japanese Patent Laid-Open No. 56-6.
Methods disclosed in Japanese Patent Laid-Open No. 707, JP-A-53-28542 and the like are known.
特公昭50−14632号の技術は、第2図に示すよう
に凸状カリバ付きエッジャロール4によつて被圧延材1
の側端部2に鍛練効果を与えるものであり、また特開昭
56−6707号の技術は被圧延材を大幅圧下すること
により、その側面に鍛練効果を与えるものであり、両技
術はいずれも被圧延材の側面に発生する割れを鍛練効果
によって防止しようとするものである。As shown in FIG. 2, the technique of Japanese Patent Publication No. 50-14632 is applied to a material 1 to be rolled by an edger roll 4 with a convex caliber.
In addition, the technique of JP-A-56-6707 gives a training effect to the side surface of the rolled material by significantly reducing the material to be rolled. Is also intended to prevent cracks occurring on the side surface of the material to be rolled by the training effect.
一方、特開昭53−28542号の技術は、第3図に示
すようにカリバ付きエッジャロール5のつばの部分6に
よって被圧延材1の稜の部分7に圧下を加えてエッジシ
ームを防止するものであり、被圧延材1の側端部2に発
生した疵を被圧延材の稜部7で平滑化しようとするもの
である。On the other hand, the technique disclosed in Japanese Patent Laid-Open No. 53-28542 is to prevent the edge seam by applying a reduction to the ridge portion 7 of the material 1 to be rolled by the brim portion 6 of the edger roll 5 with caliber as shown in FIG. Therefore, it is intended to smooth the flaw generated at the side end portion 2 of the rolled material 1 at the ridge portion 7 of the rolled material.
〈発明が解決しようとする問題点〉 しかしながら、フェライト系、オーステナイト系および
マルテンサイト系ステンレス鋼を熱間圧延した場合に発
生するエッジシームの原因は、前記した従来知られてい
る被圧延材側面に発生する割れではなく、側面表層部の
結晶粒の異方性に起因する凹凸(以下、これをしわと称
す)であることが判明している。<Problems to be solved by the invention> However, the cause of the edge seam that occurs when hot rolling ferritic, austenitic and martensitic stainless steel occurs on the side surface of the conventionally known material to be rolled described above. It has been found that the cracks are not cracks that occur, but irregularities (hereinafter referred to as wrinkles) caused by the anisotropy of the crystal grains in the side surface layer portion.
ところで、ステンレス鋼を熱間圧延する際に前記特公昭
50−14632号や特開昭56−6707号の技術を
適用する場合、すなわち被圧延材の幅圧下による鍛練効
果を利用して側面表層部の結晶粒を微細化ししわの発生
を防止するには、非常に大きな幅圧下量を必要とするか
ら、エッジャミルの能力が非常に大きなものになつて非
経済的であり、また大幅圧下を加える場合、被圧延材の
座屈が発生し易いなどの問題点があり、エッジシーム防
止のための有効な手段とはならないのである。By the way, when applying the technique of Japanese Patent Publication No. 50-14632 or Japanese Patent Laid-Open No. 56-6707 in hot rolling stainless steel, that is, the side surface layer portion is utilized by utilizing the forging effect by the width reduction of the material to be rolled. In order to reduce the size of the crystal grains and prevent the generation of wrinkles, a very large width reduction amount is required, which is uneconomical because the edger mill's capacity becomes very large, and when a large reduction is applied. However, there is a problem that the material to be rolled is likely to buckle, which is not an effective means for preventing edge seams.
また、前記特開昭53−28542号の方法を用いて被
圧延材の稜部を圧下すると、しわの倒れ込みを助長して
へげ状のエッジシームを発生させ易く、したがって有効
なエッジシーム防止方法とはならない。さらに、カリバ
付きエッジャロールを用いた場合、被圧延材の通板サイ
ズが限定されるから汎用的でないという欠点がある。Further, when the ridge portion of the material to be rolled is pressed down by using the method of the above-mentioned Japanese Patent Laid-Open No. 53-28542, wrinkle collapse is promoted to easily cause a barbed edge seam, and therefore an effective method for preventing edge seam is I won't. Further, when the edger roll with a caliber is used, there is a drawback that it is not general-purpose because the size of the strip to be rolled is limited.
本発明は、上記のような事情に鑑みなされたものであっ
て、ステンレス鋼の熱間圧延においても被圧延材の側端
部に発生する表面疵を防止するのに好適な方法を提供す
ることを目的とする。The present invention has been made in view of the above circumstances, and provides a method suitable for preventing a surface flaw generated at a side end portion of a material to be rolled even in hot rolling of stainless steel. With the goal.
〈問題点を解決するための手段〉 本発明者らは、フェライト系、オーステナイト系および
マルテンサイト系ステンレス鋼を熱間圧延時における表
面疵防止について鋭意検討を加えた結果、エッジャミル
による幅圧下パス間における水平圧下率の大きさに制限
があること、また幅圧下量の大きさにも制限があること
を見出し、その知見に基づいて本発明を完成させるに至
った。<Means for Solving Problems> The present inventors have made earnest studies on surface flaw prevention during hot rolling of ferritic, austenitic and martensitic stainless steels, and as a result, the width reduction pass by the edger mill The present invention has been completed based on the finding that there is a limit in the magnitude of the horizontal reduction rate in the above and that there is also a limitation in the width reduction amount in the width.
本発明は、ステンレス鋼を熱間圧延するに際し、水平圧
延パスと幅圧延パスを複数回組み合わせてなる粗圧延工
程において、幅圧延パス間に施される水平圧延パスの合
計圧下率を50%以下とし、かつ幅圧延パスの1回の幅
圧下量を水平圧延パス後の被圧延材の厚み方向における
板幅差に対して40〜150%とすることを特徴とする
ステンレス鋼の熱間圧延方法である。The present invention, when hot-rolling stainless steel, in a rough rolling step in which horizontal rolling passes and width rolling passes are combined multiple times, the total rolling reduction of horizontal rolling passes performed between the width rolling passes is 50% or less. And a single width reduction amount of the width rolling pass is set to 40 to 150% with respect to the plate width difference in the thickness direction of the rolled material after the horizontal rolling pass. Is.
〈作用〉 フェライト系、オーステナイト系およびマルテンサイト
系ステンレス鋼を、エッジャミルと水平圧延ロールから
なる可逆式粗圧延機と、タンデム仕上圧延機を用いて熱
間圧延実験を行ったところ、以下の点が判明した。<Operation> A hot rolling experiment was conducted on ferritic, austenitic and martensitic stainless steels using a reversible rough rolling mill consisting of an edger mill and horizontal rolling rolls and a tandem finishing rolling mill. found.
エッジャミルによる幅圧延パス間の水平圧延パスの合
計圧下率rtが50%を超えると、被圧延材の側端部に
発生するしわは、エッジャミルによる幅圧延パスで平滑
化することができないこと。If the total reduction rate r t of the horizontal rolling path between the width rolling passes according Ejjamiru exceeds 50%, wrinkles occurring at the side end portion of the material to be rolled, can not be smoothed by width rolling pass by Ejjamiru.
ここで、水平圧延パスにおける圧下率の合計が小さけれ
ば、被圧延材側面のしわは浅くかつ小さくなるので、幅
圧延パスによるしわの平滑化が容易となるため、その下
限については特に制限する必要はないこと。Here, if the total of the reduction ratios in the horizontal rolling pass is small, the wrinkles on the side surface of the rolled material are shallow and small, so that the smoothing of the wrinkles by the width rolling pass becomes easy.Therefore, the lower limit thereof needs to be particularly limited. Not be.
エッジャミルにおける1回の幅圧下量Δwが、水平圧
延パス後における被圧延材側端部の厚さ方向における板
幅差ΔB(以下、バルジング量と称す)の40%よりも
少なければ、エッジャミルで被圧延材側面を押す力が弱
くなるから、その稜部7(第3図参照)に発生している
しわを十分に平滑化することができないこと。If the width reduction Δw in one time in the edger mill is less than 40% of the plate width difference ΔB (hereinafter referred to as the bulging amount) in the thickness direction of the end portion of the material to be rolled after the horizontal rolling pass, the edger mill reduces the width. Since the pressing force on the side surface of the rolled material becomes weak, it is not possible to sufficiently smooth the wrinkles occurring at the ridge 7 (see FIG. 3).
なお、バルジング量ΔBは、第4図に示したように、被
圧延材1の表面における板幅をW1とし、両側端部2,
2での最大膨れ位置における板幅をW2とすると、ΔB
=W2−W1として表される。In addition, as shown in FIG. 4, the amount of bulging ΔB is set such that the plate width on the surface of the material 1 to be rolled is W 1, and both end portions 2,
If the plate width at the maximum bulge position at 2 is W 2 , ΔB
= Expressed as W 2 -W 1.
さらに、前記Δwがバルジング量ΔBに対して150
%よりも大きければ、大きなドッグボーンを形成し、被
圧延材稜部にかえって大きな深いしわや折れ込みが発生
し易くなること。Further, the Δw is 150 with respect to the bulging amount ΔB.
If it is larger than%, a large dog bone is formed and large deep wrinkles or folds are likely to occur on the ridge of the rolled material.
したがって、フェライト系、オーステナイト系およびマ
ルテンサイト系ステンレス鋼の熱間圧延の際に、粗圧延
工程における水平圧下と幅圧下の条件を上記の範囲内に
制御するようにすれば、被圧延材の側端部に発生するし
わを防止することができるのである。Therefore, during hot rolling of ferritic, austenitic and martensitic stainless steels, if the conditions of horizontal reduction and width reduction in the rough rolling step are controlled within the above range, the material to be rolled is It is possible to prevent wrinkles from occurring at the ends.
〈実施例〉 以下に、本発明の実施例について具体的に説明する。<Examples> Examples of the present invention will be specifically described below.
実験材として板厚180mm、板幅937mmのフェライト
系ステンレス鋼(SUS430)5本と、オーステナイ
ト系ステンレス鋼(SUS304)およびマルテンサイ
ト系ステンレス鋼(SUS410)各2本のスラブを用
いて、加熱炉で1250℃に加熱した後、粗圧延工程に
おいて第1表に示すようなパススケジュールで板厚27
mmのシートバーにし、次いで仕上圧延工程において6ス
タンドタンデム圧延で板厚3.5mmの製品に仕上げた。
なお、粗圧延におけるエッジャミルによる幅圧下は各奇
数パスの入側において実施した。As a test material, using a slab of five ferritic stainless steels (SUS430) with a plate thickness of 180 mm and a plate width of 937 mm, and two austenitic stainless steels (SUS304) and martensitic stainless steels (SUS410), in a heating furnace. After heating to 1250 ° C., the plate thickness 27 was applied in the rough rolling process according to the pass schedule shown in Table 1.
A sheet bar having a thickness of 3.5 mm was prepared, and then a product having a plate thickness of 3.5 mm was finished by a 6-stand tandem rolling in a finish rolling process.
The width reduction by the edger mill in rough rolling was performed on the entry side of each odd numbered pass.
このときの粗圧延工程における幅圧延パス間の水平圧延
パスの合計圧下率rt(%)およびエッジャミルにおけ
る1回の幅圧下量Δw(mm)と水平圧延パス後の被圧延側
端部のバルジング量ΔB(mm)の割合すなわち(Δw/Δ
B)×100(%)、さらに第1図に示すように水平圧
延パス後における被圧延材の最も幅方向中央部に位置す
るエッジシーム3の側端部2からの距離dmax(mm)とを
併せて第2表に示した。At this time, the total reduction ratio r t (%) of the horizontal rolling passes between the width rolling passes in the rough rolling process, the width reduction amount Δw (mm) once in the edger mill, and the bulging of the side end to be rolled after the horizontal rolling pass. Ratio of amount ΔB (mm), that is, (Δw / Δ
B) × 100 (%), and as shown in FIG. 1, together with the distance dmax (mm) from the side end 2 of the edge seam 3 located at the center in the width direction of the material to be rolled after the horizontal rolling pass. The results are shown in Table 2.
第2表からわかるように、従来例ではエッジャミルによ
る3パス目と4パス目の幅圧延パス間の水平圧延パスの
合計圧下率rtが50%を超えてお り、かつdmaxが17.3mmであるのに対し、本発明の
条件をすべて満足する実験材I,V,VI、のdmaxはい
ずれも2.0mm以下となり、歩留りも99.5%以上と
大幅に改善された。As can be seen from Table 2, in the conventional example, the total reduction ratio r t of the horizontal rolling pass between the third and fourth width rolling passes by the edger mill exceeds 50%. And the dmax of 17.3 mm, the dmax of the experimental materials I, V and VI satisfying all the conditions of the present invention was 2.0 mm or less, and the yield was 99.5% or more. Was improved.
ここで、歩留りは、被圧延材の板幅をWとすると下記式
により求めたものである。Here, the yield is obtained by the following equation, where W is the plate width of the material to be rolled.
なお、実験材IIはエッジャによる3パス目の幅圧下量Δ
wが本発明の条件より少ない場合であり、実験材IIIは
逆に多い場合であるが、これらのdmaxは8〜10mmと
従来例に比べて改善はみられるものの、歩留りは98%
以下となってやはり問題である。 Note that the experimental material II is the width reduction Δ of the third pass by the edger.
When w is less than the condition of the present invention and when the experimental material III is conversely large, the dmax of these is 8 to 10 mm, which is an improvement as compared with the conventional example, but the yield is 98%.
The following is still a problem.
また、実験材IVはエッジャによる幅圧下を3パスとした
ものであるが、幅圧下の1パス目と2パス目の間の水平
圧下の合計圧下率rtが50%を超えており、dmaxも
22mmに悪化している。Although experimental material IV is obtained by a three-pass width reduction by edger, it exceeded 50% of the total reduction ratio r t of the horizontal pressure between the first pass and the second pass of the width reduction, dmax Has also deteriorated to 22 mm.
なお、本発明の実施にあたって、バルジング量ΔBを以
下の方法で予測して幅圧下量Δwの設定に用いた。すな
わち、まず、エッジャミルによる幅圧延パスの間の水平
圧延パスによる被圧延材の幅拡がり量ΔB*を、前回の
幅圧下量Δw*、水平圧延パス前後の板厚比Hi/H
o、ロール径と板厚との比D/Hi、板厚と板幅との比
Hi/Bi、板幅と接触弧長との比B/ldおよび摩擦
係数μの関数とする実験式を作成した。また形状係数C
*を上記したHi/Ho、Hi/Bi、D/Hiおよび
μの関数とする実験式を作成した。そして、B=ΔB*
×C*なる実験式を作成して、バルジング量ΔBを精度
よく予測した。In carrying out the present invention, the bulging amount ΔB was predicted by the following method and used for setting the width reduction amount Δw. That is, first, the width spread amount ΔB * of the material to be rolled by the horizontal rolling pass between the width rolling passes of the edger mill is calculated by the previous width reduction amount Δw * and the plate thickness ratio Hi / H before and after the horizontal rolling pass.
o, empirical formulas as functions of roll diameter to plate thickness ratio D / Hi, plate thickness to plate width ratio Hi / Bi, plate width to contact arc length ratio B / ld, and friction coefficient μ did. Also, the shape factor C
An empirical formula was created in which * is a function of Hi / Ho, Hi / Bi, D / Hi and μ described above. And B = ΔB *
An empirical formula of × C * was created to accurately predict the bulging amount ΔB.
〈発明の効果〉 以上説明したように、本発明によれば、ステンレス鋼の
熱間圧延の際に生ずる表面疵を抑制することができるか
ら、製品の歩留り向上に寄与する。<Effects of the Invention> As described above, according to the present invention, it is possible to suppress surface defects that occur during hot rolling of stainless steel, which contributes to an improvement in product yield.
第1図は、エッジシームの概要を説明する部分斜視図、
第2図、第3図は、エッジシーム防止の従来例を示す部
分正面図、第4図は、粗圧延における水平圧延パス後の
被圧延材側端部のバルジング量を説明する正面図であ
る。 1…被圧延材(ステンレス鋼)、 2…側端部、 3…エッジシーム。FIG. 1 is a partial perspective view illustrating an outline of an edge seam,
2 and 3 are partial front views showing a conventional example of edge seam prevention, and FIG. 4 is a front view illustrating the amount of bulging at the end of the material to be rolled after a horizontal rolling pass in rough rolling. 1 ... Rolled material (stainless steel), 2 ... Side end, 3 ... Edge seam.
Claims (1)
圧延パスと幅圧延パスを複数回組み合わせてなる粗圧延
工程において、幅圧延パス間に施される水平圧延パスの
合計圧下率を50%以下とし、かつ幅圧延パスの1回の
幅圧下量を水平圧延パス後の被圧延材の厚み方向におけ
る板幅差に対して40〜150%とすることを特徴とす
るステンレス鋼の熱間圧延方法。1. A total rolling reduction of 50% of horizontal rolling passes between width rolling passes in a rough rolling process in which horizontal rolling passes and width rolling passes are combined a plurality of times during hot rolling of stainless steel. The hot rolling of stainless steel is as follows, and the width reduction amount of one time of the width rolling pass is 40 to 150% with respect to the plate width difference in the thickness direction of the rolled material after the horizontal rolling pass. Method.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP62226400A JPH06241B2 (en) | 1987-09-11 | 1987-09-11 | Hot rolling method for stainless steel |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP62226400A JPH06241B2 (en) | 1987-09-11 | 1987-09-11 | Hot rolling method for stainless steel |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS6471503A JPS6471503A (en) | 1989-03-16 |
JPH06241B2 true JPH06241B2 (en) | 1994-01-05 |
Family
ID=16844532
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP62226400A Expired - Lifetime JPH06241B2 (en) | 1987-09-11 | 1987-09-11 | Hot rolling method for stainless steel |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH06241B2 (en) |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS566707A (en) * | 1979-06-29 | 1981-01-23 | Nippon Steel Corp | Hot edging method for cast slab |
-
1987
- 1987-09-11 JP JP62226400A patent/JPH06241B2/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS566707A (en) * | 1979-06-29 | 1981-01-23 | Nippon Steel Corp | Hot edging method for cast slab |
Also Published As
Publication number | Publication date |
---|---|
JPS6471503A (en) | 1989-03-16 |
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