JPS6174719A - Method and equipment for rolling mandrel mill - Google Patents

Abstract

PURPOSE:To obtain the taper quantity as per the target at the pipe tip rear end in a extension stage and elevating the yield of a finished goods with eliminating the off-gage part of the finished goods in a drawing stage. CONSTITUTION:A rolling load is detected by a load detector 13 and with feeding the signal thereof to a co-efficient computing element 14 the elongation of the mill is found by dividing the rolling load by the mill constant and the signal thereof is fed to a computing element 15, by which the quantity reducing the roll gap is found with adding said elongation to the rolling reduction set value by the computing element 15. The command signal of the computing element 15 is comparatively operated with the output signal of a displacement detector 7 by a comparison calculator 16 and according to the signal thereof a servo valve 10 is driven. The roll gap is then controlled with regulating the quantity of press oil fed to the hydraulic cylinder 5 moving the roll 4 vertically. With said method the elongation of the mill is offset by reducing the roll gap and the taper quantity as per the target is obtd. and with making a uniform thickness from the tip to the rear end of the finished goods of after passing the drawing stage the steel pipe without any off-gage part is obtd.

Description

【発明の詳細な説明】 ［産業上の利用分野１ 本発明は、ｕＡ管の良ｆ／Ｊ向肉厚分布を均一化するた
めに、管端の肉厚を一様に薄肉化することのできるマン
ドレルミルの圧延方法及びその装置に関する乙のＣ゛あ
る９゜ ［従来の技術］ 継目無し鋼管の製ｉ？ｉｉｊ、法どじては多数の方法が
開発され実用に供されているが、その製造工程を大別す
れば、中゛や木管を製造する穿孔工程と、素管を減肉し
Ｃｉ仲する延伸圧延工程と、外径を所定の寸法に１１ヒ
げる絞り工程の３つに大別することかで３！゛る。Detailed Description of the Invention [Industrial Application Field 1] The present invention is directed to uniformly thinning the wall thickness at the end of a uA tube in order to make the wall thickness distribution in the good f/J direction uniform. Part 9 regarding the rolling method and equipment of a mandrel mill that can be used [Prior art] Production of seamless steel pipes i? A large number of methods have been developed and put to practical use, but the manufacturing process can be roughly divided into the drilling process to produce the core or wood pipe, and the drawing process to reduce the thickness of the raw pipe and create a Ci. It can be roughly divided into three steps: rolling process and drawing process to reduce the outer diameter to a predetermined size. It's true.

斯かる諸工程のうら、較り工程では、ストレッチレゾ１
−ナーで管の外径を絞って仕上り管を製造するが、その
際、管がストレッチレデユーリ“−の全スタンドに噛込
まれている定常状態に比較して噴込み■、１や尻１ルは
時のように管が全スタンドに噛込まれていない過渡状態
では、管に作用する引張ノ〕が減少し、圧延後の管の先
後端は箸しく厚肉化り゛る。而して、最終成品では、こ
の”部分はオフゲージ−となって切捨てられるため、こ
の両端クロップの長さは歩留り低下を眉来−していた。Behind these various processes, in the comparison process, stretch reso 1
- A finished tube is manufactured by reducing the outer diameter of the tube with a spray gun, but at that time, compared to the steady state in which the tube is bitten by all the stands of the stretch reduuri, there are In a transient state like when the tube is not engaged with all the stands, the tensile force acting on the tube decreases, and the front and rear ends of the tube after rolling become significantly thicker. In the final product, this portion becomes off-gauge and is cut off, so the length of the crops at both ends causes a decrease in yield.

そこで、斯かる不具合を解浦するため、例えば特公昭５
１−４３８２５号公報等に示されているように、延伸圧
延工程において２０一ル式マンドレルミルで両管端を薄
肉に仕上げる油圧圧下制御方法が提案されているが、該
方法ではマンドレルミルのスプリングバックにより両管
端に所定のテーパー吊を得られないという欠点があった
。Therefore, in order to solve this problem, for example,
As shown in Publication No. 1-43825, etc., a hydraulic reduction control method has been proposed in which both tube ends are finished thin with a 20-type mandrel mill in the elongation rolling process, but in this method, the spring of the mandrel mill There was a drawback that it was not possible to obtain a predetermined tapered suspension at both tube ends due to the bag.

詳述すれば、筒先後端を薄肉化するために、油圧圧下制
御装置の設定値を第５図の曲線工のように初かしても、
実際の管肉厚は曲線■のようにしかならなかった。これ
は、発生する圧延荷重のため、マンドレルミルが撓み、
上下ロール間のギャップが拡大するためである。従って
、予めその分を見込んでギャップを締込む必要があるが
、鋼管の圧延の場合、発生する圧延荷重を精度良く予測
することが難しく、このような方法では′Ｍ度の良いテ
ーパー看は得られながった。To be more specific, in order to thin the rear end of the cylinder tip, even if the setting value of the hydraulic pressure reduction control device is changed to the curve shown in Fig. 5,
The actual pipe wall thickness was only as shown by the curve ■. This is because the mandrel mill is deflected due to the rolling load that occurs.
This is because the gap between the upper and lower rolls increases. Therefore, it is necessary to take into account this amount in advance and tighten the gap, but in the case of rolling steel pipes, it is difficult to accurately predict the rolling load that will occur, and with this method, it is not possible to see a taper with a good M degree. I missed it.

第２図はマンドレルミルを概念的に示す斜視図、第３図
及び第４図はその２０一ル式スタンドにおけるｆ＋ｌ＋
圧シリンダ！）の組込み方を図示し、第３図は第２図の
ロールスタンドＭのＡ矢視図、第４図は第３図の〔１−
ルスタンドＮのＢ矢視図を示したものである。Figure 2 is a perspective view conceptually showing the mandrel mill, Figures 3 and 4 are f+l+ in the 20-inch stand.
Pressure cylinder! ), FIG. 3 is a view of the roll stand M shown in FIG. 2 in the direction of arrow A, and FIG.
This is a view of the stand N as viewed from arrow B.

マンドレルバ−１を挿通した素管２は孔形ロール４から
成る数ｆｉｌ、Ｉのロールスタンドを通って減肉され、
マンドレルミル出側素材３となって次工程へ送られる。The raw pipe 2 inserted through the mandrel bar 1 passes through a roll stand of several fil, I consisting of hole-shaped rolls 4, and is thinned.
The material becomes the mandrel mill exit material 3 and is sent to the next process.

油圧シリンダ５はベアリング６を介して孔形ロール４に
適切な圧下刃を加えるもので、２０−ル式スタンドで管
材の肉厚を減じる場合には、ロール軸の傾きが互に９０
度をなす２組のロールスタンドＭ及びＮを使用して管材
周方向に互に９０度をなす方向の肉厚を夫夫減肉する。The hydraulic cylinder 5 applies an appropriate rolling edge to the hole-shaped roll 4 through a bearing 6. When reducing the wall thickness of a pipe material using a 20-roll stand, the inclination of the roll axes should be 90 degrees to each other.
Using two sets of roll stands M and N that form a 90 degree angle, the wall thickness of the tube material is reduced in the circumferential direction at 90 degrees to each other.

上述の圧延を行う場合には、油圧シリンダ５の変位検出
器７により検出されたピストン５ａの変位量は比較満引
Ｉで圧下設定値９と比較され、偏差がある場合にはサー
ボ弁１０へ指令信号が出力され、圧油がサーボ弁１０を
通って油圧シリンダ５内へ送られ、ギャップが制御され
る。When performing the above-mentioned rolling, the amount of displacement of the piston 5a detected by the displacement detector 7 of the hydraulic cylinder 5 is compared with the rolling reduction set value 9 at the comparison pull-down I, and if there is a deviation, it is sent to the servo valve 10. A command signal is output, pressure oil is sent into the hydraulic cylinder 5 through the servo valve 10, and the gap is controlled.

なお制御装置は各油圧シリンダ５が各々に合訓４台設け
られるか、第３図における左右（すなわら、ドライブサ
イド、ワークサイド）、或いは第４図におＧＪる上下（
すなわち、ワークサイド、ドライブナイト）をベアとし
で合計２台設置される。In addition, the control device is configured such that four hydraulic cylinders 5 are each provided, or the left and right (i.e., drive side, work side) in FIG. 3, or the upper and lower GJ in FIG.
In other words, a total of two machines will be installed, one on the work side and one on the drive night.

斯かる制御において、マンドレルバ−１と上下の孔形ロ
ール４間のギャップをＳｏ、実際に得られる鋼管の肉厚
をｈ、圧延荷重をＰ、マンドレルミルのミル定数＜ｍ械
のバネ常数）をＫとすると、 ｈ＝　Ｓｏ十Ｐ　　　　　　　　　　・・・■に となる。■式で、右辺第２丁口が発生する圧延荷重によ
って生ずるミルの伸び（スプリングバック）による肉厚
増加分で、このままでは第５図の曲線■に示すような肉
厚となり、筒先後端の減肉化による歩留まり向上の効果
は十分に僻られない。なお、■−ル１ニドツブを直接開
度良く検出・Ｙる方法ｔｉｔ熱間圧延の高温で酸化スケ
ールの飛散する厳しい１；境下では実用化は困難である
。In such control, the gap between the mandrel bar 1 and the upper and lower grooved rolls 4 is So, the wall thickness of the actually obtained steel pipe is h, the rolling load is P, and the mill constant of the mandrel mill<m spring constant of the machine). When K, h= So0P...■. In equation (2), this is the increase in wall thickness due to the elongation (springback) of the mill caused by the rolling load generated at the second door on the right side. The effect of improving yield through thinning is not sufficiently achieved. In addition, (2) - A method of directly detecting the nib with a good degree of opening is difficult to put into practical use under harsh conditions where oxide scale is scattered at the high temperatures of hot rolling.

［発明が解決しようとマｉる問題点］ 本発明は、マンドレルミルの圧延荷重による沖び分を補
正することにより、延伸工程で筒先後端に目標通りのテ
ーパー吊を得、その結果、絞り工程でのストレッチレデ
ューサ−で圧延された成品が、先端から後端まで均一な
肉厚の鋼管になるようにし、以て上述の問題点を解決す
べくなしたちのである。[Problems to be Solved by the Invention] The present invention corrects the offset caused by the rolling load of the mandrel mill to obtain the desired taper suspension at the tip and rear end of the tube in the drawing process, and as a result, the drawing The objective is to solve the above-mentioned problems by ensuring that the product rolled by the stretch reducer in the process becomes a steel pipe with a uniform wall thickness from the tip to the rear end.

［問題点を解決づるための手段］ 本発明は、一対の孔形ロールと該孔形ロールを管に対し
て近接、離反させるようにした油圧圧下シリンダと該油
圧圧Ｆシリンダに圧油を送るサーボ弁と、圧延荷車を検
出すると荷重検出器と、該荷重検出器で検出した結果か
らミルの伸び吊を演悼する′４Ａ胃と、ロールギャップ
の圧下設定値を前記伸び吊を塁に補正し前記サーボ弁へ
指令を与える演算器とを設けている。[Means for Solving the Problems] The present invention provides a pair of grooved rolls, a hydraulic press-down cylinder in which the grooved rolls are brought close to and separated from the pipe, and pressure oil is sent to the hydraulic pressure F cylinder. A servo valve, a load detector when a rolling cart is detected, a '4A stomach that performs the stretch suspension of the mill based on the results detected by the load detector, and a roll gap set value that is corrected to the base of the stretch suspension. and a computing unit for giving commands to the servo valve.

［乍　　　　用コ 従って、本発明では、圧延荷重がマンドレルミルのミル
定数で割られてマンドレルミルの伸び申が求められ、該
伸び吊を基に、孔形ロールのロールギャップが変更され
て圧延が（１われる。Therefore, in the present invention, the rolling load is divided by the mill constant of the mandrel mill to obtain the elongation of the mandrel mill, and based on the elongation, the roll gap of the grooved roll is changed to improve the rolling. (1 will be.

［実　施　例１ 以下、本発明の実施例を添イ」図面を参照しつつ説明す
る。[Embodiment 1] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

第１図は本発明の一実施例で、ハウジング１２内に上下
一対の孔形ロール４を図示してない駆φ力装首により駆
動し得るよう配設し、該孔形ロール４の＠部をロールチ
ョック１１に内蔵せしめたベアリング６により支持ぽし
め、上方の孔形ロール４を昇降させる油圧シリンダ５の
ピストン５ａ下端を直接上方の孔形ロール４を支持する
ロールチョック１１に当接往しめ、下方の孔形ロール４
を冒降させる浦斤シリンダ５のビス１〜ン５ａ、１１喘
をロードセル等の荷重検出器１３を介してＦ方の孔形Ｅ
」−ル４を支持するロールチョック１１に当接せしめる
。油月シリンダ５にはピストン５ａの移動量を検出する
変位検出器７が取り付けられている。FIG. 1 shows an embodiment of the present invention, in which a pair of upper and lower hole-shaped rolls 4 is disposed in a housing 12 so as to be driven by a driving force neck (not shown). is supported by a bearing 6 built into the roll chock 11, and the lower end of the piston 5a of the hydraulic cylinder 5 that raises and lowers the upper hole-shaped roll 4 is brought into direct contact with the roll chock 11 that supports the upper hole-shaped roll 4, and the lower end is brought into contact with the roll chock 11 that supports the upper hole-shaped roll 4. hole-shaped roll 4
The screws 1 to 5a and 11 of the cylinder 5, which is used to lower the
'' - is brought into contact with the roll chock 11 that supports the roll 4. A displacement detector 7 is attached to the Aburayuki cylinder 5 to detect the amount of movement of the piston 5a.

前記荷ＴｒＸ検出器１３で検出した圧延荷重信号を係数
器１４を介しＣ演算器１５に送り得るようにし。The rolling load signal detected by the load TrX detector 13 can be sent to the C calculator 15 via the coefficient unit 14.

演Ω器１５ぐ圧下設定ｌｌ″ｉ９と係数器１４からの信
号を加算し得るようにし、比較演算器１６で演算器１５
の出力信号と変位検出器７の出力信号を比較演算し、そ
の結果に基づいてサーボ弁１０を駆動し、孔形［］−ル
４を胃６Ｔさせる油圧シリンダ５への圧油の間を調節し
１！するようにする。図中１はマンドレル、３はマンド
レルミル出側管材である。父上述の演搾制御装置は上布
側（ワークサイド）の油圧シリンダだけでなく残りの３
つの油圧シリング各々に設ける場合もあるし、ワークサ
イド、ドライプリイドをベアとして、上下ロール各々に
１台ずつ設ける場合もある。The reduction setting ll''i9 of the Ω operator 15 and the signal from the coefficient unit 14 can be added, and the comparator 16
The output signal of the displacement detector 7 is compared with the output signal of the displacement detector 7, and based on the result, the servo valve 10 is driven to adjust the amount of pressure oil to be supplied to the hydraulic cylinder 5 to change the hole shape 4 to the stomach 6T. Shi1! I'll do what I do. In the figure, 1 is a mandrel, and 3 is a tube material on the outlet side of the mandrel mill. The expression control device mentioned above includes not only the hydraulic cylinder on the upper cloth side (work side) but also the remaining three.
In some cases, one unit is installed in each of the two hydraulic cylinders, and in other cases, one unit is installed in each of the upper and lower rolls, with the work side and dry lead as bare.

ところで、圧延荷重Ｐによるマンドレルミルの伸びを考
慮すると、１りられる管の肉厚りはｈ＝ＳｏＩ−に−ハ
Ｐ　　　　　・・・■で表わされる。■式の右辺第３項
中Ｃはゲインであり、ミル定数にと共に係数器１４に設
定されている。而して）１伸圧延時には、マンドレルバ
−１と−Ｌ下の花形ロール４間のギャップＳ。を圧下設
定値９として演Ｑ器１５に与え、圧延を行う。By the way, considering the elongation of the mandrel mill due to the rolling load P, the wall thickness of the tube that is removed is expressed as h=SoI-, -HaP...■. C in the third term on the right side of equation (2) is a gain, which is set in the coefficient unit 14 along with the Mill constant. Therefore, during one elongation rolling, the gap S between the mandrel bar 1 and the flower-shaped roll 4 below -L. is given to the Q calculator 15 as the rolling reduction setting value 9, and rolling is performed.

圧延荷重Ｐは荷重検出器１３で検出されて係数器１４に
送られ、ここで■式の第３頂により圧延荷重Ｐがミル定
７Ｑ　ｋで割られてミルの伸び７バが求められると共に
この甲にゲインＣが［赴けられ、圧下；り定１ｉｉ９［
＋−東ｙ　シ（ｎ　−／Ｌ／　ｆ　ｖ　７１Ｇ　締込む
噂が求められ、その信号は？寅算器１５に送られる。演
ｒ５器１５からの指令１３号は比較演０器１６で変位検
出器７の出力信号と比較演舜され、そのに号に応じてリ
ーボ弁１０が駆動され、ナーボ弁１０からは圧油が上方
の？１１１圧シリンダ５に送給されてビス１−ン５ａが
移動し、ロールギせツブが制御される。変位検出器７で
検出されたピストン５ａの変位は比較演’：＞　）ｎｌ
　１６にフィードバックさ机、比較演算器１６で演篩さ
れた隔差が零になればｔ７−−ボ弁１０は閉１１−する
１、このようにマンドレルミルのワークサイド、ドライ
ブサイドの両側に配設した荷重検出７！Ａ１３により検
出した荷重をミル定数で割って（ｌｌ＋び削を求め、そ
れを圧下５Ｑ定値に上乗せしてロールギャップを締め込
むことにより、スプリングバック聞を相殺しているため
、第５図の曲線ｒに示すような目標通りのテーパー吊を
１７ることがＣき、従って、絞り工程においてス１〜し
・プチレデュ＝サーで圧延された成品は先端から後端ま
で肉厚の均一な鋼管になる。このため、Ｉｉｊ　ＩＬ’
成品の両端はオフゲージにならず、歩留りの向上が図れ
る。The rolling load P is detected by the load detector 13 and sent to the coefficient unit 14, where the rolling load P is divided by the mill constant 7Qk using the third vertex of equation (2) to obtain the mill elongation 7B. Gain C is applied to the instep;
+ - East y shi (n - / L / f v 71G A rumor to tighten is obtained, and its signal is sent to the ?? calculator 15. Command No. 13 from the operator 5 operator 15 is displaced by the comparator 0 operator 16. The signal is compared with the output signal of the detector 7, and the ribo valve 10 is driven according to the signal. Pressure oil is supplied from the ribo valve 10 to the upper pressure cylinder 5 and screws into the screw 1-5a. moves, and the roll gear is controlled.The displacement of the piston 5a detected by the displacement detector 7 is a comparison equation':> )nl
When the difference calculated by the comparator 16 becomes zero, the valve 10 closes 11-1, thus disposed on both sides of the work side and drive side of the mandrel mill. Load detection 7! Divide the load detected by A13 by the mill constant to find (ll+cutting), add it to the rolling reduction 5Q constant value, and tighten the roll gap to cancel out the springback, so the curve in Figure 5 It is possible to achieve the desired taper suspension as shown in R, and therefore, the product rolled in the S1-Petite Reducer during the drawing process becomes a steel pipe with a uniform wall thickness from the tip to the rear end. .For this reason, Iij IL'
Both ends of the finished product will not be off-gauge, improving yield.

ところで、上述の■式庖整理して ｈ＝　３０＋　１＝ｆｆｌｐ　　　　　　　・・・■１
く を得る。この０式から、制■によってミル定数は 上− Ｋｅ″″１−Ｃ”’■ となることが分る。この考え方は一般に平板の圧延別に
おいてミル定数可変副面として既に公知のものであるが
、マンドレルミルに適用した場合には以下に述べる点で
甲板の圧ＩＩＬ：ｉＱの場合とは本質的に胃なる乙ので
ある。By the way, by rearranging the above ■ formula, h = 30 + 1 = fflp...■1
get more. From this equation 0, it can be seen that by controlling ■, the mill constant becomes -Ke''''1-C'''■.This idea is generally known as the variable mill constant subsurface for flat plate rolling. However, when applied to a mandrel mill, the pressure on the deck is essentially the same as in the case of iQ, as described below.

（Ｄ　平板圧延機におりるミル定数可変制御は板厚の外
乱を除去して圧延材長手り向の板厚精度を出すことを主
目的にしでいるが、本発明では鋼管肉厚の絶対圃を所定
の値にすることを目的としＣいる。このため、マンドレ
ルミルのミル定数の伸び分を補正することを第１の目的
としている。(D) The main purpose of variable mill constant control in a flat plate rolling mill is to eliminate disturbances in plate thickness and achieve plate thickness accuracy in the longitudinal direction of the rolled material, but in the present invention, the absolute field of steel pipe wall thickness is The purpose is to set the value to a predetermined value.For this reason, the first purpose is to correct the increase in the mill constant of the mandrel mill.

（■）９ｃに述べたように、鋼管の圧延は三次元変形を
ｒｌｌうため、発生する圧延荷重を精度良く予測するこ
とが難しい。従って、平板圧延の場合のように、予めミ
ルの伸びψを予測してａ−ルギャップを伏目に設定して
おき、蘭市の変動分に対してミル定数可変制御を１１）
【ノるという方法では、先後端のテーパー圧延部の肉厚
精度が前述のように厚くなる。従って、本発明ではＣ＝
１（ミル定ｖｌ無限大）として全荷重変化に対してミル
定数可変制御を掛けることを第一義としている。(■) As described in 9c, rolling of steel pipes involves three-dimensional deformation, so it is difficult to accurately predict the rolling load that will occur. Therefore, as in the case of flat plate rolling, the elongation ψ of the mill is predicted in advance and the a-le gap is set as a foreclosure, and the mill constant variable control is performed to compensate for the fluctuation of the mill constant.
[With the rolling method, the thickness accuracy of the tapered rolled portions at the leading and trailing ends becomes thicker as described above. Therefore, in the present invention, C=
1 (Mill constant vl is infinite), and the primary meaning is to apply Mill constant variable control to all load changes.

（Ｉｌｌ）　　平板圧延ではｉ＋ｌＩ　１ｉｌｌ＋の１
〆定性のために、通常Ｃく１と設定せざるを（ｑなかっ
たが、発明者は多くの実機レベルの実験を通してＣ２０
と設定できることを見出した。このため、本発明の効果
は絶大なものと’ｃＫっている。(Ill) In flat plate rolling, i+lI 1ill+1
For the sake of quality, it is usually necessary to set it to C20, but the inventor has determined that C20 has been set through many experiments at the actual
I discovered that it is possible to set Therefore, the effects of the present invention are said to be tremendous.

［発明の効果］ 本発明のマンドレルミルの圧延方法及びその配置によれ
ば、延伸圧延［程で筒先後端に目標通りのテーパー吊を
１１１ることができるため、絞り工程でストレッチレゾ
−１−サーにより圧延された成品は先端から後端まで肉
厚の均一な鋼管になってオフゲージ部がなくなり、従っ
て成品の歩留りが向上ツるという優れた効果を奏し得る
。[Effects of the Invention] According to the rolling method and arrangement of the mandrel mill of the present invention, it is possible to create the desired taper suspension at the tip and rear end of the tube in the stretch rolling step, so that the stretch resolution 1-1 in the drawing step can be achieved. The finished product rolled by the steel tube becomes a steel pipe with a uniform wall thickness from the tip to the rear end, and there is no off-gauge part, which has the excellent effect of improving the yield of the product.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明のマンドレルミルの圧延方法及びその￥
ｅβの説明図、第２図はマンドレルミル配置例の説明図
、第３図は第２図のＡ矢視図、第４図は第２図のＢ矢視
図、第５図は本発明装置及び従来装置で限伸ｐｒ　ｊｌ
Ｅを行った場合の鋼管長手方向の肉厚分（５の説明図で
ある。 図中１はマンドレルバ−１２は素管、３は素材、４Ｃよ
孔形【Ｊ−ル、５は油圧シリンダ、５ａはピストン、Ｔ
は変位検出器、９は圧下設定１σ、１０はサーボ弁、１
３は荷重検出器、１４は係数器、１５は演σ器、１６は
比較病ｔｉ　３を示す。 特　　許　　出　　願　　人 白川島播＋ｆｆ！Ｔ！工業株式会社 特　　許　　出　　願　　人 川崎製鉄株式会社 Ｃワ 皺 ＼才 皺 涜聯ｆ呻Figure 1 shows the rolling method of the mandrel mill of the present invention and its
An explanatory diagram of eβ, FIG. 2 is an explanatory diagram of an example of mandrel mill arrangement, FIG. 3 is a view in the direction of arrow A in FIG. 2, FIG. 4 is a view in the direction of arrow B in FIG. 2, and FIG. and limited extension pr jl with conventional equipment
This is an explanatory diagram of the wall thickness in the longitudinal direction of the steel pipe (5) when E is performed. 5a is a piston, T
is a displacement detector, 9 is a reduction setting of 1σ, 10 is a servo valve, 1
3 is a load detector, 14 is a coefficient unit, 15 is a σ operator, and 16 is a comparison disease ti3. Patent application Hitoshira Kawashima Ban+ff! T! Industrial Co., Ltd. Patent application Kawasaki Steel Co., Ltd.

Claims (1)

【特許請求の範囲】 １）圧延荷重をミル定数で割ってミルの伸び量を求め、
該伸び量を圧下設定値に上乗せしてロールギャップを締
込むことにより前記ミルの伸び量を相殺し、管を圧延す
ることを特徴とするマンドレルミルの圧延方法。 ２）一対の孔形ロールと該孔形ロールを管に対して近接
、離反させるようにした油圧圧下シリンダと該油圧圧下
シリンダに圧油を送るサーボ弁とを備えたマンドレルミ
ルの圧延装置において、圧延荷重を検出する荷重検出器
と、該荷重検出器で検出した結果からミルの伸び量を演
算する装置と、ロールギャップの圧下設定値を前記伸び
量を基に補正し前記サーボ弁へ指令を与える演算器とを
設けたことを特徴とするマンドレルミルの圧延装置。[Claims] 1) Calculate the elongation of the mill by dividing the rolling load by the mill constant,
A method of rolling a mandrel mill, characterized in that the elongation amount of the mill is offset by adding the elongation amount to a set reduction value and tightening the roll gap to roll the tube. 2) A mandrel mill rolling device equipped with a pair of grooved rolls, a hydraulic reduction cylinder that moves the grooved rolls toward and away from a pipe, and a servo valve that sends pressure oil to the hydraulic reduction cylinder, A load detector that detects the rolling load, a device that calculates the amount of elongation of the mill from the result detected by the load detector, and a device that corrects the roll gap set value based on the amount of elongation and sends a command to the servo valve. What is claimed is: 1. A mandrel mill rolling device, characterized in that it is equipped with a computing unit that calculates