JP2012020292A - Laser welding technique - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser welding technique which has a high capacity of fusing a base material without using a laser beam machine of high output and which has high efficiency and high quality.SOLUTION: The laser welding technique combines a laser beam 1 and a hot wire 2, inserts the laser beam 1 into a leading part and the hot wire 2 into a following with respect to the welding advancing direction. The technique irradiates a surface of the base material 3 to be welded with the laser beam 1, wherein the laser beam 1 is defocused, and a direction of a reflecting beam 1' of the laser beam 1 on a surface of a molten pool 5 formed by the irradiation and fusion of the hot wire is defined as a front of the molten pool 5 and the welding is carried out while always forming a leading molten pool 5a.

Description

  The present invention relates to a welding method in which laser welding and hot wire welding are combined, and more particularly, to a laser welding method suitable for performing butt welding of steel plates or steel pipes with high quality and high efficiency.

  Laser welding uses a high-energy laser beam, and the laser beam is condensed by a lens and applied to a base material such as a steel plate, which is the welded part, with a higher energy density. Compared with arc welding using a heat source as a heat source, deep penetration in the thickness direction of the base metal is obtained, high speed welding is possible because the base material has a high melting speed, This is a welding method having features such that the range of the weld heat affected zone is narrow, welding deformation is small, and low distortion welding can be performed. In addition, unlike the electron beam welding which is a high-efficiency welding method, it is not necessary to place the welded part in a vacuum environment, so that it has come to be used in various fields as a high-efficiency welding method.

  A general laser welding method will be described. In order to simplify the description, an example of bead-on-plate welding in which a bead is placed on a plate will be described. The following two types are generally known. One is a deep penetration type laser welding method (sometimes referred to as a keyhole welding method), which is shown in FIGS. In FIG. 6, the laser light 1 from the laser light source is condensed by a condensing lens 15 placed between a laser light source (not shown) and the base material 3 that is a welded part, thereby forming a focal point 14. Further, in this welding method, as shown in FIG. 9, the laser beam having a very high energy density is supplied to the surface of the base material 3 by setting the position of the focal point 14 to be on the surface of the base material 3. Therefore, the surface of the base material 3 is rapidly melted and evaporated to become a metal vapor. Due to the reaction force of the metal evaporation, a gap called a keyhole 16 is formed in the thickness direction of the base material 3, and the keyhole 16 is continuously moved by moving the laser beam 1 in the welding direction with respect to the base material 3. Formed. Since the molten pool 5 is continuously formed behind the keyhole 16, the weld bead 4 having a narrow width and a deep penetration can be obtained. The cross-sectional shape of the obtained bead 4 is shown in FIG. In FIG. 10, the cross section of the weld bead 4 is thin and vertically long in the thickness direction of the base material 3. In the present specification, for convenience of explanation, the molten state of the base material 3 or the base material 3 and a filler material (not shown) such as a wire is referred to as a molten pool 5, and the solidified state by cooling is welded. It will be called bead 4 or weld metal.

  Next, the other is a heat conduction type laser welding method, which is shown in FIGS. In FIG. 6, the laser light 1 from the laser light source is condensed by a condensing lens 15 placed between a laser light source (not shown) and the base material 3 that is a welded part, thereby forming a focal point 14. Furthermore, in this welding method, as shown in FIG. 6, the position of the focal point 14 of the laser beam 1 is set so as to be closer to the light source side of the laser beam 1 than the surface of the base material 3 (this is referred to as “adding the defocus distance plus”). 9), a method of melting the base material 3 by heat conduction by irradiating the surface of the base material 3 with the laser beam 1 having a lower energy density than the case where the focal point 14 is focused. Compared with the welding method for forming the keyhole 16 shown in FIG. 1, the molten pool 5 is formed shallower and wider in the thickness direction of the base material 3. As shown in FIG. 7, by moving the laser beam 1 in the welding direction with respect to the base material 3, the molten pool 5 is continuously formed behind the welding direction and cooled to obtain the weld bead 4. The cross-sectional shape of the obtained weld bead 4 is shown in FIG. As shown in FIG. 8, in the cross-sectional shape of the weld bead 4, the base material melts into a semicircular shape that is convex in the thickness direction of the base material 3.

  The deep penetration type laser welding method and the heat conduction type laser welding method are different welding methods as described above, and are selected according to the application location. In the deep penetration type laser welding method, the penetration depth obtained in one pass is approximately 1 mm per 1 kW of output, which is greater than the heat conduction type laser welding method. For example, in the case of welding and joining by using a 5 kW class laser processing machine, welding in one pass is possible and widely used.

  When the plate thickness is thicker than 5 mm, a 10 kW output class laser processing machine with a higher output is used. However, the plate thickness that can be welded by the 10 kW output class laser processing machine is about 10 mm, which is a thicker plate. As a method for welding the thickness, a laser welding method described in JP-A-7-323386 (Patent Document 1) has been proposed. This method uses a Y-shaped narrow groove with the root penetration at the critical penetration depth of deep penetration welding as the groove provided in the welded part, and the first layer of the root face part is deeply penetrated and one pass complete penetration welding is performed. For the second and subsequent layers, the groove portion is irradiated with laser light having a reduced energy density by separating the focal point of the condensing optical system from the front layer bead by a distance of 1/20 or more of the focal length. A welding method is used in which a heat conductive bead is formed by adding a wire of filler metal.

  In addition, as a laser welding method in which efficiency is improved by using a hot wire welding method in which a wire is energized from a wire heating power source in addition to a welding power source, Japanese Patent Application Laid-Open No. 61-232080 (Patent Document 2) discloses a wire. Is disclosed in which a hot wire is supplied and welded so as to directly irradiate the laser beam after supplying heat from the front in the welding direction and bringing it into contact with the unwelded portion which is the base material in front of the welded portion to generate resistance heat by energization. In JP-A-61-232081 (Patent Document 3), a wire is supplied from the rear in the welding direction so as to contact the molten pool or weld metal part and generate electric resistance, and then directly irradiate the laser beam. A method of supplying and welding hot wire is disclosed.

JP-A-7-323386 JP-A-61-232080 JP-A-61-232081

  In the prior art described in Japanese Patent Application Laid-Open No. 7-323386, the groove provided in the welded portion is a Y-type narrow groove having a root penetration at the limit penetration depth of deep penetration welding, and one layer of the root face portion. The energy density of the second layer and above by separating the focal point of the condensing optical system from the front layer bead by a distance of 1/20 or more of the focal length. There has been proposed a welding method in which a groove portion is irradiated with a laser beam having a reduced resistance and a wire of a filler material is added to form a heat conduction type bead. In the second and subsequent layers, it is necessary to melt both the melted base metal and the filler metal wire with a laser beam having a reduced energy density. Since the reflection is large and the loss of laser energy is large, a laser processing machine of 10 kW class is used for efficient welding. The price of a laser processing machine is usually about 10 million yen per kW. The laser processing machine used in this method is a 10 kW class, which is very expensive as compared with a normally used 5 kW output class laser processing machine.

Further, the invention described in Japanese Patent Application Laid-Open Nos. 61-2332080 and 61-238201 uses a hot wire that energizes the wire and laser welding, so that the high density energy of the laser beam is melted by the filler wire. Although the welding speed and efficiency can be increased by eliminating the need to use the I-type groove, the one disclosed in the above publication is intended for one-pass welding of an I-type groove. On the other hand, in the present invention, the shape of the welding groove is not particularly limited, and this is welded in one pass, and the method disclosed in the above publication is particularly effective in forming the welded part and maintaining the welding quality. We cannot cope with difficulty at all.
An object of the present invention is to provide a high-efficiency and high-quality laser welding method using a laser processing machine having a power of 5 kW or less even when welding is performed with a welding base material having a thickness of about 20 mm.

The above-described problems of the present invention are solved by the following configuration.
The invention according to claim 1 is a laser welding method for welding a base material (3) to be welded using a welding wire (2) as a filler material, wherein the laser beam (1) is the laser beam (1). ) Is irradiated to the welded base material (3) subjected to the groove processing to melt the welded base material (3), and the welding wire (2) is connected to the welding wire (2) and the A hot wire heated by resistance heating of the wire (2) by energizing between the base material (3) to be welded, and a base material to be welded (approximate the laser beam irradiation angle behind the laser beam (1)) 3) inserted into a molten pool formed by melting the welded base material at an inclination angle with respect to 3), and into a molten pool (5) formed by melting the welded base material (3) and inserting the welding wire (2). The reflected light (1 ′) of the laser beam (1) irradiated to the molten pool (5) The laser welding method is characterized in that welding is performed while irradiating forward in the tangential direction and melting.

  The invention described in claim 2 is the reflected light (1) of the laser beam (1) irradiated to the molten pool (5) formed by melting the welded base material (3) and inserting the welding wire (2). The preceding weld pool (5a) preceding the weld pool (5) is welded by continuously irradiating ')) in front of the weld pool (5) in the welding direction. 1. The laser welding method according to 1.

  According to the third aspect of the present invention, the irradiation angle θ1 of the laser beam (1) is 80 to 100 ° with respect to the surface of the base material (3) to be welded, and the welding wire (2) is inserted into the molten pool (5). The angle θ2 is 90 to 120 ° with respect to the surface of the base metal (3) to be welded, the intersection of the center line of the welding wire (2) and the surface of the base metal (3) to be welded, and the center line of the laser beam (1) 2. The narrow groove multi-layer laser welding method according to claim 1, wherein the distance from the intersection of the surface of the base material to be welded (3) is 1 to 3 mm.

(Function)
In the first and second aspects of the present invention, first, the surface of the weld pool 5 is irradiated with the laser beam 1 at a distance away from the plus or minus side, so that the cross-sectional shape of the bead 4 is as shown in FIG. It is possible to avoid deepening as shown in.

  When the molten pool 5 is irradiated with the laser beam 1 at a distance out of focus, the laser beam 1 is directed toward the molten pool 5 having an inclined surface with an inclination angle α with respect to the surface of the base material 3 as shown in FIG. Irradiate. By irradiating the surface of the molten pool 5 with the laser beam 1 at such a distance out of focus, a bead 4 having a semicircular cross section as shown in FIG. 8 is obtained. A part of the laser energy is absorbed by the molten pool 5, a part of the laser beam 1 is reflected as reflected light 1 ′ on the surface of the molten pool 5 toward the surface of the base material 3, and the front of the molten pool 5 is melted. Thus, the preceding molten pool 5a can be formed continuously.

  Next, instead of directly irradiating and melting the wire 2 added as a filler material with the laser beam 1, the wire 2 is made into a hot wire which is heated by resistance heating by energizing the wire 2. Heat to near melting point before inserting into. Thereby, the energy of the laser beam 1 can basically be applied to the melting of only the base material 3 to be welded, so that the energy of the necessary laser beam 1 can be halved. Specifically, a laser processing machine of 8 to 10 kW is used in normal steel plate welding, but if this welding method is used, welding can be performed with a laser processing machine of 3 to 5 kW. Since the price of a laser processing machine is usually about 10 million yen per kW, the initial equipment cost can be greatly reduced.

  Further, the laser beam 1 is applied to the weld pool 5 formed on the welded portion of the base material 3 to be welded from the front in the welding direction, and the hot wire 2 is applied to the weld pool 5 from the rear to approximate the irradiation angle of the laser beam 1. The steeply inclined surface (inclined surface having the inclination angle α in FIG. 4) is formed in the molten pool 5 by being inserted at an angle at the same angle, and at the same time, the surface of the molten pool 5 in the welding direction is irradiated and melted. The reflected light 1 ′ of the laser beam 1 on the surface of the pond 5 is in the vicinity of the molten pool 5 and is melted by irradiating the surface of the molten pool 5 at an incident angle toward the surface of the base material 3 obliquely forward of the molten pool 5. The front of the pond 5 in the welding direction is melted to continuously form the preceding molten pool 5a. It is one feature of the present invention that the preceding molten pool 5a is continuously formed, thereby improving the melting ability in the groove, which is the most problematic in groove welding, and stable welding without causing poor fusion. Can be performed with high efficiency.

同じく表１において、レーザ照射角度θ１とワイヤ送給位置をそれぞれ９０°、２ｍｍとした場合に、被溶接母材３の表面に対してワイヤ挿入角度θ２を９０〜１２０°で挿入すると溶接ビード４が凹形状となり多層盛溶接に適した形状とすることができた。この範囲から外れる角度でワイヤ２を挿入すると開先の上方に設定するレーザヘッドとワイヤトーチが干渉するか、溶接ビード４が凸状になった。前者は現在の装置の大きさから物理的な制限があるためであり、後者はワイヤ２が溶融池５の温度が低い後方から挿入され、ワイヤ挿入位置で凝固し、中央が盛り上ったビードになる。 Table 1 shows a range in which a normal weld bead 4 can be obtained when the laser irradiation angle θ1, the wire insertion angle θ2, and the wire feeding position are changed. When the wire insertion angle θ2 and the wire feed position are 105 ° and 2 mm, respectively, when the irradiation angle θ1 of the laser beam 1 is applied to the surface of the base material 3 to be welded at 80 to 100 °, the weld bead 4 is recessed. It became a shape and was able to be a shape suitable for multi-layer welding. Irradiation at an angle outside this range resulted in poor fusion. This is because the reflected light 1 ′ of the laser beam 1 cannot be directed from the front of the molten pool 5 to the oblique front.

Similarly, in Table 1, when the laser irradiation angle θ1 and the wire feeding position are 90 ° and 2 mm, respectively, the welding bead 4 is inserted when the wire insertion angle θ2 is inserted at 90 to 120 ° with respect to the surface of the base material 3 to be welded. It became a concave shape and could be a shape suitable for multi-layer welding. When the wire 2 was inserted at an angle outside this range, the laser head set above the groove and the wire torch interfered with each other, or the weld bead 4 became convex. The former is due to physical limitations due to the size of the current device, and the latter is a bead in which the wire 2 is inserted from the rear where the temperature of the molten pool 5 is low, solidifies at the wire insertion position, and the center is raised. become.

  Similarly, in Table 1, when the laser irradiation angle θ1 and the wire insertion angle θ2 are 90 ° and 105 °, respectively, when the wire feed position shown in FIG. The shape was suitable for welding. When the position is out of this range, the shape of the weld bead 4 cannot be formed into a concave shape, and is uneven or convex.

  According to the third aspect of the present invention, the hot wire 2 is further moved behind the laser beam 1 in the welding direction so as not to obstruct the reflection of the laser beam 1 on the surface of the molten pool 5. 2 is melted at an insertion angle θ2 of 90 ° to 120 ° on the rear side in the welding progress direction with respect to the surface of the base metal 3, and preferably at an insertion angle θ2 of 100 to 110 °. Insert from above the pond 5. When the insertion angle θ2 is less than 90 degrees, the laser beam 1 and the wire 2 interfere with each other, and when the insertion angle θ2 exceeds 120 degrees, the wire 2 is inserted behind the molten pool 5 and the weld bead 4 is formed. Due to the convex shape, it becomes difficult to melt the groove wall 7 at the time of the next layer welding, which causes a fusion failure.

  Further, the insertion position of the wire 2 in the molten pool 5 shown in FIG. 5 is also an important parameter, and if the distance between the wire insertion position and the irradiation position of the central axis of the laser beam 1 to the molten pool 5 is too large, the molten pool. Since the wire 2 is inserted into the end of 5 and the surface shape of the bead 4 becomes a convex shape, it becomes difficult to melt the groove wall 7 at the time of the next layer welding, which causes fusion failure. On the contrary, if the distance between the insertion position of the wire 2 into the molten pool 5 and the irradiation position of the central axis of the laser beam 1 onto the molten pool 5 is small, the laser beam 1 hits the wire 2, and the wire 2 becomes the laser beam 1. As a result, the melted and melted phenomenon occurs, and the surface of the molten pool 5 is disturbed by the wave welding phenomenon, and the bead 4 is uneven. The optimal distance between the insertion position of the wire 2 into the molten pool 5 and the position of irradiation of the central axis of the laser beam 1 onto the molten pool 5 was 1 to 3 mm.

  According to the first aspect of the invention, since the wire 2 is heated to near the melting point by hot wire welding, the energy of the laser beam 1 can basically be applied to the melting of only the base material 3 to be welded. The energy of the laser beam 1 can be halved. Specifically, a laser processing machine of 8 to 10 kW is used in normal steel plate welding, but if this welding method is used, welding can be performed with a laser processing machine of 3 to 5 kW. Since the price of a laser processing machine is usually about 10 million yen per kW, the initial equipment cost can be greatly reduced.

  According to the invention described in claim 2, in addition to the effect of claim 1, in order to form the preceding molten pool 5a, the front portion of the molten pool 5 of the base material 3 is always melted in advance. The base material 3 to be welded can be completely melted by passing through the pond 5, the welding proceeds smoothly, and good welding can be performed.

  According to the second aspect of the invention, in addition to the effect of the first invention, the insertion angle θ2 of the hot wire 2 with respect to the surface of the molten pool 5 is set in the backward direction of the welding progress with respect to the surface of the base material 3. Is inserted in the welding progress direction in the upper central portion of the weld pool 5 at an insertion angle θ2 = 90 ° to 120 °, preferably 100 ° to 110 ° (see FIG. 5), and further to the surface of the base material 3 to be welded By setting the irradiation angle θ1 of the laser light 1 to 80 to 100 °, the laser light 1 and the wire 2 do not interfere with each other, and the inclination angle α (see FIG. 4) of the surface of the molten pool 5 does not become small. 1 reflected light 1 ′ can be directed to the surface of the base material 3, which brings about good results in welding stability and prevention of welding defects.

It is a schematic diagram for demonstrating 1st embodiment of the laser welding method of this invention. It is a schematic diagram for demonstrating 2nd embodiment of the laser welding method of this invention. It is a schematic diagram for demonstrating 3rd embodiment of the laser welding method of this invention. It is a schematic diagram explaining the phenomenon in which the laser beam 1 reflects on the molten pool surface. It is a schematic diagram for demonstrating laser beam 1 irradiation angle (theta) 1, wire insertion angle (theta) 2, and a wire feed position. It is a schematic diagram explaining a defocusing distance. It is a schematic diagram for demonstrating a heat conductive type laser welding method. It is a copy figure of the bead section shape of heat conduction type laser welding. It is a schematic diagram for demonstrating a deep penetration type | mold laser welding method. It is a copy figure of the bead cross-sectional shape of deep penetration type laser welding.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram for explaining the laser welding method of this embodiment, FIG. 4 is a schematic diagram for explaining a phenomenon in which the laser beam 1 is reflected on the surface of the molten pool 5, and FIG. It is a schematic diagram for demonstrating irradiation angle (theta) 1, wire insertion angle (theta) 2, and a wire insertion position.
A Y-shaped groove 6 is provided in a space portion where the groove wall 7 faces the base material 3 of the workpiece, and a welded portion is formed by the second V-shaped groove. The laser beam 1 is collected by a condensing lens of a laser processing machine (not shown), and is irradiated onto the surface of the molten pool 5 at a distance shifted from the focal point (referred to as “focal shift distance plus”).

The wire 2 uses a hot wire power supply 11, a power supply unit 12, and a ceramic guide 13 to supply current from the hot wire power supply 11 to a circuit that sequentially passes through the power supply unit 12, the wire 2, the molten pool 5, the base material 3, and the hot wire power supply 11. The wire 2 is resistance-heated.
Then, the wire 2 is heated to near the melting point before being inserted into the molten pool 5. Since the wire 2 is heated to near the melting point by hot wire welding, the energy of the laser beam 1 can be basically applied to the melting of only the base material 3 to be welded, so that the necessary energy of the laser beam can be halved. become. Accordingly, a laser beam machine of 5 to 8 kW is usually used in thick plate welding, but if this welding method is used, it becomes possible to perform plate welding with a laser beam machine of 3 to 5 kW.

  The laser beam 1 is irradiated on the welded base material 3 from the front in the welding progress direction, and the hot wire 2 is applied to the molten pool 5 from the rear in the welding progress direction of the welded base material 3 at an angle approximate to the irradiation angle of the laser light 1. A steeply inclined surface with respect to the base material 3 (an inclined surface having an inclination angle α in FIG. 4) is formed in the molten pool 5 by inserting it upright, and at the same time, the laser beam 1 is irradiated to the front surface of the molten pool 5 in the welding direction, The reflected light 1 ′ of the laser beam 1 on the surface of the molten pool 5 is in front of the molten pool 5 (the first half in the welding direction of the molten pool 5, the right slope where the wire 2 of the molten pool 5 shown in FIG. 4 is inserted. Irradiate the surface of the molten pool 5 on the surface side.

  When the laser beam 1 is irradiated to the molten pool 5 at a distance from which the focus of the laser beam 1 is removed, the molten pool 5 has an inclined surface with an inclination angle α (FIG. 4) with respect to the surface of the base material 3. The laser beam 1 is irradiated toward In this way, by irradiating the molten pool 5 with the laser beam 1 at a distance out of focus, a part of the laser energy is absorbed by the molten pool 5 and a part of the laser beam 1 is absorbed on the surface of the molten pool 5. It is reflected toward the surface side of the base material 3 and is melted completely by passing through the molten pool 5 because the front part of the molten pool 5 of the base material 3 is always melted in advance. Can do. In this way, the welding proceeds smoothly, with good results in welding stability and prevention of welding defects.

  In the present invention, it is necessary to irradiate the surface of the molten pool 5 with the laser beam 1 at a distance away from the focus on the plus side or the minus side. This is to avoid this phenomenon because the cross-sectional shape of the bead 4 becomes deep as shown in FIG. 10 when the laser beam 1 is focused on the surface of the molten pool 5. By irradiating the molten pool 5 with the laser beam 1 at a distance out of focus in this way, a bead 4 having a semicircular cross section as shown in FIG. 8 is obtained.

  The hot wire 2 is inserted into the molten pool 5 at an angle equal to or close to the irradiation angle of the laser beam 1 with respect to the surface of the base material, so that the surface of the molten pool 5 is steeply inclined with respect to the surface of the base material 3 ( The inclination angle α) shown in FIG. 4 is formed. Since the wire 2 is heated without being irradiated with the laser beam 1, it can be melted. In addition, if the temperature of the hot wire 2 is lower than the vicinity of the melting point, heat is taken away from the molten pool 5 when the hot wire 2 is inserted into the molten pool 5, so that the melting of the wall by the molten pool 5 becomes incomplete and the bead shape is concave. It will not be shaped and will cause poor fusion during next layer welding.

  As shown in FIG. 5, the wire insertion angle θ2 inclined to the front side in the welding progress direction with respect to the surface of the base material 3 is 90 ° to 120 °, preferably 100 ° to 110 °, and is inserted into the upper central portion of the molten pool 5. It is necessary. When the wire insertion angle θ2 is less than 90 degrees, the laser beam 1 and the wire 2 interfere with each other, and when the wire insertion angle θ2 exceeds 120 degrees, the inclination angle α of the surface of the molten pool 5 decreases, and the laser beam 1 cannot be irradiated to the vicinity of the molten pool 5, the melting of the groove bottom 8 from both the groove walls 7 becomes incomplete, and fusion failure occurs. In addition, since the wire is inserted behind the molten pool, it solidifies simultaneously with the insertion and the bead becomes convex.

  Further, as shown in FIG. 5, the insertion position of the wire 2 on the surface of the molten pool 5 is also an important parameter, and the insertion position of the wire 2 on the surface of the molten pool 5 (the central axis of the wire 2 and the surface of the base material). The point of intersection with the center axis of the laser beam 1 and the surface of the molten pool 5 is 1 to 3 mm behind the welding progress direction. If the insertion position of the wire 2 on the surface of the molten pool 5 is too larger than 3 mm, the wire 2 will be inserted into the end of the molten pool 5, and the bead shape becomes a convex shape and the groove wall is welded when the next layer is welded. 7 is difficult to melt, causing poor fusion. On the contrary, if the insertion position of the wire 2 on the surface of the molten pool 5 is smaller than 1 mm, the laser beam 1 hits the wire 2, and the phenomenon that the wire 2 is melted by the laser beam 1 and fusing occurs. The surface of the pond 5 is disturbed by the wave welding phenomenon, and irregularities are generated on the surface of the bead 4. The insertion position of the wire 2 was best around 2 mm.

  When the laser beam 1 is irradiated onto the molten pool 5 that forms a steep slope with respect to the surface of the base material 3, a part of the laser energy is absorbed by the molten pool 5 as shown in FIG. Reflected on the surface of the pond 5 and irradiated to the groove bottom 8 and the groove wall 7 on the front or both sides of the molten pool 5 and partially melted to form the preceding molten pool 5a shown in FIG. 1 or FIG. The groove bottom 8 and the groove wall 7 can be completely melted by passing through the pond 5.

The inclination angle θ1 inclined to the front side of the welding progress direction with respect to the surface of the base material 3 of the central axis of the laser beam 1 is optimally 80 degrees to 110 degrees, and the inclination angle α of the molten pool 5 (the parameter is the welding speed, The laser power, the wire feed amount, and the wire insertion angle θ2) need to be changed.
Typical welding test conditions using stainless steel were as follows: a welding bead could be constructed with a laser power of 3 kW, a welding speed of 0.5 m / min, a wire diameter of 1.2 mm, and a wire feed speed of 6 m / min.

Thus, according to the present embodiment, the construction of the second V-shaped groove of the Y-shaped groove can be stably performed with a laser processing machine having a laser power of 3 kW. In normal laser welding, it is necessary to supply energy for melting both the base material 3 and the wire 2 with the laser beam 1, but most of the laser energy is applied to the melting of the base material 3 by applying the hot wire 2. The laser power can be suppressed, and the equipment cost of an expensive laser processing apparatus can be reduced as compared with the prior art.
Further, in the laser welding method of this embodiment, since the base material 3 has a small penetration and a low heat input, the heat-affected zone is small, the joint quality such as the toughness of the obtained welded material is improved, and welding with low distortion is performed. It is possible to suppress solidification cracks that are likely to occur during welding.

  In FIG. 2, the schematic diagram of the other Example of the laser welding method of this invention is shown. In this embodiment, the laser beam 1 is irradiated with the defocusing distance minus (the focal point of the laser beam 1 is inside the molten pool 5). In this case, the same effect as that obtained when the defocus distance of the laser beam 1 shown in FIG. When the defocus distance of the laser beam 1 is negative, the range of the laser beam 1 reflected on the surface of the molten pool 5 is smaller than that when the defocus distance shown in FIG. Will be irradiated. Depending on the inclination angle θ1 of the laser beam 1 with respect to the surface of the base material 3 on the surface of the molten pool 5 and the irradiation power of the laser beam 1, it is possible to select whether the defocusing distance is positive or negative.

  Even with a wall thickness of about 20 mm, high-quality and high-efficiency welding can be performed with a laser processing machine of 5 kW or less by a laser welding method combining a hot wire and a laser.

DESCRIPTION OF SYMBOLS 1 Laser beam 2 Wire 3 Base material 4 Weld bead 5 Weld pool 5a Advancing weld pool
6 Groove 7 Groove Wall 8 Groove Bottom 11 Hot Wire Power Supply 12 Power Feed Unit 13 Ceramic Guide 14 Focus 15 Condenser Lens 16 Keyhole

Claims (3)

  In a laser welding method for welding a base material (3) to be welded using a welding wire (2) as a filler material, a laser beam (1) is defocused from the laser beam (1) and the opening is performed. The pre-worked workpiece base material (3) is irradiated to melt the workpiece base material (3), and the welding wire (2) is connected between the welding wire (2) and the workpiece base material (3). The wire (2) is heated by the resistance heat of the wire (2), and is heated behind the laser beam (1) at an inclination angle with respect to the welding base material (3) approximate to the laser beam irradiation angle. Laser which is inserted into a molten pool (5) formed by melting of a welding base material and irradiated to the molten pool (5) formed by melting of the base material for welding (3) and insertion of the welding wire (2) The reflected light (1 ′) of the light (1) is irradiated forward in the welding direction of the molten pool (5). Laser welding wherein the welding while melted by.   The reflected light (1 ′) of the laser beam (1) irradiated to the molten pool (5) formed by melting the welded base material (3) and inserting the welding wire (2) is used as the molten pool (5). 2) The laser welding method according to claim 1, wherein welding is performed while continuously forming the preceding molten pool (5a) preceding the molten pool (5) by irradiating forward in the welding direction.   The irradiation angle θ1 of the laser beam (1) with respect to the surface of the base material (3) to be welded is 80 to 100 °, and the insertion angle θ2 of the welding wire (2) into the molten pool (5) is the base material to be welded ( 90-120 ° with respect to the surface of 3), the intersection of the center line of the welding wire (2) and the base material to be welded (3), the center line of the laser beam (1) and the base material to be welded (3) The narrow gap multi-layer laser welding method according to claim 1, wherein an interval between the crossing points of 1 to 3 mm is 1 to 3 mm.

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