JP4871250B2 - Strip rolling method - Google Patents

Strip rolling method Download PDF

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JP4871250B2
JP4871250B2 JP2007321033A JP2007321033A JP4871250B2 JP 4871250 B2 JP4871250 B2 JP 4871250B2 JP 2007321033 A JP2007321033 A JP 2007321033A JP 2007321033 A JP2007321033 A JP 2007321033A JP 4871250 B2 JP4871250 B2 JP 4871250B2
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rolling
lubricant
rolled material
tail end
roll
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JP2009142836A (en
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仁 串田
英典 酒井
智也 土橋
剛 白野
勇希 室屋
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Kobe Steel Ltd
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本発明は、所定の間隔をおいて複数列配置した圧延スタンドの対になった圧延ロールで、圧延材を、複数のパスに分けて順次圧下方向を変えながら圧延することで、その圧延材の断面積を順次減少させて所定の製品寸法の線材、棒鋼、角材など条鋼に仕上げる条鋼の圧延方法に関するものである。   The present invention is a rolling roll which is a pair of rolling stands arranged in a plurality of rows at a predetermined interval, and the rolled material is rolled while being divided into a plurality of passes and sequentially changing the rolling direction. The present invention relates to a method for rolling a bar steel, which sequentially reduces the cross-sectional area to finish a bar steel such as a wire rod, a bar steel, a square bar having a predetermined product size.

熱間圧延等により製造される線材、棒鋼、角材などの条鋼では、表面疵が許容範囲内にあることを保証する必要がある。これは、条鋼に許容範囲以上の表面疵が残存すると、例えば、後続のいわゆる2次加工工程などでの鍛造工程で、その表面疵を起点とした割れなどの加工欠陥が発生することがあるためである。問題となる表面疵は圧延材の尾端部や先端部で多く発生し、特に尾端部での発生率が圧倒的に高い。コイルとして出荷される線材の場合は、製品の全長検査をすることが困難であるため、尾端部と先端部の端末サンプルを調査し、問題となる表面疵が発生している場合には、表面疵がなくなるまでその端部から切り込み除去しており、非常に手間な検査除去作業を伴っていた。   It is necessary to ensure that the surface flaws are within an allowable range in the steel bars such as wire rods, bar steels, and square bars manufactured by hot rolling or the like. This is because, if surface flaws exceeding the allowable range remain in the bar steel, for example, processing defects such as cracks starting from the surface flaws may occur in the subsequent forging process in the so-called secondary processing step. It is. The surface flaws that cause problems often occur at the tail end and tip end of the rolled material, and the incidence at the tail end is particularly high. In the case of wire rods shipped as a coil, it is difficult to inspect the full length of the product, so investigate the tail end and the end sample of the tip, and if there is a problem surface flaw, Until the surface flaws disappeared, the edges were cut and removed, which involved very laborious inspection and removal work.

条鋼の表面疵を低減する方法としては、発明者らが以前に発明した特許文献1に記載された発明がある。この発明は、条鋼に発生する表面疵の原因は製造時の各パスでの局部的な周方向の圧縮ひずみであることを見出し、圧延条件を適正化することでこの圧縮ひずみの値を制御するとした発明である。この発明を実施することにより、問題となる表面疵の発生は、特に条鋼の中間部において格段に低減することが可能となったが、条鋼の尾端部や先端部に発生する表面疵の低減は確実にできたとは言いえなかった。   As a method of reducing the surface flaws of the strip steel, there is an invention described in Patent Document 1 that the inventors previously invented. The present invention finds that the cause of surface flaws occurring in the bar steel is local circumferential compressive strain in each pass at the time of manufacturing, and controls the value of this compressive strain by optimizing the rolling conditions. Invention. By implementing this invention, it has become possible to significantly reduce the occurrence of surface flaws that are a problem, particularly in the middle part of the bar steel, but it is possible to reduce the surface flaws generated at the tail end and the tip part of the bar steel. I couldn't say that I was able to do it.

発明者らは、特に条鋼の尾端部や先端部において表面疵の発生が多い原因を調査した。圧延ロール1での圧延時には、図11に示すような圧延材2の中間部(定常域ともいう。)とは異なり、圧延材2の尾端部や先端部は、図9や図10に示すように、圧延ロール1での圧延時にロールバイト内の上流側や下流側に材料(圧延材2)が存在しなくなるため、他の部位より、圧延ロール1での圧延による圧延材2の幅広がりが大きくなる(そのため、尾端部や先端部を非定常域という。)。その広がった部位を、次のパスで圧下方向を変えて(条鋼圧延では、1パス毎に90度圧下方向を変えることが多い。)圧延することが表面疵発生の原因となっていることがこの調査で明らかとなった。   The inventors investigated the cause of the occurrence of surface flaws particularly at the tail end and tip end of the strip. At the time of rolling with the rolling roll 1, unlike the intermediate portion (also referred to as a steady region) of the rolled material 2 as shown in FIG. 11, the tail end portion and the tip portion of the rolled material 2 are shown in FIGS. 9 and 10. As described above, since the material (rolled material 2) does not exist on the upstream side or downstream side in the roll bite during rolling with the rolling roll 1, the width of the rolled material 2 by rolling with the rolling roll 1 is expanded from other parts. (For this reason, the tail end and the tip end are referred to as unsteady regions). Rolling the expanded part in the next pass while changing the rolling direction (in steel rolling, the rolling direction is often changed by 90 degrees for each pass) may cause surface flaws. This investigation revealed it.

この幅広がりが大きくなった部位(非定常域)の長さは、投射接触長程度の長さであるため、1パスだけを考えると一見短いようにも思えるが、例えば、155mm角の圧延材2を30パスでφ5.5mmの線材とする場合、1パス目での非定常域の長さは、表1に示すように、最終パスである30パス目の圧延が完了した時点では、800倍以上の長さになり、その長さ分に亘り問題となる表面疵が発生することになる。   Since the length of the widened part (unsteady region) is about the length of the projected contact length, it seems to be short when only one pass is considered. For example, a 155 mm square rolled material When 2 is a wire of φ5.5 mm in 30 passes, as shown in Table 1, the length of the unsteady region in the first pass is 800 when the rolling of the 30th pass, which is the final pass, is completed. The length becomes more than double, and a surface flaw that becomes a problem over the length is generated.

以下に、条鋼の尾端部と先端部での表面疵の発生メカニズムを説明する。条鋼圧延の場合、1パス目のみを考えた場合、圧延材2の圧延後の幅寸法は、尾端部、先端部ともに増大する。それに対し、厚さ寸法(圧下方向の寸法)は、先端部では減少する。先端部の厚さ寸法が減少するのは、図12及び図13に示すように、その断面で見たときの材料中心部が他の部位より前方に延ばされるためである。一方、尾端部においては、先端部と逆の状態となり、材料中心部が凹む状態になるため、厚さ寸法の増減は殆どない。   Below, the generation | occurrence | production mechanism of the surface flaw in the tail end part and front-end | tip part of a bar steel is demonstrated. In the case of strip rolling, when only the first pass is considered, the width dimension of the rolled material 2 after rolling increases for both the tail end portion and the tip end portion. On the other hand, the thickness dimension (dimension in the rolling direction) decreases at the tip. The reason why the thickness dimension of the tip portion decreases is that, as shown in FIGS. 12 and 13, the material center portion when viewed in the cross section is extended forward from the other portions. On the other hand, the tail end portion is in a state opposite to the tip portion, and the material center portion is recessed, so that there is almost no increase or decrease in the thickness dimension.

次に2パス目を考えると、一般に2パス目では90度圧下方向がずれるため、1パス目での幅方向が、2パス目での圧下方向となる。そのため、1パス目で両側に張り出した尾端部や先端部の自由面が、2パス目での圧延ロール1の圧下で押さえ込まれることとなり、折れ込まれたような状態となる。この折れ込みが表面疵の発生原因である。2パス目での圧延材2の圧延後の幅寸法は、尾端部では、1パス目と同様に増大することになるが、先端部では1パス目での圧下方向の寸法が小さくなっている分の相殺で、幅寸法の増大が殆どなくなるか、増大したとしても尾端部よりその増大は小さくなる。3パス目以降でも、2パス目での説明と同様に、尾端部でより幅寸法が増大する。以上のようなメカニズムにより各パスで幅寸法が増大するため、尾端部での表面疵の発生の方が、先端部での表面疵の発生より多くなると推定することができる。   Next, considering the second pass, since the 90-degree reduction direction is generally shifted in the second pass, the width direction in the first pass is the reduction direction in the second pass. Therefore, the free surface of the tail end portion and the tip end portion projecting on both sides in the first pass is pressed down by the rolling of the rolling roll 1 in the second pass, and is in a folded state. This folding is the cause of surface flaws. The width dimension after rolling of the rolled material 2 in the second pass increases in the tail end portion in the same manner as in the first pass, but the size in the reduction direction in the first pass decreases at the tip end portion. By offsetting the amount, the increase in the width dimension is almost eliminated, or even if it is increased, the increase is smaller than the tail end. Even after the third pass, the width dimension further increases at the tail end as in the description of the second pass. Since the width dimension increases in each pass by the mechanism as described above, it can be estimated that the generation of surface defects at the tail end is greater than the generation of surface defects at the tip.

この問題を解決する手段として、条鋼の圧延ラインにはその途中の複数箇所に、圧延材2の尾端部や先端部を切断するカット装置が設置されているが、実際切断されている寸法は僅かであり、表面疵の発生の解消までに至っていないのが現状である。切断長さを長くすることで、この問題は解消できると考えられるが、当然ながら歩留まりが低下することとなり、新たな問題が発生してしまう。   As a means for solving this problem, a cutting device for cutting the tail end or tip end of the rolled material 2 is installed at a plurality of locations on the rolling line of the bar steel, but the dimensions actually cut are The current situation is that the number of surface defects has not been solved. Although it is considered that this problem can be solved by increasing the cutting length, the yield is naturally reduced, and a new problem occurs.

また、特許文献2には、「被駆動水平ロール、入および出側に被駆動幅方向の圧延用カリバー付竪ロールを配置し、カリバー付竪ロール金属スラブの幅圧延を行う場合に、該幅方向圧延によって生じた局部的板厚増大部を水平圧下圧延し、再度幅方向圧延を繰返しおこなう熱間可逆式圧延において、金属スラブを竪ロールで幅圧延をおこなって発生する局部的板厚増大部がさらに該竪ロールの逆転方向幅圧延により増長する場合に、該増長する局部的板厚増大部の接する竪ロールの入側カリバー側壁に熱間圧延油を塗布するとともに、出側カリバー側壁部分をロール研削砥石により研削することを特徴とする金属スラブの熱間幅圧延方法」が開示されている。   Further, Patent Document 2 discloses that when a driven horizontal roll, a roll with a caliber for rolling in the driven width direction is arranged on the entry and exit sides, and the width rolling of the rivet roll with a caliber is performed, the width In a hot reversible rolling process in which a local plate thickness increasing portion generated by directional rolling is horizontally reduced, and width direction rolling is repeated again, a local plate thickness increasing portion is generated by width rolling of a metal slab with a roll. Is further increased by rolling in the reverse direction width of the heel roll, hot rolling oil is applied to the inlet caliber side wall of the heel roll in contact with the increased local plate thickness increasing portion, and the outlet caliber side wall portion is A method for hot width rolling of a metal slab characterized by grinding with a roll grinding wheel is disclosed.

しかしながら、この特許文献2記載の圧延方法は、ロールの肌荒れの材料への転写による線状疵を低減することを対象としたものであり、油圧延に研削手段を組み合わせることにより、優れたロール肌荒れ防止効果を得るとしたものである。従って、この圧延方法からは、幅寸法が増大した尾端部や先端部を、次のパスで押さえ込むことにより発生する表面疵を低減するという本発明特有の作用効果は達成することは不可能であると考えられる。また、この特許文献2記載の圧延方法では、入側カリバー側壁に熱間圧延油(潤滑油)を塗布しているが、ロールの肌荒れの防止を目的としているため、その潤滑油は、圧延工程中、常に連続して供給されると考えられ、非常に多量の潤滑油を供給する必要があるという問題がある。   However, the rolling method described in Patent Document 2 is intended to reduce linear wrinkles due to the transfer of the rough surface of the roll to the material. By combining a grinding means with oil rolling, an excellent rough surface of the roll is obtained. The prevention effect is obtained. Therefore, from this rolling method, it is impossible to achieve the operational effect peculiar to the present invention to reduce surface flaws generated by pressing down the tail end and the tip with increased width dimensions in the next pass. It is believed that there is. Moreover, in the rolling method described in Patent Document 2, hot rolling oil (lubricating oil) is applied to the inlet caliber side wall, but since the purpose is to prevent roughening of the roll, the lubricating oil is used in the rolling process. Among them, it is considered that the oil is always supplied continuously, and there is a problem that it is necessary to supply a very large amount of lubricating oil.

特許文献2記載の潤滑油を常時供給するという技術を、本発明の従来技術に適用した場合、確かに、尾端部や先端部といった非定常域の幅寸法の増大を低減することはできるが、それに併せ、定常域の幅寸法まで小さくなってしまうこととなり(図6の○を参照)、その結果、圧延後の圧延材を全長に亘って略同一幅とすることができないという問題が発生する。   When the technique of constantly supplying the lubricating oil described in Patent Document 2 is applied to the conventional technique of the present invention, it is possible to reduce the increase in the width dimension of the unsteady region such as the tail end and the tip. At the same time, the width of the steady region is reduced (see ○ in FIG. 6), and as a result, the rolled material after rolling cannot be made substantially the same width over the entire length. To do.

特開2007−90429号公報JP 2007-90429 A 特開昭63−2502号公報JP-A 63-2502

本発明は、上記従来の問題を解決せんとしてなされたもので、圧延ロールを圧下することで幅寸法が増大した尾端部や先端部を、次のパスの圧延ロールで押さえ込むことにより発生する表面疵を低減することができ、歩留まりの低下もない条鋼の圧延方法を提供することを課題とするものである。   The present invention was made as a solution to the above-described conventional problems, and the surface generated by pressing the tail end and the tip increased in width by pressing the rolling roll with the rolling roll of the next pass. It is an object of the present invention to provide a method for rolling steel bars that can reduce wrinkles and does not reduce yield.

請求項1記載の条鋼の圧延方法は、所定の間隔をおいて複数列配置した圧延スタンドの対になった圧延ロールで、圧延材を、複数のパスに分けて順次圧下方向を変えながら圧延することで、その圧延材の断面積を順次減少させて所定の製品寸法に仕上げる条鋼の圧延方法であって、前記圧延材の尾端部および/または先端部を各パスで圧延する際のみに、潤滑剤を、前記圧延ロールの表面と前記圧延材の表面の間に供給し、前記圧延材の尾端部および/または先端部を圧延することを特徴とする。   The method of rolling a steel bar according to claim 1 is a rolling roll which is a pair of rolling stands arranged in a plurality of rows at a predetermined interval, and the rolled material is rolled while being divided into a plurality of passes and sequentially changing the rolling direction. By this, it is a rolling method of the strip steel to finish the predetermined product dimensions by sequentially reducing the cross-sectional area of the rolled material, only when rolling the tail end portion and / or the tip portion of the rolled material in each pass, A lubricant is supplied between the surface of the rolling roll and the surface of the rolled material, and the tail end portion and / or the front end portion of the rolled material is rolled.

また、請求項2記載の条鋼の圧延方法は、前記潤滑剤を供給する領域は、各パスでの投射接触長に相当する領域であることを特徴とする。   According to a second aspect of the present invention, the region for supplying the lubricant is a region corresponding to the projected contact length in each pass.

更には、請求項3記載の条鋼の圧延方法は、表面疵が発生した最終製品の尾端部および/または先端部の端縁からの長さをα´としたとき、複数列配置した前記圧延スタンドのうち、前記潤滑剤を供給する圧延スタンドは、下記の式を満足する各圧延スタンドであることを特徴とする。
α´≧A0/A´×Ld
上式で、A0は該当圧延スタンドの入り側の圧延材の断面積、A´は最終製品(条鋼)の断面積、Ldは該当圧延スタンドの投射接触長である。
Furthermore, the rolling method of the strip according to claim 3 is the rolling in which a plurality of rows are arranged when the length from the tail edge and / or the edge of the tip of the final product where surface flaws occur is α ′. Among the stands, the rolling stand that supplies the lubricant is each rolling stand that satisfies the following formula.
α ′ ≧ A0 / A ′ × Ld
In the above equation, A0 is the cross-sectional area of the rolled material on the entry side of the rolling stand, A ′ is the cross-sectional area of the final product (steel bar), and Ld is the projected contact length of the rolling stand.

本発明の請求項1記載の条鋼の圧延方法によると、圧延ロールを圧下することで幅寸法が増大した尾端部や先端部を、次のパスの圧延ロールで押さえ込むことにより発生する表面疵を低減することができる。また、表面疵が発生した非常に長い尾端部や先端部をカットする必要もないので、歩留まりの低下もなくすることができる。   According to the rolling method of the bar steel according to claim 1 of the present invention, the surface flaw generated by pressing the tail end portion and the tip end portion whose width dimension is increased by rolling the rolling roll with the rolling roll of the next pass. Can be reduced. Further, since it is not necessary to cut a very long tail end or tip end where surface flaws have occurred, it is possible to prevent a decrease in yield.

本発明の請求項2記載の条鋼の圧延方法によると、潤滑剤の供給量を、ロール隙の調整による誤差を吸収できる範囲とすることができ、潤滑剤を必要量だけ無駄なく確実に利用することができる。   According to the method for rolling steel bars according to claim 2 of the present invention, the supply amount of the lubricant can be set within a range in which an error due to the adjustment of the roll gap can be absorbed, and the necessary amount of the lubricant is reliably used without waste. be able to.

本発明の請求項3記載の条鋼の圧延方法によると、たとえ表面疵が発生したとしても、その表面疵の発生領域を、歩留まり低下がないとされる必要最低限の長さ分とすることができ、潤滑剤を供給する圧延スタンドの数を、必要最低限の圧延スタンドだけとすることができる。   According to the method for rolling strip according to claim 3 of the present invention, even if surface flaws occur, the surface flaw occurrence region can be set to the minimum necessary length that does not cause yield reduction. The number of rolling stands for supplying the lubricant can be limited to the minimum necessary rolling stands.

以下、本発明を添付図面に示す実施形態に基づいて更に詳細に説明する。   Hereinafter, the present invention will be described in more detail based on embodiments shown in the accompanying drawings.

発明者らは、歩留まりの低下や圧延安定性の低下を引き起こさず、且つ大きなコストもかけずに、確実に条鋼の尾端部や先端部の表面疵の発生を低減することができる方法として、潤滑剤3を、圧延時の圧延ロール1の表面と圧延材2の表面の間に供給する方法を発明した。図1は、圧延ロール1で圧延材2の尾端部を圧延する状態を示し、図2は圧延ロール1で圧延材2の先端部を圧延する状態を示す。先に説明したが、これら尾端部と先端部を非定常域という。また、図3は圧延ロール1で圧延材2の中間部を圧延する状態を示す。この圧延材2の中間部を定常域という。尚、各図面は便宜上、圧延ロール1で圧延される圧延材2の上半分のみを図示しているが、圧延材2の下半分も線対称で同様の形状であり、図示した圧延ロール1と対になった圧延ロール1で圧延される。   As a method that can reduce the occurrence of surface flaws at the tail end and the tip of the steel bar without causing a reduction in yield and rolling stability, and without incurring a large cost, the inventors, A method of supplying the lubricant 3 between the surface of the rolling roll 1 and the surface of the rolled material 2 during rolling was invented. 1 shows a state in which the tail end portion of the rolled material 2 is rolled by the rolling roll 1, and FIG. 2 shows a state in which the tip portion of the rolled material 2 is rolled by the rolling roll 1. As described above, the tail end and the tip end are referred to as unsteady regions. FIG. 3 shows a state where the intermediate part of the rolled material 2 is rolled by the rolling roll 1. The intermediate portion of the rolled material 2 is referred to as a steady region. In addition, although each drawing has shown only the upper half of the rolling material 2 rolled with the rolling roll 1 for convenience, the lower half of the rolling material 2 is also axisymmetric and the same shape, Rolled with a pair of rolling rolls 1.

この圧延方法による効果を確認するために、角−オーバル(楕円)1パスで、圧延ロール1による圧延を実施し、圧延材2の幅寸法の変動量を確認した。尚、角、オーバルとは、夫々の圧延ロール1の表面に形成された孔型のことで、断面形状を示す。   In order to confirm the effect of this rolling method, rolling by the rolling roll 1 was performed in one pass of an angle-oval (ellipse), and the amount of variation in the width dimension of the rolled material 2 was confirmed. In addition, a corner | angular and an oval are the hole types formed in the surface of each rolling roll 1, and show a cross-sectional shape.

まず、予備実験を行い、圧延材2の定常域、非定常域での、幅寸法の変動を確認した。この予備実験の実験条件を図4に、実験結果を図5に示す。尚、図4に示す右の縦断面図は、圧延ロール1の要部拡大縦断面図でありオーバル孔型を示す。図5に示す縦軸は圧延材2の幅寸法を、横軸は供給する潤滑剤3の濃度を示す。○は圧延材2の中間部、即ち定常域の測定値であり、●は圧延材2の尾端部、即ち非定常域の測定値である。この実験では、潤滑剤3は一般的な熱間圧延用の噴射式の液体潤滑剤を用いたが、グリースのような圧延ロール1に塗布する固形潤滑剤を用いることもできる。何れにしても高温下で使用するため、1パスでの圧延後には、揮発してしまったり、燃え尽きてしまったりする。尚、この実験では1パスのみの圧延であったが、次パスでも圧延を行い潤滑剤を使用する場合には次パスで再度潤滑剤3を供給することとなる。   First, a preliminary experiment was performed, and the fluctuation of the width dimension in the steady region and the unsteady region of the rolled material 2 was confirmed. The experimental conditions of this preliminary experiment are shown in FIG. 4, and the experimental results are shown in FIG. The right vertical sectional view shown in FIG. 4 is an enlarged vertical sectional view of a main part of the rolling roll 1 and shows an oval hole type. The vertical axis shown in FIG. 5 indicates the width dimension of the rolled material 2, and the horizontal axis indicates the concentration of the lubricant 3 to be supplied. ○ is the measured value of the middle part of the rolled material 2, that is, the steady region, and ● is the measured value of the tail end of the rolled material 2, ie, the unsteady region. In this experiment, a general hot-rolling jet type liquid lubricant was used as the lubricant 3, but a solid lubricant applied to the rolling roll 1 such as grease can also be used. In any case, since it is used at a high temperature, it will volatilize or burn out after rolling in one pass. In this experiment, rolling was performed only for one pass. However, when rolling is performed in the next pass and the lubricant is used, the lubricant 3 is supplied again in the next pass.

図5より、潤滑剤3の濃度(質量%)が高くなるほど、圧延材2の幅寸法は広がらず小さくなることが確認できた。また、潤滑剤3の濃度(質量%)が同じ条件では、非定常域の幅寸法は、定常域の幅寸法より大きくなることも確認できた。定常域に潤滑剤3を供給しない(無潤滑)場合の圧延後の定常域の幅寸法は26.0mmであるが、非定常域の幅寸法を、定常域の幅寸法と同一の26.0mmとするためには、潤滑剤3の濃度を0.05質量%にすれば良いことが図5から分かる。   From FIG. 5, it was confirmed that as the concentration (mass%) of the lubricant 3 increases, the width dimension of the rolled material 2 does not increase but decreases. It was also confirmed that the width dimension of the unsteady region was larger than the width dimension of the steady region under the same concentration (mass%) of the lubricant 3. When the lubricant 3 is not supplied to the steady region (no lubrication), the width of the steady region after rolling is 26.0 mm, but the width of the unsteady region is 26.0 mm which is the same as the width of the steady region. In order to achieve this, it can be seen from FIG. 5 that the concentration of the lubricant 3 should be 0.05 mass%.

従って、本実験では、供給する潤滑剤3の濃度を0.05質量%に固定し、圧延材2の全長に亘って潤滑剤3を供給しなかった場合(△で示す)、圧延材2の全長に亘って潤滑剤3を供給した場合(○で示す)、圧延材2の尾端部のみに潤滑剤3を供給した場合(●で示す)の3条件で実験を行い、夫々圧延後の幅寸法の変化を測定した。その測定結果を図6に示す。この図6の横軸は圧延材2の尾端部の端縁からの長さ(単位:mm)、縦軸は圧延材2の幅寸法(単位:mm)を夫々示す。尚、尾端部のみ潤滑剤3を供給する場合は、実験での圧延途中のサンプルから投射接触長を求め出し、その投射接触長(30mm)分に潤滑剤3を供給した。この投射接触長とは、投影接触長とも呼ばれ、圧延時に圧延ロール1が圧延材2に接触している範囲(接触弧)をX軸(圧延方向の軸)に投影した長さのことを示す。   Therefore, in this experiment, when the concentration of the lubricant 3 to be supplied is fixed to 0.05% by mass and the lubricant 3 is not supplied over the entire length of the rolled material 2 (indicated by Δ), When the lubricant 3 was supplied over the entire length (indicated by a circle), and the lubricant 3 was supplied only to the tail end of the rolled material 2 (indicated by a circle), the experiment was performed, The change in width dimension was measured. The measurement results are shown in FIG. The horizontal axis of this FIG. 6 shows the length (unit: mm) from the edge of the tail end part of the rolled material 2, and the vertical axis shows the width dimension (unit: mm) of the rolled material 2, respectively. In addition, when supplying the lubricant 3 only to the tail end portion, the projected contact length was obtained from a sample during rolling in the experiment, and the lubricant 3 was supplied for the projected contact length (30 mm). The projected contact length is also called a projected contact length, and is a length obtained by projecting a range (contact arc) where the rolling roll 1 is in contact with the rolled material 2 during rolling onto the X axis (axis in the rolling direction). Show.

圧延材2の全長に亘って潤滑剤3を供給しなかった場合(△で示す)と、圧延材2の全長に亘って潤滑剤3を供給した場合(○で示す)を比較すると、潤滑剤3を供給すると、定常域(中間部)、非定常域(尾端部)ともに、圧延材2の幅寸法が減少していることが分かる。これに対し、圧延材2の尾端部のみに潤滑剤3を供給した場合(●で示す)と、圧延材2の全長に亘って潤滑剤3を供給しなかった場合(△で示す)を比較すると、尾端部のみに潤滑剤3を供給した場合は、課題とした非定常域(尾端部)のみの幅寸法が減少し、定常域(中間部)の幅寸法には変化がなく、全長に亘って略同一幅となっていることが分かる。   When the lubricant 3 is not supplied over the entire length of the rolled material 2 (indicated by Δ) and the case where the lubricant 3 is supplied over the entire length of the rolled material 2 (indicated by ○), the lubricant When 3 is supplied, it can be seen that the width dimension of the rolled material 2 decreases in both the steady region (intermediate portion) and the unsteady region (tail end portion). In contrast, when the lubricant 3 is supplied only to the tail end portion of the rolled material 2 (indicated by ●), and when the lubricant 3 is not supplied over the entire length of the rolled material 2 (indicated by Δ). In comparison, when the lubricant 3 is supplied only to the tail end portion, the width dimension of only the unsteady region (tail end portion) as a problem is reduced, and the width dimension of the steady region (intermediate portion) is not changed. It can be seen that the width is substantially the same over the entire length.

以上の実験結果から、潤滑剤3を供給することで、圧延材2の幅寸法を低減させることはできるが、非定常域のみに潤滑剤3を供給することで、圧延後の圧延材2を全長に亘って略同一幅とすることができることが分かった。また、圧延材2の全長に亘って潤滑剤3を供給する場合と比較すると、潤滑剤3を供給する領域は非定常域の長さ分の僅かであるため、潤滑剤3の供給量も大幅に低減することができる。   From the above experimental results, it is possible to reduce the width of the rolled material 2 by supplying the lubricant 3, but by supplying the lubricant 3 only to the unsteady region, the rolled material 2 after rolling can be reduced. It turned out that it can be made into the substantially same width over the full length. Further, compared to the case where the lubricant 3 is supplied over the entire length of the rolled material 2, the supply region of the lubricant 3 is a little as long as the length of the unsteady region. Can be reduced.

実機においては、各圧延スタンドでの投射接触長を事前に求めておき、その投射接触長に相当する領域を、潤滑剤3を供給する領域(長さ)とすることで対応することができる。尚、潤滑剤3を供給する適正な領域は、ロール隙の調整により若干変動すると考えられる。本発明で述べる投射接触長に相当する領域とは、必ずしも投射接触長そのものの長さを示すものではなく、ロール隙により投射接触長の1.0倍から1.3倍の長さの範囲で変動する。実機では、余裕を鑑みて投射接触長の1.1倍から1.3倍の長さの領域としておくことが望ましい。   In an actual machine, the projection contact length in each rolling stand is calculated | required beforehand, and it can respond by making the area | region corresponded to the projection contact length into the area | region (length) which supplies the lubricant 3. FIG. In addition, it is thought that the appropriate area | region which supplies the lubricant 3 changes a little by adjustment of a roll gap. The region corresponding to the projection contact length described in the present invention does not necessarily indicate the length of the projection contact length itself, but is in a range of 1.0 to 1.3 times the projection contact length depending on the roll gap. fluctuate. In an actual machine, it is desirable to set the area as 1.1 to 1.3 times the projection contact length in consideration of the margin.

(実施例1)
この実施例1では、非定常域の幅寸法の増大が、表面疵発生の原因となることの確認と、潤滑剤を供給する必要最低限の圧延スタンド数の確認を、実機実験にて検証した。この実施例1では、SCM435の155mm角の素材(圧延材)を用い、φ5.5mmの線材となるまで、圧延スタンドに設けた圧延ロールで圧延した。圧延スタンドの数は合計32スタンド、線材速度は100m/sである。
Example 1
In Example 1, the increase in the width dimension of the unsteady region was confirmed to cause surface flaws, and the minimum number of rolling stands required to supply the lubricant was verified by actual machine experiments. . In Example 1, a 155 mm square material (rolled material) of SCM435 was used and rolled with a rolling roll provided on a rolling stand until it became a φ5.5 mm wire. The number of rolling stands is 32 in total, and the wire speed is 100 m / s.

各圧延スタンドでの入り側の圧延材の断面積をA0、最終製品(線材)の断面積をA´、各圧延スタンドの投射接触長をLdとすると、以下の式により、各圧延スタンドの入り側での圧延材の断面積と、その対象スタンドまで潤滑剤を供給した場合の最終製品での尾端部の換算長さαの関係を表すことができる。
A0×Ld=A´×α
α=A0/A´×Ld
Assuming that the cross-sectional area of the rolling material on the entry side at each rolling stand is A0, the cross-sectional area of the final product (wire) is A ', and the projected contact length of each rolling stand is Ld, The relationship between the cross-sectional area of the rolled material on the side and the converted length α of the tail end in the final product when the lubricant is supplied to the target stand can be expressed.
A0 × Ld = A ′ × α
α = A0 / A ′ × Ld

今回の実機実験で使用したパススケジュールにおける各圧延スタンド入り側での圧延材の断面積と、その各断面積における最終製品での尾端部の換算長さ(計算値)αとの関係を図7に示す。最終製品での尾端部の換算長さαが8m以下(巻き取ったコイル2巻き分以下)になることを目標とすると、尾端部の幅寸法の増大による影響を回避するためには、1スタンドから8スタンドまで潤滑剤を供給すれば良いことが分かる。(8スタンドでのαは10m程度であり、8スタンドまで潤滑剤を供給すれば、計算上9スタンドでのα=6.85mとなる。)   Figure shows the relationship between the cross-sectional area of the rolled material on each roll stand entry side in the pass schedule used in this actual machine experiment and the converted length (calculated value) α of the tail end of the final product in each cross-sectional area 7 shows. In order to avoid the influence due to the increase in the width of the tail end, if the converted length α of the tail end in the final product is 8 m or less (less than 2 windings of the wound coil), It can be seen that the lubricant may be supplied from 1 stand to 8 stands. ([Alpha] at 8 stands is about 10 m, and if lubricant is supplied up to 8 stands, [alpha] at 9 stands is calculated to be 6.85 m.)

次に、実際この仮説が正しいことを確認するために、表2に示す各条件で実機実験を実施した。各断面積から計算した尾端部の換算長さ(計算値)αと、実機実験で圧延して製造した最終製品で0.01mm深さ以上の表面疵が発生した尾端部の端縁からの長さとの関係を図8に示す。計算値αと実機実験での確認結果は略同等であり、8スタンドまで潤滑剤を供給することで、全く潤滑剤を適用しない場合の最終製品で、その尾端部の端縁からの長さ約60mまでに発生した0.01mm深さ以上の表面疵の発生領域を、目標値の8m以下にまで短縮することが実現できた。   Next, in order to confirm that this hypothesis was actually correct, an actual machine experiment was conducted under each condition shown in Table 2. From the converted length (calculated value) α of the tail end calculated from each cross-sectional area, and from the edge of the tail end where surface flaws of 0.01 mm or more occurred in the final product manufactured by rolling in an actual machine experiment FIG. 8 shows the relationship with the length of. The calculated value α is almost equal to the confirmation result in the actual machine experiment. By supplying the lubricant up to 8 stands, it is the final product when no lubricant is applied, and the length from the edge of the tail end part. It was possible to reduce the generation area of surface flaws having a depth of 0.01 mm or more generated up to about 60 m to a target value of 8 m or less.

従って、複数列配置した圧延スタンドのうち潤滑剤を供給する圧延スタンドは、表面疵が発生した最終製品の尾端部または先端部の端縁からの長さをα´としたときに、α´≧A0/A´×Ldという数式を満足する圧延スタンドであるということができる。   Therefore, the rolling stand that supplies the lubricant among the rolling stands arranged in a plurality of rows, when the length from the tail end portion or the end edge of the end portion of the final product in which surface flaws occur is α ′, It can be said that this is a rolling stand that satisfies the mathematical formula ≧ A0 / A ′ × Ld.

尚、図8によると、上流スタンド(A〜D)で、実機実験での確認結果が計算値αより多少短くなる傾向となっているが、これは、上流スタンドになるほど下流スタンドの数が多くなるため、以後の圧延スタンドでの圧延によって材料が延伸し、表面疵の深さが浅くなること、およびスケールオフの影響があると考えられる。   According to FIG. 8, the confirmation result in the actual machine experiment tends to be slightly shorter than the calculated value α in the upstream stands (A to D), but this is because the number of downstream stands increases as the number of upstream stands increases. Therefore, it is considered that the material is stretched by rolling at a subsequent rolling stand, the depth of the surface defects is reduced, and there is an influence of scale-off.

(実施例2)
次に、実施例2では、圧延材の尾端部だけではなく、先端部にも潤滑剤を供給した場合の効果を確認するために実機実験を実施した。この実施例2でも実施例1と同様に、SCM435の155mm角の素材(圧延材)を用い、φ5.5mmの線材となるまで、圧延スタンドに設けた圧延ロールで圧延した。圧延スタンドの数は合計32スタンド、線材速度は100m/sである。
(Example 2)
Next, in Example 2, an actual machine experiment was performed in order to confirm the effect when the lubricant was supplied not only to the tail end portion but also to the tip end portion of the rolled material. In Example 2, similarly to Example 1, a 155 mm square material (rolled material) of SCM435 was used and rolled with a rolling roll provided on a rolling stand until it became a φ5.5 mm wire. The number of rolling stands is 32 in total, and the wire speed is 100 m / s.

また、この実機実験では、圧延材の全長に亘り無潤滑の場合(比較例)、圧延材の尾端部のみに潤滑剤を供給した場合(発明例1)、圧延材の尾端部と先端部に潤滑剤を供給した場合(発明例2)の3条件で実験を行った。尚、3条件とも潤滑剤を供給した圧延スタンドは、実施例1の実験結果に基づき1スタンドから8スタンドまでとした。   Further, in this actual machine experiment, when the lubricant was not lubricated over the entire length of the rolled material (comparative example), when the lubricant was supplied only to the tail end portion of the rolled material (Invention example 1), the tail end portion and the tip end of the rolled material The experiment was conducted under three conditions when the lubricant was supplied to the part (Invention Example 2). Based on the experimental results of Example 1, the number of rolling stands to which the lubricant was supplied in all three conditions was from 1 to 8 stands.

表面疵の評価は、材質上等の理由で通常切り捨てられている長さ分(この実験ではコイル2巻き分=実施例1での目標値)を除いた尾端部と先端部のサンプルをN=10採取し、その断面を光学顕微鏡で確認することで評価した。深さ0.01mm以上の表面疵が全く認められないものを◎で合格、深さ0.02mm以上の表面疵が認められないものを○で合格、深さ0.02mm以上の表面疵が1ヶ所でも確認できたものを×で不合格と評価した。その実験による評価結果を表3に示す。尚、深さ0.02mm以上の表面疵がないものを○で合格としたのは、この程度の深さの表面疵であれば、後続の2次加工工程で、その表面疵を起点とした割れなどの加工欠陥が発生することはないからである。   The surface flaws are evaluated by removing samples at the tail end and the tip excluding the length that is usually discarded for reasons such as the material (in this experiment, two turns of the coil = target value in Example 1). = 10 samples were taken and evaluated by checking the cross section with an optical microscope. If no surface defects with a depth of 0.01 mm or more are recognized, pass with ◎, if no surface defects with a depth of 0.02 mm or more are accepted, pass with ○, and surface defects with a depth of 0.02 mm or more are 1 Those that could be confirmed at some locations were evaluated as failing with ×. Table 3 shows the evaluation results of the experiment. In addition, if there was no surface flaw of 0.02 mm or more in depth, it was accepted as “good” if the surface flaw of such a depth was used as the starting point in the subsequent secondary processing step. This is because processing defects such as cracks do not occur.

表3より、比較例では非定常域の評価は、先端部で○、尾端部で×になっているのに対し、尾端部に潤滑剤を供給した発明例1では、尾端部の評価は定常域である中間部と同等の◎となっている。また、尾端部に加え先端部にも潤滑剤を供給した発明例2では、先端部の評価も中間部と同等の◎となっている。以上のように、先端部や尾端部といった非定常域に圧延時に潤滑剤を供給することで、定常域と同様に、深さ0.01mm以上の表面疵の発生をなくすることができることが確認できた。   From Table 3, in the comparative example, the evaluation of the unsteady region is ○ at the tip portion and × at the tail end portion, whereas in Invention Example 1 in which the lubricant is supplied to the tail end portion, the tail end portion is evaluated. The evaluation is ◎ which is equivalent to the middle part which is a steady region. Further, in Invention Example 2 in which the lubricant is supplied to the tip portion in addition to the tail end portion, the evaluation of the tip portion is ◎ equivalent to that of the intermediate portion. As described above, by supplying the lubricant during rolling to the unsteady regions such as the tip and tail, it is possible to eliminate the occurrence of surface defects having a depth of 0.01 mm or more, as in the steady region. It could be confirmed.

本発明の一実施形態を示し、圧延ロールで圧延材の尾端部を圧延する状態を示す側面図である。It is a side view which shows one Embodiment of this invention and shows the state which rolls the tail end part of a rolling material with a rolling roll. 同実施形態を示し、圧延ロールで圧延材の先端部を圧延する状態を示す側面図である。It is a side view which shows the same embodiment and shows the state which rolls the front-end | tip part of a rolling material with a rolling roll. 同実施形態を示し、圧延ロールで圧延材の中間部を圧延する状態を示す側面図である。It is a side view which shows the same embodiment and shows the state which rolls the intermediate part of a rolling material with a rolling roll. (a)は圧延材の定常域、非定常域での幅寸法の変動を確認するための実験条件を示す説明図、(b)はその実験に用いた圧延ロールを示す要部拡大縦断面図である。(A) is explanatory drawing which shows the experimental condition for confirming the fluctuation | variation of the width dimension in the stationary region of a rolling material, and a non-stationary region, (b) is a principal part expanded longitudinal sectional view which shows the rolling roll used for the experiment. It is. 供給する潤滑剤の濃度と、その潤滑剤を供給して圧延した圧延材の幅寸法の関係を示す説明図である。It is explanatory drawing which shows the relationship between the density | concentration of the lubricant to supply, and the width dimension of the rolling material which supplied the lubricant and rolled. 潤滑剤の供給条件を変えて圧延した場合の圧延材の幅寸法の変化を示す説明図である。It is explanatory drawing which shows the change of the width dimension of a rolling material at the time of rolling by changing the supply conditions of a lubricant. 各圧延スタンド入り側での圧延材の断面積と、その各断面積における最終製品での尾端部の換算長さαとの関係を示す説明図である。It is explanatory drawing which shows the relationship between the cross-sectional area of the rolling material in each rolling stand entering side, and the conversion length (alpha) of the tail end part in the final product in each cross-sectional area. 各圧延スタンド入り側での圧延材の断面積から計算した尾端部の換算長さαと、実機実験で圧延して製造した最終製品で0.01mm深さ以上の表面疵が発生した尾端部の端縁からの長さとの関係を示す説明図である。Converted length α of the tail end calculated from the cross-sectional area of the rolled material on the rolling stand entry side, and the tail end where surface flaws of 0.01 mm depth or more occurred in the final product manufactured by rolling in an actual machine experiment It is explanatory drawing which shows the relationship with the length from the edge of a part. 背景技術を示し、圧延ロールで圧延材の尾端部を圧延する状態を示す側面図である。It is a side view which shows a state which shows background art and rolls the tail end part of a rolling material with a rolling roll. 背景技術を示し、圧延ロールで圧延材の先端部を圧延する状態を示す側面図である。It is a side view which shows background art and shows the state which rolls the front-end | tip part of a rolling material with a rolling roll. 背景技術を示し、圧延ロールで圧延材の中間部を圧延する状態を示す側面図である。It is a side view which shows a state which shows background art and rolls the intermediate part of a rolling material with a rolling roll. 圧延ロールで圧延した際の圧延材の先端部の変形挙動を示す1/4モデルの解析結果図である。It is an analysis result figure of the 1/4 model which shows the deformation behavior of the tip part of the rolling material at the time of rolling with a rolling roll. 圧延ロールで圧延した際の圧延材の先端部の変形状態を示し、(a)は平面図、(b)は側面図である。The deformation | transformation state of the front-end | tip part of the rolling material at the time of rolling with a rolling roll is shown, (a) is a top view, (b) is a side view.

符号の説明Explanation of symbols

1…圧延ロール
2…圧延材
3…潤滑剤
DESCRIPTION OF SYMBOLS 1 ... Roll roll 2 ... Rolled material 3 ... Lubricant

Claims (3)

所定の間隔をおいて複数列配置した圧延スタンドの対になった圧延ロールで、圧延材を、複数のパスに分けて順次圧下方向を変えながら圧延することで、その圧延材の断面積を順次減少させて所定の製品寸法に仕上げる条鋼の圧延方法であって、
前記圧延材の尾端部および/または先端部を各パスで圧延する際のみに、潤滑剤を、前記圧延ロールの表面と前記圧延材の表面の間に供給し、前記圧延材の尾端部および/または先端部を圧延することを特徴とする条鋼の圧延方法。
By rolling the rolled material into a plurality of passes and sequentially rolling the rolling material while changing the rolling direction with a rolling roll that is a pair of rolling stands arranged in a plurality of rows at predetermined intervals, the cross-sectional area of the rolled material is sequentially changed. A method of rolling a strip that reduces to finish to a predetermined product dimension,
Only when rolling the tail end and / or tip of the rolled material in each pass, a lubricant is supplied between the surface of the rolling roll and the surface of the rolled material, and the tail end of the rolled material. And / or the rolling method of the bar steel characterized by rolling a front-end | tip part.
前記潤滑剤を供給する領域は、各パスでの投射接触長に相当する領域であることを特徴とする請求項1記載の条鋼の圧延方法。   2. The method for rolling steel bars according to claim 1, wherein the region to which the lubricant is supplied is a region corresponding to a projected contact length in each pass. 表面疵が発生した最終製品の尾端部および/または先端部の端縁からの長さをα´としたとき、
複数列配置した前記圧延スタンドのうち、前記潤滑剤を供給する圧延スタンドは、下記の式を満足する各圧延スタンドであることを特徴とする請求項1または2記載の条鋼の圧延方法。
α´≧A0/A´×Ld
上式で、A0は該当圧延スタンドの入り側の圧延材の断面積、A´は最終製品(条鋼)の断面積、Ldは該当圧延スタンドの投射接触長である。
When the length from the tail edge and / or the edge of the tip of the final product where surface flaws occur is α ′,
The rolling method according to claim 1 or 2, wherein among the rolling stands arranged in a plurality of rows, the rolling stand that supplies the lubricant is each rolling stand that satisfies the following formula.
α ′ ≧ A0 / A ′ × Ld
In the above equation, A0 is the cross-sectional area of the rolled material on the entry side of the rolling stand, A ′ is the cross-sectional area of the final product (steel bar), and Ld is the projected contact length of the rolling stand.
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