JP2004298896A - Groove working method and composite welding method using laser and arc - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a groove working method which can work, at low cost and with accuracy, a groove that is less affected by weld heat and that realizes deep penetration in composite welding using laser and arc, and to provide a laser/arc composite welding method which can increase penetration depth. <P>SOLUTION: In the groove working method, two materials 1, 2 to be welded are abutted in a manner that the two abutting faces 3 are almost in contact with each other, and a through groove of a required shape is formed in the abutting faces 3. In front of the welding advancing direction of welding means 20 (laser head 21, arc welding torch 12), groove working means 10 (gouging head 11, thermal cutting head 12) are arranged. The two means 10, 20 are moved relative to the materials to be welded along the abutting faces 3 while maintaining the interval between the two means. Thus, the groove working on the abutting faces 3 by the groove working means 10 is performed simultaneously with the composite welding by the laser and arc of the welding means 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００３２】
また、Ｙ形開先の複合溶接におけるルートギャップのギャップ幅と溶込み深さとの関係の一例（試験結果）を図７に示す。図８は溶込み深さの定義を示す図である。溶込み深さＰは、溝部（開先開口部）４の底部における突合せ面の上端７から開先溶融部の最下端までの距離である。
【００３３】
まず、平板の試験片に対するビードオン複合溶接を行った場合、溶込み深さＰはレーザ単独溶接の場合と同等（減る場合もある）である。すなわち、この場合の溶込み深さは５ｍｍ程度である。
一方、Ｙ形開先の場合、キーホール形成用間隙なし（ギャップ零）のときには、溶込み深さはビードオンのギャップ零のときとほとんど変わらないが、キーホール形成用間隙を設けると、図８に示すように、溶込み深さが大幅に増加する。例えば、ギャップ幅がスポット径以上の１．０ｍｍのときは、溶込み深さは１０ｍｍにもなる。ギャップ幅がスポット径と同等の０．５ｍｍのときは、溶込み深さは７．０ｍｍ程度である。また、この実験の場合は、溶込み深さの極大値はギャップ幅が４ｍｍのときにみられ、４ｍｍを超えると、溶込み深さが急激に減少する傾向を示す。また、溶込み深さはレーザとアーク間距離ＬＡにより影響を受けるが、ＬＡ＝０〜２ｍｍの範囲では、ギャップ幅の上限値は４ｍｍが適当である。その理由は、これ以上ギャップ幅が大きくなると、前述のように溶け落ちが生じるからである。
【００３４】
実施の形態２．
図９は本発明の実施の形態２を示すものである。また、図１０は図９のＥ−Ｅ線、Ｆ−Ｆ線、Ｇ−Ｇ線の拡大断面図である。
前述の実施形態１では開先加工を熱切断加工によるものとしたが、本実施形態は機械加工により開先を加工する方法である。複合溶接方法は実施形態１と同じであるので、説明は省略する。
【００３５】
本実施形態の開先加工手段３０は、フライスカッター３１、３２、３３を用いて構成されている。つまり、Ｙ形開先５をフライス加工にて１パスで形成するものである。
先頭のフライスカッター３１は、図１０（ａ）に示すように、被溶接材１、２の突合せ面３の上端部にＶ形等任意断面形状の溝部４を切削加工するものである。そのため、このフライスカッター３１は総形カッターとなっている。
２番目および３番目のフライスカッター３２、３３は、図１０（ｂ）、（ｃ）に示すように、所要のルートギャップ６の溝を掘り下げていくものであり、最終的には、突合せ面３の厚みを貫通して、ギャップ幅がレーザ光のスポット径以上で４ｍｍ以下となるようなルートギャップ６（すなわち、キーホール形成用間隙ＲＧ）を形成することにしている。ただし、１パスで厚板の突合せ面３を切削加工する必要があるため、２枚以上複数のフライスカッター３２、３３を用い、切り込み深さを変えて多段切削加工としてある。もちろん、薄板の場合には１枚のフライスカッターでも１パスで加工可能であり、そのような場合を排除するものではない。
また、上記溝部４の溝加工も場合によっては、複数の総形フライスカッターにより多段切削加工とする必要がある。
さらに、切り粉を排除するために、エアーあるいは水、加工液等を噴出する複数のノズル３４が配設されている。また、フライスカッター３１、３２、３３の回転方向や配置間隔ａ、ｂ、Ｌ２についても切り粉が溶接部や隣接のフライスカッターに巻き込まれないように配慮する必要がある。なお、レーザヘッド２１と最後尾のフライスカッター３３間の距離Ｌ２は、必ずしも実施形態１で示したレーザヘッド２１と熱切断ヘッド１２間の距離Ｌ１と等しくする必要はない。
【００３６】
この開先加工手段３０は溶接手段２０と同期して走行し、フライス加工による開先加工と前記複合溶接が同時進行で実施されるものである。したがって、機械加工による開先加工であっても、溶接部の前方において突合せ面３に順次開先５を連続的に形成していくものであるので、溶接熱の影響を受けることが少なくルートギャップ６を所定のギャップ幅に精度よく保持することができる。その結果、複合溶接による溶接品質も向上する。
【００３７】
なお、上記実施形態２において、フライスカッター３１〜３３の代わりに回転砥石を用いれば、研削加工によって開先を加工することができる。
【００３８】
本発明は、前述のように開先加工と複合溶接とを同時進行的に行うものであるので、更なる溶込み深さの増大化が可能であり、そのため、長大な厚板の突合せ溶接、特に溶接鋼管や造船、一般構造物等の突合せ溶接に好適なものである。
【００３９】
【発明の効果】
以上のように、本発明の開先加工方法によれば、突合せ継手のレーザとアークの複合溶接に先行して、被溶接材の突合せ面に所要形状の貫通溝を順次連続的に形成していくものである。したがって、ほぼ接触状態に突き合わされた突合せ面にキーホール形成用間隙となる貫通溝が溶接と同時に、かつ溶接箇所の直近で形成されるため、溶接熱の影響による間隙幅の変動が極めて少なく、重厚・長大な被溶接材の場合でも溶接継手を拘束する必要がない。さらに、溶接点近傍における開先形状精度が良いため、複合溶接の品質が向上するとともに、溶込み深さを増加させることが可能となる。
上述の利点により、レーザとアークの複合溶接における溶込み深さの増加に有効なキーホール形成用間隙の開先加工を従来の機械加工により行う方式と比較して、開先加工のコストを大幅に低減できるとともに、溶接前の開先加工工程や溶接継手の拘束作業が不要であるため、施工コストを大幅に低減でき、さらにキーホール形成用間隙の精度が向上するため、溶接品質が安定化するなどの効果が得られる。
【図面の簡単な説明】
【図１】本発明の実施の形態１による開先加工方法およびレーザとアークの複合溶接方法の概要を示す側面図である。
【図２】図１の開先加工部および溶接部の上面図である。
【図３】図２のＡ−Ａ線、Ｂ−Ｂ線、Ｃ−Ｃ線、Ｄ−Ｄ線の拡大断面図である。
【図４】本発明の複合溶接方法の作用を示す模式図である。
【図５】本発明の開先加工により形成される開先形状の例を示す断面図である。
【図６】実施例における、通常のビードオン複合溶接の場合とＹ形開先に対する複合溶接の場合を示す図である。
【図７】Ｙ形開先の複合溶接におけるルートギャップのギャップ幅と溶込み深さとの関係（試験結果）を示す図である。
【図８】溶込み深さの定義を示す図である。
【図９】本発明の実施の形態２による開先加工方法およびレーザとアークの複合溶接方法の概要を示す側面図である。
【図１０】図９のＥ−Ｅ線、Ｆ−Ｆ線、Ｇ−Ｇ線の拡大断面図である。
【符号の説明】
１、２ 被溶接材
３ 突合せ面
４ 溝部
５ 開先
６ ルートギャップ
１０ 開先加工手段
１１ ガウジングヘッド
１２ 熱切断ヘッド
２０ 溶接手段
２１ レーザヘッド
２２ アーク溶接トーチ
２３ 溶接ワイヤ
２４ アーク
２５ 溶融池
２６ レーザ光
２７ キーホール
２８ 溶接ビード
２９ 集光レンズ
３０ 開先加工手段
３１、３２、３３ フライスカッター
３４ ノズル[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser and arc composite welding method, and more particularly, to a groove processing method and a laser and arc composite welding method suitable for butt welding of long thick plates.
[0002]
[Prior art]
The combined welding method that combines laser and arc is generally welding with the laser beam leading in the welding direction and the arc following the welding direction. By utilizing the deep penetration characteristics of the laser, deeper penetration can be achieved. It is a welding method to obtain (for example, refer patent document 1). For this reason, usually, before generating molten metal by arc, laser light is irradiated to the root gap of the groove, and the root face surface is melted by laser and then molten metal by arc is introduced. It has been.
In such combined laser / arc welding, in order to obtain deeper penetration than laser single welding, it is effective to form a root gap having a predetermined gap on the butt face of the groove. Therefore, in Patent Document 1, the gap of the root gap is set to 10% or more of the thickness of the material to be welded and less than the beam diameter of the laser beam.
[0003]
[Patent Document 1]
JP 10-216972 A (claims, paragraphs [0012]-[0015], FIG. 1, FIG. 2)
[0004]
[Problems to be solved by the invention]
However, in the prior art as described above, it is necessary to make a groove having a root gap with a narrow gap width by machining in advance, and to maintain the root gap width within an appropriate range during welding. There was a problem as shown.
(1) In the construction work, especially when the material to be welded is heavy and long, it is extremely difficult to keep the root gap uniform over the entire line because the weld line is long. For this reason, means such as restraining the welded joint is required, which increases the cost.
(2) When the restraint of the welded joint is insufficient, the root gap may decrease due to welding thermal deformation, and a desired weld quality may not be obtained. In particular, if the root gap is smaller than the appropriate range, the necessary penetration cannot be obtained.
(3) The groove processing method by machining increases the processing cost compared to thermal processing such as plasma cutting and gas cutting, and increases the pre-welding process, which increases the cost.
[0005]
Accordingly, the present invention provides a groove processing method capable of processing a groove having a good shape accuracy at low cost with less influence of shrinkage due to welding heat in combined welding of a laser and an arc, and a penetration depth. It is an object of the present invention to provide a laser and arc combined welding method and a groove processing method capable of increasing the thickness.
[0006]
[Means for Solving the Problems]
The groove processing method according to the present invention is a groove processing method in which the butted surfaces of two materials to be welded are almost brought into contact with each other, and a through groove having a required shape is formed on the butted surfaces,
The groove processing means is arranged in front of the welding direction of the welding means,
While maintaining the distance between both means, move both means relative to the material to be welded along the butt surface,
The groove processing of the butt surface by the groove processing means and the composite welding by laser and arc of the welding means are performed simultaneously.
[0007]
In the groove processing method of the present invention, prior to the composite welding of the butt joint by laser and arc, through-grooves of a required shape are sequentially formed on the butt surfaces where the butt surfaces of the two workpieces are brought into contact with each other. It is formed continuously. For this purpose, groove processing means is arranged in front of the welding means in the welding direction, and both means are moved relative to the material to be welded along the abutting surface while keeping the distance between the two means. In addition, when a to-be-welded material is fixed, it moves synchronously, maintaining the space | interval of both means, and when both means are fixed, a to-be-welded material is moved. Thereby, the groove processing of the butt surface by the groove processing means and the combined welding of the laser and the arc by the welding means are simultaneously performed. Therefore, since the through groove that becomes the keyhole forming gap is formed on the butted surface almost in contact with the welding surface at the same time as the welding and in the immediate vicinity of the welding location, the fluctuation of the gap width due to the influence of the welding heat is extremely small. In addition, even in the case of heavy and long workpieces, there is no need to restrain the welded joint, so that the welding cost can be greatly reduced. Further, since the groove shape accuracy in the vicinity of the welding point is good, the quality of the composite welding is improved and the penetration depth can be increased.
[0008]
In the groove processing method of the present invention, the groove processing is performed by thermal cutting or machining. Thermal cutting is through-groove processing by plasma cutting or the like.
In addition, the groove processing method of the present invention can be machined as long as simultaneous welding and welding can be performed.
[0009]
Moreover, it is preferable to process the said butt | matching surface so that the width | variety of the said groove | channel through-groove may be more than the spot diameter of a laser beam and 4 mm or less.
The width of the groove through-groove is not particularly limited. However, as long as it is a through-groove having a gap width not less than the spot diameter of the laser beam and not more than 4 mm, the depth of penetration is reduced in combined welding by laser and arc as described later. An increase in the length can be achieved.
Therefore, it is particularly suitable for butt welding of long thick plates.
[0010]
The groove shape in combined welding by laser and arc can be freely selected, such as I-shape, U-shape, Y-shape, etc. However, when using U-shape or Y-shape groove, the end face of the workpiece is almost contacted after machining A method of forming a through-groove of a required shape on the abutting surface by the groove processing means is generally used. The machining step may be omitted by performing U-shaped or Y-shaped groove processing by the processing means, and immediately after that, by processing the through-groove by the subsequent groove processing means.
[0011]
The thermal cutting process is preferably performed using plasma, laser, or gas, and the machining process is preferably performed by milling or grinding.
In the case of machining, it is preferable to perform multi-stage milling or grinding with a plurality of milling cutters or grindstones having different cutting depths.
[0012]
The combined welding method of laser and arc according to the present invention, when the butted surfaces of the two workpieces are butted substantially in contact with each other, and when the through-groove of the required shape formed on the butted surfaces is combined by laser and arc,
The groove processing means is arranged in front of the welding direction of the welding means,
While maintaining the distance between both means, move both means relative to the material to be welded along the butt surface,
The groove processing of the butt surface by the groove processing means and the composite welding by laser and arc of the welding means are simultaneously performed.
[0013]
In the laser and arc combined welding method of the present invention, a groove having a desired shape is formed on a butt surface obtained by butting the butt surfaces of two materials to be welded in a substantially contact state immediately before welding. Composite welding is performed by arc. That is, it is characterized in that the groove processing of the butt surface by the groove processing means and the composite welding by laser and arc of the welding means are simultaneously performed.
As described above, since the accuracy of the through groove serving as the gap for forming the keyhole is good, the quality of the composite welding is improved and deep penetration can be obtained.
[0014]
In the laser / arc combined welding method of the present invention, the groove processing is performed by arc welding while forming a gap for forming a keyhole such that the width of the through groove is not less than the spot diameter of the laser beam and not more than 4 mm. A keyhole is formed by irradiating the formed molten pool with a laser beam, and welding is performed while flowing a weld metal by arc welding into the keyhole and the gap for forming the keyhole.
[0015]
In the present invention, even when the root gap, that is, the width of the groove on the groove butting surface is equal to or larger than the spot diameter of the laser beam, the laser beam does not pass through the root gap and is formed on the molten pool formed by arc welding. Irradiated to form a keyhole. And since a root gap is larger than a prior art, the penetration depth of a keyhole increases, As a result, a keyhole with a penetration depth larger than a prior art can be formed easily.
Therefore, in the present invention, deep penetration can be obtained even with a low-power laser. The penetration depth is represented by P in FIG.
This is because the upper limit value of 4 mm for the gap for forming the keyhole is burned out when the gap width is further increased.
[0016]
The laser used in the present invention is a YAG laser or a carbon dioxide gas laser, and the arc can be a gas metal arc, a gas tungsten arc, or a plasma arc.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
Embodiment 1 FIG.
1 is a side view showing an outline of a groove working method and a laser and arc combined welding method according to Embodiment 1 of the present invention, FIG. 2 is a top view of the groove working portion and the welded portion of FIG. 1, and FIG. FIG. 4 is an enlarged cross-sectional view taken along lines AA, BB, CC, and DD in FIG. 2, and FIG. 4 is a schematic diagram showing the operation of the composite welding method.
In these drawings, the two materials to be welded 1 and 2 are arranged so as to face each other with their flat end surfaces substantially in contact with each other before welding. The butting surfaces 3 are basically butted with a gap 0. Accordingly, the groove shape is an I-shaped groove having a gap 0 or a minute gap.
[0019]
In FIG. 1, assuming that the welding progress direction is the direction of the arrow (the groove processing direction is the same direction), the groove processing means 10 is disposed in front of the welding progress direction, and the welding means 20 is disposed behind the welding progress direction. The means 10 and 20 are configured to move at regular intervals along the abutting surface 3.
In this example, the groove processing means 10 is based on thermal cutting, and a gouging head 11 and a thermal cutting head 12 are arranged in order from the front in the welding progress direction.
The welding means 20 includes a laser head 21 and an arc welding torch 22. The gouging head 11 and the thermal cutting head 12, the laser head 21 and the arc welding torch 22 may be configured integrally or may be configured to travel independently. However, even in the case of independent driving, it is preferable that the groove processing means 10 and the welding means 20 are synchronously driven while maintaining a predetermined distance.
Each means 10 and 20 is basically configured to travel along one or both base materials (materials to be welded) along a guide rail or the like in a traveling carriage system. In addition, you may comprise each means 10 and 20 to a fixed type, and the direction of a to-be-welded material may be movable. For example, this method is preferable in the case of a pipe material. When moving the material to be welded, the means 10 and 20 may be arranged as shown in FIG. 1, and the moving direction of the base material may be the left to right direction in FIG.
[0020]
In this embodiment, prior to the combined welding of the laser and the arc, in front of the welding point, the groove processing means 10 including the gouging head 11 and the thermal cutting head 12 on the butt surface 3 of the materials 1 and 2 to be welded, The groove 5 having a required shape is successively formed.
[0021]
That is, first, the workpieces 1 and 2 are brought into contact with each other, and the gouging head 11 is moved along the butted surface 3. The gouging head 11 forms the groove part 4 which has arbitrary cross-sectional shapes, such as V shape, U shape, and an arc shape, at the upper end part of the butting surface 3 by plasma gouging, for example. As a result, the butting surface 3 includes a Y-shaped groove 5a having a groove portion 4 such as a V shape, a U shape, or an arc shape (hereinafter referred to as “Y shape opening” including those having a groove portion 4 having a U shape or an arc shape). Called “first”). However, at this stage, the Y-shaped groove 5a has a groove shape with a root gap of almost zero.
[0022]
Next, when the thermal cutting head 12 is moved along the Y-shaped groove 5a, a through groove is formed between the butted surfaces 3 of the workpieces 1 and 2 by, for example, plasma arc generated from the tip of the thermal cutting head 12. A Y-shaped groove 5 having a predetermined route gap 6 is formed. Plasma, laser, or gas is used for the thermal cutting head 12. In particular, plasma and laser are suitable for the groove processing method of the present invention because they have a high energy density, a narrow range of heat influence, a good cutting surface, and high-speed cutting.
In addition, the said groove part 4 may form an inclined part etc. in the upper part of the end surface of each to-be-welded material 1 and 2 by machining beforehand.
[0023]
In this way, prior to the combined welding of the laser and the arc, the Y-shaped groove 5 having the required route gap 6 is formed in one pass on the butt surface 3 in front of the welded parts of the workpieces 1 and 2. To go.
Then, while forming the Y-shaped groove 5, laser and arc composite welding is performed by the welding means 20. That is, groove processing and composite welding are performed simultaneously.
Accordingly, even in the case of heavy and long members, it is relatively easy to machine the machining method, so that the previous process can be omitted, and the groove 5 having the required route gap 6 can be machined much more easily. Since the groove 5 is successively formed in front of the gap, the gap width of the route gap 6 is less likely to fluctuate due to thermal cutting and thermal deformation of welding. For this reason, the required route gap 6 can be kept uniform even if the welded joint is not restrained, and the welding cost can be greatly reduced. Further, since the accuracy of the groove shape in the vicinity of the welding point is good, it is possible to increase the penetration depth and improve the welding quality.
[0024]
The laser and arc composite welding is performed simultaneously by the welding means 20 including the laser head 21 and the arc welding torch 22 immediately after the groove 5 is formed.
That is, first, arc welding is performed by generating an arc 24 from the tip of the welding wire 23 of the arc welding torch 22. Next, the laser beam 26 converged from the laser head 21 is irradiated onto the molten pool 25 formed by arc welding, and welding is performed while forming the keyhole 27 in the molten pool 25 by the laser beam 26. Reference numeral 28 denotes a weld bead.
[0025]
The laser head 21 is installed perpendicular to the welding line, and the arc welding torch 22 is installed with the torch angle θ with respect to the vertical line perpendicular to the welding line inclined at an advancing angle of about 30 °. Further, although a YAG laser is used as the laser, it is not particularly limited to this, and a carbon dioxide laser may be used.
The arc welding torch 22 is a consumable electrode type (gas metal arc), a non-consumable electrode type (gas tungsten arc), or a plasma type. In general, a gas metal arc is preferable. In the case of a gas tungsten arc, the filler wire is added.
The distance LA between the irradiation position of the laser beam 26 and the target position of the arc 24 is suitably in the range of 0 to 2 mm.
[0026]
The laser head 21 converges a laser beam guided through an optical fiber, an optical system, or the like with a condenser lens 29, and a so-called beam waist, which is a focal point of a spot beam, is formed at a predetermined position (Y-shaped opening). The route part 5) is irradiated. If necessary, a nozzle (not shown) for injecting an assist gas (for example, argon gas or carbon dioxide gas) is provided coaxially with the laser head 21 or in the vicinity thereof.
[0027]
The arc welding torch 22 generates an arc 24 from the tip of the welding wire 23 that is automatically fed, and mainly melts the welding wire 23 by the heat of the arc 24 to generate a molten pool 25. Further, during arc welding, a shielding gas (for example, an inert gas such as Ar, an active gas such as CO ₂ , or a mixed gas of Ar and CO ₂ ) is ejected through the arc welding torch 22.
The distance L1 between the laser head 21 and the thermal cutting head 12 is set to a range in which the root gap 6 of the welded portion does not vary greatly due to thermal deformation of cutting and welding. This distance L1 varies depending on the length and thickness of the material to be welded, the power of the thermal cutting head 12 used, the power of the welding head such as the laser head, and the like.
[0028]
FIG. 5 is a cross-sectional view showing an example of a groove shape produced by the groove processing method of the present invention.
(1) I-shaped groove (see Fig. 5 (a))
The use of gouging is optional, and when no gouging is used, an I-shaped groove is formed. The gap width RG of the root gap 6 processed by thermal cutting for the I-shaped groove is not particularly limited, but is processed so that the gap width RG is not less than the laser beam spot diameter and not more than 4 mm. It is preferable. Thus, the root gap 6 in which the gap width RG is equal to or larger than the laser beam spot diameter is particularly referred to as a “keyhole forming gap” in the present invention.
If the groove width RG of the root gap 6 is not less than the spot diameter of the laser beam and 4 mm or less, deep penetration can be obtained as will be described later, and is particularly suitable for butt welding of thick plates of 10 mm or more. ing.
[0029]
(2) Y-shaped groove (see FIGS. 5 (b-1) to (b-3))
By using gouging, a Y-shaped groove having a groove shape as shown can be formed. The gap width RG of the Y-shaped groove root gap (keyhole forming gap) 6 is preferably in the same range as described above.
The optimum values of the groove dimensions such as the groove angle α or groove width Gb and depth Dg of the groove portion (groove opening portion) 4 and the thickness RF of the root face portion are the thickness T of the material to be welded, the processing It is determined according to conditions, welding conditions, etc.
[0030]
Laser and arc composite welding is performed while forming the groove 5 having any one of the above shapes on the butted surfaces 3 of the workpieces 1 and 2. This composite welding method will be described with reference to FIGS.
First, an arc 24 is generated from the tip of the welding wire 23 of the arc welding torch 22 to form a molten pool 25 in the groove 5. After the molten pool 25 is formed, a laser beam 26 converged by the laser head 21 is irradiated perpendicularly to the weld line from above the molten pool 25 in the vicinity of the arc 24. The laser beam 26 is irradiated so that the (geometrical) focal position is located at the root portion of the groove 5. The distance LA between the laser and the arc is set within a range of 0 to 2 mm. The groove 5 is formed on the butt surface 3 in front of the welded portion so that the gap width RG of the root gap 6 is equal to or larger than the spot diameter of the laser beam by the preceding thermal cutting process, that is, the keyhole forming gap RG. Since it is formed, there is almost no variation in the gap width RG due to welding heat and cutting heat, and the predetermined gap width is maintained. At the same time, by irradiating the laser beam from the molten pool 25, a keyhole 27 is formed by the laser beam through the molten pool 25, and the key deeper to the deep portion in the groove 5 (the deep portion in the welded plate thickness direction). The hole 27 can be easily formed. Therefore, the weld metal flows into the deep keyhole 27. Therefore, since a deep keyhole can be formed even with a relatively low power laser, the weld metal is allowed to flow into the keyhole 27 and the keyhole forming gap while forming the keyhole 27 in this way. Butt welding with deep penetration is possible.
[0031]
【Example】
An embodiment of the present invention will be described with reference to FIG. 6A shows the case of normal bead-on composite welding, and FIG. 6B shows the case of composite welding with respect to a Y-shaped groove, each having no keyhole forming gap. The specifications and test conditions of the test piece, laser, arc, etc. used in the experiment are as follows.

[0032]
FIG. 7 shows an example (test result) of the relationship between the gap width of the root gap and the penetration depth in the Y-shaped groove composite welding. FIG. 8 is a diagram showing the definition of the penetration depth. The penetration depth P is a distance from the upper end 7 of the butting surface at the bottom of the groove (groove opening) 4 to the lowest end of the groove melting portion.
[0033]
First, when bead-on composite welding is performed on a flat test piece, the penetration depth P is the same as that in the case of laser single welding (may be reduced). That is, the penetration depth in this case is about 5 mm.
On the other hand, in the case of the Y-shaped groove, when there is no keyhole forming gap (zero gap), the penetration depth is almost the same as when the bead-on gap is zero, but if a keyhole forming gap is provided, FIG. As shown, the penetration depth is greatly increased. For example, when the gap width is 1.0 mm which is equal to or greater than the spot diameter, the penetration depth is 10 mm. When the gap width is 0.5 mm, which is the same as the spot diameter, the penetration depth is about 7.0 mm. In the case of this experiment, the maximum value of the penetration depth is seen when the gap width is 4 mm, and when it exceeds 4 mm, the penetration depth tends to decrease rapidly. The penetration depth is affected by the distance LA between the laser and the arc, but in the range of LA = 0 to 2 mm, the upper limit of the gap width is suitably 4 mm. The reason for this is that if the gap width is further increased, the melt-down occurs as described above.
[0034]
Embodiment 2. FIG.
FIG. 9 shows a second embodiment of the present invention. FIG. 10 is an enlarged cross-sectional view taken along lines EE, FF, and GG in FIG.
In the first embodiment described above, the groove processing is performed by thermal cutting, but this embodiment is a method of processing the groove by machining. Since the composite welding method is the same as that of the first embodiment, the description thereof is omitted.
[0035]
The groove processing means 30 of the present embodiment is configured using milling cutters 31, 32, and 33. That is, the Y-shaped groove 5 is formed in one pass by milling.
As shown in FIG. 10A, the leading milling cutter 31 cuts a groove portion 4 having an arbitrary cross-sectional shape such as a V shape at the upper end portion of the abutting surface 3 of the workpieces 1 and 2. Therefore, this milling cutter 31 is a total shape cutter.
As shown in FIGS. 10B and 10C, the second and third milling cutters 32 and 33 are for digging a groove of a required route gap 6, and finally the butt surface 3. The root gap 6 (that is, the keyhole forming gap RG) is formed so that the gap width is not less than the spot diameter of the laser beam and not more than 4 mm. However, since it is necessary to cut the abutting surface 3 of the thick plate in one pass, two or more milling cutters 32 and 33 are used, and the cutting depth is changed to perform multistage cutting. Of course, in the case of a thin plate, even a single milling cutter can be processed in one pass, and such a case is not excluded.
Further, in some cases, it is necessary to perform multi-stage cutting with a plurality of general-purpose milling cutters.
Further, a plurality of nozzles 34 for ejecting air, water, machining fluid, or the like are disposed in order to eliminate chips. In addition, it is necessary to consider the rotation direction of the milling cutters 31, 32, 33 and the arrangement intervals a, b, L2 so that the chips do not get caught in the welded part or the adjacent milling cutter. The distance L2 between the laser head 21 and the last milling cutter 33 is not necessarily equal to the distance L1 between the laser head 21 and the thermal cutting head 12 shown in the first embodiment.
[0036]
The groove processing means 30 runs in synchronization with the welding means 20, and the groove processing by milling and the composite welding are carried out simultaneously. Accordingly, even in the case of groove machining by machining, the groove 5 is successively formed on the abutting surface 3 in front of the welded portion, so that it is less affected by welding heat and is less affected by the root gap. 6 can be accurately maintained within a predetermined gap width. As a result, the welding quality by composite welding is also improved.
[0037]
In addition, in the said Embodiment 2, if a rotary grindstone is used instead of the milling cutters 31-33, a groove | channel can be processed by grinding.
[0038]
Since the present invention performs the groove processing and the composite welding simultaneously as described above, it is possible to further increase the penetration depth, and therefore, butt welding of a long thick plate, In particular, it is suitable for butt welding of welded steel pipes, shipbuilding, general structures and the like.
[0039]
【The invention's effect】
As described above, according to the groove processing method of the present invention, prior to the combined welding of the laser and arc of the butt joint, through-grooves having a required shape are sequentially and continuously formed on the butt surface of the workpiece. It is going. Therefore, since a through groove that becomes a keyhole forming gap is formed at the same time as welding on the butted surface that is almost in contact with the contact state, the variation in the gap width due to the influence of welding heat is extremely small, There is no need to restrain the welded joint even in the case of heavy and long workpieces. Further, since the groove shape accuracy in the vicinity of the welding point is good, the quality of the composite welding is improved and the penetration depth can be increased.
Due to the above-mentioned advantages, the groove machining cost is greatly increased compared to the conventional machining method for the groove machining for keyhole formation, which is effective for increasing the penetration depth in laser and arc combined welding. In addition, it eliminates the need for groove processing before welding and restraint work on welded joints, greatly reducing construction costs and improving the accuracy of the gap for keyhole formation, thus stabilizing the welding quality. The effect of doing etc. is acquired.
[Brief description of the drawings]
FIG. 1 is a side view showing an overview of a groove processing method and a laser / arc combined welding method according to Embodiment 1 of the present invention;
2 is a top view of a groove processing portion and a welding portion in FIG. 1; FIG.
3 is an enlarged cross-sectional view taken along lines AA, BB, CC, and DD in FIG. 2;
FIG. 4 is a schematic diagram showing the operation of the composite welding method of the present invention.
FIG. 5 is a cross-sectional view showing an example of a groove shape formed by groove processing according to the present invention.
FIG. 6 is a diagram showing a case of normal bead-on composite welding and a case of composite welding for a Y-shaped groove in an example.
FIG. 7 is a diagram showing a relationship (test result) between a gap width of a root gap and a penetration depth in composite welding with a Y-shaped groove.
FIG. 8 is a diagram showing the definition of penetration depth.
FIG. 9 is a side view showing an outline of a groove processing method and a laser / arc combined welding method according to Embodiment 2 of the present invention;
10 is an enlarged cross-sectional view taken along lines EE, FF, and GG in FIG. 9;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 2 To-be-welded material 3 Butting surface 4 Groove part 5 Groove 6 Root gap 10 Groove processing means 11 Gouging head 12 Thermal cutting head 20 Welding means 21 Laser head 22 Arc welding torch 23 Welding wire 24 Arc 25 Molten pool 26 Laser beam 27 Keyhole 28 Weld Bead 29 Condensing Lens 30 Groove Processing Means 31, 32, 33 Milling Cutter 34 Nozzle

Claims (11)

A groove processing method in which the butted surfaces of two materials to be welded are almost brought into contact with each other, and a through groove having a required shape is formed on the butted surfaces,
The groove processing means is arranged in front of the welding direction of the welding means,
While maintaining the distance between both means, move both means relative to the material to be welded along the butt surface,
A groove processing method characterized by simultaneously performing groove processing of the butt surface by the groove processing means and composite welding by laser and arc of the welding means. The groove processing method according to claim 1, wherein the groove processing is performed by thermal cutting or machining. 3. The groove processing method according to claim 1, wherein the butt surface is processed so that a width of the through groove of the groove is not less than a spot diameter of the laser beam and not more than 4 mm. In the groove processing of the butt surface by the groove processing means, the groove processing of the succeeding groove is performed immediately after the groove processing for forming the groove portion of the required shape at the upper end portion of the butt surface by the preceding groove processing means. The groove processing method according to claim 1, wherein the through groove is processed by a means. The groove processing method according to any one of claims 1 to 4, wherein the groove processing is performed by thermal cutting using plasma, laser, or gas. The groove processing method according to claim 1, wherein the groove processing is performed by milling or grinding. The groove processing method according to claim 6, wherein multi-stage milling or grinding is performed by a plurality of milling cutters or grindstones having different cutting depths. When the groove where the butted surfaces of the two workpieces are almost in contact with each other is welded together by laser and arc,
The groove processing means is arranged in front of the welding direction of the welding means,
While maintaining the distance between both means, move both means relative to the material to be welded along the butt surface,
A laser / arc combined welding method, wherein groove processing of the butt surface by the groove processing means and composite welding of welding of the welding means by laser and arc are performed simultaneously. A laser beam is formed on the molten pool formed by arc welding while forming a gap for forming a keyhole so that the width of the through groove is not less than the spot diameter of the laser beam and not more than 4 mm by the groove processing. The laser and arc combined welding method according to claim 8, wherein a keyhole is formed by irradiating and welding while welding a weld metal by arc welding into the keyhole and a gap for forming the keyhole. 10. The laser / arc combined welding method according to claim 8 or 9, wherein a YAG laser or a carbon dioxide gas laser is used as the laser. 11. The laser / arc combined welding method according to claim 8, wherein a gas metal arc, a gas tungsten arc, or a plasma arc is used for the arc.

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