JPH03204111A - Manufacturing method and device for steel pipe with thick wall and small diameter - Google Patents

Abstract

PURPOSE:To execute a work of comparatively largely reducing diameter and increasing thickness, to make the surface skin fine and to improve the efficiency by executing the specific diameter reduction to a normalized or a hot finished pipe with the squeezing roll and then pressing the pipe into the drawing dies in cold state. CONSTITUTION:The blank pipe 1 of the normalized or hot finished steel pipe is subjected to the >=5% drawing work of outer diameter in cold state with the rotating squeezing roll 5, and then it is pressed into the dies 3 with the pressing device 4, so the outer diameter is reduced and the thickness is simultaneously increased, then the small diameter pipe 2 with thick wall is obtained. The squeezing roll 5 is a general squeezing roll which is provided with about 3 - 4 rolls in one section area over 1 stand. By this outer diameter drawing work, the blank pipe 1 is increased in its thickness and also is hardened due to working. Therefore, because the buckling can be prevented in the case of pressing the blank pipe into the dies 2 arranged for next process, the increasing ratio of thickness per one time can be enlarged.

Description

【発明の詳細な説明】 ［産業上の利用分野］ 本発明は焼準または熱間仕上の鋼管の肉厚を増加させる
ための加工技術に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a processing technique for increasing the wall thickness of a normalized or hot finished steel pipe.

［従来の技術］ 従来の熱間押し込み加工による肉厚を増加させる加工技
術例としては特開平０１−０４４２］］があり、該明細
書には第３図にみられるような増肉加工方法か記載され
ている。これによると素管１を移動端４てダイス内に押
し込みながら加熱コイル８で誘導加熱する。ダイス７内
には外径絞り部９を有しているため、誘導加熱された部
分は軸方向の圧縮を受けて容易に増肉し、小径厚肉管２
を得る。[Prior Art] An example of a processing technique for increasing wall thickness by conventional hot pressing is JP-A-01-0442], which describes a thickness increasing processing method as shown in FIG. Are listed. According to this, the raw tube 1 is induction heated by the heating coil 8 while being pushed into the die through the moving end 4. Since the die 7 has an outer diameter constriction part 9, the induction heated part is easily thickened by being compressed in the axial direction, and the small diameter thick walled pipe 2
get.

この際、素管１は外側に膨らもうとするが、素管ｌの外
周はセラミックス製のダイス７てカバーされているので
座屈しないで加工できる。At this time, the raw tube 1 tends to expand outward, but since the outer periphery of the raw tube 1 is covered with a ceramic die 7, it can be processed without buckling.

また、簡便な方法として第４図に示すような冷間にて絞
り用のダイスに押し込み増肉させる方法か公知である。Further, as a simple method, a method is known in which the thickness is increased by pushing the material into a drawing die in a cold state as shown in FIG. 4.

さらに第５図に示すような絞りロールを数多く並べて、
熱間または冷間て、これを通　スことにより縮径増肉さ
せる方法も公知である。Furthermore, a large number of squeezing rolls as shown in Fig. 5 are lined up,
A method of reducing the diameter and increasing the thickness by passing it through hot or cold is also known.

［発明が解決しようとする課題］ 特開平０１−０４４２１１の例は、加熱装置が必要であ
り設備費が高くなる。また冷間にて絞りダイスに押し込
む従来方法は、鋼管の加工硬化により押し込み力が大き
くなるため管軸方向の座屈または偏肉が生じやすく、−
度に大きな加工率が取れない。通常、機械構造用等の鋼
管は熱間または焼準仕上げの鋼管が多い。このような鋼
管は降伏点が低いのて特に座屈しやすい。したがって所
定の厚肉管を得るためには何回かの押し込みが必要とな
り、加工費か高くなる。また、絞りロールを数多く並へ
てこわを通すことにより縮径増肉させる方法は設備費が
高くなる。[Problems to be Solved by the Invention] The example of JP-A-01-044211 requires a heating device, resulting in high equipment costs. In addition, in the conventional method of cold pressing into a drawing die, the pushing force increases due to work hardening of the steel pipe, which tends to cause buckling or uneven thickness in the pipe axis direction.
It is not possible to obtain a large machining rate at the same time. Usually, steel pipes for mechanical structures are often hot-worked or normalized steel pipes. Such steel pipes have a low yield point and are particularly susceptible to buckling. Therefore, in order to obtain a predetermined thick-walled tube, it is necessary to press the tube several times, which increases the processing cost. Furthermore, the method of reducing the diameter and increasing the thickness by passing a large number of squeeze rolls through a number of strained rolls increases the equipment cost.

本発明は上記の課題を解決し、設備費を安くし、経済的
な小径厚肉鋼管製造方法と装置を提供しようとするもの
である。The present invention aims to solve the above-mentioned problems, reduce equipment costs, and provide an economical method and apparatus for producing small-diameter, thick-walled steel pipes.

［課題を解決するための手段］ 本発明の要旨は、焼準または熱間仕上の鋼管を絞りロー
ルによって予め５％以上の縮径加工を施した後に絞りダ
イス内に冷間にて押し込むことにより増肉加工すること
を特徴とする厚肉管の製造方イ去、および 焼準または熱間仕上の鋼管を押し込む押し込み装置と、
駆動する絞りロールと、絞り用のダイスとからなる厚肉
管の製造装置 にある。[Means for Solving the Problems] The gist of the present invention is to reduce the diameter of a normalized or hot-finished steel pipe by 5% or more using a drawing roll, and then coldly push it into a drawing die. A method for manufacturing a thick-walled pipe characterized by increasing the wall thickness, and a pushing device for pushing a normalized or hot-finished steel pipe,
This is a thick-walled tube manufacturing device consisting of a driven squeezing roll and a squeezing die.

以下に本発明を第１図に基いて詳細に説明する。The present invention will be explained in detail below with reference to FIG.

焼準または熱間仕上の鋼管である素管１を、図にない駆
動装置により回転する絞りロール５によって、冷間にて
５％以上の外径絞り加工を行った後、ライス３内に押し
込み装置４により押し込み、外径を減少させると同時に
肉厚を増加させて小径厚肉管２を得る。絞りロール５は
１スタンド以上の１断面内に３〜４０−ルを配した一般
的な絞りロールであり、１スタンド当り数％の外径絞り
が可能である。この外径絞り加工により素管１は増肉と
ともに加工硬化する。したがって次に配置したダイス３
に押し込む際の座屈を防止できるため、１回当りの加工
による増肉率を大きくできる。なお、カイトロール６は
素管１をガイドし、座屈を防止する。A raw pipe 1, which is a normalized or hot-finished steel pipe, is cold-reduced to an outer diameter of 5% or more by a drawing roll 5 rotated by a drive device (not shown), and then pushed into a rice 3. The small diameter thick-walled tube 2 is obtained by pressing with the device 4 to decrease the outer diameter and increase the wall thickness at the same time. The squeezing roll 5 is a general squeezing roll in which 3 to 40 rolls are arranged in one cross section of one or more stands, and it is possible to reduce the outer diameter by several percent per stand. This outer diameter drawing process increases the thickness of the raw pipe 1 and work-hardens it. Therefore, the next placed dice 3
Since buckling can be prevented when the material is pushed into the material, the rate of increase in thickness per processing can be increased. Note that the kit roll 6 guides the raw pipe 1 and prevents buckling.

第２図はロールの外径絞り率と最大増肉率の関係を示す
実験値である。絞りロール５により５％以上の加工率を
与えることにより１回当りの増肉率はほぼ２倍になって
いる。しかし、絞りロール５の数をあまり増やしても最
大増肉率への効果は小さくなるのて、設備費との兼ね合
いて絞りロールの加工率を決定すべきである。次に実施
例を示す。FIG. 2 shows experimental values showing the relationship between the outer diameter reduction rate of the roll and the maximum thickness increase rate. By applying a processing rate of 5% or more using the squeeze roll 5, the rate of increase in thickness per time is almost doubled. However, if the number of squeeze rolls 5 is increased too much, the effect on the maximum thickness increase rate will be small, so the processing rate of the squeeze rolls should be determined in consideration of equipment costs. Next, examples will be shown.

［実施例］ 金属管１：　材質　ＪＩＳ規格ＳＴＫＭ１２Ａ寸法　外
径φ３４．０〜１１４．３ｍｍ肉厚　４．０〜１０．０
ｍ［Ｉ＋ 絞りロール：　３０−ルタイプ、２スタンド外径絞り率
　５〜１５％ ダイス：　　材質　超硬 形状　ダイス半角　２０゜ 押し込み装置ご　最大荷重　１００Ｔｏｎ最大速度　３
０ｍ　７分 潤滑油二　　市販冷間引き抜き油をダイス３の入口で塗
布 小径厚肉管：　寸法　外径φ２５．Ｏ〜Ｊ３９．１ｍｍ
肉厚　５．０〜１３．［１ｍｍ 本発明の原理は、焼準または熱間仕上げのために降伏点
か小さくなっている素管１を増肉加工を行う際に、ダイ
ス押し込み時の座屈防止のために予め５％以上の縮径加
工を、加工か容易な絞りロールによって行うことである
。したがって、本発明の方法は同一ライン上で行った方
が能率上望ましいが、別ラインても従来の方法に比較す
ると効果が大きい。[Example] Metal tube 1: Material JIS standard STKM12A dimensions Outer diameter φ34.0 to 114.3 mm Wall thickness 4.0 to 10.0
m[I+ Squeezing roll: 30-ru type, 2-stand outer diameter drawing ratio 5-15% Die: Material Carbide shape Die half-width 20° with pushing device Maximum load 100Ton Maximum speed 3
0m 7 minutes Lubricating oil 2 Apply commercially available cold drawing oil at the inlet of die 3. Small diameter thick walled pipe: Dimensions Outer diameter φ25. O~J39.1mm
Wall thickness 5.0~13. [1 mm] The principle of the present invention is that when increasing the thickness of a raw tube 1 whose yield point has become smaller due to normalizing or hot finishing, the thickness is increased by 5% or more in advance to prevent buckling when pushing the die. The diameter reduction process is carried out using a drawing roll, which is easy to process. Therefore, although it is more efficient to perform the method of the present invention on the same line, it is more effective even on separate lines than the conventional method.

［発明の効果］ 以上説明した本発明によれば、特別に加熱装置または多
くの絞りロールを必要゛とせず、冷間て比較的大きな縮
径増肉加工が得られるので、設備費が安い、表面肌がき
れい、能率が良い等の利点がある。また最後に精度の良
いダイス７を通すので外径精度の良い鋼管が得られる。[Effects of the Invention] According to the present invention described above, a relatively large diameter reduction process can be achieved in a cold manner without requiring a special heating device or a large number of squeezing rolls, so equipment costs are low. It has advantages such as a clean surface and good efficiency. Furthermore, since the steel pipe is finally passed through a highly accurate die 7, a steel pipe with a highly accurate outer diameter can be obtained.

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

第１図は本発明の実施例を示す断面図、第２図は本発明
のロール外径絞り率の最大増肉率に及ぼす効果を示す実
験値、第３図、第４図および第５図は従来の加工方法の
一例を示す断面図である。 ！・・・素管、２・・・小径厚肉管、３・・・ダイス、
４・・・押し込み装置、５・・・絞りロール、６・・・
ガイドロール、７・・・ダイス、８・・・加熱コイル、
９・・・絞り部、１０ １１・・・絞りロールFIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is an experimental value showing the effect of the roll outside diameter reduction ratio of the present invention on the maximum thickness increase rate, and FIGS. 3, 4, and 5 is a sectional view showing an example of a conventional processing method. ! ...Main pipe, 2...Small diameter thick wall pipe, 3...Dice,
4... Pushing device, 5... Squeezing roll, 6...
Guide roll, 7...Dice, 8...Heating coil,
9... Squeezing section, 10 11... Squeezing roll

Claims (1)

【特許請求の範囲】 １、焼準または熱間仕上の鋼管を絞りロールによって予
め５％以上の縮径加工を施した後に絞りダイス内に冷間
にて押し込むことにより増肉加工することを特徴とする
厚肉管の製造方法。 ２、焼準または熱間仕上の鋼管を押し込む押し込み装置
と、駆動する絞りロールと、絞り用のダイスとからなる
厚肉管の製造装置。[Claims] 1. A normalized or hot finished steel pipe is reduced in diameter by 5% or more using a drawing roll, and then coldly pushed into a drawing die to increase its thickness. A method for manufacturing thick-walled pipes. 2. A thick-walled tube manufacturing device consisting of a pushing device for pushing a normalized or hot-finished steel tube, a driven drawing roll, and a drawing die.