JPS5970408A - Rolling method of pipe in reducing mill - Google Patents
Rolling method of pipe in reducing millInfo
- Publication number
- JPS5970408A JPS5970408A JP18058182A JP18058182A JPS5970408A JP S5970408 A JPS5970408 A JP S5970408A JP 18058182 A JP18058182 A JP 18058182A JP 18058182 A JP18058182 A JP 18058182A JP S5970408 A JPS5970408 A JP S5970408A
- Authority
- JP
- Japan
- Prior art keywords
- rolling
- pipe
- mill
- stands
- stress
- 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
Classifications
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Control Of Metal Rolling (AREA)
Abstract
Description
【発明の詳細な説明】 本発明は絞り圧延機における管の圧延方法に関する。[Detailed description of the invention] The present invention relates to a method of rolling a tube in a reducing mill.
□一般に、継目無鋼管の製造ラインにおいては、加熱炉
において所要の温度まで加熱された素材(ビレット)を
穿孔圧延機において穿孔してボロー(穿孔素管)を得た
後、ホローを延伸圧延機において延伸圧延してシェル(
延伸素管)を得た後、更にシェルを絞り圧延機において
所要寸法にまで絞り圧延してチューブ(鋼管)を得るこ
きを可能としている。□Generally, in a seamless steel pipe manufacturing line, the material (billet) is heated to the required temperature in a heating furnace, then perforated in a perforation rolling machine to obtain a bore (perforated base pipe), and then the hollow is passed through a stretching mill. The shell (
After obtaining the drawn blank tube, the shell is further reduced and rolled to a required size in a reducing mill to obtain a tube (steel pipe).
ところで、上記継目無鋼管にあっては、その内面に内部
疵を生ずる場合がある。従来、この内部疵の発生原因と
して、ビレット材質、穿孔圧延機による穿孔条件、延伸
圧延機による延伸条件等が着目され、内部疵がら旋状の
欠陥であれば穿孔段階、直線状であれば穿孔圧延機のプ
ラグバーあるいは延伸圧延機のマンドレルバ−による引
っかき疵であると判断されてきた。しかしながら、従来
、絞り圧延機による圧延条件が内部疵に及ぼす影響につ
いては何ら考慮されていない。By the way, internal flaws may occur on the inner surface of the seamless steel pipe. Conventionally, the causes of internal flaws have been focused on the billet material, perforation conditions by a perforation rolling machine, stretching conditions by a stretching mill, etc.; if the internal flaw is a spiral defect, it is determined at the perforation stage, and if it is a linear defect, it is determined at the perforation stage. It has been determined that the scratches were caused by the plug bar of the rolling mill or the mandrel bar of the elongation mill. However, conventionally, no consideration has been given to the influence of rolling conditions by a reducing mill on internal flaws.
本発明は、絞り圧延機による圧延条件が内部疵に及ぼす
影響を考慮し、絞り圧延における内部疵の発生を防止す
ることができる絞り圧延機における管の圧延方法を提供
することを目的とする。SUMMARY OF THE INVENTION An object of the present invention is to provide a method for rolling a pipe in a reducing mill, which takes into consideration the influence of rolling conditions by the reducing mill on internal defects, and can prevent the occurrence of internal defects in reducing rolling.
上記目的を達成するために、本発明は、複数スタンドか
らなる圧延ロール群によって素管を絞り圧延する絞り圧
延機における管の圧延方法において、各スタンドの圧延
ロールが素管に与えるストレツチ係数(引張応力/降伏
応力)の全スタンドに関する平均値を、0.45以下に
設定するようにしたものである。In order to achieve the above object, the present invention provides a method for rolling a tube in a reducing mill in which a group of rolls consisting of a plurality of stands reduces and rolls a tube, in which the stretch coefficient (tensile The average value of (stress/yield stress) for all stands is set to 0.45 or less.
以下、本発明をより詳細に説明する。The present invention will be explained in more detail below.
第1図は本発明が適用される継目無鋼管製造ラインを示
す工程図である。ビレット(素材)11は加熱炉12に
おいて加熱された後、穿孔圧延機(例え□ばピアサ)に
よって穿孔されてホロー(穿孔素管)14となり、史に
延伸圧延機(例えばマンドレルミル)15において延伸
圧延されてシェル(延伸素’!F)16となり、更に再
加熱炉18において再加熱された後、絞り圧延機(例え
ばストレッチレデューサ〕19において絞り圧延されて
外径を絞られたチューブ(鋼管)20吉なる。鋼管20
は、クーリングベッド21で空冷され、矯正機22で真
直状に矯正された後、一定の長さに切断されて製品とな
る。FIG. 1 is a process diagram showing a seamless steel pipe production line to which the present invention is applied. After the billet (raw material) 11 is heated in a heating furnace 12, it is perforated by a piercing rolling mill (e.g., Piasa) to become a hollow (perforated pipe) 14, and then stretched in a stretching mill (for example, a mandrel mill) 15. A tube (steel pipe) that is rolled into a shell (stretched element'!F) 16, further reheated in a reheating furnace 18, and then reduced and rolled in a reducing mill (for example, a stretch reducer) 19 to reduce its outer diameter. 20 lucky. Steel pipe 20
is air-cooled in a cooling bed 21, straightened by a straightening machine 22, and then cut into a certain length to become a product.
上記絞り圧延機19は、複数スタンドからなる圧延ロー
ル群によって構成され、各スタンドの圧延ロールは、例
えば第1図に示すような30一ル配列とされ、各スタン
ドのロール回転速度比を調整することにより、圧延中の
シェル16に加わる張力を制御し、その肉厚を制御可能
としている。The reducing rolling mill 19 is composed of a group of rolling rolls consisting of a plurality of stands, and the rolling rolls of each stand are arranged, for example, in a 30-row arrangement as shown in FIG. 1, and the roll rotation speed ratio of each stand is adjusted. This makes it possible to control the tension applied to the shell 16 during rolling and control its wall thickness.
上記絞り圧延機19における絞り圧延中の管の変形機構
について説明すれば以下の通りである。The deformation mechanism of the tube during the reduction rolling in the reduction rolling mill 19 will be explained as follows.
すなわち、シェル16は第2図に示すように均等な外圧
と引張りを受けて変形するものとすれば、応カー歪関係
式から下記(1)式が成立する。That is, assuming that the shell 16 deforms under equal external pressure and tension as shown in FIG. 2, the following equation (1) is established from the stress-strain relational equation.
(σ、−σm):(σl−σm)=(σθ−σm)=ψ
r:ψl:ψθ−(1)また、平均応力式として下記(
2)式が成立する。(σ, −σm): (σl−σm)=(σθ−σm)=ψ
r: ψl: ψθ−(1) In addition, the average stress formula is given below (
2) The formula holds true.
1 ・・・ (2)σ□=
了(σ、+σl+σθ)
また、Trescaの降伏条件式より下記(3)式が成
立する。1... (2) σ□=
(σ, +σl+σθ) Furthermore, the following equation (3) holds true from Tresca's yield condition equation.
σl−σθ=Kf ・・ (
3)また、半径方向の応力は比較的小さいとしてσ、二
〇とすれば、下記(4)式が成立する。σl−σθ=Kf ・・(
3) Furthermore, assuming that the stress in the radial direction is relatively small and σ is 20, the following equation (4) holds true.
σ□=了(2σ1−Kf) ・・
(4)以上の各式より下記(5)式に係るNeuma
nnとHanckeの基礎式が導かれる。σ□=end(2σ1-Kf)...
(4) From each of the above equations, Neuma according to the following equation (5)
The basic equations of nn and Hanke are derived.
(1−2Z) : (Z+1) : (Z−2) =ψ
1:ψl:ψθ ・・・ (5)ただし、上記(1)式
ないしく5)式において、σ、は半径方向応力、σlは
管軸方向応力、σθは接線方向応力、σ□は平均応力、
ψ、は半径方向対数歪、ψlは管軸方向対数歪、ψθは
接線方向対数歪、Kfは材料の降伏応力、Zはストレッ
チ係数(引張応力σl/降伏応力Kf )である。(1-2Z) : (Z+1) : (Z-2) =ψ
1: ψl: ψθ ... (5) However, in the above equations (1) or 5), σ is the radial stress, σl is the tube axial stress, σθ is the tangential stress, and σ□ is the average stress. ,
ψ is the logarithmic strain in the radial direction, ψl is the logarithmic strain in the tube axis direction, ψθ is the logarithmic strain in the tangential direction, Kf is the yield stress of the material, and Z is the stretch coefficient (tensile stress σl/yield stress Kf).
上、記(5)式が示すように、絞り圧延機19の各スタ
ンドの圧延ロールがシェル16に与えるストレッチ係数
Z=0(σ1=0)の場合は、1 : 1 : −2=
cp、:ψI!:ψθとなり、外径の減少は長さの伸び
き肉厚の増加をもまたらすことが認められる。り=0.
5(σ/l = 0.5Kf)の場合は、O:1.5ニ
ー1.5=ψr:ψ1.:ψθとなり外径の減少は長さ
の伸びのみをもたらすことが認められる。また、l>Z
〉0、5 (Kf) Z ) 0.5Kf)では外径の
減少とともに肉厚が減、少することが認められる。As shown in equation (5) above, when the stretch coefficient Z given to the shell 16 by the rolling rolls of each stand of the reducing rolling mill 19 is Z=0 (σ1=0), 1:1:-2=
cp, :ψI! :ψθ, and it is recognized that a decrease in the outer diameter also causes an increase in length and wall thickness. ri=0.
5 (σ/l = 0.5Kf), O: 1.5 knee 1.5 = ψr: ψ1. :ψθ, and it is recognized that a decrease in the outer diameter only results in an increase in length. Also, l>Z
〉0,5 (Kf) Z ) 0.5Kf), it is recognized that the wall thickness decreases as the outer diameter decreases.
ここで、絞り圧延機19の入側材料としてのシェル16
において、その内表面近傍に第3図(A)に゛ おいて
23で示すような異材質(例えば非金属介在物M)があ
る場合には、この部分の引張強度は母材相の引張強度よ
りも弱いと考えられる。したがって、第3図(A)に示
すようなシェル16に一定以上の引張応力を加えると第
3図(I3)に示すように異材質23の部分で分離24
を発生し、これが管内面の欠陥となることが考えられる
。すなわち、より強いストレッチ係数2の条件下で絞り
圧延を行なう時程、シェル16の内面に破断、剥離が起
こり易く、内部疵が発生し易いものと考えられる。Here, the shell 16 is used as the input material of the reducing rolling mill 19.
If there is a foreign material (e.g. non-metallic inclusion M) near the inner surface as shown at 23 in Figure 3(A), the tensile strength of this part is equal to the tensile strength of the base metal phase. considered to be weaker than Therefore, if a tensile stress above a certain level is applied to the shell 16 as shown in FIG.
This is thought to cause defects on the inner surface of the tube. That is, it is considered that when the reduction rolling is performed under conditions of a stronger stretch coefficient of 2, the inner surface of the shell 16 is more likely to break or peel, and internal defects are more likely to occur.
そこで、絞り圧延におけるストレッチ係数と内部疵の発
生との関係を1べたところ、以下の結果を得た。まず、
第4図は一般材料(STKM 13A。Therefore, when we investigated the relationship between the stretch coefficient during reduction rolling and the occurrence of internal defects, we obtained the following results. first,
Figure 4 shows general materials (STKM 13A).
素材WTK15.外径70φ)の素管に対する絞り圧延
の結果を、横軸に各スタンドの圧延ロールが素管に与え
るストレッチ係数Zの全スタンドに関する平均値として
の平均ストレッチ係数Zmをとり、縦軸に実験に供した
全素管数に対する内部疵の生じた素管数としての内面カ
ブレ発生率(%)をとつ−て示したものである。この第
4図によれば、平均ストレッチ係aZmを0.45以下
に設定する場合に、内部疵の発生率が許容可能な程度に
まで減少可能となることが認められる。Material WTK15. The horizontal axis shows the average stretch coefficient Zm, which is the average value of the stretch coefficient Z given to the raw pipe by the rolling rolls of each stand, for all stands, and the vertical axis shows the results of the reduction rolling for the raw pipe with an outer diameter of 70φ). The figure shows the rate of occurrence of inner surface rash (%) as the number of blank tubes with internal flaws relative to the total number of blank tubes used. According to FIG. 4, it is recognized that when the average stretch coefficient aZm is set to 0.45 or less, the incidence of internal flaws can be reduced to an acceptable level.
また、第5図は合金鋼(SCM415.素材W’l”−
8CM41.5.外径50.8φ)の素管に対する絞り
王延の結果を、第4図における古同様に、横軸に平均ス
トレッチ係数Z、nをとり、縦軸に内面カブレ発生率(
チ)をとって示したものである。この第5図によっても
、平均ストレッチ係数Zmを0.45以Fに設定する場
合に、内部疵の発生率が許容可能な程度にまで減少可能
となることが認められる。In addition, Figure 5 shows alloy steel (SCM415.Material W'l"-
8CM41.5. As in Figure 4, the average stretch coefficients Z and n are plotted on the horizontal axis, and the inner surface curvature occurrence rate is plotted on the vertical axis.
h). It is also recognized from FIG. 5 that when the average stretch coefficient Zm is set to 0.45 F or more, the incidence of internal flaws can be reduced to an acceptable level.
なお、上記平均ストレッチ係数Zmと、絞り圧延機19
が素管に与える減肉率ΔSとの関係を示せば以下のコm
りである。すなわち、減肉率Δgは、下記(6)式によ
って表わされる。In addition, the average stretch coefficient Zm and the reduction rolling mill 19
The relationship between ΔS and the thinning rate ΔS given to the raw pipe can be expressed as follows.
It is. That is, the thickness reduction rate Δg is expressed by the following equation (6).
また、半径方向対数歪ψ、は、下記(7)式によって表
わされる。Further, the radial logarithmic strain ψ is expressed by the following equation (7).
また、円周方向対数歪ψθは、下記(8)式によって表
わされる。Further, the logarithmic strain ψθ in the circumferential direction is expressed by the following equation (8).
平均ストレッチ係数Zmは、下記(9)式によって表こ
こで、上記(9)式におけるε市は、下記0())式に
よって表わされる。The average stretch coefficient Zm is expressed by the following equation (9). Here, ε in the above equation (9) is expressed by the following 0()) equation.
また、上記各式において、dlはシェル16の外径、S
lはシェル16の肉厚、d2はチューブ20の外径、S
2はチューブ20の肉厚である。すなわち、本発明の実
施においては、シェル16およびチューブ20の圧延寸
法に基づく圧下スケジュールを調整することにより、絞
り圧延機19における平均ストレッチ係数Zmを0.4
5以下に設定し、チューブ20に対する内部疵の発生を
抑制することが可能となる。In addition, in each of the above formulas, dl is the outer diameter of the shell 16, and S
l is the wall thickness of the shell 16, d2 is the outer diameter of the tube 20, S
2 is the wall thickness of the tube 20. That is, in carrying out the present invention, by adjusting the rolling schedule based on the rolling dimensions of the shell 16 and the tube 20, the average stretch coefficient Zm in the reducing mill 19 is set to 0.4.
By setting the value to 5 or less, it is possible to suppress the occurrence of internal flaws in the tube 20.
以上のように、本発明に係る絞り圧延機における管の圧
延方法は、各スタンドの圧延ロールカ素管に与えるスト
レッチ係数(引張応力/降伏応力)の全スタンドに関す
る平均値を、0.45以下に設定するようにしたので、
絞り圧延における内部疵の発生を防止することができる
という効果を有する。As described above, the tube rolling method in the reducing rolling mill according to the present invention reduces the average value of the stretch coefficient (tensile stress/yield stress) given to the rolled carbon tube of each stand to 0.45 or less for all stands. I decided to set it, so
This has the effect of preventing the occurrence of internal flaws during reduction rolling.
第1図は本発明が適用される継目無鋼管製造ラインを示
す工程図、第2図は絞り圧延中の管に生ずる応力を示す
斜桃図、第3図(Nおよび(B)は異材質を内在した材
料の変形状態を示すモデル図、第4図は一般材料におけ
る平均ストレッチ係数と内面カブレ発生率との関係を示
す図、第5図は合金鋼における平均ストレッチ係数と内
面カブレ発生率との関係を示す図である。
16・・シェル、 19・・・絞り圧延機、20 ・
チューブ、 Z・・・ストレッチ係数、Zm・・平均ス
トレッチ係数、
σl・・・引張応力、Kf・・降伏応力。
代理人 弁理士 塩 川 修 治
に旧痙−配州蛭i
K〜いP6ハ棺相劃ドFig. 1 is a process diagram showing a seamless steel pipe production line to which the present invention is applied, Fig. 2 is a diagonal diagram showing the stress generated in the pipe during reduction rolling, and Fig. 3 (N and (B) are Fig. 4 is a diagram showing the relationship between the average stretch coefficient and the occurrence rate of inner surface rash in general materials, and Fig. 5 shows the relationship between the average stretch coefficient and the incidence of inner rash in alloy steel. 16...Shell, 19...Reducing mill, 20.
Tube, Z: stretch coefficient, Zm: average stretch coefficient, σl: tensile stress, Kf: yield stress. Agent Patent Attorney Osamu Shiokawa's old constipation - Saishu Hiru I K ~ I P6 is a coffin de
Claims (1)
を絞り圧延する絞り圧延機における管の圧延方法におい
て、各スタンドの圧延ロールが素管に□与えるストレッ
チ係数〔引張応力/降伏応力〕の全・スタンドに関する
平均値を、0.45以下に設定することを特徴とする絞
り圧延機における管の圧延方法。(1) In a pipe rolling method in a reducing mill in which the raw pipe is reduced and rolled by a group of rolling rolls consisting of multiple stands, the total stretch coefficient [tensile stress/yield stress] given to the raw pipe by the rolling rolls of each stand is A method for rolling a pipe in a reducing mill, characterized in that an average value regarding the stands is set to 0.45 or less.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18058182A JPS5970408A (en) | 1982-10-16 | 1982-10-16 | Rolling method of pipe in reducing mill |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18058182A JPS5970408A (en) | 1982-10-16 | 1982-10-16 | Rolling method of pipe in reducing mill |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5970408A true JPS5970408A (en) | 1984-04-20 |
JPS619084B2 JPS619084B2 (en) | 1986-03-19 |
Family
ID=16085760
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP18058182A Granted JPS5970408A (en) | 1982-10-16 | 1982-10-16 | Rolling method of pipe in reducing mill |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5970408A (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6327182U (en) * | 1986-08-06 | 1988-02-23 | ||
JPS6357991U (en) * | 1986-10-01 | 1988-04-18 |
-
1982
- 1982-10-16 JP JP18058182A patent/JPS5970408A/en active Granted
Also Published As
Publication number | Publication date |
---|---|
JPS619084B2 (en) | 1986-03-19 |
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