【発明の詳細な説明】[Detailed description of the invention]
〔発明の技術分野〕
この発明は本溶接に先立つて、多電極ガスシー
ルドアーク溶接を用い仮付溶接を高速度で連続的
に行なう高速連続仮付溶接方法に関するものであ
る。
〔従来技術〕
従来、本溶接に先立つて行なう仮付溶接は消耗
電極を用いるガスシールドアーク溶接により行な
われている。
この仮付溶接においては、例えば１電極による
炭酸ガスアーク溶接の場合、溶接速度の限界は４
ｍ／分程度であり、また第４図に示すように先行
電極１と後行電極２の２電極を用いて炭酸ガスア
ーク溶接を行なつても、溶接速度の限界はせいぜ
い６ｍ／分程度である。これは第４図に示した従
来例の場合、溶接電源は先行電極１および後行電
極２とも同極性の直流が用いられるので、先行電
極１のアーム７と後行電極２のアーク８は互いに
強力に引き合い、引き合つたアークおよび溶融金
属は両電極１，２に対してほぼ一定の位置となる
が、開先状態や溶接条件の若干の変動に対して溶
融金属は両電極１，２の間で不規則に変動し、時
どき、後行電極２をくぐり抜けて後方へ流出す
る。この現象が生じるとスパツタを多く発生しや
すく、またビード形状も不連続になりやすいため
である。
したがつて、この溶接速度の限界を超えた溶接
速度によつて仮付溶接を行なうと、ビード形状が
凹凸の著しい不整ビード（ハンピングビード）を
生じ、その結果本溶接においてスラグ巻込みや融
合不良などの溶接欠陥が発生し易く、さらに本溶
接を行なう場合に溶接線ならいが困難であるとい
うのが現状であり、このため非常に早い溶接速度
の仮付溶接法の出現が望まれている。
〔発明の目的〕
この発明は上記の問題点を克服し、高速度で連
続的に仮付溶接を行なうことができる高速連続仮
付溶接方法を提案することを目的とするものであ
る。
〔発明の概要〕
この発明の高速連続仮付溶接方法は複数の消耗
電極を用い、この消耗電極の相隣接する先行電極
及び後行電極に180°未満の位相差を与えたパルス
電流を流すことにより前記先行電極及び後行電極
間に形成される溶融金属を両電極間でアークによ
り前後に振動させ、もつて電極に対する溶融金属
の相対的位置関係を安定させ、高速度で連続的に
仮付溶接を行なうものである。
〔発明の実施例〕
第１図は、この発明の一実施例を示すブロツク
図であり、４は溶接装置の電源、５は電源４から
供給する電流をパルス電流I1に変換し先行電極１
に供給する第１のパルス電流発生器、６は電源４
から供給する電流を先行電極１に供給するパルス
電流I1に対し180°未満の位相差を有するパルス電
流I2に変換して後行電極２に供給する第２のパル
ス電流発生器である。
この先行電極１に流れるパルス電流I1は母材の
溶込み深さを得るに必要な電流値に設定され、後
行電極２に流れるパルス電流I2は先行電極１によ
り溶かされた溶融金属が後行電極２の後方に急速
に流されるのを塞ぎ止めるのに必要十分な電流値
に設定され、このためパルス電流I1より低い電流
値に設定される。
第２図ａ，ｂは上記先行電極１に流れるパルス
電流I1と後行電極２に流れるパルス電流I2の電流
波形を示す。図に示すようにパルス電流I1とパル
ス電流I2間には位相差φが与えられている。位相
差φは180°未満であれば何度でもよく、後述する
ように両電極１，２間の溶融金属にアークによる
前後振動を与えるものであればよい。
上記した高速仮付溶接方法の作用を説明する。
第２図ａ，ｂに示すように先行電極１に流れるパ
ルス電流I1と後行電極２に流れるパルス電流I2に
位相差φを与えておくと、この位相差φにより先
行電極１に流れるパルス電流I1の電流値が高く、
後行電極２に流れるパルス電流I2の電流値が低く
なる場合は第３図ａに示すように、両電極１，２
のアーク７，８により生じた溶融金属３の位置が
後行電極２側に流される。次に先行電極１に流れ
るパルス電流I1の電流値が低くなり、後行電極２
に流れるパルス電流I2の電流値が高くなると、両
電極１，２間の溶融金属３は第３図ｂに示すよう
に先行電極１側に動く。したがつて第２図に示す
ように位相差を与えたパルス電流I1，I2を先行電
極１及び後行電極２に連続して通電することによ
り、両電極１，２間の溶融金属３をパルス電流
I1，I2の振幅に応じて前後に振動させることがで
きる。
溶融金属３に振動を与えた結果、開先状態や溶
融速度など溶接条件が若干変動しても、溶融金属
３の位置は両電極１，２の間からほとんど動かな
いという効果を生じ、このため後行電極２が溶融
金属３を有効に塞ぎ止めることができ、後行電極
２方向へ流出することを阻止することができる。
このため溶接ビードの形成が一層安定して行なわ
れる。したがつて仮付溶接速度を増しても、ビー
ドの形成が安定しており、高速度においても連続
してなめらかな溶接ビードを得ることができる。
次に上記実施例により具体的に仮付溶接した場
合の結果を従来例と共に示す。すなわち板厚12mm
の鋼板を用いて開先角度90度、深さ４mmのＹ開先
に対して仮付溶接を行ない、不整ビードを生じな
い溶接速度の限界を求めた結果を第１表に示す。
[Technical Field of the Invention] The present invention relates to a high-speed continuous tack welding method in which tack welding is continuously performed at high speed using multi-electrode gas-shielded arc welding prior to main welding. [Prior Art] Conventionally, tack welding prior to main welding has been performed by gas-shielded arc welding using a consumable electrode. In this tack welding, for example, in the case of carbon dioxide arc welding with one electrode, the welding speed limit is 4
m/min, and even if carbon dioxide gas arc welding is performed using two electrodes, leading electrode 1 and trailing electrode 2, as shown in Figure 4, the welding speed limit is at most about 6 m/min. . In the case of the conventional example shown in Fig. 4, the welding power source uses direct current with the same polarity for both the leading electrode 1 and the trailing electrode 2, so the arm 7 of the leading electrode 1 and the arc 8 of the trailing electrode 2 are mutually connected. The arc and the molten metal that are strongly attracted to each other stay at a nearly constant position relative to both electrodes 1 and 2, but due to slight variations in the groove condition or welding conditions, the molten metal moves between the electrodes 1 and 2. It fluctuates irregularly between the two, and sometimes passes through the trailing electrode 2 and flows out to the rear. This is because when this phenomenon occurs, many spatters tend to occur and the bead shape tends to become discontinuous. Therefore, if tack welding is performed at a welding speed that exceeds this welding speed limit, an irregular bead with a significantly uneven bead shape (humping bead) will occur, resulting in slag entrainment and fusion during main welding. The current situation is that welding defects such as defects are likely to occur, and furthermore, it is difficult to follow the weld line when performing main welding.Therefore, it is desired that a tack welding method with an extremely fast welding speed be developed. . [Object of the Invention] It is an object of the present invention to overcome the above-mentioned problems and to propose a high-speed continuous tack welding method that can perform tack welding continuously at high speed. [Summary of the Invention] The high-speed continuous tack welding method of the present invention uses a plurality of consumable electrodes, and passes a pulsed current giving a phase difference of less than 180° to adjacent leading and trailing electrodes of the consumable electrodes. The molten metal formed between the leading electrode and the trailing electrode is vibrated back and forth by an arc between both electrodes, thereby stabilizing the relative positional relationship of the molten metal to the electrode, and continuously tacking at high speed. It performs welding. [Embodiment of the Invention] FIG. 1 is a block diagram showing an embodiment of the present invention, in which numeral 4 represents a power source of a welding device, and numeral 5 converts a current supplied from the power source 4 into a pulse current I 1 and connects the leading electrode 1 to the pulse current I 1 .
6 is the power supply 4
This is a second pulse current generator that converts the current supplied from the current into a pulse current I 2 having a phase difference of less than 180° with respect to the pulse current I 1 supplied to the leading electrode 1 and supplies the pulse current I 2 to the trailing electrode 2 . The pulse current I 1 flowing through the leading electrode 1 is set to a current value necessary to obtain the penetration depth of the base metal, and the pulse current I 2 flowing through the trailing electrode 2 is set to a current value necessary to obtain the penetration depth of the base metal. The current value is set to be necessary and sufficient to prevent the current from flowing rapidly behind the trailing electrode 2, and therefore the current value is set to be lower than the pulse current I1 . FIGS. 2a and 2b show the current waveforms of the pulse current I 1 flowing through the preceding electrode 1 and the pulse current I 2 flowing through the trailing electrode 2. FIG. As shown in the figure, a phase difference φ is given between the pulse current I 1 and the pulse current I 2 . The phase difference φ may be any number as long as it is less than 180°, and it is sufficient that the molten metal between the electrodes 1 and 2 is caused to vibrate back and forth by the arc, as will be described later. The operation of the above-described high-speed tack welding method will be explained.
As shown in Figure 2 a and b, if a phase difference φ is given to the pulse current I 1 flowing to the leading electrode 1 and the pulse current I 2 flowing to the trailing electrode 2, the current flows to the leading electrode 1 due to this phase difference φ. The current value of pulse current I 1 is high,
When the current value of the pulse current I2 flowing to the trailing electrode 2 becomes low, as shown in FIG.
The position of the molten metal 3 generated by the arcs 7 and 8 is swept toward the trailing electrode 2 side. Next, the current value of the pulse current I1 flowing through the leading electrode 1 becomes low, and the current value of the pulse current I1 flowing through the leading electrode 1 becomes low,
When the current value of the pulse current I 2 flowing through the electrode increases, the molten metal 3 between the electrodes 1 and 2 moves toward the leading electrode 1 as shown in FIG. 3b. Therefore, as shown in FIG. 2, by continuously applying pulse currents I 1 and I 2 with a phase difference to the leading electrode 1 and the trailing electrode 2, the molten metal 3 between the two electrodes 1 and 2 is heated. the pulse current
It can be oscillated back and forth depending on the amplitudes of I 1 and I 2 . As a result of applying vibration to the molten metal 3, the position of the molten metal 3 hardly moves from between the electrodes 1 and 2 even if the welding conditions such as the groove condition and the melting speed change slightly. The trailing electrode 2 can effectively block the molten metal 3 and prevent it from flowing in the direction of the trailing electrode 2.
Therefore, the weld bead can be formed more stably. Therefore, even if the tack welding speed is increased, the bead formation is stable, and a smooth weld bead can be continuously obtained even at high speeds. Next, the results of tack welding according to the above embodiment will be shown together with the conventional example. i.e. board thickness 12mm
Table 1 shows the results of tack welding on a Y-groove with a groove angle of 90 degrees and a depth of 4 mm using a steel plate, and the limits of welding speed that do not cause irregular beads were determined.
【表】【table】
〔発明の効果〕〔Effect of the invention〕
この発明は以上説明したように、複数の消耗電
極を用い、この消耗電極の相隣接する先行電極と
後行電極に180°未満の位相差を与えたパルス電流
を流すことにより、両電極間に形成される溶融金
属を両電極間でアークにより前後に振動させなが
ら仮付溶接を行うものであるから、アークを交互
に引き合う結果、後行電極による溶融金属の塞ぎ
止め効果を良好に発揮できるものであり、そのた
め、ビード形成を安定させることができ、従来法
に比べて格段の高速度で連続的に安定した仮付溶
接を行なうことができる。さらにパルス電流の時
間比や電流の高低比を変えることにより仮付溶接
速度に応じた仮付溶接を行なうことができ、本溶
接での溶接欠陥防止を図ることができる。
As explained above, this invention uses a plurality of consumable electrodes, and by passing a pulse current with a phase difference of less than 180 degrees between the leading electrode and the trailing electrode, which are adjacent to each other, between the two consumable electrodes. Since tack welding is performed while the molten metal being formed is vibrated back and forth by an arc between both electrodes, the arcs alternately attract each other, and as a result, the trailing electrode can effectively block the molten metal. Therefore, bead formation can be stabilized, and tack welding can be performed continuously and stably at a much higher speed than conventional methods. Further, by changing the time ratio of the pulse current and the height ratio of the current, tack welding can be performed in accordance with the tack welding speed, and welding defects in main welding can be prevented.
【図面の簡単な説明】[Brief explanation of drawings]
第１図はこの発明の実施例を示すブロツク図、
第２図ａ，ｂは各々第１図に示した実施例の溶接
電流波形図、第３図ａ，ｂは第１図に示した実施
例の動作説明図、第４図は従来の２電極仮付溶接
のアーク形態図である。
１……先行電極、２……後行電極、３……溶融
金属、４……電源、５……第１のパルス電流発生
器、６……第２のパルス電流発生器、７，８……
アーク、I1……先行電極のパルス電流、I2……後
行電極のパルス電流。
FIG. 1 is a block diagram showing an embodiment of this invention.
Figures 2a and b are welding current waveform diagrams of the embodiment shown in Figure 1, Figures 3a and b are operation explanatory diagrams of the embodiment shown in Figure 1, and Figure 4 is a conventional two-electrode welding current waveform diagram. FIG. 3 is a diagram showing the arc configuration of tack welding. DESCRIPTION OF SYMBOLS 1... Leading electrode, 2... Trailing electrode, 3... Molten metal, 4... Power supply, 5... First pulse current generator, 6... Second pulse current generator, 7, 8... …
Arc, I 1 ... Pulse current of the leading electrode, I 2 ... Pulse current of the trailing electrode.