JP2973696B2 - Hot extrusion pipe making method - Google Patents
Hot extrusion pipe making methodInfo
- Publication number
- JP2973696B2 JP2973696B2 JP4092035A JP9203592A JP2973696B2 JP 2973696 B2 JP2973696 B2 JP 2973696B2 JP 4092035 A JP4092035 A JP 4092035A JP 9203592 A JP9203592 A JP 9203592A JP 2973696 B2 JP2973696 B2 JP 2973696B2
- Authority
- JP
- Japan
- Prior art keywords
- extrusion
- speed
- hollow billet
- mandrel
- pipe
- 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.)
- Expired - Fee Related
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- Extrusion Of Metal (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、ステンレス鋼、高合金
等の難加工性金属材からなる継目無金属管の製造に使用
される熱間押出し製管方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-extrusion pipe manufacturing method used for manufacturing a seamless metal pipe made of a hard-to-work metal material such as stainless steel or a high alloy.
【０００２】[0002]
【従来の技術】熱間押出し製管方法として代表的なユジ
ーン法では、図１に示すように、先端側にダイス１が配
されたコンテナ２内に加熱したホロービレット３を装入
し、コンテナ２内の基端側からホロービレット３の心孔
にマンドレル４を通す。そして、ホロービレット３を、
後方からダミーブロック５を介してステム６により前方
へ押しながら、マンドレル４を同期的に前進させる。こ
れにより、ダイス１とマンドレル４との間の環状の隙間
からホロービレット３が前方へ押し出される。2. Description of the Related Art In a typical hot extrusion tube making method, as shown in FIG. 1, a heated hollow billet 3 is charged into a container 2 having a die 1 disposed on the tip side, as shown in FIG. The mandrel 4 is passed through the hole of the hollow billet 3 from the base end side of the inside 2. And the hollow billet 3
The mandrel 4 is synchronously advanced from the rear while being pushed forward by the stem 6 via the dummy block 5. Thereby, the hollow billet 3 is pushed forward from the annular gap between the die 1 and the mandrel 4.
【０００３】ここで、ステム６は、水圧または油圧プレ
スを駆動源としており、そのため、ダイス２から押出さ
れる押出管７の速度は、プレスのラム速度により決定さ
れる。この押出管速度は、コンテナ２内のホロービレッ
ト３の加圧熱による発熱量や、ホロービレット３とダイ
ス１の潤滑を行う正面ガラス８の消費量を支配するた
め、押出しの全期間を通じて一定に維持される。Here, the stem 6 is driven by a hydraulic or hydraulic press, and the speed of the extruded tube 7 extruded from the die 2 is determined by the ram speed of the press. This extrusion pipe speed is constant throughout the extrusion period because it governs the amount of heat generated by pressurizing heat of the hollow billet 3 in the container 2 and the consumption of the front glass 8 for lubricating the hollow billet 3 and the die 1. Will be maintained.
【０００４】これに対して、特開昭５８−１６８４２２
号公報および特開昭５８−１７６０２０号公報には、押
出し終了時の工具停止位置精度を高めるために、押出し
終期に押出管速度を通常より低下させる熱間押出し製管
法が開示されている。On the other hand, Japanese Patent Application Laid-Open No. 58-168422 discloses
Japanese Patent Application Laid-Open No. 58-176020 and Japanese Patent Application Laid-Open No. Sho 58-176020 disclose a hot extrusion pipe manufacturing method in which the extrusion pipe speed is decreased from the ordinary speed at the end of extrusion in order to increase the accuracy of the tool stop position at the end of extrusion.
【０００５】ところで、このような熱間押出し製管法
は、難加工性金属材を容易に製管できる点で他の継目無
管製造法より優位にあり、ステンレス鋼はもとより、こ
れよりも更に加工性が悪い高合金等の製管にも多く使用
されている。熱間押出しでの加工性は捩回値や高温延性
にて評価されるが、この加工性の悪い難加工材の押出し
では、押出し途中のホロービレット温度低下による材料
詰まりや、加工中に高温高圧力を受けるマンドレルの寿
命の観点から、通常鋼の場合よりも高い押出管速度（５
〜１０ｍ／ｓ）で押出しが実施されている。[0005] Incidentally, such a hot-extrusion pipe manufacturing method is superior to other seamless pipe manufacturing methods in that a difficult-to-work metal material can be easily manufactured. It is often used for pipes made of high alloys with poor workability. Workability in hot extrusion is evaluated based on the torsion value and high-temperature ductility. However, when extruding difficult-to-process materials with poor workability, material clogging due to a drop in hollow billet temperature during extrusion and high temperature In view of the life of the mandrel under pressure, higher extruder tube speeds (5
〜１０10 m / s).
【０００６】[0006]
【発明が解決しようとする課題】このような難加工材の
熱間押出しでは、押出管のボトム部内面にヘゲ疵と呼ば
れる割れ疵が発生する頻度の高いことが知られている。
このヘゲ疵は、押出し終期にコンテナ内のホロービレッ
トの冷却が進んで押出し力が急激に大きくなり、潤滑が
充分でないホロービレット内面とマンドレル外面との間
が拘束状態となることにより生じる。これが生じると不
良部の切捨てに伴う歩留低下を招くのは勿論のこと、押
出管の内面チェックが必要となって検査作業の工数増加
を招く。It is known that in such hot extrusion of difficult-to-process materials, cracks called scabs occur frequently on the inner surface of the bottom of the extruded tube.
The burrs are caused by the fact that the hollow billet in the container is cooled at the end of the extrusion and the pushing force is rapidly increased, so that the inner surface of the hollow billet and the outer surface of the mandrel with insufficient lubrication are restricted. When this occurs, not only the yield is reduced due to the truncation of the defective part, but also the inner surface of the extruded pipe needs to be checked, which leads to an increase in the number of inspection operations.
【０００７】このヘゲ疵を防止するために、特開平１−
１３３６０９号公報には、ホロービレットとダミーブロ
ックとの間にガラス等からなるディスクを介在させる方
法が紹介されているが、作業が煩雑になるとか、押出し
終了時に未軟化のディスクがダイスに噛み込み、押出管
のボトム部外面にダイス疵を生じたりダイス寿命を損な
うといった問題を伴う。In order to prevent this scab defect, Japanese Patent Laid-Open No.
No. 133609 introduces a method of interposing a disk made of glass or the like between a hollow billet and a dummy block. However, the work becomes complicated, or an unsoftened disk bites into a die at the end of extrusion. In addition, there is a problem that a die flaw is generated on the outer surface of the bottom portion of the extruded tube or the life of the die is shortened.
【０００８】本発明の目的は、押出管のボトム部内面に
おけるヘゲ疵を防ぎ、しかも作業性悪化等の弊害を生じ
ない熱間押出し製管方法を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a hot extrusion pipe-making method which prevents burrs on the inner surface of the bottom portion of an extrusion pipe and which does not cause adverse effects such as deterioration in workability.
【０００９】[0009]
【課題を解決するための手段】ステンレス鋼等の難加工
材の熱間押出しで問題となる押出管のボトム部内面のヘ
ゲ疵は、前述したようにホロービレットの冷却が原因で
ある。これは、詳しくは図２のようなプロセスで生じ
る。As described above, the burrs on the inner surface of the bottom portion of the extruded tube, which are a problem in hot extrusion of a difficult-to-process material such as stainless steel, are caused by the cooling of the hollow billet. This occurs in a process as shown in FIG.
【００１０】押出し中、ホロービレット３はダミーブロ
ック５との接触により抜熱され、また、マンドレル４と
の接触により抜熱される。そのため、押出し終期におい
ては、マンドレル４とダミーブロック５とで囲まれ領域
に変形抵抗の大きい低温部３ａが生じる。低温部３ａは
マンドレル４の外面およびダミーブロック５の前面に強
固に付着し、後向きの拘束張力ｆb を生じる。一方、低
温部３ａの前方にある非低温部３ｂは、変形抵抗が小さ
く、低温部３ａに沿って前方へのメタルフローを生じ、
低温部３ａとの間に流動による剪断力をｆs を生じる。
その結果、低温部３ａと非低温部３ｂとの境界のマンド
レル４に接する部分では、ｆb およびｆs が相乗して大
きな剪断力を生じヘゲ疵に至る。During extrusion, the hollow billet 3 is removed by contact with the dummy block 5 and is removed by contact with the mandrel 4. Therefore, at the end of the extrusion, a low-temperature portion 3a having a large deformation resistance is generated in a region surrounded by the mandrel 4 and the dummy block 5. Low temperature portion 3a is firmly adhered to the front surface of the outer surface and the dummy block 5 of the mandrel 4, resulting in rearward restraining tension f b. On the other hand, the non-low-temperature portion 3b in front of the low-temperature portion 3a has a small deformation resistance, causing a metal flow forward along the low-temperature portion 3a,
The shear force due to the flow between the low-temperature portion 3a cause f s.
As a result, the portion in contact with the mandrel 4 of the boundary between the low temperature portion 3a and the non-low-temperature portion 3b, f b and f s reaches the scab defects caused a large shearing force synergistically.
【００１１】このとき、ホロービレットの内面に生じる
剪断力を上回る延性がホロービレットにあれば、ヘゲ疵
は生じない。普通鋼等の加工性が良好な鋼材の押出しで
ヘゲ疵が生じないものこのためである。At this time, if the hollow billet has ductility exceeding the shearing force generated on the inner surface of the hollow billet, no barbed flaw is generated. Extrusion of a steel material having good workability, such as ordinary steel, does not cause bark flaws.
【００１２】本発明者らは、難加工材の熱間押出しでの
ヘゲ疵を防ぐために、種々実験を繰り返した結果、ホロ
ービレットボトム部の押出速度を低下させるのが有効な
ことを知見した。これは、ホロービレットの押出速度の
低下が、その内面に発生する剪断力を低下させているた
めと考えられる。The present inventors have repeated various experiments in order to prevent scabs in hot extrusion of difficult-to-process materials, and have found that it is effective to reduce the extrusion speed of the hollow billet bottom portion. . It is considered that this is because the reduction in the extrusion speed of the hollow billet reduces the shearing force generated on the inner surface thereof.
【００１３】本発明はかかる知見に基づきなされたもの
で、先端側にダイスを配したコンテナ内に、ステンレス
鋼またはそれより加工性の悪い金属材からなるホロービ
レットを加熱して装入し、そのホロービレットの心孔に
マンドレルを通した状態で、マンドレルを前進させなが
らホロービレットを後方からステムにより押して、ダイ
スとマンドレルとの間からホロービレットを押出す熱間
押出し製管方法において、押出管のボトム端部の長さ
０．５〜２．０ｍにおける押出管速度を０．５〜３ｍ／
ｓに低下させることを特徴とする熱間押出製管方法を要
旨とする。The present invention has been made based on this finding, and a hollow billet made of stainless steel or a metal material having a lower workability is heated and charged into a container provided with a die on the tip side. With the mandrel passed through the core hole of the hollow billet, the hollow billet is pushed by the stem from the rear while the mandrel is advanced, and the hollow billet is extruded from between the die and the mandrel . Bottom end length
The extrusion tube speed at 0.5 to 2.0 m is set to 0.5 to 3 m /
The present invention provides a hot-extrusion pipe-making method characterized by lowering the temperature to s.
【００１４】[0014]
【作用】図３は本発明法における押出管速度の基本的な
変化パターンを示す。押出管速度の低下は、ホロービレ
ット押出速度の低下を意味し、押出し終期にこれが３ｍ
／ｓ以下に低下する減速を行うことにより、難加工材の
熱間押出しでの押出管のボトム部内面のヘゲ疵が防止さ
れる。減速期間中（低速押出中）の押出管速度の下限
は、極端な速度低下は押出し終期といえどもホロービレ
ットの温度低下やプレスの制御安定性を欠くので、0.５
ｍ／ｓ以上とする。FIG. 3 shows a basic change pattern of the extrusion tube speed in the method of the present invention. A decrease in the extrusion pipe speed means a decrease in the hollow billet extrusion speed, which is 3 m at the end of extrusion.
By performing the deceleration that is reduced to not more than / s, the burrs on the inner surface of the bottom portion of the extruded tube in the hot extrusion of the difficult-to-process material are prevented. Since the lower limit of the extruded tube velocity in the deceleration period (low and middle speed extrusion) is extreme slowdown lacks control stability of the temperature drop and press the hollow billet even the extrusion end, 0.5
and m / s or more.
【００１５】０．５〜３ｍ／ｓの押出管速度は、ステン
レス鋼の熱間押出しでは、通常速度（５〜１０ｍ／ｓ）
のほぼ１／２以下に相当し、加工性の劣る材料ほど低速
とするのがよい。The extruded tube velocity of 0.5-3 m / s, in the hot extrusion of stainless steel, normal speed (5 to 10 m / s)
It is preferable that the lower the material, the lower the workability.
【００１６】押出管速度の低下、即ち低速押出を開始す
る時期は、定性的には、ヘゲ疵の原因となる大きな剪断
力がホロービレットのボトム部内面に発生する前と説明
される。しかし、早くから速度を低下させると、製管能
率が低下するだけでなく、むしろホロービレットの温度
低下を助長し、押滓重量増加に伴う歩留低下やホロービ
レット内面の潤滑剤ガラス粘度増大による潤滑不良等の
弊害を生じる。このようなことから、押出管速度の減速
期間（低速押出期間）は、押出管のボトム端部の長さで
表わして0.５〜2.０ｍとし、加工性の劣る材料ほど早く
低速押出を開始するのがよい。It is qualitatively described that the time at which the extrusion pipe speed is reduced, that is, the time at which low-speed extrusion is started, is before a large shear force causing a flaw is generated on the inner surface of the bottom of the hollow billet. However, if the speed is reduced from an early stage, not only does the pipe production efficiency decrease, but it also promotes a decrease in the temperature of the hollow billet, resulting in a decrease in the yield due to an increase in the weight of the slag and an increase in the viscosity of the lubricant glass on the inner surface of the hollow billet. It causes adverse effects such as defects. For this reason, deceleration period of the extruded tube speed (low extrusion period), and 0.5~2.0m represents the length of the bottom end of the extruded tube, as fast as the material having inferior workability
It is good to start low speed extrusion .
【００１７】なお、押出し終期に押出管速度を通常より
低下させる熱間押出製管法は、特開昭５８−１６８４２
２号公報および特開昭５８−１７６０２０号公報に開示
されているが、この方法は押出管速度のレベルからして
アルミニウム等の易加工性非鉄金属を対象としたものと
推定される。アルミニウム等の易加工性非鉄金属は通常
0.１ｍ／ｓ程度の極低速で押出しが行われ、また、前記
開示法における押出速度低下の目的は押出し終了時の工
具停止位置精度の改善にある。従って、前記開示法は本
発明法に一見類似しているが、本質は無関係なものであ
る。Incidentally, a hot extrusion pipe manufacturing method in which the speed of the extrusion pipe is decreased from the ordinary speed at the end of the extrusion is disclosed in Japanese Patent Application Laid-Open No. 58-16842.
No. 2 and JP-A-58-176020, it is presumed that this method is intended for easily workable non-ferrous metals such as aluminum from the level of the extrusion tube speed. Non-ferrous metals, such as aluminum, are usually
The extrusion is performed at an extremely low speed of about 0.1 m / s, and the purpose of the reduction of the extrusion speed in the disclosed method is to improve the accuracy of the tool stop position at the end of the extrusion. Accordingly, the disclosed method is seemingly similar to the present invention, but is irrelevant in nature.
【００１８】[0018]
【実施例】以下に本発明の実施例を説明する。Embodiments of the present invention will be described below.
【００１９】ＳＵＳ３０４鋼からなる外径２０７ｍｍ×
内径５０ｍｍ×長さ７００ｍｍのホロービレットを外径
６３ｍｍ×肉厚８ｍｍに押出した。マンドレルは、ＪＩ
ＳＳＫＤ６１を機械加工し、焼入れ・焼戻しにより所定
の機械的性質を付与した後、表面に硬質クロムめっきを
施した外径４７ｍｍのものを使用した。本押出しにおけ
る押出管速度の標準値は６ｍ／ｓである。この標準値に
対し、押出し終期の押出管速度を２，３，4.５ｍ／ｓに
低下させた。減速期間（低速押出期間）は、押出管のボ
トム端部の長さで表わして１ｍとした。参考のために、
押出しの全期間を２，３，4.５ｍ／ｓの押出管速度とし
て押出しを行った。Outer diameter 207 mm x made of SUS304 steel
A hollow billet having an inner diameter of 50 mm and a length of 700 mm was extruded to an outer diameter of 63 mm and a wall thickness of 8 mm. Mandrel is JI
SSKD61 was machined, given predetermined mechanical properties by quenching and tempering, and then having a surface with hard chrome plating and having an outer diameter of 47 mm was used. The standard value of the extrusion pipe speed in the main extrusion is 6 m / s. The extrusion tube speed at the end of extrusion was reduced to 2, 3, 4.5 m / s with respect to this standard value. The deceleration period (low-speed extrusion period) was 1 m as expressed by the length of the bottom end of the extrusion tube. for reference,
Extrusion was carried out at an extrusion tube speed of 2, 3, 4.5 m / s during the entire extrusion period.
【００２０】各条件での押出管のボトム部内面のヘゲ疵
発生状況およびマンドレル寿命を表１に示す。マンドレ
ル寿命は、マンドレル表面に肌荒れ、焼付けが生じて再
使用に耐え得なくなるまでの総押出し本数で評価した。Table 1 shows the occurrence of barbed flaws on the inner surface of the bottom of the extruded tube and the mandrel life under each condition. The mandrel life was evaluated in terms of the total number of extrusions until the surface of the mandrel became rough and was baked and could not withstand reuse.
【００２１】[0021]
【表１】 [Table 1]
【００２２】No. １〜４は、押出し終期の減速（低速押
出）を行わずに、押出しの全期間を一定速度で押出した
方法である。押出管速度が６ｍ／ｓの従来法は、高速押
出しによるマンドレル寿命改善の目的は達成している
が、押出管ボトム部の内面ヘゲ疵の発生率が高く、ボト
ム部切り捨てによる歩留り低下を避け得ない。また、全
ての押出管についてボトム部の内面調査が必要となり、
作業性が悪化する。押出管速度を低下させると、ヘゲ疵
の発生率は低下するが、マンドレル寿命は低下する。押
出し中にビレットの冷却が進み、当然の結果である。Nos. 1-4 are deceleration at the end of extrusion (low speed pressing).
This is a method in which extruding is performed at a constant speed throughout the entire period of extrusion. The conventional method with an extrusion pipe speed of 6 m / s has achieved the purpose of improving the life of the mandrel by high-speed extrusion, but has a high incidence rate of internal burrs on the bottom of the extrusion pipe, and avoids a decrease in yield due to truncation of the bottom. I can't get it. In addition, it is necessary to investigate the inner surface of the bottom of all extruded tubes,
Workability deteriorates. When the extrusion tube speed is reduced, the rate of occurrence of barbed flaws is reduced, but the mandrel life is reduced. Cooling of the billet proceeds during extrusion, a natural consequence.
【００２３】No. ５〜７は、６ｍ／ｓの押出管速度に対
し、押出し終期のみを減速させて低速で押出した場合で
ある。低速押出時の押出管速度を３ｍ／ｓ、２ｍ／ｓと
した本発明法では、押出管ボトム部の内面ヘゲ疵が完全
に防止され、しかも、高速押出しによるマンドレル寿命
改善の効果が享受される。ただし、低速押出時の押出管
速度が３ｍ／ｓを超えると、ヘゲ疵が発生し始める。Nos. 5 to 7 are cases where the extrusion speed was reduced only at the end of extrusion at a low extrusion speed of 6 m / s. According to the method of the present invention in which the extrusion pipe speed at the time of low-speed extrusion is 3 m / s and 2 m / s, the inner surface of the bottom of the extrusion pipe is completely prevented from fraying, and the effect of improving the mandrel life by high-speed extrusion is enjoyed. You. However, when the extrusion pipe speed at the time of low-speed extrusion exceeds 3 m / s, scabs begin to occur.
【００２４】[0024]
【発明の効果】以上の説明から明らかなように、本発明
の熱間押出し製管方法は、ステンレス鋼等の難加工材を
製管する場合の押出管ボトム部の内面ヘゲ疵を防止し、
しかも、高速押出しによるマンドレル寿命延長等の効果
を阻害しない。更に、ヘゲ疵の防止を圧延管速度の変更
で実現し、潤滑ディスク等を必要としないので、作業を
煩雑にせず、未軟化ガラスの噛み込みによるダイス疵等
の弊害を派生させるおそれもない。As is apparent from the above description, the hot extrusion pipe making method of the present invention prevents the inner surface of the extruded pipe bottom from being scorched when a difficult-to-process material such as stainless steel is made. ,
Moreover, the effect of extending the mandrel life by high-speed extrusion is not impaired. Furthermore, since the prevention of bark flaws is realized by changing the rolling tube speed and no lubrication disk is required, the operation is not complicated, and there is no danger of detrimental effects such as die flaws caused by the bite of unsoftened glass. .
【図１】熱間押出し製管法の概念を示す断面図である。FIG. 1 is a cross-sectional view showing the concept of a hot extrusion pipe manufacturing method.
【図２】ヘゲ疵の発生メカニズムを概念的に示す断面図
である。FIG. 2 is a cross-sectional view conceptually showing a generation mechanism of a barbed flaw.
【図３】本発明法における製管速度パターンの概念図で
ある。FIG. 3 is a conceptual diagram of a pipe production speed pattern in the method of the present invention.
１ ダイス ２ コンテナ ３ ホロービレット ４ マンドレル ５ ダミーブロック ６ ステム ７ 押出管 Reference Signs List 1 die 2 container 3 hollow billet 4 mandrel 5 dummy block 6 stem 7 extrusion tube
Claims (1)
ステンレス鋼またはそれより加工性の悪い金属材からな
るホロービレットを加熱して装入し、そのホロービレッ
トの心孔にマンドレルを通した状態で、マンドレルを前
進させながらホロービレットを後方からステムにより押
して、ダイスとマンドレルとの間からホロービレットを
押出す熱間押出し製管方法において、押出管のボトム端
部の長さ０．５〜２．０ｍにおける押出管速度を０．５
〜３ｍ／ｓに低下させることを特徴とする熱間押出製管
方法。1. A container in which a die is arranged on a tip side,
A hollow billet made of stainless steel or a metal material with lower workability is heated and charged, and the hollow billet is pushed forward by the stem while the mandrel is advanced while the mandrel is passed through the mandrel in the hole of the hollow billet. In a hot extrusion pipe making method for extruding a hollow billet between a die and a mandrel, a bottom end of an extruded pipe is formed.
The extruding tube speed at a part length of 0.5 to 2.0 m is 0.5
A hot extrusion pipe-making method characterized by lowering to 3 m / s .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4092035A JP2973696B2 (en) | 1992-03-17 | 1992-03-17 | Hot extrusion pipe making method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4092035A JP2973696B2 (en) | 1992-03-17 | 1992-03-17 | Hot extrusion pipe making method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05261427A JPH05261427A (en) | 1993-10-12 |
| JP2973696B2 true JP2973696B2 (en) | 1999-11-08 |
Family
ID=14043277
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4092035A Expired - Fee Related JP2973696B2 (en) | 1992-03-17 | 1992-03-17 | Hot extrusion pipe making method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2973696B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4420140B2 (en) | 2008-06-13 | 2010-02-24 | 住友金属工業株式会社 | High alloy seamless pipe manufacturing method |
| JP4692650B2 (en) | 2009-02-13 | 2011-06-01 | 住友金属工業株式会社 | Seamless pipe manufacturing method |
-
1992
- 1992-03-17 JP JP4092035A patent/JP2973696B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05261427A (en) | 1993-10-12 |
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