JP3103496B2 - Joining method of hot rough bar - Google Patents
Joining method of hot rough barInfo
- Publication number
- JP3103496B2 JP3103496B2 JP07209309A JP20930995A JP3103496B2 JP 3103496 B2 JP3103496 B2 JP 3103496B2 JP 07209309 A JP07209309 A JP 07209309A JP 20930995 A JP20930995 A JP 20930995A JP 3103496 B2 JP3103496 B2 JP 3103496B2
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- Japan
- Prior art keywords
- welding
- rolling
- joining
- bar
- thickness
- Prior art date
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- Metal Rolling (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、熱間圧延分野にお
いて、熱間粗バーを数本から数十本をつなぎ合わせて、
仕上げの熱間連続圧延を破断なく連続的に行うための接
合方法に関する。The present invention relates to the field of hot rolling in the field of hot rolling by joining several to several tens of hot rough bars.
The present invention relates to a joining method for continuously performing hot continuous rolling without breaking.
【０００２】[0002]
【従来の技術】従来の熱延ラインでは、スラブを１本ず
つ加熱−粗圧延−仕上げ圧延を行っていたが、この方法
では、圧延される材料の先端・後端部分の熱延時の温度
制御や冷却制御が困難なため、材質不良や疵発生を起こ
し易く、歩留りの低下を招いていた。そこで近年では、
この問題の解決のため、仕上げ連続圧延の前で、粗バー
を接合し、数本から数十本をまとめて仕上げ圧延を行う
方式が採用されるようになってきた。このための粗バー
の接合方法としては、各種の提案がなされており、例え
ば、特開平４−２８８９０６号公報、特開平５−１０４
１０７号公報では両端部を接触させ、断面は幅両端部よ
り幅中央部が厚くなるバー端面形状を圧延する方法を提
案している。特公平５−６２０３５号公報では、長手方
向で先行圧延材の後端部と後行圧延材の先端部を重ね合
わせて切断するため、厚み方向で全面接触する方法を提
案している。また、特公平４−６４４１号公報では端面
をプレスによって薄くすることで、接合厚を減らす試み
がなされている。2. Description of the Related Art In a conventional hot rolling line, heating-rough rolling-finish rolling of slabs is performed one by one. However, according to this method, temperature control at the time of hot rolling of a front end portion and a rear end portion of a material to be rolled is performed. And it is difficult to control the cooling, which is liable to cause a defective material or a flaw, thereby lowering the yield. So in recent years,
In order to solve this problem, a method has been adopted in which a rough bar is joined before finish continuous rolling, and several to several tens of finish bars are collectively subjected to finish rolling. Various proposals have been made on the method of joining the rough bars for this purpose, for example, Japanese Patent Application Laid-Open Nos. 4-288906 and 5-104.
No. 107 proposes a method in which both ends are brought into contact with each other and a bar end surface shape in which the cross section is thicker at the center in width than at both ends in width is proposed. Japanese Patent Publication No. 5-62035 proposes a method in which the rear end portion of a preceding rolled material and the front end portion of a subsequent rolled material are overlapped and cut in the longitudinal direction, so that the entire surface is brought into contact in the thickness direction. In Japanese Patent Publication No. 4-6441, an attempt is made to reduce the joining thickness by making the end face thinner by pressing.
【０００３】[0003]
【発明が解決しようとする課題】粗バーの接合で重要な
点は、接合部分が仕上げ圧延から巻き取るまでの間で破
断を起こさないことである。ここではスタンド間、コイ
ラーまでの間で張力が設定されるため、接合部は圧延を
繰り返しながらも張力以上の接合部強度を確保する必要
がある。設定される最大張力はミルにより異なるが２〜
４ｋｇｆ／ｍｍ2程度、また、１１００℃程度の鋼材の
熱間引張強度は引張速度によって異なるが４〜８ｋｇｆ
／ｍｍ2 程度であり、概算検討では最も厳しい条件下
（極薄材圧延時の仕上げ後段張力が最も高く、必要強度
も大）断面の１／２程度の接合が必要となる。しかし、
接合面積が大きいと溶接に時間がかかり、鋼材の温度低
下を招き接合されて破断を起こさなかったとしてもＡｒ
3 変態点以下の圧延になるため、表層に粗大粒が発生し
て加工性に悪影響を及ぼす。このため、溶接後の圧延に
よって界面の接合部を増加する方法が検討されている。An important point in the joining of the rough bars is that the joining portion does not break between finish rolling and winding. Here, since tension is set between the stands and the coiler, it is necessary to secure the joint strength higher than the tension while repeating rolling at the joint. The maximum tension to be set depends on the mill,
The hot tensile strength of steel at about 4 kgf / mm 2 and about 1100 ° C. varies depending on the tensile speed, but is 4 to 8 kgf.
/ Mm 2 , and the roughest study requires about 1/2 of the cross section of the cross section under the most severe conditions (the highest post-stage tension during rolling of ultra-thin material and the required strength is also large). But,
If the joint area is large, it takes time to weld, and even if the joint does not break due to a decrease in the temperature of the steel material,
Since the rolling is performed at three transformation points or less, coarse grains are generated on the surface layer, which adversely affects workability. For this reason, a method of increasing the number of joints at the interface by rolling after welding has been studied.
【０００４】しかし、上記の方法では、初期圧延におい
て接触面の押しつけ力が小さく、圧着力が不十分で接合
不良が発生するため、溶接としての接合エネルギーを増
大させるか押しつけ力を増大させる必要があり、エネル
ギー効率が非常に悪い。また、特公平４−６４４１号公
報で示されるごとく、プレスによって厚みを減少させる
と両断面が膨れるため、そのまま突き合わせると接合面
積が小さくなりすぎるため、結局、さらにシャーで切断
する必要が生じ、端面温度が低下してしまう。また、プ
レス成形では、温度低下防止のため極力圧延材との接触
面を減らす必要があり、ポンチ径は小さくなる。このた
め、圧延材とポンチの接点部分が鋼材中に入り込んで疵
の原因となる。本発明は上記の問題を解決し、初期圧延
による圧着を十分に活用するための端面の接合方法、お
よび初期圧延の条件を提供することを目的とする。However, in the above-mentioned method, in the initial rolling, the pressing force on the contact surface is small, and the bonding force is insufficient due to insufficient pressing force. Therefore, it is necessary to increase the joining energy as welding or increase the pressing force. Yes, very poor energy efficiency. Also, as shown in Japanese Patent Publication No. 4-6441, the thickness is reduced by pressing, so that both cross sections swell, and if they are directly abutted, the joining area becomes too small. The end face temperature decreases. In press molding, it is necessary to reduce the contact surface with the rolled material as much as possible in order to prevent a temperature drop, and the punch diameter is reduced. For this reason, the contact portion between the rolled material and the punch enters the steel material and causes a flaw. An object of the present invention is to solve the above-mentioned problems and to provide a method of joining the end faces to make full use of crimping by initial rolling, and to provide conditions for initial rolling.
【０００５】[0005]
【課題を解決するための手段】上記課題を解決するため
の本発明の構成は、完全連続化を狙った熱延ラインのバ
ー接合に供するバー厚（ｔ）の先行、後行の粗バーの両
端部を突き合わせ、溶接する断面の上部または下部もし
くは両方を開先角度９０°以上の開先状態にし、実質溶
接可能厚範囲を０．３〜０．８ｔとした後、この溶接可
能部を不可避的未溶接部を除き全幅を厚み方向２０％以
上を溶接した後、３秒以上３０秒以内で初期圧延率３５
〜７０％の圧延を開始することを特徴としており、鋼材
の両端部から５０ｍｍ以上、好ましくは１００ｍｍ以上
の厚み方向溶接率を３０％以上とすることによって、端
部の耳割れ防止を可能とする。さらに粗バーの溶接後、
仕上げ圧延終了まで、接合部の位置をパスライン上の０
〜５００ｍｍとすることによって、接合部の強度をさら
に高めることができる。The structure of the present invention for solving the above-mentioned problems is based on the following: the leading and trailing coarse bars of the bar thickness (t) used for the bar joining of the hot-rolled line aiming at complete continuity. Both ends are butted, and the upper or lower part or both of the sections to be welded are in a groove state with a groove angle of 90 ° or more, and the actual weldable thickness range is 0.3 to 0.8 t. After welding 20% or more of the entire width in the thickness direction except for the target unwelded portion, the initial rolling reduction 35
It is characterized by starting rolling of up to 70%, and by preventing a thickness direction welding rate of 50 mm or more, preferably 100 mm or more from both ends of the steel material to 30% or more, it is possible to prevent edge cracks at the ends. . After further welding of the coarse bar,
Until finish rolling is completed, the position of the joint is set to 0 on the pass line.
By setting the thickness to 500 mm, the strength of the joint can be further increased.
【０００６】[0006]
【作用】粗バーの接合においては、全厚全幅を溶接する
ことが理想的であるが、冷片を溶接するのと異なり、限
られた時間内で溶接を終了させる必要がある。その理由
は、以下のとおりである。 、連続的に仕上げ圧延を続けるため、接合するシート
バーは移動しながらの接合となり、仕上げ開始前に溶接
を終了させるため時間的制約がある。 、の移動速度が遅い場合、仕上げ圧延温度が低下し
てしまい、所定の材質が得られなくなる。このため、温
度確保のため早急な溶接が必要。このため、時間、温度
確保の点で効率的な接合が必要である。工程順に必要な
項目を説明する。まず、溶接する先行、後行の端面につ
いては、突き合わせたときに溶接可能な面にしておく必
要がある。このため、溶接の前に両端面をシャーなどの
切断によって揃える必要がある。先行、後行バーの突き
合わせではできるだけ接合部を増やすために切断線は圧
延方向に対して直角にするほうがよい。溶接可能面積
は、両端部を突き合わせた時に接触する部分および突き
合わせ時には若干隙間があっても溶接によって十分接触
する可能性を有する（３ｍｍ以内）部分を意味する。溶
接率をかせぐために可能面積はできる限り広い方が好ま
しい。In the joining of a rough bar, it is ideal to weld the entire thickness and width, but unlike welding a cold piece, the welding must be completed within a limited time. The reason is as follows. In addition, since the finish rolling is continuously performed, the sheet bar to be joined is joined while moving, and there is a time constraint for terminating the welding before starting the finishing. If the moving speed is slow, the finish rolling temperature decreases, and a predetermined material cannot be obtained. Therefore, immediate welding is necessary to secure the temperature. Therefore, efficient joining is required in terms of securing time and temperature. Necessary items will be described in the order of steps. First, the leading and trailing end surfaces to be welded must be weldable surfaces when they are butted together. For this reason, both ends need to be aligned by cutting with a shear or the like before welding. In the butting of the leading and trailing bars, it is better to make the cutting line perpendicular to the rolling direction in order to increase the number of joints as much as possible. The weldable area means a portion that comes into contact when both ends are butted and a portion that has a possibility (within 3 mm) that there is a possibility of making sufficient contact by welding even if there is a slight gap at the time of butting. In order to increase the welding rate, it is preferable that the possible area is as large as possible.
【０００７】必要な接合強度は、仕上げ圧延における張
力によって決まり、接合部強度はこの張力以上が必要で
ある。張力は仕上げ圧延の後半ほど高くなる。本発明者
らは、突き合わせ時の端部長手方向の形状の影響につい
て調査を行った。その結果、端部開先形状が初期圧延後
の接合比率に大きな影響を及ぼすことが明らかになっ
た。開先の開口部の角度が広い場合は、圧延時に開口深
さ分だけ圧下されないため、実質的には接触部の接合比
率が残存する。このため、溶接による溶接深さが一定で
あれば、開口部が深いほど残存接合比率が高くなる。こ
の方法では、接合強度を確保しながら初期溶接面積を減
らすことが可能である。[0007] The required bonding strength is determined by the tension in the finish rolling, and the bonding strength needs to be higher than this tension. Tension increases in the latter half of finish rolling. The present inventors investigated the influence of the shape in the longitudinal direction of the end portion at the time of abutting. As a result, it became clear that the edge groove shape had a great effect on the joining ratio after the initial rolling. If the angle of the opening of the groove is wide, it is not reduced by the opening depth during rolling, so that the joining ratio of the contact portion substantially remains. For this reason, if the welding depth by welding is constant, the deeper the opening, the higher the remaining joining ratio. With this method, it is possible to reduce the initial welding area while securing the joining strength.
【０００８】この開口部深さは、浅いと溶接面積減少の
効果がなくなり、深いと接合強度の確保が困難になるた
め適度の範囲が存在する。本発明者らの調査の結果、有
効な開口部深さはバー厚の２０〜８０％であった。ま
た、開口部の角度も圧延後接合率に影響する。角度が狭
い場合、開口部は圧延によって倒れ込み、へげ状欠陥と
なるが、広いと倒れ込みはなく、上述の効果が得られ
る。この角度は９０°以上で有効になり、シャーなどに
よる端部切断時に形状調整しておくことが重要である。
スラブの温度低下、表面スケール生成防止の観点から、
切断後はできるだけ早急に溶接可能状態にすることが肝
要である。When the opening depth is shallow, the effect of reducing the welding area is lost, and when the opening depth is deep, it is difficult to secure the joining strength, so that there is an appropriate range. Our investigations have shown that the effective opening depth is 20-80% of the bar thickness. The angle of the opening also affects the joining ratio after rolling. When the angle is small, the opening falls down due to rolling, resulting in a barbed defect. However, when the opening is wide, there is no falling down, and the above-described effect is obtained. This angle becomes effective at 90 ° or more, and it is important to adjust the shape when cutting the end with a shear or the like.
From the viewpoint of lowering the temperature of the slab and preventing the generation of surface scale,
After cutting, it is important to make the weldable state as soon as possible.
【０００９】次に溶接の条件について記す。目的の粗バ
ー端面を全幅全厚溶接するには、現在の溶接方法による
溶接速度は不十分である。最も出力が高いレーザーを用
いた場合でも、バー厚２５ｍｍの溶接速度は４ｃｍ／秒
程度であり、２ｍ幅の鋼板の溶接には５０秒が必要にな
る。この時間では、時間的制約・温度低下共に問題であ
る。溶接速度を早めると溶接深さは浅くなる。バー接合
を効率的に行うためには、浅い溶接深さでも十分溶接強
度を確保できることが重要である。発明者らの調査によ
ると、バー厚の２０％以上の溶接率があれば破断を起こ
さず仕上げ通板が可能である。この溶接率は、上述のご
とく０．３〜０．８ｔの接触厚を持つ開先付き接合端部
であれば、圧延後の接合部比率は２５〜１００％にな
り、初期圧延時の強度確保は十分である。さらに以降の
圧着により接合強度は増加する。Next, welding conditions will be described. The welding speed of the current welding method is insufficient to weld the desired coarse bar end face to the entire width and thickness. Even when the laser with the highest output is used, the welding speed for a bar thickness of 25 mm is about 4 cm / sec, and welding of a steel plate having a width of 2 m requires 50 seconds. At this time, there are problems with both time constraints and temperature drop. Increasing the welding speed decreases the welding depth. In order to perform bar joining efficiently, it is important that sufficient welding strength can be ensured even at a shallow welding depth. According to the investigation by the inventors, if the welding rate is equal to or more than 20% of the bar thickness, the finished threading can be performed without breaking. If the welding rate is a joint end with a groove having a contact thickness of 0.3 to 0.8 t as described above, the joint ratio after rolling is 25 to 100%, and strength is secured during initial rolling. Is enough. Further, the bonding strength is increased by the subsequent pressing.
【００１０】溶接後圧延までは、溶接部は溶融〜凝固の
状態である。溶融状態では強度確保ができないため、直
ちに圧延することはできない。しかし、溶接時の溶融幅
を４ｍｍ以内にすることで凝固速度は早くなり、溶接後
約１秒で凝固し、３秒後には連続圧延操業で発生してい
る張力や圧延による負荷でも破断しない強度を確保でき
るようになる。溶融幅を１ｍｍ以下にするためには高い
溶接精度が必要となり、ハード・ソフト上非常に難しく
なる。溶接−凝固後は、仕上げ温度確保の観点からでき
るだけ早く圧延したほうがよく、圧延までの時間が３０
秒を超えると温度低下により材質を劣化させてしまう。[0010] Until rolling after welding, the welded portion is in a molten to solidified state. Since the strength cannot be secured in the molten state, it cannot be rolled immediately. However, by setting the melting width during welding to within 4 mm, the solidification speed increases, solidifies in about 1 second after welding, and after 3 seconds, the strength that does not break even under the tension generated by continuous rolling operation or the load due to rolling. Can be secured. In order to reduce the melting width to 1 mm or less, high welding accuracy is required, which is extremely difficult in terms of hardware and software. After welding and solidification, it is better to roll as soon as possible from the viewpoint of securing the finishing temperature.
If the time exceeds seconds, the material is deteriorated due to the temperature drop.
【００１１】溶接後の初期圧下条件は、圧着に対して重
要である。まずロール径、圧下率は開口部との関係で圧
延後の接合部比率に影響する。ロール径が大きくなるほ
ど接触弧長が長くなるため先行材の押しつけ力を後行材
が受け易くなり、圧着しやすい。また、ロール径が小さ
いと開口部への力は開先を広げる方向に働くため、溶接
部を引き裂くことになる。これより、ロール径は大きい
ほどよい。ロール径を大きくしても、板厚が薄いと接触
弧長は短くなる。したがって、接触弧長が長くなるバー
厚が厚いうち、すなわち初期圧下の時に３５％以上の大
きな圧下を加えることが圧着に対して有効になる。しか
し、１パスの圧下率には限界があるため、初期圧下率上
限は７０％とした。[0011] The initial rolling reduction condition after welding is important for crimping. First, the roll diameter and the reduction ratio affect the joint ratio after rolling in relation to the opening. The larger the roll diameter is, the longer the contact arc length is, so that the subsequent material is more likely to receive the pressing force of the preceding material and is easily pressed. In addition, when the roll diameter is small, the force to the opening acts in the direction to widen the groove, so that the weld is torn. Thus, the larger the roll diameter, the better. Even if the roll diameter is increased, if the plate thickness is small, the contact arc length becomes short. Therefore, while the bar thickness at which the contact arc length is long is large, that is, applying a large reduction of 35% or more at the time of initial reduction is effective for crimping. However, since the rolling reduction of one pass is limited, the upper limit of the initial rolling reduction was set to 70%.
【００１２】以上が接合強度を確保するための基本的条
件となるが、溶接率が低いと張力が高い両端部から割れ
が発生してくる。この耳割れが発生しても破断なく通板
できれば問題はないが、トラブル発生比率が高まるため
可能なら回避した方がよい。これには、張力が発生する
端部の強度を確保しておけばよく、両端部から幅中央に
向けて５０ｍｍ以上、好ましくは１００ｍｍ以内の厚み
方向の溶接率を３０％以上にすることで十分耳割れを回
避することができる。また、圧延によって圧着された接
触界面は、曲げ力に対して弱いため、圧延中はできるだ
けパスライン上にあることが好ましい。５．５ｍの圧延
スタンド間での曲げの影響について調査した結果、パス
ライン上の０〜５００ｍｍの高さ範囲であれば曲げの影
響なく通板できた。しかし、これを超えるとスタンド間
での破断などのトラブルが発生した。The above is the basic condition for securing the joining strength. However, when the welding rate is low, cracks occur from both ends where the tension is high. There is no problem if this cracking occurs, as long as it can be passed without breakage. However, since the trouble occurrence ratio increases, it is better to avoid it if possible. For this purpose, it is sufficient to secure the strength of the end where the tension is generated, and it is sufficient to set the welding rate in the thickness direction of 50 mm or more, preferably 100 mm or less from both ends to the center of the width to 30% or more. Ear cracks can be avoided. In addition, since the contact interface pressed by rolling is weak against bending force, it is preferable that the contact interface be on the pass line as much as possible during rolling. As a result of investigating the effect of bending between the 5.5 m rolling stands, it was possible to pass the plate without the effect of bending in the height range of 0 to 500 mm on the pass line. However, exceeding this caused troubles such as breakage between stands.
【００１３】[0013]
【実施例】次に、本発明の実施例を比較例とともに説明
する。鋼材は、表１に示す３鋼種を用いた。Next, examples of the present invention will be described together with comparative examples. As steel materials, three steel types shown in Table 1 were used.
【００１４】[0014]
【表１】 [Table 1]
【００１５】バー厚２５〜４０ｍｍの材料をシャー切断
条件を変えて切断し、付き合わせてレーザー溶接を行っ
た。溶接した材料は圧延までの時間、溶接後最初の圧下
率、圧下温度を変えて圧延し、７パスの仕上げ通板を行
った。仕上げ圧延の各スタンド間は５．５ｍであり、こ
の間で上下するルーパーの高さから、仕上げ圧延間で得
られるパスライン上の最大高さを測定した。以上の実施
例について、巻取りまでの間での破断の有無、最終接合
率、また、巻取り後の観察から幅両端部の耳割れ有無を
評価した。最終接合率が５０％以上であれば薄手材の圧
延でも破断は見られなかった。A material having a bar thickness of 25 to 40 mm was cut under different shear cutting conditions, and the pieces were laser welded together. The welded material was rolled by changing the time until rolling, the initial rolling reduction after welding, and the rolling temperature, followed by 7-pass finishing. The distance between the stands of the finish rolling was 5.5 m, and the maximum height on the pass line obtained between the finish rollings was measured from the height of the looper moving up and down between the stands. For the above examples, the presence or absence of breakage before winding, the final joining rate, and the presence or absence of edge cracks at both ends of the width were evaluated from observation after winding. If the final joining ratio was 50% or more, no fracture was observed even when rolling the thin material.
【００１６】[0016]
【表２】 [Table 2]
【００１７】表２に試験条件と結果を示す。試験Ｎｏ．
１，４，５，７，８，１１〜１５で示すように、本発明
条件内で実施すれば、鋼種を変えても破断なく通板可能
である。ただし、Ｎｏ．７の場合は、両端部が３０％以
上の溶接率を確保できていないため、破断はなかったが
耳割れの発生が認められた。本発明条件から外れた場合
は、Ｎｏ．２は開先深さが浅いため開先効果がなく、Ｎ
ｏ．３は深すぎるため溶接可能厚の比率が低くなりいず
れも破断した。また、Ｎｏ．６のように開口部の角度が
９０°未満では、開先効果はなく破断した。Ｎｏ．９で
は平均溶接率が低くまた初期圧下率が低く、Ｎｏ．１０
では圧延までの時間が長く、パスライン上の最大高さが
高いため、いずれも破断を起こした。Table 2 shows the test conditions and results. Test No.
As shown by 1,4,5,7,8,11 to 15, if carried out within the conditions of the present invention, even if the steel type is changed, it is possible to pass the steel without breaking. However, no. In the case of No. 7, since the welding rate of 30% or more was not secured at both ends, there was no breakage but generation of ear cracks was recognized. When the conditions deviate from the conditions of the present invention, No. 2 has no groove effect because the groove depth is shallow, and N
o. Since No. 3 was too deep, the ratio of the weldable thickness was low, and all fractured. In addition, No. When the angle of the opening was less than 90 ° as in No. 6, the groove broke without the groove effect. No. In No. 9, the average welding rate was low and the initial draft was low. 10
In this case, the time required for rolling was long, and the maximum height on the pass line was high, so that all fractured.
【００１８】[0018]
【発明の効果】以上のように、本発明によれば粗バーを
効果的に接合することができ、接合部の破断なく完全連
続圧延が可能である。したがって、熱延鋼板の製造にお
ける歩留りを向上でき、経済効果が非常に高い。As described above, according to the present invention, the rough bars can be effectively joined, and complete continuous rolling can be performed without breaking the joint. Therefore, the yield in the production of a hot-rolled steel sheet can be improved, and the economic effect is extremely high.
【図１】溶接比率と最終接合率の関係を示した図FIG. 1 is a diagram showing a relationship between a welding ratio and a final joining ratio.
フロントページの続き (56)参考文献 特開 平９−29306（ＪＰ，Ａ) 特開 平９−10803（ＪＰ，Ａ) 特開 平４−262804（ＪＰ，Ａ) 特開 平８−300008（ＪＰ，Ａ) 特開 平８−290277（ＪＰ，Ａ) 特開 平８−290204（ＪＰ，Ａ) 特開 平８−252668（ＪＰ，Ａ) 特開 平７−290111（ＪＰ，Ａ) 特開 平７−275903（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B21B 15/00 B21B 1/26 B23K 20/00 340 B23K 26/00 310 Continuation of the front page (56) References JP-A-9-29306 (JP, A) JP-A-9-10803 (JP, A) JP-A-4-262804 (JP, A) JP-A-8-300008 (JP) JP-A-8-290277 (JP, A) JP-A-8-290204 (JP, A) JP-A-8-252668 (JP, A) JP-A-7-290111 (JP, A) 7-275903 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) B21B 15/00 B21B 1/26 B23K 20/00 340 B23K 26/00 310
Claims (4)
合に供するバー厚（ｔ）の先行、後行の粗バーの両端部
を突き合わせ、溶接する断面の上部または下部もしくは
両方を開先角度９０°以上の開先状態にし、実質溶接可
能厚範囲を０．３〜０．８ｔとした後、この溶接可能部
を不可避的未溶接部を除き全幅の厚み方向２０％以上を
溶接した後、３秒以上３０秒以内で初期圧延を開始する
ことを特徴とする熱間粗バーの接合方法。1. Both ends of a preceding and succeeding rough bar of a bar thickness (t) to be used for bar joining of a hot rolling line aiming for complete continuity are joined, and an upper portion or a lower portion or both of a cross section to be welded are grooved. After making the groove state at an angle of 90 ° or more and setting the substantial weldable thickness range to 0.3 to 0.8 t, this weldable portion is welded by 20% or more in the thickness direction of the entire width except for the unavoidable unwelded portion. 3. A method for joining hot rough bars, wherein the initial rolling is started within 3 seconds to 30 seconds.
率を３０％以上とする請求項１記載の熱間粗バーの接合
方法。2. The method according to claim 1, wherein the welding rate in the thickness direction of 50 mm or more from both ends is 30% or more.
る請求項１または請求項２記載の熱間粗バーの接合方
法。3. The method according to claim 1, wherein the initial draft after welding is 35 to 70%.
合部の位置をパスライン上の０〜５００ｍｍとする請求
項１ないし請求項３いずれかに記載の熱間粗バーの接合
方法。4. The method for joining a hot rough bar according to claim 1, wherein after welding of the rough bar, the position of the joining portion is set to 0 to 500 mm on the pass line until finish rolling is completed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07209309A JP3103496B2 (en) | 1995-07-26 | 1995-07-26 | Joining method of hot rough bar |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07209309A JP3103496B2 (en) | 1995-07-26 | 1995-07-26 | Joining method of hot rough bar |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0929308A JPH0929308A (en) | 1997-02-04 |
| JP3103496B2 true JP3103496B2 (en) | 2000-10-30 |
Family
ID=16570827
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP07209309A Expired - Fee Related JP3103496B2 (en) | 1995-07-26 | 1995-07-26 | Joining method of hot rough bar |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3103496B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6217791B1 (en) | 1991-12-18 | 2001-04-17 | Asahi Denka Kogyo K.K. | Refrigerant incorporating a polyoxyalkylene glycol monomethylether |
-
1995
- 1995-07-26 JP JP07209309A patent/JP3103496B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6217791B1 (en) | 1991-12-18 | 2001-04-17 | Asahi Denka Kogyo K.K. | Refrigerant incorporating a polyoxyalkylene glycol monomethylether |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0929308A (en) | 1997-02-04 |
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