JP2007301623A - High speed gas shielded arc welding method for horizontal lap joint of steel sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a weld bead with a wide bead width, regarding gas shielded arc welding in the horizontal posture of a lap joint part of steel sheets, without generating melt-down upon the welding even when the gap between the steel sheets is wide. <P>SOLUTION: In the gas shielded arc welding method where a horizontal lap joint part of steel sheets each having an Si content of ≤0.1 mass% and a thickness of 2.0 to 4.5 mm is subjected to gas shielded arc welding at a welding speed of ≥1.2 m/min, using a solid wire comprising 0.02 to 0.10% C, 0.5 to 1.0% Si and 1.0 to 1.6% Mn, a wire feeding speed is controlled to ≥11 m/min, and a pulse in which pulse peak current Ip is 440 to 520 A, pulse base current Ib is 30 to 80 A, and also, the pulse peak current Ip and pulse peak time Tp satisfy the inequality (1) of 415≤Ip(A)×Tp(msec)≤780 is applied, so as to perform welding. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、薄鋼板の横向重ね継手の高速ガスシールドアーク溶接方法に関し、更に詳しくは、板厚が２．０〜４．５ｍｍの薄鋼板の横向重ね継手部を高速度、高電流の条件の消耗電極式パルスガスシールドアーク溶接（以下、パルスＭＡＧ溶接という）においても溶接金属の溶け落ちがなく、かつ溶接部の開先間隙（以下、ギャップという）が大きい場合でも良好な溶接ビードが得られる薄鋼板の横向重ね継手の高速ガスシールドアーク溶接方法に係るものである。   The present invention relates to a high-speed gas shielded arc welding method for a transverse lap joint of a thin steel plate. More specifically, the transverse lap joint portion of a thin steel plate having a thickness of 2.0 to 4.5 mm is subjected to high speed and high current conditions. Even in consumable electrode type pulse gas shielded arc welding (hereinafter referred to as pulse MAG welding), a weld bead can be obtained even when the weld metal does not melt and the groove gap (hereinafter referred to as gap) of the welded portion is large. The present invention relates to a high-speed gas shield arc welding method for a transverse lap joint of thin steel plates.

ソリッドワイヤを用いたガスシールドアーク溶接方法は高能率であり、機械的性能の良好な溶接金属と良好なビード外観が得られることから薄板の溶接に広く適用されている。また、スパッタ発生量の低減および高速溶接性確保の面からＡｒガスにＣＯ_２を混合、更にはＯ_２ガスを混合させたシールドガスを使用したパルスＭＡＧ溶接方法が近年増加している。これらの溶接は生産性の向上から高速度で高電流の溶接条件で施工され、良好な溶接ビードを形成し健全な溶接継手を作製している。 A gas shielded arc welding method using a solid wire is highly efficient and widely applied to thin plate welding because it provides a weld metal with good mechanical performance and a good bead appearance. Further, reduction and high-speed weldability mixture of CO ₂ from the surface to the Ar gas to secure the spatter generation rate, further the pulse MAG welding method using a shielding gas obtained by mixing O ₂ gas is increased in recent years. These welds are constructed under high-speed and high-current welding conditions to improve productivity, and form a good weld bead to produce a sound welded joint.

パルスＭＡＧ溶接とは、平均溶接電流より高電流となるピーク電流と平均電流より低電流としたベース電流を数十Ｈｚないし３００Ｈｚの周波数で周期的に付加し、ピーク電流期間でワイヤを溶融しベース電流期間で溶滴を溶融池に移行させることにより、平均のアーク電圧が低い場合でも溶滴が溶融池と短絡することなく溶滴を移行させる溶接方法である。このように、パルス電源の適用は、パルスＭＡＧ溶接において、ピーク電流、ピーク電圧、ピーク時間などを制御してワイヤの溶融エネルギーを適正にし、１回のパルスピーク電流時に１個の溶滴を生成しベース電流期間に溶滴を移行する１パルス−１ドロップ移行となるパルス条件にすることにより、溶滴はスムーズに溶融池に移行しスパッタ発生量が低減される。   In pulse MAG welding, a peak current that is higher than the average welding current and a base current that is lower than the average current are periodically added at a frequency of several tens of Hz to 300 Hz, and the wire is melted during the peak current period. This is a welding method in which the droplets are transferred to the molten pool without causing a short circuit with the molten pool even when the average arc voltage is low by transferring the droplets to the molten pool during the current period. In this way, the application of the pulse power supply controls the peak current, peak voltage, peak time, etc. in pulse MAG welding to make the wire melting energy appropriate, and generate one droplet at one pulse peak current. By setting the pulse condition to be 1 pulse-1 drop transition for transferring the droplet during the base current period, the droplet smoothly moves to the molten pool and the amount of spatter generated is reduced.

一方、ピーク電流、ピーク電圧、ピーク時間などのワイヤを溶融するエネルギーが不均衡になると溶滴移行時期がベース電流期間およびピーク電流期間に不連続に発生することになり、溶滴移行はスムーズに行われることがなくスパッタとして飛散することになる。また、特に高速度の溶接においてはアンダーカットが発生し易く、これを抑制する手段としてアーク電圧を低下した条件を採用することが一般的であるが、アークの広がりが小さくなることによりビード幅も狭くなり、ビード幅の広い良好な継手の形成が困難となる。   On the other hand, if the energy to melt the wire, such as peak current, peak voltage, and peak time, becomes imbalanced, the droplet transfer timing will occur discontinuously in the base current period and peak current period, and the droplet transfer will be smooth. It will be spattered without being performed. In particular, in high-speed welding, undercut is likely to occur, and it is common to adopt the condition in which the arc voltage is reduced as a means to suppress this, but the bead width is also reduced by reducing the arc spread. It becomes narrow and it becomes difficult to form a good joint with a wide bead width.

また、薄板構造物の溶接部材に適用される薄板鋼材は、Ｓｉ含有量が０．１％以下の成分系が多いが、低Ｓｉの鋼板をＭＡＧ溶接するとアーク力により鋼板が溶け落ち易く溶融池を形成し難くなる。近年では生産性向上や構造物の煩雑さから横向姿勢による溶接も多くなっているが、低Ｓｉ鋼板の横向姿勢の溶接では溶融池の形成がさらにでき難く、溶融金属が垂れてビード形成が難くなる。   In addition, thin steel plates applied to welded members of thin plate structures have many component systems with a Si content of 0.1% or less. However, when MAG welding is performed on a low-Si steel plate, the steel plate is easily melted down by arc force. It becomes difficult to form. In recent years, welding in the horizontal orientation has been increasing due to productivity improvements and the complexity of the structure, but welding in the horizontal orientation of low-Si steel sheets makes it difficult to form a molten pool and makes it difficult to form beads due to dripping of molten metal. Become.

図４（ａ）、（ｂ）、（ｃ），（ｄ）に薄鋼板の重ね継手部の横向姿勢においてギャップがある場合のビード形成状態の例を示す。図中１は前板、２は後板、３は溶接金属、７はギャップである。図４（ａ）は、ビード幅Ｗが広く、溶け落ちやビードの垂れがなく良好なビード外観の溶接金属３が得られた例を示す。図４（ｂ）はアンダーカット８が生じた例、図４（ｃ）は溶融金属が前板１側に垂れた例、図４（ｄ）は溶融金属が前板１と後板２の間のギャップ７内に垂れ落ちた例を示す。このように、重ね継手部のギャップが大きい場合は溶融金属が垂れ易くなり、良好な溶接ビード形成が得難いという問題があった。   FIGS. 4A, 4B, 4C, and 4D show examples of a bead formation state when there is a gap in the lateral orientation of the lap joint portion of the thin steel plate. In the figure, 1 is a front plate, 2 is a rear plate, 3 is a weld metal, and 7 is a gap. FIG. 4A shows an example in which a weld metal 3 having a wide bead width W and having a good bead appearance without melting or dripping is obtained. 4B is an example in which an undercut 8 occurs, FIG. 4C is an example in which molten metal hangs down to the front plate 1, and FIG. 4D is a case in which molten metal is between the front plate 1 and the rear plate 2. An example of dripping into the gap 7 is shown. As described above, when the gap of the lap joint portion is large, the molten metal is liable to sag and there is a problem that it is difficult to obtain a good weld bead.

従来、薄鋼板の溶接方法として、例えば特開昭５６−８０３７７号公報（特許文献１）には、第１段階の溶接として、溶接ワイヤが母材と短絡して赤熱、溶断、短時間のスタッビング状態のアーク発生を繰り返す溶接条件によって一定時間溶接を行ってギャップを埋めた後、第２段階の溶接として安定な定常アークによる溶接を行なうことにより、１ｍｍ以下の板厚の溶接において、溶接部にギャップがある場合でも安定してギャップを埋めながら溶接することのできる薄板溶接法が提案されている。しかし、この溶接方法ではスタッビング状態で溶接を行なう際にスパッタが多量に発生することや、高速溶接に向かないなど能率面で実用的ではなかった。   Conventionally, as a method for welding thin steel sheets, for example, in Japanese Patent Laid-Open No. 56-80377 (Patent Document 1), as a first stage welding, a welding wire is short-circuited with a base material to cause red hot, fusing, and short-time stubbing. After welding for a certain period of time according to welding conditions in which arc generation is repeated, the gap is filled, and then welding with a stable steady-state arc is performed as the second stage welding. A thin plate welding method has been proposed that enables welding while filling the gap stably even when there is a gap. However, this welding method is not practical in terms of efficiency, for example, a large amount of spatter is generated when welding in a stubbed state, and it is not suitable for high-speed welding.

特開２００１−３２１９８５号公報（特許文献２）には、溶接部材のギャップが大きくても架橋性に優れ、耐割れ性に優れたガスシールドアーク溶接用ワイヤおよびパルスＭＡＧ溶接方法が提案されている。しかし、この溶接方法では横向重ね継手の溶接に適用した場合、溶融金属が垂れて適用は困難である。   Japanese Patent Application Laid-Open No. 2001-321985 (Patent Document 2) proposes a gas shielded arc welding wire and a pulse MAG welding method that are excellent in crosslinkability and excellent in crack resistance even if the gap of the welding member is large. . However, when this welding method is applied to the welding of a lateral lap joint, it is difficult to apply the molten metal due to dripping.

また、特開平８−２４３７４９号公報（特許文献３）には、板厚１．２〜１．６ｍｍの薄鋼板に対し、所定の化学成分のワイヤを使用し、Ａｒに３〜７体積％のＯ_２を混合したシールドガスによるパルスＭＡＧ溶接で、溶け落ちを防止し高能率な溶接を可能とする溶接方法が開示されている。しかし、この方法はシールドガス成分を限定することにより、比較的板厚の薄い鋼板においても高能率なガスシールドアーク溶接を可能とするものであるが、横向姿勢における薄鋼板の重ね継手部の特に隙間が大きい場合においては、溶接金属が垂れて適用が困難である。 Japanese Patent Laid-Open No. 8-243749 (Patent Document 3) uses a wire of a predetermined chemical component for a thin steel plate having a thickness of 1.2 to 1.6 mm, and contains 3 to 7% by volume of Ar. There has been disclosed a welding method that prevents melt-down and enables high-efficiency welding by pulse MAG welding using a shielding gas mixed with O ₂ . However, this method allows high-efficiency gas shield arc welding even for a relatively thin steel plate by limiting the shielding gas component. When the gap is large, the weld metal drips and is difficult to apply.

さらに、特開平９−２０６９８４号公報（特許文献４）には、ガスシールドアーク溶接用鋼ワイヤを用いる薄鋼板でのパルスＭＡＧ溶接において、耐ギャップ性を確保する溶接方法が開示されている。しかし、横向姿勢における薄鋼板の重ね継手の高速度、高電流条件の溶接への適用は困難であり、溶融金属の耐垂れ性と広幅ビードを確保できない。   Furthermore, Japanese Patent Laid-Open No. 9-206984 (Patent Document 4) discloses a welding method for ensuring gap resistance in pulse MAG welding with a thin steel plate using a steel wire for gas shielded arc welding. However, it is difficult to apply the high-speed, high-current condition welding of the thin steel plate lap joint in the horizontal orientation, and it is impossible to secure the dripping resistance and wide bead of the molten metal.

上記のように、薄鋼板の溶接における溶け落ち防止の手段、各種ワイヤ組成、シールドガス組成など種々の検討がなされてきたが、Ｓｉ量の低い薄鋼板の横向重ね継手溶接における高速・高電流での溶融金属の耐垂れ性、広幅ビード確保および耐ギャップ性を改善するには至っていない。
特開昭５６−８０３７７号公報 特開２００１−３２１９８５号公報 特開平８−２４３７４９号公報 特開平９−２０６９８４号公報 As described above, various investigations such as means for preventing burn-off in welding of thin steel sheets, various wire compositions, and shielding gas compositions have been made, but at high speed and high current in transverse lap joint welding of thin steel sheets with low Si content. However, the molten metal has not been improved in dripping resistance, wide bead securing and gap resistance.
JP-A-56-80377 JP 2001-321985 A Japanese Patent Laid-Open No. 8-243749 JP-A-9-206984

本発明は、薄鋼板の重ね継手部の横向姿勢におけるガスシールドアーク溶接において、高速度、高電流で適正なパルス条件を付加して、ギャップが大きい場合でも溶接時に溶け落ちを発生することなく、ビード幅の広い良好な溶接ビードが得られる溶接方法を提供することを目的とする。   In the gas shielded arc welding in the horizontal orientation of the lap joint portion of the thin steel plate, the present invention adds an appropriate pulse condition at a high speed and high current without causing burnout even when the gap is large, An object of the present invention is to provide a welding method capable of obtaining a good weld bead having a wide bead width.

本発明の要旨は、Ｓｉ含有量が０．１質量％以下で厚さ２．０〜４．５ｍｍの薄鋼板の横向重ね継手部を１．２ｍ／ｍｉｎ以上の溶接速度でガスシールドアーク溶接する方法において、質量％で、Ｃ：０．０２〜０．１０％、Ｓｉ：０．５〜１．０％、Ｍｎ：１．０〜１．６％を含有し、残部はＦｅおよび不可避不純物よりなるソリッドワイヤを用いて、ワイヤ送給速度：１１ｍ／ｍｉｎ以上、パルスピーク電流Ｉｐ：４４０〜５２０Ａ、パルスベース電流Ｉｂ：３０〜８０Ａで、かつパルスピーク電流Ｉｐとパルスピーク時間Ｔｐが下記（１）式を満足するパルスを付加して溶接することを特徴とする薄鋼板の横向重ね継手の高速ガスシールドアーク溶接方法にある。
４１５≦Ｉｐ（Ａ）×Ｔｐ（ｍｓｅｃ） ≦ ７８０ ・・・・（１） The gist of the present invention is that gas shielded arc welding is performed on a transverse lap joint of a thin steel plate having a Si content of 0.1% by mass or less and a thickness of 2.0 to 4.5 mm at a welding speed of 1.2 m / min or more. In the method, by mass%, C: 0.02 to 0.10%, Si: 0.5 to 1.0%, Mn: 1.0 to 1.6%, the balance is Fe and inevitable impurities The wire feed speed is 11 m / min or more, the pulse peak current Ip is 440 to 520 A, the pulse base current Ib is 30 to 80 A, and the pulse peak current Ip and the pulse peak time Tp are (1 The high-speed gas shielded arc welding method for the transverse lap joint of a thin steel plate, characterized in that welding is performed by adding a pulse that satisfies the formula (1).
415 ≦ Ip (A) × Tp (msec) ≦ 780 (1)

本発明の薄鋼板の横向重ね継手の高速ガスシールドアーク溶接方法によれば、Ｓｉ量の低い鋼板の横向重ね継手溶接の高速パルスＭＡＧ溶接においても、溶接部の溶け落ちや垂れの発生がなく、かつ溶接部のギャップが大きい場合でも良好な広幅な溶接ビードが高能率に得られる。   According to the high-speed gas shielded arc welding method for the transverse lap joint of the thin steel sheet of the present invention, even in the high-speed pulse MAG welding of the transverse lap joint welding of the steel sheet having a low Si amount, there is no occurrence of melting or sagging of the welded portion. In addition, even when the weld gap is large, a good wide weld bead can be obtained with high efficiency.

本発明者らは、上記の問題点を解決するために、Ｓｉ含有量が０．１質量％以下で板厚２．０〜４．５ｍｍの薄鋼板を重ね継手とし、各種成分のソリッドワイヤを用いて、横向姿勢で各種パルス条件で１．２ｍ／ｍｉｎ以上の高速度の溶接を行い、溶融金属の垂れ性と耐ギャップ性につき詳細に調査した結果、次の知見を得た。
（１）ワイヤ組成は、Ｃ、ＳｉおよびＭｎ量の調整によって、アークの安定性、ワイヤ溶融量の増加、溶融金属の粘性および表面張力の増加を図り、スパッタ発生量減および広幅で外観の良好なビードが得られる。
（２）パルス条件が１パルス−１ドロップの溶滴移行となる領域では、幅広のビードが得られない。ビード幅を広くするために溶接電圧を高くすると、ビードが垂れてビード外観不良となる。
（３）パルス条件はｎパルス−１ドロップの溶滴移行となる領域により、溶接電圧が高い場合でも短絡がピーク時にも生じて溶融金属の垂れが大幅に減少する。
以下、本発明におけるワイヤ組成とその含有量およびパルス条件の限定理由について説明する。 In order to solve the above-mentioned problems, the inventors made a thin steel plate having a Si content of 0.1% by mass or less and a plate thickness of 2.0 to 4.5 mm as a lap joint, and made solid wires of various components. As a result of conducting a high-speed welding of 1.2 m / min or more under various pulse conditions in a lateral orientation and investigating in detail about the sagability and gap resistance of the molten metal, the following knowledge was obtained.
(1) The wire composition is controlled by adjusting the amounts of C, Si and Mn to improve the stability of the arc, increase the amount of wire melt, increase the viscosity and surface tension of the molten metal, reduce the amount of spatter generated, and wide and good appearance Bead.
(2) A wide bead cannot be obtained in a region where the pulse condition is 1 pulse-1 drop droplet transfer. If the welding voltage is increased to widen the bead width, the bead drips and the bead appearance is poor.
(3) Depending on the region where the pulse condition is n pulse-1 drop droplet transfer, even if the welding voltage is high, a short circuit occurs even at the peak, and dripping of the molten metal is greatly reduced.
Hereinafter, the reasons for limiting the wire composition, its content, and pulse conditions in the present invention will be described.

［Ｃ：０．０２〜０．１０質量％］
Ｃはアークを安定化し溶滴を細粒化する作用があるが、０．０２質量％（以下、％という。）未満ではアークの安定性を確保できず、また、０．１０％を超えると溶融金属の粘性が劣り耐垂れ性を確保できない。また、スパッタが増加するばかりでなく、溶接金属を著しく硬化させ耐割れ性が劣化する。 [C: 0.02 to 0.10% by mass]
C has the effect of stabilizing the arc and making the droplets finer, but if it is less than 0.02% by mass (hereinafter referred to as%), the stability of the arc cannot be secured, and if it exceeds 0.10%. The viscosity of the molten metal is inferior and the sag resistance cannot be secured. Moreover, not only the spatter increases, but the weld metal is remarkably hardened and the crack resistance is deteriorated.

［Ｓｉ：０．５〜１．０％］
Ｓｉは溶接金属の主脱酸剤として不可欠であると共に、ワイヤの電気抵抗を増大させてワイヤの溶融量を増加させ、更に溶融金属の粘度および表面張力を増大させる効果が大きい元素である。これによって、横向重ね継手の溶融金属の垂れを軽減して耐ギャップ性が得られ、広幅の溶接ビードを形成できる。しかし、０．５％未満では上記効果が得られず、また、１．０％を超えると溶融金属の表面張力が過度に上昇するため溶融金属が溶接速度に追従できずハンピングビードとなり易い。 [Si: 0.5 to 1.0%]
Si is an indispensable element as a main deoxidizer for weld metal, and is an element having a large effect of increasing the electric resistance of the wire to increase the melting amount of the wire and further increasing the viscosity and surface tension of the molten metal. As a result, dripping of the molten metal in the lateral lap joint is reduced, gap resistance is obtained, and a wide weld bead can be formed. However, if the content is less than 0.5%, the above effect cannot be obtained. If the content exceeds 1.0%, the surface tension of the molten metal excessively increases, so that the molten metal cannot follow the welding speed and tends to be a humping bead.

［Ｍｎ：１．０〜１．６％］
ＭｎはＳｉと共に脱酸剤として作用する他、溶融金属の粘度および表面張力を増大させる効果がある。１．０％未満ではその効果が得られず、ブローホール等の気孔欠陥が発生しやすくなると共に、溶融金属の粘度および表面張力が低下することから、溶融金属が垂れビード形状が劣化し、十分な耐ギャップ性が得られない。一方、Ｍｎが１．６％を超えると、溶融金属の粘度および表面張力が増加し過ぎて広幅のビードが得られない。 [Mn: 1.0 to 1.6%]
Mn acts as a deoxidizer together with Si, and has the effect of increasing the viscosity and surface tension of the molten metal. If it is less than 1.0%, the effect cannot be obtained, and pore defects such as blow holes are likely to occur, and the viscosity and surface tension of the molten metal are lowered, so that the molten metal droops and the bead shape deteriorates sufficiently. Gap resistance cannot be obtained. On the other hand, if Mn exceeds 1.6%, the viscosity and surface tension of the molten metal increase excessively, and a wide bead cannot be obtained.

上記成分の残部はＦｅおよび不可避不純物であるが、他の成分としてＡｌおよびＴｉを、それぞれ０．１０％以下の範囲で含有することができる。また、Ｓはビード止端部のなじみを良好にするので０．００５％以上含有することが好ましい。しかし、ＳおよびＰが０．０２０％を超えると溶接金属の耐割れ性が劣化する。   The balance of the above components is Fe and inevitable impurities, but as other components, Al and Ti can be contained in the range of 0.10% or less, respectively. Further, S is preferably contained in an amount of 0.005% or more in order to improve the familiarity of the bead toe. However, if S and P exceed 0.020%, the crack resistance of the weld metal deteriorates.

図１は、ワイヤ送給速度が１１ｍ／ｍｉｎ以上で溶接速度が１．２ｍ／ｍｉｎ以上での横向重ね継手における、各パルス条件での溶滴の移行状態を調査した結果である。調査方法は、毎秒２０００駒の高速撮影が可能な高速度ビデオカメラを用いて、各パルス条件と溶滴の移行状態の関係およびビード形状などを調べた。   FIG. 1 is a result of investigating the state of transition of droplets under each pulse condition in a lateral lap joint with a wire feed speed of 11 m / min or more and a welding speed of 1.2 m / min or more. As a survey method, a high-speed video camera capable of high-speed shooting at 2000 frames per second was used to examine the relationship between each pulse condition and the state of droplet transfer, the bead shape, and the like.

ここにおいて溶接電源はパルスＭＡＧ溶接用として一般に使用されているもので、溶接電流（ベース電流とピーク電流との平均的な電流）の調整とパルス周波数の調整がリンクして行われるいわゆる一元化制御のものである。良く知られているようにＭＡＧ溶接において溶接電流の調整はワイヤ送給速度の調整によってなされる。溶接電流を増大させるべくワイヤ送給速度を増大させた場合、溶滴の大きさは大体同じであるので、１パルス−１ドロップの移行状態を維持するためには単位時間あたりの溶滴の数が増大するようにパルス周波数を増大させる必要がある。上記実験において使用した溶接電源はパルスを数十Ｈｚないし３００Ｈｚの周波数範囲で自動調整することにより、従来からの一般の溶接条件において１パルス−１ドロップの移行状態を維持するように設計されたものである。   Here, the welding power source is generally used for pulse MAG welding, and is a so-called centralized control in which the adjustment of the welding current (average current of the base current and the peak current) is linked with the adjustment of the pulse frequency. Is. As is well known, in MAG welding, the welding current is adjusted by adjusting the wire feed speed. When the wire feed speed is increased in order to increase the welding current, the size of the droplets is approximately the same, so the number of droplets per unit time is required to maintain the transition state of 1 pulse-1 drop. It is necessary to increase the pulse frequency so that. The welding power source used in the above experiment was designed to maintain a transition state of 1 pulse to 1 drop under conventional general welding conditions by automatically adjusting the pulse in the frequency range of several tens of Hz to 300 Hz. It is.

この実験によれば、ワイヤ送給速度が１１ｍ／ｍｉｎ以上においては、１パルス−１ドロップ移行が可能なパルスピーク電流（Ｉｐ）は５２０Ａ以上となる。しかし、ビード形成面からアーク電圧を下げてアーク長を短く保つことにより溶接は可能であるが、ビード形状は凸状になり良好な継手特性を得られない。また、Ｓｉ量が０．１％以下の鋼板においては溶融金属が垂れることと、ギャップが大きい場合には特に垂れ性が顕著になり耐ギャップ性が劣化する。   According to this experiment, when the wire feed speed is 11 m / min or more, the pulse peak current (Ip) capable of 1 pulse-1 drop transition is 520 A or more. However, welding is possible by lowering the arc voltage from the bead forming surface and keeping the arc length short, but the bead shape becomes convex and good joint characteristics cannot be obtained. In addition, in a steel sheet having an Si content of 0.1% or less, the molten metal sags, and when the gap is large, the sagging property becomes particularly significant and the gap resistance deteriorates.

そこで、ビード幅が広くしかも垂れ落ちしない最適パルス条件範囲を確認した結果、ｎパルス１ドロップ領域であるパルスピーク電流（Ｉｐ）が低く、パルスピーク時間（Ｔｐ）の短い領域において、アーク電圧が高い場合においても、溶滴の短絡がピーク時およびベース時に適度に生じることにより溶融金属の垂れが生じ難く、広幅ビードが得られる最適のパルス条件範囲を見出した。   Therefore, as a result of confirming the optimum pulse condition range where the bead width is wide and does not sag, the pulse peak current (Ip) which is the n-pulse 1 drop region is low, and the arc voltage is high in the region where the pulse peak time (Tp) is short. Even in this case, the optimum pulse condition range in which a wide bead can be obtained is obtained because it is difficult for the molten metal to sag because the short circuit of the droplets occurs appropriately at the peak and base times.

［ワイヤ送給速度：１１ｍ／ｍｉｎ以上］
溶接速度が１．２ｍ／ｍｉｎ以上の高速度溶接において、ワイヤ送給速度が１１ｍ／ｍｉｎ未満では溶融金属がハンピング状態となり安定したビードを得ることができない。 [Wire feeding speed: 11m / min or more]
In high-speed welding with a welding speed of 1.2 m / min or higher, if the wire feed speed is less than 11 m / min, the molten metal is in a humped state and a stable bead cannot be obtained.

［パルスピーク電流（Ｉｐ）：４４０〜５２０Ａ］
パルスピーク電流（Ｉｐ）が４４０Ａ未満では、電磁ピンチ効果による溶滴の離脱がスムーズに行われなくなり、アークが不安定でスパッタ発生量が多くなる。また、ビードが広がらず不均一な凸ビードとなる。一方、５２０Ａを超えると、アーク力により溶融池が垂れ易くなるとともに溶け落ちが発生しやすくなる。 [Pulse peak current (Ip): 440-520A]
When the pulse peak current (Ip) is less than 440 A, the droplets are not released smoothly due to the electromagnetic pinch effect, the arc is unstable, and the amount of spatter generated increases. Further, the bead does not spread and becomes a non-uniform convex bead. On the other hand, if it exceeds 520A, the molten pool is liable to sag due to the arc force, and melt-down is likely to occur.

［パルスベース電流（Ｉｂ）：３０〜８０Ａ］
パルスベース電流（Ｉｂ）はベース期間でアークを保持できる電流値が必要となる。３０Ａ未満ではアークが不安定となり、８０Ａを超えると溶滴の離脱が速やかに行われず、溶滴の移行が不安定となり、アークが不安定でスパッタ発生量が多くなる。また、ビードが広がらず不均一な凸ビードとなる。 [Pulse base current (Ib): 30-80A]
The pulse base current (Ib) requires a current value that can hold the arc in the base period. If it is less than 30A, the arc becomes unstable, and if it exceeds 80A, the detachment of the droplets is not performed quickly, the transfer of the droplets becomes unstable, the arc is unstable, and the amount of spatter is increased. Further, the bead does not spread and becomes a non-uniform convex bead.

［４１５≦Ｉｐ（Ａ）×Ｔｐ（ｍｓｅｃ） ≦ ７８０］
前述のワイヤ送給速度が１１ｍ／ｍｉｎ以上で溶接速度が１．２ｍ／ｍｉｎ以上での横向重ね継手時のパルスピーク電流（Ｉｐ）およびパルスベース電流（Ｉｂ）に加えて、下記（１）式で示すパルスピーク電流（Ｉｐ）とパルスピーク時間（Ｔｐ）の積（Ｉｐ×Ｔｐ）で得られる値を限定することによって、ピーク時間の短い領域でアーク電圧が高い場合においても、溶滴の短絡がピーク時およびベース時に適度に生じて溶融金属の垂れが生じ難く、広幅ビードが得られる。パルスピーク電流（Ｉｐ）とパルスピーク時間（Ｔｐ）の積（Ｉｐ×Ｔｐ）が４１５（Ａ・ｍｓｅｃ）未満ではピーク電流期間で溶滴を形成するためのエネルギーが不足し十分な溶滴の形成ができず、ビード幅が狭く、スパッタ発生量が多くなるとともに溶融金属が垂れやすくなる。一方、７８０（Ａ・ｍｓｅｃ）を超えると過度に成長した溶滴が短絡しやすくなり再点弧時のアーク力で溶融池が吹き飛ばされることからスパッタ発生量が多くなるとともに溶融金属が垂れ、耐ギャップ性も劣化する。
４１５≦Ｉｐ（Ａ）×Ｔｐ（ｍｓｅｃ） ≦ ７８０ ・・・・（１）
以下、実施例により本願発明を具体的に説明する。 [415 ≦ Ip (A) × Tp (msec) ≦ 780]
In addition to the pulse peak current (Ip) and pulse base current (Ib) at the time of the transverse lap joint when the wire feed speed is 11 m / min or more and the welding speed is 1.2 m / min or more, the following equation (1) By limiting the value obtained from the product (Ip × Tp) of the pulse peak current (Ip) and the pulse peak time (Tp) shown in FIG. Occurs moderately at the peak and at the base, and the dripping of the molten metal hardly occurs, and a wide bead can be obtained. If the product (Ip × Tp) of the pulse peak current (Ip) and the pulse peak time (Tp) is less than 415 (A · msec), there is insufficient energy to form a droplet in the peak current period, and sufficient droplet formation is achieved. , The bead width is narrow, the amount of spatter generated increases, and the molten metal tends to sag. On the other hand, if it exceeds 780 (A · msec), excessively grown droplets are likely to be short-circuited, and the molten pool is blown off by the arc force at the time of re-ignition. Gap properties also deteriorate.
415 ≦ Ip (A) × Tp (msec) ≦ 780 (1)
Hereinafter, the present invention will be described specifically by way of examples.

表１に示す成分の板厚２．６ｍｍ、長さ５００ｍｍの鋼板を、図２に示すテーパ型スペーサ４を後板２と前板１に挟んでギャップ長さＧ_１＝２ｍｍ、Ｇ_２＝４ｍｍのテーパギャップを形成した横向重ね継手とし、表２に示す各種成分のワイヤ径１．２ｍｍのソリッドワイヤを用いて、表３に示す各種溶接条件で溶接した。なお、溶接は図３に示すように、ワイヤ狙い位置５は前板１側の鋼板板厚の中心でトーチ６の角度θは３０°とし、コンタクトチップ−母材間距離は１５ｍｍ、シールドガスはＡｒ−２０％ＣＯ_２、平均アーク電圧は２６〜３２Ｖでギャップ長さＧ_１（２ｍｍ）側からスタートして溶融金属が架橋できなくなったところまで溶接を実施した。 A steel plate having a thickness of 2.6 mm and a length of 500 mm having the components shown in Table 1 is sandwiched between the rear plate 2 and the front plate 1 with the tapered spacer 4 shown in FIG. 2 between the gap length G ₁ = 2 mm and G ₂ = 4 mm. A horizontal lap joint with a taper gap of 1 mm and a solid wire having a wire diameter of 1.2 mm with various components shown in Table 2 was welded under various welding conditions shown in Table 3. As shown in FIG. 3, the wire aiming position 5 is the center of the steel plate thickness on the front plate 1 side, the angle θ of the torch 6 is 30 °, the distance between the contact tip and the base material is 15 mm, and the shielding gas is Welding was carried out until Ar-20% CO ₂ and an average arc voltage of 26 to 32 V started from the gap length G ₁ (2 mm) side and the molten metal could not be cross-linked.

各条件における溶融金属のビード幅Ｗ、溶接可能ギャップ長さＧ、アンダーカット長さＣ（図４（ｂ）参照）および溶接作業性を調査した。評価は、図４（ａ）に示す溶融金属のビード幅Ｗは６．５ｍｍ以上、溶接可能ギャップ長さＧは２.８ｍｍ以上を良好とした。それらの結果を表４にまとめて示す。   The weld metal bead width W, weldable gap length G, undercut length C (see FIG. 4B) and welding workability under each condition were investigated. In the evaluation, the bead width W of the molten metal shown in FIG. 4A was 6.5 mm or more, and the weldable gap length G was 2.8 mm or more. The results are summarized in Table 4.

表３および表４において試験Ｎｏ．１〜Ｎｏ．９が本発明例、試験Ｎｏ．１０〜Ｎｏ．２２が比較例である。
本発明例である試験Ｎｏ．１〜Ｎｏ．９は、ワイヤ成分が適正で、ワイヤ送給速度およびパルス条件も適正であるので、１．２ｍ／ｍｉｎ以上の溶接速度においても溶接作業性が良好で、ビード幅および溶接可能ギャップが広く、アンダーカット長さも短いなど、極めて満足な結果であった。 In Tables 3 and 4, test no. 1-No. 9 is an example of the present invention, test no. 10-No. 22 is a comparative example.
Test No. which is an example of the present invention. 1-No. No. 9, because the wire component is appropriate, the wire feed speed and pulse conditions are also appropriate, the welding workability is good even at a welding speed of 1.2 m / min or more, the bead width and the weldable gap are wide, The results were extremely satisfactory, including a short cut length.

比較例中試験Ｎｏ．１０はワイヤ送給速度が遅いので、試験Ｎｏ．１１はパルスピーク電流（Ｉｐ）が低いので、いずれもアークが不安定で、ビード幅および溶接可能ギャップも狭くなった。
試験Ｎｏ．１２は、パルスピーク電流（Ｉｐ）が高く後板側に溶け落ちたので溶接を中止した。 Test No. in Comparative Examples. No. 10 has a slow wire feeding speed, so No. 11 had a low pulse peak current (Ip), so that the arc was unstable and the bead width and weldable gap became narrow.
Test No. In No. 12, since the pulse peak current (Ip) was high and melted down to the rear plate side, welding was stopped.

試験Ｎｏ．１３は、パルスベース電流（Ｉｂ）低いのでアークが不安定であった。
試験Ｎｏ．１４は、パルスベース電流（Ｉｂ）が高いのでアークが不安定でスパッタ発生量が多く、ビード幅および溶接可能ギャップも狭くなった。 Test No. In No. 13, the arc was unstable because the pulse base current (Ib) was low.
Test No. In No. 14, since the pulse base current (Ib) was high, the arc was unstable and the amount of spatter was large, and the bead width and weldable gap were also narrowed.

試験Ｎｏ．１５は、パルスピーク電流（Ｉｐ）とパルスピーク時間（Ｔｐ）の積（Ｉｐ×Ｔｐ）が低いので、スパッタ発生量が多く、ビード幅および溶接可能ギャップも狭くなった。また、溶融金属の垂れも生じた。
試験Ｎｏ．１６は、パルスピーク電流（Ｉｐ）とパルスピーク時間（Ｔｐ）の積（Ｉｐ×Ｔｐ）が高いので、スパッタ発生量が多く、溶接可能ギャップも狭く溶融金属の垂れも生じた。 Test No. No. 15, because the product (Ip × Tp) of the pulse peak current (Ip) and the pulse peak time (Tp) was low, the amount of spatter was large, and the bead width and weldable gap were also narrowed. Moreover, dripping of the molten metal also occurred.
Test No. No. 16 had a high product (Ip × Tp) of the pulse peak current (Ip) and the pulse peak time (Tp), so that the amount of spatter was large, the weldable gap was narrow, and molten metal sagging occurred.

試験Ｎｏ．１７はワイヤ記号Ｗ８のＭｎが低いので、試験Ｎｏ．１８はワイヤ記号Ｗ９のＳｉが低いので、いずれもビード幅および溶接可能ギャップが狭く、溶融金属の垂れも生じた。
試験Ｎｏ．１９はワイヤ記号Ｗ１０のＳｉが高いで、試験Ｎｏ．２０はワイヤ記号Ｗ１１のＭｎが高いので、ビード幅および溶接可能ギャップが狭くなった。 Test No. No. 17 has a low Mn of the wire symbol W8. No. 18 had a low Si of the wire symbol W9, so that the bead width and the weldable gap were both narrow, and molten metal sagging occurred.
Test No. No. 19 has a high Si of the wire symbol W10. In No. 20, since the Mn of the wire symbol W11 was high, the bead width and the weldable gap became narrow.

試験Ｎｏ．２１は、ワイヤ記号Ｗ１２のＣが高いのでスパッタ発生量が多く、溶融金属の垂れも生じた。
試験Ｎｏ．２２は、ワイヤ記号Ｗ１３のＣが低いのでアークが不安定であった。 Test No. In No. 21, since the C of the wire symbol W12 was high, the amount of spatter generated was large and dripping of the molten metal also occurred.
Test No. No. 22 had an unstable arc because C of the wire symbol W13 was low.

パルスピーク時間Ｔｐおよびパルスピーク電流Ｉｐの溶滴移行との関係を示すグラフThe graph which shows the relationship with the droplet transfer of pulse peak time Tp and pulse peak current Ip 本発明の実施例に用いた横向重ね継手の試験板を示す図The figure which shows the test plate of the horizontal lap joint used for the Example of this invention. 本発明の実施例における横向重ね継手部のワイヤ狙い位置を示す図The figure which shows the wire aim position of the horizontal lap joint part in the Example of this invention. （ａ）、（ｂ）、（ｃ）、（ｄ）はそれぞれ薄鋼板の重ね継手部の横向姿勢溶接におけるビード形成状態の例を示す図(A), (b), (c), (d) is a figure which shows the example of the bead formation state in the horizontal posture welding of the lap joint part of a thin steel plate, respectively.

符号の説明Explanation of symbols

１ 前板
２ 後板
３ 溶接金属
４ スペーサ
５ ワイヤ狙い位置
６ トーチ
７ ギャップ
８ アンダーカット
θ トーチ角度
Ｗ ビード幅
Ｃ アンダーカット長さ
Ｇ ギャップ長さ 1 Front plate 2 Rear plate 3 Weld metal 4 Spacer 5 Wire target position 6 Torch 7 Gap 8 Undercut θ Torch angle W Bead width C Undercut length G Gap length

Claims (1)

Ｓｉ含有量が０．１質量％以下で厚さ２．０〜４．５ｍｍの薄鋼板の横向重ね継手部を１．２ｍ／ｍｉｎ以上の溶接速度でガスシールドアーク溶接する方法において、質量％で、Ｃ：０．０２〜０．１０％、Ｓｉ：０．５〜１．０％、Ｍｎ：１．０〜１．６％を含有し、残部はＦｅおよび不可避不純物よりなるソリッドワイヤを用いて、ワイヤ送給速度：１１ｍ／ｍｉｎ以上、パルスピーク電流Ｉｐ：４４０〜５２０Ａ、パルスベース電流Ｉｂ：３０〜８０Ａで、かつパルスピーク電流Ｉｐとパルスピーク時間Ｔｐが下記（１）式を満足するパルスを付加して溶接することを特徴とする薄鋼板の横向重ね継手の高速ガスシールドアーク溶接方法。
４１５≦Ｉｐ（Ａ）×Ｔｐ（ｍｓｅｃ） ≦ ７８０ ・・・・（１） In the method of gas shield arc welding of a transverse lap joint of a thin steel plate having a Si content of 0.1% by mass or less and a thickness of 2.0 to 4.5 mm at a welding speed of 1.2 m / min or more, , C: 0.02 to 0.10%, Si: 0.5 to 1.0%, Mn: 1.0 to 1.6%, and the balance using a solid wire made of Fe and inevitable impurities , Wire feed speed: 11 m / min or more, pulse peak current Ip: 440 to 520 A, pulse base current Ib: 30 to 80 A, and pulse peak current Ip and pulse peak time Tp satisfy the following formula (1) A high-speed gas shielded arc welding method for a transverse lap joint of thin steel sheets, characterized in that welding is performed.
415 ≦ Ip (A) × Tp (msec) ≦ 780 (1)

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