JP2000158015A - Method for rolling metal tube - Google Patents
Method for rolling metal tubeInfo
- Publication number
- JP2000158015A JP2000158015A JP10337719A JP33771998A JP2000158015A JP 2000158015 A JP2000158015 A JP 2000158015A JP 10337719 A JP10337719 A JP 10337719A JP 33771998 A JP33771998 A JP 33771998A JP 2000158015 A JP2000158015 A JP 2000158015A
- Authority
- JP
- Japan
- Prior art keywords
- stand
- outer diameter
- stands
- rolling
- metal tube
- 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.)
- Granted
Links
Landscapes
- Reduction Rolling/Reduction Stand/Operation Of Reduction Machine (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、サイザ等の定径圧
延機で金属管の外径圧下をおこなう際の圧延方法に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling method for reducing the outer diameter of a metal tube by a constant diameter rolling mill such as a sizer.
【0002】[0002]
【従来の技術】一般に継目無金属管(以下、金属管とい
う)の製造工程においては、ピアサにより穿孔された中
空素管をマンドレルミルなどの延伸圧延機を用いて減肉
圧延し、次いでサイザあるいはストレッチレデューサな
どの定径圧延機を用いて所要の外径に圧延する。上記サ
イザおよびストレッチレデューサはほぼ同様の構成であ
り、以下サイザにより説明する。2. Description of the Related Art Generally, in a manufacturing process of a seamless metal pipe (hereinafter, referred to as a metal pipe), a hollow shell pierced by a piercer is reduced in thickness using a stretching rolling machine such as a mandrel mill, and then a sizer or a sizer. Roll to the required outer diameter using a constant diameter rolling mill such as a stretch reducer. The sizer and the stretch reducer have substantially the same configuration, and will be described below with the sizer.
【0003】図1はサイザのロール配置を模式的に示す
概要図である。図2はサイザのロールスタンドの断面図
で、同図(a)は図1のA−A断面図、同図(b)は図
1のB−B断面図である。図1および図2で、符号1は
ロールスタンド、2は孔型ロール、3は金属管、Oはパ
スセンタである。FIG. 1 is a schematic diagram schematically showing a roll arrangement of a sizer. 2A and 2B are cross-sectional views of the roll stand of the sizer. FIG. 2A is a cross-sectional view taken along the line AA of FIG. 1, and FIG. 2B is a cross-sectional view taken along the line BB of FIG. 1 and 2, reference numeral 1 denotes a roll stand, 2 denotes a hole type roll, 3 denotes a metal tube, and O denotes a pass center.
【0004】サイザは、図2(a)、(b)に示すよう
に一般に3個の孔型ロール2を垂直面内でパスセンタO
の回りに120゜の間隔で組み込んだロールスタンド1
(単に、スタンドともいう)を隣接するスタンド間で互
いに60°ずつ変えて、楕円度を適当な範囲となした複
数の圧延スタンドと、その後続に、楕円度を持った被圧
延材を真円の製品に仕上げる複数の仕上スタンドとを図
1に示すように連続的に5〜28基配列した圧延機で、
スタンド数は最終寸法となる金属管の外径に応じて決定
される。As shown in FIGS. 2 (a) and 2 (b), a sizer generally includes three hole-shaped rolls 2 in a vertical direction in a path center O.
Stand 1 with a 120 ° spacing around the roll
(Also referred to simply as a stand) is changed by 60 ° between adjacent stands to form a plurality of rolling stands having an appropriate ellipticity, followed by a rolled material having an ellipticity in a perfect circle. A plurality of finishing stands for finishing into a product of a rolling mill in which 5-28 units are continuously arranged as shown in FIG.
The number of stands is determined according to the outer diameter of the metal tube which is the final dimension.
【0005】仕上スタンドの圧延では、仕上スタンドの
外径加工度が高すぎるとロールエッジ部で噛み出し疵が
発生しやすく、また前記外径加工度が低すぎるとロール
への材料の未充満が生じ金属管の外面が真円にならず外
径形状不整となり易い。エッジでの噛み出しはロールに
充満しやすい薄肉材で起こりやすく、厚肉材ではロール
への未充満による外面形状不整が起こりやすい。したが
って、薄肉材から厚肉材まで同じ仕上スタンドを用いて
圧延をおこなうためには、仕上スタンドを3〜5基用い
て徐々に外面を真円に近づけて仕上げることが必要とな
る。[0005] In the rolling of the finishing stand, if the degree of working of the outer diameter of the finishing stand is too high, biting flaws are likely to occur at the roll edge portion, and if the degree of working of the outer diameter is too low, the roll is not filled with material. The resulting outer surface of the metal tube is not perfectly round and the outer diameter is likely to be irregular. The biting at the edge is likely to occur in a thin material that easily fills the roll, and in a thick material, the outer shape is likely to be irregular due to the unfilled roll. Therefore, in order to perform rolling from the thin material to the thick material using the same finishing stand, it is necessary to finish the outer surface gradually closer to a perfect circle by using three to five finishing stands.
【0006】仕上スタンドは製品外径に応じた孔型ロー
ルを保有する必要があるので、ロール保有数が多くなり
設備コストの増加やロール置場不足などの問題が発生す
る。また、製品寸法が変わるとロールの交換が必要で、
そのために多大な時間と労力を必要とし、生産性の面で
も問題である。[0006] Since the finishing stand needs to hold a roll in accordance with the outer diameter of the product, the number of rolls to be held increases, causing problems such as an increase in equipment cost and a shortage of roll storage space. Also, when the product dimensions change, the roll needs to be replaced,
This requires a great deal of time and effort, and is a problem in terms of productivity.
【0007】ロール保有数の削減、ロール交換頻度の削
減に関連して、特開平7−16616号公報には、孔型
ロールのパスセンタとロール軸間の距離を調整すること
で孔型ロールの楕円率を変更して管の内面角張り率を抑
制する圧延方法が開示されている。[0007] In connection with the reduction of the number of rolls held and the frequency of roll replacement, Japanese Patent Application Laid-Open No. Hei 7-16616 discloses an elliptical hole-shaped roll by adjusting the distance between the path center of the roll and the roll axis. A rolling method is disclosed in which the rate of change of the inner surface angle of a pipe is changed by changing the rate.
【0008】[0008]
【発明が解決しようとする課題】上記特開平7−166
16号公報に開示された方法は、全スタンドにおいてパ
スセンタとロール軸間の距離の調整が必要であり、設備
コストの増大を招くといった問題がある。また、外面形
状の不整や外面疵の防止に関する記載は無く、これらの
対策としては不十分である。SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 7-166.
The method disclosed in Japanese Patent Publication No. 16 requires adjustment of the distance between the pass center and the roll axis in all the stands, which causes a problem of increasing equipment cost. In addition, there is no description regarding prevention of irregularities in the outer surface shape or flaws on the outer surface, and these measures are insufficient.
【0009】本発明の課題は、上記従来技術の問題点を
解決し、サイザなどの定径圧延機において、広範囲の肉
厚の製品を外面形状の不整および外面疵の発生を抑制す
るとともに、仕上スタンド数を削減して圧延することが
できる金属管の圧延方法を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art described above, and to reduce the occurrence of irregularities in the outer surface shape and the occurrence of outer surface flaws in products having a wide range of thickness in a constant diameter rolling mill such as a sizer, and to finish the product. It is an object of the present invention to provide a method for rolling a metal tube that can reduce the number of stands and perform rolling.
【0010】[0010]
【課題を解決するための手段】サイザでは、通常、3〜
5基の仕上スタンドを用いて、肉厚の異なる製品の圧延
がおこなわれるが、仕上スタンドを削減すると、厚肉材
の圧延では、ロールへの未充満が生じ、薄肉材の圧延で
はロールエッジ部の噛み出し疵が発生しやすい。したが
って、厚肉材では最終スタンド(第Nスタンド)の外径
加工度を高くして未充満を改善し、薄肉材では第Nスタ
ンドの外径加工度を低くして噛み出しを防止する必要が
ある。そこで、第N−1スタンドのパスセンタと孔型ロ
ール溝底中央部間の距離(以下、この距離をギャップと
いい、符号Aで表す)を調整して第Nスタンドの外径加
工度を変えた圧延試験をおこない、未充満や噛み出しの
発生を調査した。Means for Solving the Problems In sizers, usually, 3 to
Rolling of products having different wall thicknesses is performed using five finishing stands. However, when the number of finishing stands is reduced, unfilled rolls occur in the rolling of thick-walled materials, and the roll edge portion in the rolling of thin-walled materials. Is easily generated. Therefore, in the case of thick material, it is necessary to increase the degree of outer diameter processing of the final stand (the Nth stand) to improve unfilling, and in the case of thin material, it is necessary to reduce the degree of outer diameter processing of the Nth stand to prevent biting. is there. Therefore, the distance between the pass center of the (N-1) th stand and the center of the bottom of the grooved roll groove (hereinafter, this distance is referred to as a gap and represented by symbol A) was adjusted to change the outer diameter working degree of the Nth stand. A rolling test was conducted to investigate the occurrence of unfilling and biting.
【0011】図3は、圧延時の外径加工度の説明図であ
り、外径加工度は下記式で定義される。 外径加工度=(Mi-1 −Mi )/Mi-1 ・100(%) M:平均径(=A+B)、添え字iは第iスタンドを表
す、 A:パスセンタと孔型ロール溝底中央部間の距離、 B:パスセンタと孔型ロールエッジ間の距離。FIG. 3 is an explanatory diagram of the degree of outer diameter working during rolling. The degree of outer diameter working is defined by the following equation. Outer working ratio = (M i-1 −M i ) / M i−1 · 100 (%) M: average diameter (= A + B), subscript i represents the i-th stand, A: pass center and hole-shaped roll B: distance between the center of the groove bottom and B: distance between the path center and the roll edge.
【0012】図4は、第Nスタンドにおける未充満と噛
み出しの発生領域を示すグラフで、横軸は金属管の製品
の肉厚(t)と外径(D)の比(t/D)、縦軸は第N
スタンドの外径加工度YN である。図中の○印は未充満
や噛み出しの発生がなく、×印は未充満や噛み出しの発
生があることを表す。FIG. 4 is a graph showing the unfilled area and the area of occurrence of biting at the Nth stand. The horizontal axis represents the ratio (t / D) of the wall thickness (t) of the metal tube product to the outer diameter (D). , The vertical axis is Nth
The outside diameter working degree Y N of the stand. In the figure, the mark “○” indicates that there is no unfilled state and no biting out, and the mark “X” indicates that there is no unfilled state or biting out.
【0013】同図に示すように、第Nスタンドの外径加
工度が下記の式で表される直線1と直線2に挟まれた領
域では未充満や噛み出しの発生がない。直線2より上側
では、噛み出し疵が発生し、直線1より下側では、未充
満となる。 直線1:YN =1.3・(t/D)+0.05、 直線2:YN =3.1・(t/D)+0.40。As shown in FIG. 1, there is no occurrence of unfilling or biting in the region between the straight line 1 and the straight line 2 in which the outer diameter working degree of the N-th stand is expressed by the following equation. A biting flaw occurs above the straight line 2 and becomes unfilled below the straight line 1. Line 1: Y N = 1.3 · (t / D) +0.05, Line 2: Y N = 3.1 · (t / D) +0.40.
【0014】次ぎに、第N−2スタンドのギャップを調
整して第N−1スタンドの外径加工度を変えた圧延試験
をおこない、第Nスタンドにおける未充満や噛み出しの
発生を調査した。但し、第Nスタンドの外径加工度は
0.35〜0.50%とした。Next, a rolling test was carried out in which the gap of the (N-2) th stand was adjusted to change the degree of working of the outer diameter of the (N-1) th stand, and the occurrence of unfilling and biting in the (N) th stand was investigated. However, the outer diameter working ratio of the Nth stand was 0.35 to 0.50%.
【0015】図5は、第N−1スタンドにおける未充満
と噛み出しの発生領域を示すグラフで、横軸は金属管の
製品の肉厚(t)と外径(D)の比(t/D)、縦軸は
第N−1スタンドの外径加工度YN-1 であり、未充満や
噛み出しの発生有無は図4と同じ記号で表す。FIG. 5 is a graph showing the unfilled area and the area of occurrence of biting in the N-1st stand. The horizontal axis is the ratio (t / t) of the wall thickness (t) of the metal tube to the outer diameter (D). D), the vertical axis is the outer diameter working degree Y N-1 of the (N-1) th stand, and the presence or absence of unfilling or occurrence of biting is represented by the same symbol as in FIG.
【0016】同図に示すように、第N−1スタンドの外
径加工度が下記の式で表される直線3および直線4に挟
まれた領域では、未充満や噛み出しの発生がない。直線
4より上側では、噛み出し疵が発生し、直線3より下側
では、未充満となる。 直線3:YN-1 =5.0・(t/D)+0.3、 直線4:YN-1 =5.0・(t/D)+1.9。As shown in the figure, in the region between the straight line 3 and the straight line 4 in which the outer diameter working degree of the (N-1) -th stand is expressed by the following formula, there is no occurrence of unfilling or biting. A biting flaw occurs above the straight line 4 and becomes unfilled below the straight line 3. Line 3: Y N-1 = 5.0 · (t / D) +0.3, Line 4: Y N-1 = 5.0 · (t / D) +1.9.
【0017】したがって、第N−1スタンドのギャップ
を調整して第Nスタンドの外径加工度を特定範囲とす
る、あるいは、第N−1スタンドおよび第N−2スタン
ドのギャップを調整して、第Nスタンドおよび第N−1
スタンドの外径加工度を、それぞれ特定範囲とする、こ
とにより、仕上スタンド数を削減して広範囲の肉厚の金
属管を圧延することができる。Therefore, by adjusting the gap of the (N-1) th stand to make the outer diameter working degree of the (N) th stand a specific range, or by adjusting the gap between the (N-1) th and (N-2) th stands, Nth stand and N-1th
By setting the degree of working of the outer diameter of the stand to a specific range, the number of finishing stands can be reduced and a metal pipe having a wide range of wall thickness can be rolled.
【0018】本発明は、上記知見に基づき完成されたも
ので、その要旨は以下の通りである。 (1) 1スタンド内に3または4個の孔型ロールを垂直面
内に有する複数スタンドから成る定径圧延機を用いた金
属管の圧延方法であって、定径圧延機のスタンド数をN
個としたとき、金属管の製品の肉厚(t)と外径(D)
の比(t/D)に応じて第N−1番目のスタンドのパス
センタと孔型ロール溝底中央部間の距離を調整して第N
番目のスタンドの外径加工度を変更することを特徴とす
る金属管の圧延方法。The present invention has been completed based on the above findings, and the gist thereof is as follows. (1) A method for rolling a metal tube using a constant diameter rolling mill comprising a plurality of stands having three or four hole-shaped rolls in a vertical plane in one stand, wherein the number of stands of the constant diameter rolling mill is N
When made into pieces, the wall thickness (t) and outer diameter (D) of the metal tube product
The distance between the pass center of the (N-1) th stand and the center of the bottom of the roll-shaped roll groove is adjusted according to the ratio (t / D) of the N-th stand.
A method for rolling a metal tube, comprising changing a degree of outer diameter processing of a second stand.
【0019】(2) 第N番目のスタンドの外径加工度を下
記式で定まるSN 以上TN 以下の範囲とすることを特徴
とする上記(1) 項に記載の金属管の圧延方法。 SN =1.3・(t/D)+0.05、 TN =3.1・(t/D)+0.40。(2) The method for rolling a metal tube as described in the above item (1), wherein the outer diameter working degree of the N-th stand is in a range from SN to TN determined by the following equation. S N = 1.3 · (t / D) +0.05, T N = 3.1 · (t / D) +0.40.
【0020】(3) 第N−1番目のスタンドの外径加工度
を下記式で定まるSN-1 以上TN-1以下の範囲とするこ
とを特徴とする上記(2) 項に記載の金属管の圧延方法。 SN-1 =5.0・(t/D)+0.3、 TN-1 =5.0・(t/D)+1.9。(3) The degree of outer diameter working of the (N-1) -th stand is in a range from S N-1 to T N-1 determined by the following equation. Rolling method of metal tube. S N-1 = 5.0. (T / D) +0.3, T N-1 = 5.0. (T / D) +1.9.
【0021】[0021]
【発明の実施の形態】本発明の方法は、定径圧延機のス
タンド数をN個としたとき、少なくとも第N−1番目の
スタンドには垂直面内にギャップの調整が可能な、3ま
たは4個の孔型ロールを備えたスタンドを配置し、金属
管の製品の肉厚(t)と外径(D)の比(t/D)に応
じて前記ギャップを調整して第N番目のスタンドの外径
加工度を変更することを特徴し、その好適態様にあって
は、第N番目のスタンドの外径加工度を下記式で定まる
SN 以上TN 以下の範囲とすることを特徴とする。 SN =1.3・(t/D)+0.05、 TN =3.1・(t/D)+0.40。BEST MODE FOR CARRYING OUT THE INVENTION The method of the present invention is characterized in that, when the number of stands of a constant-diameter rolling mill is N, at least the (N-1) -th stand can adjust the gap in a vertical plane. A stand having four hole-shaped rolls is arranged, and the gap is adjusted according to the ratio (t / D) of the thickness (t) of the product of the metal tube to the outer diameter (D), and the N-th position is adjusted. It is characterized in that the degree of outer diameter processing of the stand is changed, and in a preferred embodiment, the degree of outer diameter processing of the N-th stand is in the range from SN to TN determined by the following equation. And S N = 1.3 · (t / D) +0.05, T N = 3.1 · (t / D) +0.40.
【0022】図4に示すように、第N−1番目のスタン
ドのギャップを調整して、第N番目のスタンドの外径加
工度をt/Dで求まるSN 以上TN 以下の範囲とするこ
とにより、広範囲の肉厚の金属管を未充満や噛み出しの
発生を抑制して圧延することができ、仕上スタンド数の
削減が可能となる。好ましくは、第N番目スタンドの外
径加工度は、(SN +TN )/2の0.8〜1.2倍の
範囲である。また、本発明方法を適用するt/Dの範囲
は0.03以上0.23以下が望ましい。As shown in FIG. 4, the gap of the (N-1) th stand is adjusted so that the outer diameter working degree of the (N) th stand is in the range from SN to TN obtained by t / D. Thus, a metal pipe having a wide range of thickness can be rolled while suppressing the occurrence of unfilling and bulging, and the number of finishing stands can be reduced. Preferably, the outer diameter working ratio of the N-th stand is in the range of 0.8 to 1.2 times (S N + T N ) / 2. The range of t / D to which the method of the present invention is applied is desirably 0.03 or more and 0.23 or less.
【0023】本発明の別の好適態様にあっては、第N−
1番目のスタンドのギャップを調整し第N番目のスタン
ドの外径加工度を上述した所定範囲内とするのに加え、
更に、第N−2番目のスタンドのギャップを調整して第
N−1番目のスタンドの外径加工度を下記式で定まるS
N-1 以上TN-1 以下の範囲とすることを特徴とする。 SN-1 =5.0・(t/D)+0.3、 TN-1 =5.0・(t/D)+1.9。In another preferred embodiment of the present invention, the N-th
In addition to adjusting the gap of the first stand so that the outer diameter machining degree of the Nth stand is within the above-described predetermined range,
Further, by adjusting the gap of the (N-2) -th stand, the outer diameter working ratio of the (N-1) -th stand is determined by the following equation.
Characterized by the N-1 or T N-1 or less. S N-1 = 5.0. (T / D) +0.3, T N-1 = 5.0. (T / D) +1.9.
【0024】図5に示すように、第N−2番目のスタン
ドのギャップを調整して、第N−1番目のスタンドの外
径加工度をt/Dで求まるSN-1 以上TN-1 以下の範囲
とすることにより、第Nスタンドにおいて広範囲の肉厚
の金属管を未充満や噛み出しの発生を抑制して圧延する
ことができるため、仕上スタンド数の削減が可能とな
る。好ましくは、第N−1番目のスタンドの外径加工度
は、(SN-1 +TN-1 )/2の0.8〜1.2倍の範囲
である。また、本発明方法を適用するt/Dの範囲は
0.03以上0.23以下が望ましい。As shown in FIG. 5, by adjusting the gap of the (N-2) -th stand, the outer diameter working degree of the (N-1) -th stand can be obtained by t / D from S N-1 to T N-. By setting the range to 1 or less, a metal pipe having a wide range of thickness can be rolled in the N-th stand while suppressing unfilling and bulging, so that the number of finishing stands can be reduced. Preferably, the outer diameter working ratio of the ( N-1 ) -th stand is in the range of 0.8 to 1.2 times (S N-1 + T N-1 ) / 2. The range of t / D to which the method of the present invention is applied is desirably 0.03 or more and 0.23 or less.
【0025】本発明は、少なくとも第N−1番目のスタ
ンドをギャップ可変機能を備えたスタンドとすること
で、仕上スタンド数を削減することができる。ギャップ
調整は、電動式あるいは油圧式の圧下機構をスタンドに
設けることにより可能である。According to the present invention, the number of finishing stands can be reduced by using at least the (N-1) th stand as a stand having a variable gap function. The gap can be adjusted by providing an electric or hydraulic pressure reduction mechanism on the stand.
【0026】なお、ギャップ可変機能を持たないギャッ
プ固定型スタンドのサイザであっても、t/Dを限定し
て製管する場合においては、外径加工度を上記範囲とす
ることにより未充満や噛み出しの発生を抑制して圧延す
ることができる。Incidentally, even in the case of a sizer of a fixed gap type stand having no gap variable function, in the case of forming a tube with a limited t / D, it is possible to reduce the unfilled size by setting the degree of outer diameter working within the above range. Rolling can be performed while suppressing occurrence of biting.
【0027】[0027]
【実施例】油圧圧下方式のギャップ調整機能を有するス
タンド数8または9の3ロール式のサイザを用い、外径
280mm、肉厚6mm、25mm、50mmの素管
を、それぞれ外径220mmで肉厚が7mm、28m
m、50mmの金属管に圧延した。表1にスタンド数8
の場合のサイザの孔型寸法を、表2に主要スタンドの外
径加工度の設定条件を示す。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A three-roll type sizer having 8 or 9 stands having a gap adjusting function of a hydraulic pressure reduction method is used. A raw tube having an outer diameter of 280 mm, a thickness of 6 mm, 25 mm, and 50 mm is formed with an outer diameter of 220 mm and a thickness of 220 mm. Is 7mm, 28m
m, and rolled into a 50 mm metal tube. Table 1 shows 8 stands
Table 2 shows the setting conditions of the outer diameter working ratio of the main stand.
【0028】[0028]
【表1】 [Table 1]
【0029】[0029]
【表2】 [Table 2]
【0030】本発明例1は、スタンド数を8とし、第7
番目のスタンドのギャップを調整して、第8番目のスタ
ンドの外径加工度を、肉厚7、28、50mmの管に対
して、それぞれ0.4、0.7、1.0%とした。な
お、第7番目のスタンドの外径加工度は1.8%とし
た。In Example 1 of the present invention, the number of stands
By adjusting the gap of the eighth stand, the outer diameter working degree of the eighth stand was set to 0.4, 0.7, and 1.0% for pipes having a wall thickness of 7, 28, and 50 mm, respectively. . In addition, the outer diameter working ratio of the seventh stand was 1.8%.
【0031】本発明例2は、スタンド数を8とし、第7
番目のスタンドのギャップを調整して、第8番目のスタ
ンドの外径加工度を、肉厚7、28、50mmの管に対
して、それぞれ0.2、0.3、0.5%とした。な
お、第7番目のスタンドの外径加工度は1.8%とし
た。In Example 2 of the present invention, the number of stands was set to eight and the seventh
The gap of the 8th stand was adjusted so that the working degree of the outer diameter of the 8th stand was 0.2, 0.3 and 0.5% for pipes with a wall thickness of 7, 28 and 50 mm, respectively. . In addition, the outer diameter working ratio of the seventh stand was 1.8%.
【0032】本発明例3は、スタンド数を8とし、第6
番目のスタンドのギャップを調整して、第7番目のスタ
ンドの外径加工度を、肉厚7、28、50mmの管に対
して、それぞれ0.7、1.1、1.6%とし、更に、
第7番目のスタンドのギャップを調整して、第8番目の
スタンドの外径加工度を、肉厚7、28、50mmの管
に対して、それぞれ0.4、0.7、1.0%とした。In Example 3 of the present invention, the number of stands
By adjusting the gap of the seventh stand, the outer diameter working degree of the seventh stand is set to 0.7, 1.1, and 1.6% for pipes having a wall thickness of 7, 28, and 50 mm, respectively. Furthermore,
By adjusting the gap of the seventh stand, the outer diameter working degree of the eighth stand was set to 0.4, 0.7, and 1.0% for pipes having a wall thickness of 7, 28, and 50 mm, respectively. And
【0033】本発明例4は、スタンド数を8とし、第6
番目のスタンドのギャップを調整して、第7番目のスタ
ンドの外径加工度を、肉厚7、28、50mmの管に対
して、それぞれ1.9、2.3、2.8%とし、更に、
第7番目のスタンドのギャップを調整して、第8番目の
スタンドの外径加工度を、肉厚7、28、50mmの管
に対して、それぞれ0.2、0.3、0.5%とした。In Example 4 of the present invention, the number of stands was set to eight and the sixth
By adjusting the gap of the seventh stand, the outer diameter working degree of the seventh stand is set to 1.9, 2.3, and 2.8% for pipes having a wall thickness of 7, 28, and 50 mm, respectively. Furthermore,
By adjusting the gap of the seventh stand, the outer diameter working degree of the eighth stand is set to 0.2, 0.3, and 0.5% for pipes having a wall thickness of 7, 28, and 50 mm, respectively. And
【0034】比較例1、2は、スタンド数が8で、全ス
タンドのギャップを固定とした。すなわち、第7番目と
第8番目のスタンドの外径加工度は、肉厚によらず一定
とした。In Comparative Examples 1 and 2, the number of stands was 8, and the gap of all stands was fixed. That is, the outer diameter working ratio of the seventh and eighth stands was constant regardless of the wall thickness.
【0035】従来例は、スタンド数が9で、全スタンド
のギャップを固定した。すなわち、第7〜9番目のスタ
ンドの外径加工度は、肉厚によらず一定とした。In the conventional example, the number of stands is 9, and the gaps of all stands are fixed. That is, the outside diameter working ratio of the seventh to ninth stands was constant regardless of the wall thickness.
【0036】表2に、上記圧延により得られた金属管の
真円度の測定結果と外面疵の発生状況を示す。真円度は
外半径差(最大外半径−最小外半径)を平均外半径で除
した値を%表示したもので、5%以下を合格とした。な
お、外半径とは製品断面において、重心から表面までの
距離を指す。外面疵は、表面に疵が全く認められない場
合が◎、長手方向の一部分に薄く模様状に現れる程度で
製品上問題がない場合が○、疵手入れが必要な場合を×
とした。総合評価は、肉厚7、28、50mmの製品
を、スタンド数が8で、真円度が5%以下で、外面疵が
◎または○で圧延することができた場合を合格として判
定した。Table 2 shows the results of the measurement of the roundness of the metal tube obtained by the above rolling and the state of occurrence of external flaws. The roundness is a value obtained by dividing an outer radius difference (maximum outer radius−minimum outer radius) by an average outer radius in%, and a value of 5% or less is regarded as acceptable. The outer radius refers to the distance from the center of gravity to the surface in a product cross section. Outer surface flaws: ◎: no flaws are observed on the surface, ○: a product that does not have any problem on the product because it appears in a thin pattern in a part of the longitudinal direction, x:
And In the overall evaluation, products having wall thicknesses of 7, 28 and 50 mm were judged to pass if the number of stands was 8, the roundness was 5% or less, and the outer surface flaw could be rolled with ◎ or ○.
【0037】表2に示すように、スタンド数が9である
従来例では真円度が良好で外面疵の発生が抑制された品
質良好な管を圧延することができたが、スタンド数を削
減した比較例1、2では、真円度の不良や外面疵の発生
といった問題が生じた。すなわち、比較例1では肉厚2
8mmと50mmにおいて真円度が不良となり、比較例
2では肉厚7mmで外面疵が発生した。本発明例1〜4
は、スタンド数を削減したにもかかわらず真円度が良好
で外面疵の発生が抑制された品質良好な管を圧延するこ
とができた。As shown in Table 2, in the conventional example in which the number of stands is 9, a pipe having good roundness and good quality in which the occurrence of external flaws is suppressed can be rolled, but the number of stands is reduced. In Comparative Examples 1 and 2, problems such as poor roundness and occurrence of external flaws occurred. That is, in Comparative Example 1, the thickness 2
Roundness was poor at 8 mm and 50 mm, and in Comparative Example 2, an outer surface flaw occurred at a thickness of 7 mm. Invention Examples 1-4
Was able to roll a good quality tube with good roundness and reduced occurrence of external flaws despite the reduced number of stands.
【0038】[0038]
【発明の効果】本発明によれば、少ないスタンド数で広
範囲の肉厚の管を良好な真円度でかつ外面疵の発生を抑
制して圧延することができる。したがって、スタンド台
数の削減による設備コストの低減やスタンド交換時間の
短縮などによる生産性の向上を図ることができる。According to the present invention, a pipe having a wide range of wall thickness can be rolled with good roundness and with less occurrence of external flaws with a small number of stands. Therefore, it is possible to improve the productivity by reducing the equipment cost by reducing the number of stands and shortening the time for replacing the stands.
【図1】サイザのロール配置を模式的に示す概要図であ
る。FIG. 1 is a schematic diagram schematically showing a roll arrangement of a sizer.
【図2】サイザのロールスタンドの断面図で、同図
(a)は図1のA−A断面図、同図(b)は図1のB−
B断面図である。2A and 2B are cross-sectional views of a roll stand of a sizer, wherein FIG. 2A is a cross-sectional view taken along line AA of FIG. 1, and FIG.
It is B sectional drawing.
【図3】圧延時の外径加工度の説明図である。FIG. 3 is an explanatory diagram of the degree of outer diameter working during rolling.
【図4】第Nスタンドにおける未充満と噛み出しの発生
領域を示すグラフである。FIG. 4 is a graph showing an unfilled area and an occurrence area of a bite at an Nth stand.
【図5】第N−1スタンドにおける未充満と噛み出しの
発生領域を示すグラフである。FIG. 5 is a graph showing an unfilled area and an occurrence area of a bite at the N-1st stand.
1:ロールスタンド、 2:孔型ロール、 3:金属管、 O:パスセンタ、 A:パスセンタと孔型ロール溝底中央部間の距離、 B:パスセンタと孔型ロールエッジ間の距離。 1: Roll stand, 2: Roll roll, 3: Metal tube, O: Pass center, A: Distance between pass center and roll roll groove bottom center, B: Distance between pass center and roll roll edge.
Claims (3)
ルを垂直面内に有する複数スタンドから成る定径圧延機
を用いた金属管の圧延方法であって、定径圧延機のスタ
ンド数をN個としたとき、金属管の製品の肉厚(t)と
外径(D)の比(t/D)に応じて第N−1番目のスタ
ンドのパスセンタと孔型ロール溝底中央部間の距離を調
整して第N番目のスタンドの外径加工度を変更すること
を特徴とする金属管の圧延方法。1. A method for rolling a metal tube using a constant diameter rolling mill comprising a plurality of stands having three or four hole-shaped rolls in a vertical plane in one stand, wherein the number of stands of the constant diameter rolling mill is Is N, the path center of the (N-1) -th stand and the center of the bottom of the hole-shaped roll groove according to the ratio (t / D) of the thickness (t) of the product of the metal tube to the outer diameter (D). A method for rolling a metal tube, comprising changing an outer diameter working degree of an N-th stand by adjusting a distance therebetween.
式で定まるSN 以上TN 以下の範囲とすることを特徴と
する請求項1に記載の金属管の圧延方法。 SN =1.3・(t/D)+0.05 TN =3.1・(t/D)+0.402. A rolling method of a metal tube according to claim 1, characterized in that the N-th S N or T N less range determined outer diameter working ratio by the following equation stands. SN = 1.3 · (t / D) +0.05 T N = 3.1 · (t / D) +0.40
まるSN-1 以上TN-1 以下の範囲とすることを特徴とす
る請求項2に記載の金属管の圧延方法。 SN-1 =5.0・(t/D)+0.3 TN-1 =5.0・(t/D)+1.93. The method for rolling a metal tube according to claim 2, wherein the (N-1) -th outer diameter working degree is in a range from S N-1 to T N-1 determined by the following equation. . S N-1 = 5.0. (T / D) +0.3 T N-1 = 5.0. (T / D) +1.9
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Cited By (3)
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 |
WO2011148613A1 (en) * | 2010-05-25 | 2011-12-01 | 住友金属工業株式会社 | Fixed diameter rolling method for seamless pipe |
JP2021098215A (en) * | 2019-12-23 | 2021-07-01 | Jfeスチール株式会社 | Seamless steel pipe manufacturing method |
-
1998
- 1998-11-27 JP JP33771998A patent/JP3339434B2/en not_active Expired - Fee Related
Cited By (6)
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 |
US8276424B2 (en) | 2007-02-08 | 2012-10-02 | Sumitomo Metal Industries, Ltd. | Grooved roll for a reducer and a reducer |
WO2011148613A1 (en) * | 2010-05-25 | 2011-12-01 | 住友金属工業株式会社 | Fixed diameter rolling method for seamless pipe |
JPWO2011148613A1 (en) * | 2010-05-25 | 2013-07-25 | 住友金属工業株式会社 | Seamless pipe diameter rolling method |
JP2021098215A (en) * | 2019-12-23 | 2021-07-01 | Jfeスチール株式会社 | Seamless steel pipe manufacturing method |
JP7180586B2 (en) | 2019-12-23 | 2022-11-30 | Jfeスチール株式会社 | Method for manufacturing seamless steel pipe |
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