JP4113662B2 - How to control the number of rotations to minimize internal angularity - Google Patents
How to control the number of rotations to minimize internal angularity Download PDFInfo
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- JP4113662B2 JP4113662B2 JP2000253587A JP2000253587A JP4113662B2 JP 4113662 B2 JP4113662 B2 JP 4113662B2 JP 2000253587 A JP2000253587 A JP 2000253587A JP 2000253587 A JP2000253587 A JP 2000253587A JP 4113662 B2 JP4113662 B2 JP 4113662B2
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
- B21B37/78—Control of tube rolling
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B17/00—Tube-rolling by rollers of which the axes are arranged essentially perpendicular to the axis of the work, e.g. "axial" tube-rolling
- B21B17/14—Tube-rolling by rollers of which the axes are arranged essentially perpendicular to the axis of the work, e.g. "axial" tube-rolling without mandrel, e.g. stretch-reducing mills
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Abstract
Description
【０００１】
【発明の属する技術分野】
本発明は、ストレッチレデューサ列の後方で管肉厚を測定するための装置と測定値を処理するための計算装置と駆動電動機の回転数を制御するための装置とを用いて、多スタンド連続ストレッチレデューサ列内で管肉厚を制御する方法に関する。
【０００２】
【従来の技術】
継目無溶接鋼管を製造するとき、僅かな素製品（Vorprodukt）寸法から直径及び肉厚の異なる多数の仕上げ管寸法をごく柔軟な方法で生成するために、いわゆる絞り圧延がしばしば利用される。内部工具なしに間に合うこの方法の利点は肉厚と直径を迅速安価に変化させることにある。
【０００３】
絞り圧延のとき管の塑性加工は連続して配置される多数のスタンド内で行われ、その際、個々のスタンド内で回転数を変えることによってスタンドの間に相互作用が生成され、こうして完成管の肉厚が適切に調整される。ストレッチレデューサ列（ＳＲＷ：Streckreduzierwalzstrasse）内での塑性加工は今日一般に３ロールスタンド内で行われる。管の直径を低減するとき圧延材がロールの間の間隙に入り、その結果として表面マーク疵が現れることのないように、ロールの孔型（カリバ）は円形ではなく、（３ロールスタンドでは３面が）楕円形に設計される。孔型のこの３面形状は基本的に不可避である。使用されるスタンド列の最終スタンドのみは一般に円形に設計される。これが可能であるのは、このスタンド内での直径変化が小さいからである。そのことが必要であるのは、仕上げ圧延された管が十二分に円形でなければならないからである。
【０００４】
孔型の「楕円度」は、直径低減、管の肉厚等に基づいて最適に調整されねばならない。楕円度が過度に小さく選定されると、外面にマーク疵や損傷を生じることになる。楕円度が過度に大きく選定されると、絞り圧延管の横断面に著しい肉厚不均一が生じる。これらの肉厚不均一は（３ロールスタンドの場合）六角形形状を有し、内面角張り（Innenpolygon）と称される。あらゆる偏肉と同様に、内面角張りも品質低下を意味する。内面角張りは特に肉厚に、又は一層適切には肉厚と管直径との比に、依存しているので、大きな肉厚範囲を生成するために一般にロール孔型のさまざまな規格化（Kalibrierungen）、即ちロール孔型規格のさまざまな楕円度が必要となる。ロールスタンドの保管はかなりの支出を意味するので、一般に僅か２種類の規格、つまり厚肉管用の孔型開口の楕円度が小さい円形規格と薄肉管用の孔型開口の楕円度が大きい楕円形規格、が使用される。その他、塑性加工時に圧延材中の平均引張応力又は「張力」を最適に調整することによって、六角形角張りを小さく抑えることが試みられる。
【０００５】
特定の内面角張り率を選択すると、張力に依存して角張り率が直線的に変化することが実験によって確認される。張力を変更するために母管（Vorrohr）の肉厚が変更される。曲線の勾配と位置は多くの影響量（管の肉厚と直径との比、孔型形状、ロール直径、温度、素材…）に依存しているので、圧延スケジュール全体について張力最適化を実行するために大きな実験費用が必要となる。この最適化を大きな努力を払って実行した場合、それにもかかわらず、影響量の実際の変化は不可避であるので、内面角張りの少ない管が常に得られるわけではない。この状況において、鋼塊肉厚を変更することによって内面角張りを低減することをやはり試みることができる。しかしこれは、前段に設けられる塑性加工段階の管圧延法に応じて、時間損失や支出なくしては可能でない。結局、多くの管製造業者は内面角張りに基づく品質低下のこの問題と対決し、製品品質向上のためにかなりの支出を費やすか、又は低い製品品質を甘受することになる。
【０００６】
管の横断面に現れて管の長さにわたってほぼ一定した偏肉の他に、管の長さにわたって現れる偏肉がある。圧延材の長さにわたるこれらの偏肉を補正する回転数制御方法及びその装置は確かに存在するが、しかし内面角張りを低減するための回転数制御方法は存在しない。上記張力最適化のためには鋼塊肉厚を適切に変更する必要がある。しかし鋼塊肉厚は、ストレッチレデューサ列とは独自に作動する他の圧延装置内で生成されるので、制御回路の制御要素ではあり得ない。先行技術によれば、塑性加工条件が実際に変化するので内面角張りは甘受されねばならず、生産の前段で最適化を行うためにかなりの支出を費やさねばならない。
【０００７】
【発明が解決しようとする課題】
本発明の課題は、ロールの回転数制御を利用して継目無管の絞り圧延時に内面角張りを最小にする方法を提供することである。
【０００８】
【課題を解決するための手段】
この課題を解決するために、本発明によれば、管通過中に駆動電動機の回転数を計算機で制御しながら変更することによって総伸び率を一定に保ち、これにより内面角張りを最小に低減することが提案される。
【０００９】
本発明による方法は、冒頭に述べた先行技術の問題を、生産工程中、制御回路と張力パラメータの変更とによって内面角張りの低減を実行することによって解決する。張力パラメータは回転数系列の変更を定義し、それに伴い、圧延装置内での総伸び率が影響を受けないままとなるように圧延装置内の張力分布を定義する。張力分布パラメータと内面角張りとの間には明確な関連性が存在するので、母管の肉厚に影響を及ぼすことなく内面角張りを自動的に低減することに成功する。
【００１０】
張力パラメータの変更時に回転数比が１ロールスタンド群内で高められ、同時に他のロールスタンド群内では減らされ、こうして管の伸び率が全体として一定に留まるように、張力パラメータは定義される。その際、ストレッチレデューサ列のスタンド列の内部で内面角張りに影響する量が一般にきわめてさまざまであることが利用される。ストレッチレデューサ列の入側領域を出側領域と比較すると、ここでは
−管肉厚と管直径との比が一層小さく、
−管直径とロール直径との比が一層大きく、
−温度が一層高く、
−孔型楕円度が一層大きい
ことが確認される。更に、例えば、調整可能な回転数曲線の確定された特性のようなストレッチレデューサ列の構造様式の影響が加わる。
【００１１】
張力の変更は、内面角張りに関して、それがストレッチレデューサ列の入側領域で起きるのかそれとも出側領域で起きるのかに応じて、異なる効果を有する。従って、張力パラメータに対する内面角張りの依存関係が生じる。こうして、内面角張りを低減するための制御過程の前提条件が与えられている。
【００１２】
考えられる制御回路は以下の如くである。管通過中、ストレッチレデューサ列から進出する管の角張り率が測定技術的に（例えばＵＳ肉厚測定によって）検出され、張力パラメータを変更して角張り率の依存関係が求められ、内面角張りが最小となるようにパラメータが調整される。
【００１３】
例えば、ストレッチレデューサ列内で平均張力が一定に留まるように、圧延スケジュールの各寸法について回転数変更が既に工程計画時に定義されることによって、伸び率の恒常性は確保される。また、生産操業中、そのために適応計算法を利用することができる。
【００１４】
【発明の実施の形態】
図１〜図４に基づいて本発明を説明する。
図１は内面角張りの構成と角張り率Ｐの計算とを示す。ここにｓaはロールの孔型底部領域における管の肉厚、ｓbは孔型側面の中心領域における肉厚を表す。管内輪郭の六角形対称構成に基づいて、ほぼ同一変形の管横断面領域ｓa、ｓbがそれぞれ６ヶ所に見られる。これらの箇所で測定した肉厚値は図１に示すようにして求められる。角張り率Ｐは、肉厚の一層小さい個所が孔型底部にある場合正値、肉厚の一層小さい個所が孔型側面の中心にある場合には負値である。
【００１５】
図２は、張力に対する角張り率の依存関係を示す。角張り率は張力が大きくなるのに伴って直線的に増加する。角張り率は張力値が小さい場合負、張力値が大きい場合正である。角張り率がゼロに等しいときの張力値が“最適張力”と称される。
【００１６】
図３は、ストレッチレデューサ列内で総伸び率が一定に留まる張力分布の可能な変更を示す。張力曲線ＺＰ1では、ストレッチレデューサ列の入側領域における張力が、従って圧延材の伸び率が、出側領域におけるよりも高くなる。張力分布ＺＰ2では、張力と伸び率がスタンド設置箇所にわたってほぼ均一に分布している。ＺＰ3では、入側スタンド内の張力と伸び率が出側スタンド内よりも小さい。
【００１７】
張力パラメータＺＰに対する角張り率の依存関係が図４に示してある。この例では張力パラメータの上昇に伴って角張り率が直線的に増加している。ＺＰ1、ＺＰ2、ＺＰ3は、無段調整可能な張力変更の具体的状態である。圧延操業中に求められる張力パラメータに対する角張り率の依存関係から、角張り率がゼロに等しくなる張力パラメータ値が算定される。
【図面の簡単な説明】
【図１】内面角張りの構成と角張り率Ｐの計算とを示す。
【図２】張力に対する角張り率の依存関係を示す。
【図３】ストレッチレデューサ列内で総伸び率が一定に留まる張力分布の可能な変更を示す。
【図４】張力パラメータＺＰに対する角張り率の依存関係を示す。
【符号の説明】
ｓa ロールの孔型底部領域における管の肉厚
ｓam ｓaの平均値
ｓb 孔型側面の中心領域における管の肉厚
ｓbm ｓaの平均値
Ｐ 角張り率[0001]
BACKGROUND OF THE INVENTION
The present invention provides a multi-stand continuous stretch using a device for measuring tube wall thickness behind a stretch reducer row, a computing device for processing the measured values, and a device for controlling the rotational speed of a drive motor. The present invention relates to a method for controlling pipe wall thickness in a reducer row.
[0002]
[Prior art]
When producing seamless welded steel pipes, so-called drawn rolling is often used to produce a large number of finished pipe dimensions with different diameters and wall thicknesses from a few Vorprodukt dimensions in a very flexible manner. The advantage of this method in time without internal tools is that the wall thickness and diameter can be changed quickly and inexpensively.
[0003]
In the case of drawing rolling, the plastic processing of the pipe is carried out in a number of stands arranged in succession, in which case an interaction is generated between the stands by changing the number of revolutions in the individual stands, thus completing the finished pipe. The wall thickness is adjusted appropriately. Plastic working in a stretch reducer train (SRW) is generally performed in a three-roll stand today. The roll hole shape (cariba) is not circular so that the rolled material does not enter the gap between the rolls when reducing the diameter of the tube, and as a result surface marks are visible (3 for a 3 roll stand). The surface is designed to be oval. This three-surface shape of the hole type is basically inevitable. Only the last stand of the stand row used is generally designed in a circular shape. This is possible because the change in diameter within this stand is small. This is necessary because the finished rolled tube must be sufficiently round.
[0004]
The "ellipsity" of the hole type must be optimally adjusted based on diameter reduction, tube wall thickness, etc. If the ellipticity is selected to be too small, mark defects or damage will occur on the outer surface. If the ellipticity is selected to be excessively large, a noticeable thickness non-uniformity occurs in the cross section of the drawn rolled tube. These non-uniform thicknesses (in the case of a three roll stand) have a hexagonal shape and are referred to as Innerpolygon. Like all uneven thicknesses, internal angulation also means quality degradation. The internal angulation depends in particular on the wall thickness, or more appropriately on the ratio of wall thickness to tube diameter, so in order to produce a large wall thickness range, various standardizations of the roll hole type (Kalibrierungen) ), That is, various ellipticities of the roll hole type standard are required. Since storing roll stands means considerable expenditure, there are generally only two types of standards: a circular standard with a small ellipticity for a thick-walled hole opening and an elliptical standard with a large ellipticity for a thin-walled hole opening. , Is used. In addition, it is attempted to keep hexagonal squareness small by optimally adjusting the average tensile stress or “tension” in the rolled material during plastic working.
[0005]
When a specific inner surface angularity is selected, it is experimentally confirmed that the angularity changes linearly depending on the tension. In order to change the tension, the wall thickness of the mother pipe (Vorrohr) is changed. Since the slope and position of the curve depend on many influences (ratio of tube wall thickness to diameter, hole shape, roll diameter, temperature, material ...), perform tension optimization for the entire rolling schedule Therefore, a large experiment cost is required. If this optimization is carried out with great effort, nevertheless pipes with less internal angulation are not always obtained, since the actual change of the influence quantity is inevitable. In this situation, it is still possible to try to reduce the internal angularity by changing the thickness of the steel ingot. However, this is not possible without time loss and expenditure depending on the tube rolling method in the plastic working stage provided in the preceding stage. Eventually, many pipe manufacturers will confront this problem of quality degradation due to internal cornering and will either spend a considerable amount of money to improve product quality or accept lower product quality.
[0006]
In addition to the uneven thickness appearing in the cross section of the tube and almost constant over the length of the tube, there is also an uneven thickness appearing over the length of the tube. There is certainly a rotational speed control method and apparatus for correcting these uneven thicknesses over the length of the rolled material, but there is no rotational speed control method for reducing internal angularity. In order to optimize the tension, it is necessary to appropriately change the thickness of the steel ingot. However, the steel ingot wall thickness cannot be a control element of the control circuit because it is generated in another rolling apparatus that operates independently of the stretch reducer train. According to the prior art, the internal cornering must be accepted because the plastic working conditions actually change, and considerable expenditures must be spent on optimization prior to production.
[0007]
[Problems to be solved by the invention]
It is an object of the present invention to provide a method for minimizing internal surface angularity during seamless pipe drawing using roll speed control.
[0008]
[Means for Solving the Problems]
In order to solve this problem, according to the present invention, the total elongation is kept constant by changing the rotational speed of the drive motor while passing through the pipe by a computer, thereby reducing the internal angularity to a minimum. Proposed to do.
[0009]
The method according to the invention solves the problems of the prior art mentioned at the outset by performing a reduction in internal angulation during the production process by changing the control circuit and tension parameters. The tension parameter defines the change in the rotational speed series, and accordingly, the tension distribution in the rolling mill is defined so that the total elongation in the rolling mill remains unaffected. Since there is a clear relationship between the tension distribution parameter and the internal angularity, the internal angularity is successfully reduced without affecting the wall thickness of the mother pipe.
[0010]
The tension parameter is defined so that when the tension parameter is changed, the speed ratio is increased in one roll stand group and simultaneously reduced in the other roll stand group, so that the overall elongation of the tube remains constant. In that case, it is generally used that the amount of influence on the internal angularity within the stand row of the stretch reducer row is quite varied. Comparing the entry side region of the stretch reducer row with the exit region, here-the ratio of tube wall thickness to tube diameter is even smaller,
-The ratio of tube diameter to roll diameter is greater,
-The temperature is higher,
-It is confirmed that the hole ellipticity is even greater. Furthermore, the influence of the structure of the stretch reducer row is added, for example, the established characteristics of the adjustable speed curve.
[0011]
The change in tension has a different effect on the internal angulation, depending on whether it occurs in the entry or exit region of the stretch reducer array. Therefore, the dependency of the inner surface angularity on the tension parameter occurs. Thus, the preconditions of the control process for reducing the internal angularity are given.
[0012]
Possible control circuits are as follows. During the passage of the tube, the angularity of the tube advancing from the stretch reducer row is detected in terms of measurement technology (for example, by measuring the US wall thickness), the dependency of the angularity is obtained by changing the tension parameter, The parameter is adjusted so that is minimized.
[0013]
For example, the constancy of the elongation rate is ensured by the fact that the rotational speed change is already defined at the time of the process planning for each dimension of the rolling schedule so that the average tension remains constant in the stretch reducer train. Also, during production operations, an adaptive calculation method can be used for that purpose.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described with reference to FIGS.
FIG. 1 shows the configuration of the internal angularity and the calculation of the angularity P. Here s a wall thickness of the pipe in the hole-type bottom region of the roll, s b represents a thickness in the central region of the grooved side. Based on the hexagonal symmetric configuration of the inner pipe contour, pipe cross-sectional areas s a and s b having almost the same deformation can be seen at six locations. The wall thickness values measured at these locations are determined as shown in FIG. The squareness ratio P is a positive value when a portion having a smaller thickness is at the bottom of the hole mold, and a negative value when a portion having a smaller thickness is at the center of the hole side surface.
[0015]
FIG. 2 shows the dependence of the angularity on the tension. The squareness rate increases linearly as the tension increases. The squareness rate is negative when the tension value is small and positive when the tension value is large. The tension value when the angularity is equal to zero is referred to as “optimum tension”.
[0016]
FIG. 3 shows a possible modification of the tension distribution where the total elongation remains constant within the stretch reducer train. In the tension curve ZP 1 , the tension in the entry side region of the stretch reducer array, and hence the elongation of the rolled material, is higher than in the exit region. In the tension distribution ZP 2 , the tension and the elongation rate are almost uniformly distributed over the stand installation location. In ZP 3, less than the tension and the growth rate is in the exit side stand of the entry side in the stand.
[0017]
The dependence of the angularity on the tension parameter ZP is shown in FIG. In this example, the angularity increases linearly as the tension parameter increases. ZP 1 , ZP 2 , and ZP 3 are specific states of tension change that can be continuously adjusted. From the dependence of the angularity on the tension parameter required during the rolling operation, the tension parameter value at which the angularity becomes equal to zero is calculated.
[Brief description of the drawings]
FIG. 1 shows the configuration of the inner surface angularity and the calculation of the angularity ratio P.
FIG. 2 shows the dependence of the angularity on the tension.
FIG. 3 shows a possible modification of the tension distribution where the total elongation remains constant within the stretch reducer train.
FIG. 4 shows the dependence of the angularity on the tension parameter ZP.
[Explanation of symbols]
Mean value P Kakubari rate of s a roll caliber bottom average value of the thickness s am s a tube in the area s b thickness of the pipe in the central region of the grooved side s bm s a
Claims (3)
管通過中、前記ストレッチレデューサ列から進出する管の角張り率が前記肉厚に基づいて検出され、
前記管の張力分布を定義する張力パラメータを変更して、この張力パラメータに対する前記角張り率の依存関係が求められ、
前記依存間関係に基づいて、内面角張りが最小となるように前記張力パラメータを調整し、
前記張力パラメータの調整は、管通過中、前記各駆動電動機の回転数を計算機で制御しながら変更することによって実施され、
前記各駆動電動機の回転数は、管の伸び率を全体として一定に留めるべく、回転数比が１ロールスタンド群内で高められ、同時に他のロールスタンド群内では減らされるように変更され、
これにより内面角張りが最小に低減されることを特徴とする管肉厚制御方法。Using a device for measuring the tube wall thickness at the rear of the stretch reducer train, the calculation device for processing the measured values, and a device for controlling the rotational speed of the drive motor of each stand, multi-stand continuous In the method of controlling the tube thickness in the stretch reducer row,
During the passage of the tube, the angularity of the tube advancing from the stretch reducer row is detected based on the wall thickness,
By changing the tension parameter defining the tension distribution of the tube, the dependence of the angularity on the tension parameter is determined,
Based on the interdependence relationship, adjust the tension parameter so that the internal angularity is minimized,
The adjustment of the tension parameter is performed by changing the number of rotations of each drive motor while controlling with a computer while passing through the pipe,
The rotational speed of each of the drive motors is changed so that the rotational speed ratio is increased in one roll stand group and simultaneously reduced in other roll stand groups in order to keep the elongation rate of the tube constant as a whole.
As a result , the tube thickness control method is characterized in that the internal surface angularity is reduced to a minimum .
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19941163A DE19941163A1 (en) | 1999-08-24 | 1999-08-24 | Speed control method to minimize internal polygon formation |
| DE19941163:8 | 1999-08-24 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2001071012A JP2001071012A (en) | 2001-03-21 |
| JP4113662B2 true JP4113662B2 (en) | 2008-07-09 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000253587A Expired - Lifetime JP4113662B2 (en) | 1999-08-24 | 2000-08-24 | How to control the number of rotations to minimize internal angularity |
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| Country | Link |
|---|---|
| EP (1) | EP1078700B1 (en) |
| JP (1) | JP4113662B2 (en) |
| AT (1) | ATE306993T1 (en) |
| CZ (1) | CZ298954B6 (en) |
| DE (2) | DE19941163A1 (en) |
| ES (1) | ES2249229T3 (en) |
| RU (1) | RU2247615C2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008096864A1 (en) | 2007-02-08 | 2008-08-14 | Sumitomo Metal Industries, Ltd. | Reducer pass roll and reducer |
| RU2564194C2 (en) * | 2013-07-04 | 2015-09-27 | Открытое акционерное общество "Синарский трубный завод" (ОАО "СинТЗ") | Hot-rolled tube manufacturing method |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58167003A (en) * | 1982-03-27 | 1983-10-03 | Sumitomo Metal Ind Ltd | Device for preventing thickness deviation of reducing mill |
| JPS61216811A (en) * | 1985-03-22 | 1986-09-26 | Nippon Kokan Kk <Nkk> | Multi-stand continuous drawing and rolling method for metallic pipe |
| JPS62192210A (en) * | 1986-02-17 | 1987-08-22 | Kawasaki Steel Corp | Method for controlling tube wall thickness for reducing mill |
-
1999
- 1999-08-24 DE DE19941163A patent/DE19941163A1/en not_active Withdrawn
-
2000
- 2000-08-09 EP EP00250266A patent/EP1078700B1/en not_active Expired - Lifetime
- 2000-08-09 AT AT00250266T patent/ATE306993T1/en active
- 2000-08-09 ES ES00250266T patent/ES2249229T3/en not_active Expired - Lifetime
- 2000-08-09 DE DE50011358T patent/DE50011358D1/en not_active Expired - Lifetime
- 2000-08-23 RU RU2000122303/02A patent/RU2247615C2/en active
- 2000-08-24 JP JP2000253587A patent/JP4113662B2/en not_active Expired - Lifetime
- 2000-08-24 CZ CZ20003105A patent/CZ298954B6/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| CZ298954B6 (en) | 2008-03-19 |
| CZ20003105A3 (en) | 2001-07-11 |
| ATE306993T1 (en) | 2005-11-15 |
| EP1078700A2 (en) | 2001-02-28 |
| ES2249229T3 (en) | 2006-04-01 |
| EP1078700B1 (en) | 2005-10-19 |
| DE50011358D1 (en) | 2005-11-24 |
| EP1078700A3 (en) | 2003-09-24 |
| DE19941163A1 (en) | 2001-03-01 |
| JP2001071012A (en) | 2001-03-21 |
| RU2247615C2 (en) | 2005-03-10 |
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