JPS6111122B2

JPS6111122B2 -

Info

Publication number: JPS6111122B2
Application number: JP11436382A
Authority: JP
Inventors: Chihiro Hayashi; Kazuyuki Nakasuji
Original assignee: Sumitomo Metal Industries Ltd
Current assignee: Nippon Steel Corp
Priority date: 1982-06-30
Filing date: 1982-06-30
Publication date: 1986-04-01
Also published as: BE897181A; JPS594905A

Description

【発明の詳細な説明】[Detailed description of the invention]

本発明は中空棒材の製造方法に関するものであ
る。なおここに中空棒材とは一般の棒鋼圧延工場で
製造されている超厚肉の中空棒状体を総称するも
のとし、その寸法例を示せば現今のマンドレルミ
ル工場における継目無管としての製造が不可能と
される肉厚／外径比（以下単にＴ／Ｄという）が
25〜30％以上（外径自体に制限はない）の中空棒
状体であつて、例えば油井用ドリルカラーの加工
素材として用いられるもの等を含むものとする。この種の中空棒材は従来第６図に示す如く次の
ような工程で製造されていた。第６図は従来にお
ける中空棒材の製造工程を示す模式図であり、先
ず第６図イに示す如く鋼片B₁を圧延機３１に通
して所要寸法仕様の角ビレツトB₂を得、この角
ビレツトB₂の中心部に第６図ロに示す如くドリ
ル３２を用いて穿孔し、角形の中空素材B₃を製
作し、次いでこれに第６図ハに示す如くマンガン
鋼製の芯金３３を挿通し、この状態で第６図ニに
示す如く加熱炉３４にて所要温度に加熱した後、
第６図ホに示す如く孔型ロール３５ａを有する10
数段のスタンド列からなる連続式棒鋼圧延機３５
に通して中空素材B₃をその外径、肉厚が目標値
に一致するよう仕上げ、第６図ヘに示す如く芯金
３３を抜き取つてこれを定尺切断し、次いで第６
図トに示す如く矯正機３６にて曲り矯正を施し、
成品としての中空棒材B₄を得ている。ところでこのような従来の製造方法にあつては
次のような問題点があつた。即ち、(1)中空素材
B₃内に内面規制工具たる芯金３３を挿入介在せ
しめた状態で圧延するが、芯金３３自体も塑性変
形するため成品の真円度が悪く偏肉の発生を避け
難いこと、(2)内径のばらつきが大きく、従つてま
た当然肉厚もばらつき全体としての寸法精度が低
いこと、(3)芯金３３は塑性変形するため使い捨て
られることとなり、工具原単位が高く不経済であ
ること、等である。このような従来方法における
問題点のうち、芯金の使用のため工具原単位が高
いという欠点の解消を図つたものとして従来次の
ような中空棒材の製造方法が提案されている。即
ち、先ずプレスピアシングミルを用いてブルーム
に穿孔を行い、次いでこの中空素材を内面規制工
具たる芯金を用いることなく、オーバルラウンド
型の孔型ロールを水平−垂直交互に配した連続式
圧延機に通して絞り圧延する方法である（特開昭
55−114407号）。しかしこの方法も本発明者等の実験によると、
孔型ロールを用いた２段ロール式の圧延機列では
十分な真円度を確保することは極めて難しいこと
が確認されている。なお同じ孔型ロールを用いる
３方ロール式の圧延機列では２段ロール式の場合
に比較して真円度は良好となるが、これにも一定
の限界があることも確認された。本発明はかかる事情に鑑みなされたものであつ
て、その目的とするところは３個又は４個のコー
ン型ロールを有する傾斜圧延機を用いて、中空素
材をその外径、肉厚を共に減じる延伸圧延を行う
ことによつて内面規制工具を用いる必要がなく、
しかも外径、肉厚ともに大幅な寸法精度の向上を
図り得るようにした中空棒材の製造方法を提供す
るにある。本発明に係る丸棒材に機械加工又は塑性加工に
より穿孔して得た肉厚／外径比が25％以上の中空
素材を、内面規制工具を用いることなく、目標と
する仕上外径、肉厚に応じて交叉角、傾斜角が調
節可能な３個又は４個のコーン型ロールを有する
交叉型の傾斜圧延機に通し、その外径を減じると
同時に肉厚をも減じて目標値に仕上げる延伸圧延
工程を含むことを特徴とする。なお、上述した如き本発明とはその技術内容を
全く異にするが、加工対象域が相近接している方
法として本発明の発明者の１人の発明に係り、既
に本出願人により、出願を行なつている継目無管
の製造方法がある（特願昭56−22540号）ので、
この方法と本発明方法との基本的な技術的相違点
につき触れておくこととする。この既出願の発明
の要旨は、パスライン周りに臨んで３又は４個の
ロールが配設され、その軸心線は、同側の軸端が
周方向の同じ側に向くよう傾斜せしめられ、且つ
同側の軸端が前記パスライン側に向けて接近又は
離反するよう傾斜（交叉）せしめ得るようにした
交叉型の傾斜圧延機により、内面規制工具を用い
ることなく素管の外径に絞り加工を施す工程を含
むことを特徴とする継目無金属管の製造方法にあ
る。即ち、素管の外径をその肉厚が増すよう絞つた
とき、増肉の程度は素管に偏肉が存する場合、厚
肉部分よりも薄肉部分の方が増肉割合が大きいこ
とを利用して偏肉の矯正を行う方法である。ただ
この方法は本発明者等の実験に依れば上述した如
き矯正効果が得られる範囲はＴ／Ｄが25〜30％以
下の範囲内であつて、これを越える範囲では仮令
従来技術をそのまま適用したとしても外径の絞り
加工によつて肉厚を増大せしめることは物理的に
不可能であることが確認された。このことは既出
願の技術の適用対象は自ずからＴ／Ｄ＝25〜30％
以下であることを意味する。これに対し本発明の
適用対象はこれと逆に外径、肉厚をともに減じ得
るＴ／Ｄ＝25％以上、望ましくは30％以上を適用
対象とすること、また既出願の技術は肉厚につい
てはこれを増肉する絞り圧延加工を施すものであ
るのに対し、本発明方法は外径は勿論、肉厚もこ
れを減ずる所謂延伸圧延加工を施すものであるこ
とから両者はその技術内容を全く異にするもので
あることが解る。以下本発明をその実施状態を示す図面に基いて
具体的に説明する。第１図は本発明に係る中空棒
材の製造方法（以下本発明方法という）をその工
程順に示す模式図であり、先ず第１図イに示す如
き所要直径の丸棒材A₁（丸鋼片でもよい）を用
意し、これを第１図ロに示す如くドリル１を用い
て機械加工により穿孔して中空素材A₂を形成
し、この中空素材A₂を第１図ハに示す如く所要
温度に加熱し、第１図ニに示す如く傾斜圧延機４
による延伸圧延を行うか、又は用意した丸棒材
A₁を先ず第１図ロ′に示す如く加熱炉２にて塑性
加工に適した所要温度に加熱し、第１図ハ′に示
す如く加熱した丸棒材A₁を押出機３を用いてそ
の中心部に穿孔して中空素材A₂を形成し、これ
に上記第１図ニに示す如く傾斜圧延機４による延
伸圧延を施した後定尺切断して中空棒材A₃を得
る。傾斜圧延機４は第２図イ，ロ，ハに示す如く
構成されている。第２図イは傾斜圧延機４にて中
空素材A₂を延伸圧延中の状態を示す中空素材の
入側から見た模式的正面図、第２図ロは同じく第
２図イのロ−ロ線による断面図、第２図ハは同じ
く第２図イのハ−ハ線による側面図であり、ロー
ル４１はいずれも軸線方向の一端部近くにゴージ
部４１ａを備え、このゴージ部４１ａを境いに軸
線方向の一端側には軸端に向けて漸次直径を縮小
され、また他端側は軸端に向けて漸次直径を拡大
されて円錐台状をなす入口面４１ｂ、出口面４１
ｃを備えたコーン型として構成されている。各ロ
ール４１はいずれもその入口面４１ｂ側を中空素
材A₂の移動方向上流側に位置させた状態であつ
て、且つ軸心線Ｙ−Ｙとゴージ部４１ａを夫々含
む平面との交点Ｏ（以下ロール設定中心という）
を中空素材A₂のパスラインＸ−Ｘと直交する同
一平面上に位置させてパスラインＸ−Ｘの周りに
略等間隔に配設され夫々両端の軸部４１ｄ，４１
ｅを図示しない軸受に支持された状態でその軸心
線Ｙ−Ｙが設定中心Ｏを中心にして中空素材A₂
のパスラインＸ−Ｘとの関係において、第２図ロ
に示す如く平面視的に前端部、即ち前方の軸端が
パスラインＸ−Ｘに向けて接近するよう所要角度
γ（以下交叉角という）だけ交叉せしめられ、且
つ側面視的には第２図ハに示す如く、前方の軸端
が中空素材A₂の周方向の同じ側に向けて所要角
度β（以下傾斜角という）だけ傾斜せしめられて
配設されている。各ロール４１はいずれも図示しない駆動源に連
結されており、第２図イに示す如く矢符方向に回
転駆動され、これら各ロール４１間に噛み込まれ
た中空素材A₂は軸心線回りに回転駆動されつつ
パスライン方向に移動される、所謂螺進移動せし
められつつ外径と同時に肉厚を減じつつ高圧下で
延伸圧延される。第３図イ，ロ，ハは本発明にお
いて用いる延伸圧延工程及びこれに用いる傾斜圧
延機の別の構成を示しており、第３図イは圧延機
出側から見たその模式的正面図、第３図ロは第３
図イのロ−ロ線による模式的断面図、第３図ハは
第３図ロのハ−ハ線による模式的側面図であり、
図中５１はいずれも圧延用のロールを示してい
る。ロール５１それ自体の構成は前記第２図イ，
ロ，ハに示す実施態様と実質上同じであり、中空
素材A₂の移動方向に対する姿勢は逆向きとなつ
ている。即ちロール５１はいずれも軸線方向の一
端部近くにゴージ部４１ａを備え、このゴージ部
５１ａの周りに軸線方向の一端側には軸端に向け
て漸次直径を縮小され、また他端側は軸端に向け
て漸次直径を拡大されて円錐台状をなす出口面５
１ｃ、入口面５１ｂを備えたコーン型として構成
されている。各ロール５１はいずれもその入口面
５１ｂ側を中空素材A₂の移動方向上流側に位置
させた状態でロール設定中心Ｏを中空素材A₂の
パスラインＸ−Ｘと直交する同一平面上に位置さ
せ、パスラインＸ−Ｘの周りに略等間隔に配設さ
れている。そして各ロール５１の軸心線Ｙ−Ｙは
設定中心Ｏを中心として第３図ロに示す如く平面
視的に後端部がパスラインＸ−Ｘから離反するよ
う交叉角γ、また第３図ハに示す如く前方の軸端
が中空素材A₂の同方向の同じ側に向けて傾斜角
βだけ傾斜せしめて配設されている。なお第３図イ，ロ，ハに示す傾斜圧延機のロー
ル５１の交叉角γは第２図ロに明らかな如く中空
素材A₂のパスラインＸ−Ｘに対する角と第３図
ロに示す中空素材A₂のパスラインＸ−Ｘに対す
る角度とは逆向きとなつているから、前者の場合
を正（γ＞０）、後者の場合を負（γ＜０）とす
る。上述した交叉角、傾斜角は製品たる中空棒材の
内径と密接な関係があり、交叉角、傾斜角と内径
との関係を予め求めておき、目標値に応じて適宜
に設定制御すればよい。交叉角、傾斜角の設定手
段については特に限定するものではなく、従来よ
り用いられている構成をそのまま、又は設定範囲
を大きくとれるよう適宜の改良を加えて採用すれ
ばよい。交叉角、傾斜角と孔径との関係について
その一例を示すと第４図イ，ロ，ハに示す如くで
ある。第４図イ，ロ，ハはいずれも横軸に圧延前の中
空素材の孔径mmを、また縦軸に圧延後の素材の孔
径mmをとつて示してある。なお交叉角γは第４図
イについては９゜、第４図ロについては０゜、第
４図ハについては−９゜に設定し、一方傾斜角は
夫々、３゜、５゜、７゜、９゜、11゜、13゜の６
段階に変化させた。傾斜圧延機はいずれもコーン
型の３ロール式のものであつて、ロールの材質は
SCM、ゴージ部直径は205mmのものを用いた。ま
た供試材たる丸鋼材としてはS45C炭素鋼を供試
材とし、直径70mm、長さ300mmのものを用い、こ
れらに夫々、中心に直径８mm、10mm、12mm、14
mm、16mm、18mmの孔を機械加工により穿孔して中
空素材とし、これを芯金等の内面規制工具を用い
ることなく外径：30mmφにすべく交叉角、傾斜角
を調節された３ロールの交叉型の傾斜圧延機にて
加熱温度1200℃で延伸圧延し、圧延前後の孔径を
検出した。このグラフから明らかな如く、中空素材と圧延
後のものとを比較してみると外径、肉厚ともに減
少せしめられていること、また交叉角はその値γ
＝９゜、０゜、−９゜のいずれにおいても孔径の
縮小効果があらわれるが、その縮小効果はγ＝９
゜で最大となつていること、更に交叉角を一定と
して傾斜角を変化させた場合にも、孔径が変化し
ていることから、交叉角、傾斜角を夫々適切に設
定制御することによつて、孔径の制御が可能であ
ることが解る。次に本発明方法と従来方法との比較試験結果に
ついて説明する。ここに本発明方法としてはS45C丸棒鋼を供試
材とし、これを機械加工によつて穿孔し、中空素
材を得、これを加熱炉にて1200℃に加熱しこれを
第２図イ，ロ，ハに示す如き、交叉角が３％（γ
＝３゜）、傾斜角が４゜（β＝４゜）に設定され
た３ロールの交叉型の傾斜圧延機を用いて延伸圧
延を行つて中空棒材を製造する方法を用い、また
従来方法としてはS45C丸ビレツトの中心にドリ
ルを用いて穿孔し、中空素材内にマンガン鋼製の
芯金を装入し、これをオーバルラウンド孔型ロー
ルを水平−垂直交互に配した連続式の棒鋼圧延機
により圧延して中空棒材を得る方法を用いた。中空素材としては外径110mm、内径30mmのもの
を用い、これを外径33mm、内径11mmを目標値とし
て圧延し、圧延後の中空棒材の外径、内径及びそ
の真円度、偏肉を検出した。結果は表１に示すと
おりである。なお本発明方法によつて得た中空棒
材の断面は第５図イに、また従来方法によつて得
た中空棒材の断面は第５図ロに示すとおりであ
る。 The present invention relates to a method for manufacturing a hollow bar. Note that the term "hollow bar" here is a general term for ultra-thick hollow rod-shaped bodies manufactured in general steel bar rolling mills, and an example of their dimensions would be that they can be manufactured as seamless pipes at current mandrel mill mills. The impossible wall thickness/outer diameter ratio (hereinafter simply referred to as T/D)
This includes hollow rod-shaped bodies with a diameter of 25 to 30% or more (there is no limit to the outer diameter itself), which are used, for example, as processed materials for drill collars for oil wells. This type of hollow bar material has conventionally been manufactured by the following process as shown in FIG. FIG. 6 is a schematic diagram showing the conventional manufacturing process for hollow bars. First _, as _shown in FIG. A hole is made in the center of the square billet B ₂ using a drill 32 as shown in FIG. 6B to produce a square hollow material B ₃ , and then a manganese steel core 33 is inserted into this as shown in FIG. 6C. is inserted, and heated in this state to the required temperature in the heating furnace 34 as shown in FIG. 6D,
10 having a grooved roll 35a as shown in FIG.
Continuous steel bar rolling mill 35 consisting of several rows of stands
The hollow material B ₃ is finished so that its outer diameter and wall thickness match the target values, and the core bar 33 is removed and cut to a specified length as shown in FIG.
As shown in the figure, the bending is straightened by a straightening machine 36,
Hollow bar B ₄ was obtained as a finished product. However, such conventional manufacturing methods have the following problems. That is, (1) hollow material
Although rolling is performed with the core metal 33, which is an inner surface regulating tool, inserted into _B3 , the core metal 33 itself is also plastically deformed, so the roundness of the finished product is poor and it is difficult to avoid uneven thickness; (2) (3) The core metal 33 is plastically deformed and is therefore disposable, making the tool unit consumption high and uneconomical. etc. Among the problems with such conventional methods, the following method for manufacturing hollow bars has been proposed in an effort to overcome the disadvantage that the tool consumption is high due to the use of a cored metal. That is, first, a press piercing mill is used to perforate the bloom, and then this hollow material is passed through a continuous rolling mill in which oval round hole rolls are arranged horizontally and vertically alternately, without using a core bar as an inner surface regulating tool. This is a method of reducing rolling by passing the
55-114407). However, according to the experiments of the present inventors, this method also
It has been confirmed that it is extremely difficult to ensure sufficient roundness in a two-roll rolling mill row using grooved rolls. Although a three-way rolling mill row using the same grooved rolls provides better roundness than a two-roll mill, it was also confirmed that this also has certain limits. The present invention was made in view of the above circumstances, and its purpose is to reduce both the outer diameter and wall thickness of a hollow material using an inclined rolling mill having three or four cone-shaped rolls. By performing stretch rolling, there is no need to use an inner surface regulating tool,
Moreover, it is an object of the present invention to provide a method for manufacturing a hollow bar material, which can significantly improve dimensional accuracy in both outer diameter and wall thickness. A hollow material with a wall thickness/outer diameter ratio of 25% or more obtained by drilling a round bar material according to the present invention by machining or plastic working can be made into a hollow material with a target finished outer diameter and wall thickness without using an inner surface regulating tool. The material is passed through a cross-type inclined rolling mill with three or four cone-type rolls whose cross angle and inclination angle can be adjusted according to the thickness, reducing the outer diameter and wall thickness at the same time to achieve the target value. It is characterized by including a stretching and rolling process. Although the technical content of the present invention is completely different from the above-mentioned present invention, it relates to an invention by one of the inventors of the present invention as a method in which the processing target areas are close to each other, and the present applicant has already filed an application. There is a method of manufacturing seamless pipes that is currently in use (Patent Application No. 56-22540).
The basic technical differences between this method and the method of the present invention will be mentioned. The gist of the invention of this previously filed application is that three or four rolls are arranged facing around the pass line, the axis lines of which are inclined so that the shaft ends on the same side face the same side in the circumferential direction, In addition, a cross-type inclined rolling mill in which the shaft end on the same side can be inclined (crossed) so as to approach or move away from the pass line side is used to reduce the outer diameter of the raw pipe without using an inner surface regulating tool. A method for manufacturing a seamless metal tube, characterized by including a step of processing. In other words, when the outer diameter of the raw pipe is reduced so that its wall thickness increases, the degree of wall increase is determined by using the fact that if there is uneven thickness in the raw pipe, the rate of increase in wall thickness is greater in thinner parts than in thicker parts. This is a method of correcting uneven thickness. However, according to the experiments conducted by the present inventors, the range in which the above-mentioned correction effect can be obtained is within the range where T/D is 25 to 30% or less, and beyond this range, the conventional technology can be used as is. Even if applied, it was confirmed that it is physically impossible to increase the wall thickness by drawing the outer diameter. This means that the applied technology of the existing application is naturally T/D = 25 to 30%.
It means that: On the other hand, the present invention is applicable to T/D = 25% or more, preferably 30% or more, where both the outer diameter and wall thickness can be reduced. In contrast, the method of the present invention applies so-called elongation rolling to reduce not only the outer diameter but also the wall thickness. It turns out that they are completely different. The present invention will be specifically explained below based on drawings showing its implementation state. FIG. 1 is a schematic diagram showing the process order of the method for manufacturing a hollow bar according to the present invention (hereinafter referred to as the method of the present invention). First, a round bar A ₁ (round steel Prepare _a hollow material A ₂ as shown in FIG. The inclined rolling mill 4 is heated as shown in FIG.
A round bar material that is stretched or rolled by
A ₁ is first _heated in a heating furnace 2 to a required temperature suitable for plastic working as shown in FIG. A hole is punched in the center to form a hollow bar _A2 , which is then subjected to elongation rolling using an inclined rolling mill ₄ as shown in FIG. The inclined rolling mill 4 is constructed as shown in FIG. 2 A, B, and C. FIG. 2A is a schematic front view of the hollow material A ₂ seen from the entrance side showing the condition in which the hollow material A 2 is being stretched and rolled in the inclined rolling mill 4, and FIG. 2B is the same as that shown in FIG. 2A. FIG. 2C is a side view taken along the line H--H in FIG. In addition, an inlet surface 41b and an outlet surface 41 have a truncated conical shape, with the diameter gradually decreasing toward the shaft end on one end side in the axial direction, and the diameter gradually increasing toward the shaft end on the other end side.
It is configured as a cone type with c. Each roll 41 has its entrance surface 41b side located upstream in the moving direction of the hollow material _A2 , and the intersection point O( (hereinafter referred to as role setting focus)
are located on the same plane orthogonal to the pass line XX of the hollow material _A2 , and are arranged at approximately equal intervals around the pass line XX, and are located at both ends of the shaft portions 41d, 41, respectively.
When e is supported by a bearing (not shown), its axis Y-Y is centered on the set center O, and the hollow material A ₂
In relation to the pass line XX, the required angle γ (hereinafter referred to as the intersection angle) is set so that the front end, that is, the front shaft end approaches the pass line XX in plan view as shown in FIG. ), and as shown in Fig. 2 C from a side view, the front shaft end is inclined toward the same side in the circumferential direction of the hollow material A ₂ by a required angle β (hereinafter referred to as the inclination angle). It is arranged according to the requirements. Each of the rolls 41 is connected to a drive source (not shown) and is driven to rotate in the direction of the arrow as shown in _FIG . While being rotationally driven and moved in the pass line direction, so-called spiral movement, the material is elongated and rolled under high pressure while reducing the outer diameter and wall thickness at the same time. Figures 3A, 3B, and 3C show another configuration of the elongation rolling process used in the present invention and the inclined rolling mill used therein, and Figure 3A is a schematic front view thereof as seen from the exit side of the rolling mill; Figure 3 (b) is the third
FIG. 3C is a schematic sectional view taken along the line RO-RO in FIG. 3, and FIG.
In the figure, numeral 51 indicates rolling rolls. The structure of the roll 51 itself is shown in FIG.
This is substantially the same as the embodiments shown in (b) and (c), and the attitude of the hollow material A ₂ with respect to the moving direction is reversed. That is, each roll 51 has a gorge portion 41a near one end in the axial direction, and around this gorge portion 51a, the diameter is gradually reduced toward the axial end on one end side in the axial direction, and the diameter on the other end side is gradually reduced. An exit surface 5 having a truncated conical shape whose diameter is gradually enlarged toward the end.
1c, and is configured as a cone shape with an inlet surface 51b. Each roll 51 has its entrance surface 51b side positioned upstream in the moving direction of the hollow material A ₂ , and the roll setting center O is positioned on the same plane orthogonal to the pass line XX of the hollow material A ₂ . and are arranged at approximately equal intervals around the pass line XX. The axial center line Y-Y of each roll 51 is set at an intersection angle γ such that the rear end part is separated from the pass line X-X in plan view, as shown in FIG. As shown in C, the front shaft end is inclined toward the same side of the hollow material A ₂ in the same direction by an inclination angle β. Note that the intersection angle γ of the rolls 51 of the inclined rolling mill shown in Fig. 3 A, B, and C is the angle between the hollow material A ₂ and the pass line Since the angle of the material A ₂ with respect to the pass line XX is opposite, the former case is assumed to be positive (γ>0), and the latter case is assumed to be negative (γ<0). The above-mentioned intersecting angle and inclination angle have a close relationship with the inner diameter of the hollow bar that is the product, so the relationship between the intersecting angle and inclination angle and the inner diameter can be determined in advance and the settings and controls should be adjusted appropriately according to the target value. . There are no particular limitations on the means for setting the crossing angle and the inclination angle, and the configurations conventionally used may be used as they are, or appropriate improvements may be made to increase the setting range. An example of the relationship between the crossing angle, the inclination angle, and the hole diameter is as shown in Fig. 4 A, B, and C. In each of FIGS. 4A, 4B, and 4, the horizontal axis represents the hole diameter (mm) of the hollow material before rolling, and the vertical axis represents the hole diameter (mm) of the hollow material after rolling. Note that the crossing angle γ is set to 9° for Figure 4 A, 0° for Figure 4 B, and -9° for Figure 4 C, while the inclination angles are 3°, 5°, and 7°, respectively. , 9°, 11°, 13° 6
changed in stages. All inclined rolling mills are cone-shaped three-roll type, and the material of the rolls is
An SCM with a gorge diameter of 205 mm was used. In addition, the round steel material used as the test material was S45C carbon steel, with a diameter of 70 mm and a length of 300 mm.
mm, 16 mm, and 18 mm holes are machined to make a hollow material, and this is made into a 3-roll material with the intersecting angle and inclination angle adjusted to make the outer diameter 30 mmφ without using inner surface regulating tools such as core metal. It was stretched and rolled using a cross-type inclined rolling mill at a heating temperature of 1200°C, and the hole diameters before and after rolling were detected. As is clear from this graph, when comparing the hollow material and the rolled material, both the outer diameter and wall thickness have been reduced, and the intersection angle is the value γ
= 9°, 0°, and -9°, the effect of reducing the pore diameter appears, but the reduction effect is greater when γ = 9°.
The hole diameter is maximum at ゜°, and even when the angle of inclination is changed while keeping the angle of intersection constant, the pore diameter changes. It can be seen that the pore diameter can be controlled. Next, the results of a comparative test between the method of the present invention and the conventional method will be explained. Here, in the method of the present invention, a S45C round steel bar is used as a test material, a hole is bored through this by machining, a hollow material is obtained, and this is heated to 1200°C in a heating furnace, and this is shown in Fig. 2 A and B. , C, the intersection angle is 3% (γ
= 3°), a method of producing a hollow bar by elongation rolling using a three-roll cross-type inclined rolling mill with an inclination angle of 4° (β = 4°), and a conventional method. In this process, a hole is drilled in the center of an S45C round billet, a manganese steel core is inserted into the hollow material, and this is rolled using continuous bar rolling using oval round hole rolls arranged horizontally and vertically alternately. A method of obtaining a hollow bar by rolling with a machine was used. The hollow material used was one with an outer diameter of 110 mm and an inner diameter of 30 mm. It was rolled with an outer diameter of 33 mm and an inner diameter of 11 mm as the target values, and the outer diameter, inner diameter, roundness, and uneven thickness of the hollow bar material after rolling were measured. Detected. The results are shown in Table 1. The cross section of the hollow bar obtained by the method of the present invention is shown in FIG. 5A, and the cross section of the hollow bar obtained by the conventional method is shown in FIG. 5B.

【表】この表１及び第５図イ，ロから明らかな如く本
発明方法に依つた場合は外径、肉厚、ともに従来
方法に比較して飛躍的に向上していることが解
る。以上の如く本発明方法にあつては中空素材を内
面規制具を用いることなく目標値に応じ交叉角、
傾斜角を調節した３個又は４個のコーン型ロール
を有する傾斜圧延機にて外径、肉厚をともに減じ
るべく延伸圧延を行うこととしているから、外
径、肉厚のばらつきが少なく、成品の寸法精度が
著しく向上し、また内面規制工具を用いないため
に工具単位が低く、更に交叉角、傾斜角の操作に
よつて内径を広範囲にわたつて制御することが可
能となり、全体の設備費も安価であるなど、本発
明は優れた効果を奏するものである。なお、上述の実施例はハウジングが固定で、材
料が回転する構成の場合であるが、これに限らず
例えばハウジングが回転し、材料が回転しない構
成の場合にも適用して同様の効果が得られるもの
である。[Table] As is clear from Table 1 and FIGS. 5A and 5B, it can be seen that when the method of the present invention is used, both the outer diameter and the wall thickness are dramatically improved compared to the conventional method. As described above, in the method of the present invention, the hollow material can be adjusted to the cross angle according to the target value without using an inner surface regulating device.
Since stretch rolling is performed to reduce both the outer diameter and wall thickness using an inclined rolling mill with three or four cone-shaped rolls with adjusted inclination angles, there is little variation in outer diameter and wall thickness, and the finished product is The dimensional accuracy has been significantly improved, the tool unit is small because no inner surface regulating tool is used, and the inner diameter can be controlled over a wide range by manipulating the intersection angle and inclination angle, reducing the overall equipment cost. The present invention has excellent effects such as being inexpensive. Note that although the above-mentioned embodiment is a case where the housing is fixed and the material rotates, the present invention is not limited to this, and the same effect can be obtained by applying it to, for example, a configuration where the housing rotates and the material does not rotate. It is something that can be done.

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

第１図は本発明方法をその工程順に示した模式
図、第２図イは本発明方法の実施に用いる傾斜圧
延機の模式的正面図、第２図ロは第２図イのロ−
ロ線による模式的断面図、第２図ハは第２図ロの
ハ−ハ線による模式的側面図、第３図イは本発明
方法の実施に用いる他の傾斜圧延機の模式的正面
図、第３図ロは第３図イのロ−ロ線による模式的
断面図、第３図ハは第３図ロのハ−ハ線による模
式的側面図、第４図イ，ロ，ハは交叉角、傾斜角
と中空棒材の孔径との関係を示すグラフ、第５図
イは本発明方法によつて得た中空棒材の断面図、
第５図ロは従来方法によつて得た中空棒材の断面
図、第６図は従来方法をその工程順に示す模式図
である。１……ドリル、２……加熱炉、３……押出機、
４……傾斜圧延機、４１……ロール、４１ａ……
ゴージ部、４１ｂ……入口面、４１ｃ……出口
面、５１……ロール、５１ａ……ゴージ部、５１
ｂ……入口面、５１ｃ……出口面。 FIG. 1 is a schematic diagram showing the method of the present invention in the order of its steps, FIG. 2A is a schematic front view of an inclined rolling mill used to carry out the method of the present invention, and FIG.
FIG. 2C is a schematic sectional view taken along line B, FIG. 2C is a schematic side view taken along line H--H in FIG. , Fig. 3B is a schematic cross-sectional view taken along line 3A in Fig. 3A, Fig. 3C is a schematic side view taken along line 3B in Fig. 3B, and Fig. 4A, B, and C are A graph showing the relationship between the intersecting angle, the inclination angle, and the hole diameter of the hollow bar, FIG. 5A is a cross-sectional view of the hollow bar obtained by the method of the present invention,
FIG. 5B is a sectional view of a hollow bar obtained by the conventional method, and FIG. 6 is a schematic diagram showing the conventional method in the order of its steps. 1...Drill, 2...Heating furnace, 3...Extruder,
4... inclined rolling mill, 41... roll, 41a...
Gorge part, 41b... Entrance surface, 41c... Outlet surface, 51... Roll, 51a... Gorge part, 51
b...Entrance surface, 51c...Exit surface.

Claims

【特許請求の範囲】[Claims]

１丸棒材に機械加工又は塑性加工により穿孔し
て得た肉厚／外径比が25％以上の中空素材を、内
面規制工具を用いることなく、目標とする仕上外
径、肉厚に応じて交叉角、傾斜角が調節可能な３
個又は４個のコーン型ロールを有する交叉型の傾
斜圧延機に通し、その外径を減じると同時に肉厚
をも減じて目標値に仕上げる延伸圧延工程を含む
ことを特徴とする中空棒材の製造方法。1. A hollow material with a wall thickness/outer diameter ratio of 25% or more obtained by drilling a round bar material by machining or plastic processing, without using an internal regulating tool, according to the target finished outer diameter and wall thickness. Cross angle and inclination angle can be adjusted 3
The hollow bar is passed through a cross-type inclined rolling mill having two or four cone-shaped rolls to reduce its outer diameter and at the same time reduce its wall thickness to a target value. Production method.