JP6637272B2 - Welding method - Google Patents

Description

  The present invention relates to a welding method.

  In butt welding in which end surfaces of a pair of base materials are welded so that the end surfaces are joined in a state where the end surfaces are opposed to each other, a molten region formed by welding is formed so as to penetrate the base material in the thickness direction. By doing so (penetration welding), the working efficiency of welding can be improved. The use of submerged arc welding is effective for achieving penetration welding. In butt welding employing submerged arc welding, measures have been proposed for achieving improvement in the quality of a welded portion (see, for example, Patent Documents 1 and 2).

JP 2010-222298 A JP 2007-260692 A

  However, in submerged arc welding, it is necessary to supply a granular flux to the weld. Therefore, in submerged arc welding, the welding position is limited. In submerged arc welding, the size of a welding apparatus tends to be large.

  Although submerged arc welding makes it easy to achieve penetration welding, it also has the disadvantages described above. Therefore, an object of the present invention is to provide a welding method that can improve welding work efficiency by achieving penetration welding in butt welding by GMA (Gas Metal Arc) welding.

  A welding method according to the present invention includes a step of preparing a first base material and a second base material, and a step of preparing a first base material and a second base material such that the first end surface of the first base material and the second end surface of the second base material face each other. A step of disposing the base material and the second base material; and a step of welding the first base material and the second base material such that the first end face and the second end face are joined. In the step of welding the first base material and the second base material, an arc is formed between the welding wire and the first base material and the second base material, and the first base material and the second base material are formed by the heat of the arc. The first base material and the second base material are welded by forming a molten region in the first base material. In the step of welding the first base material and the second base material, an arc is formed in a state where the welding wire has penetrated to the region surrounded by the melting region, so that the melting region is formed by the first base material and the second base material. It is formed so as to penetrate the material in the thickness direction.

  The present inventors have studied a measure for achieving penetration welding by GMA welding. As a result, it has been found that through welding can be achieved by performing welding while maintaining a state in which an arc is formed in a state where a welding wire has penetrated into a region surrounded by a melting region (a buried arc state). Was.

  In the welding method of the present invention, an arc is formed in a state where the welding wire has penetrated to the region surrounded by the melting region, so that the melting region penetrates the first base material and the second base material in the thickness direction. Formed. Therefore, according to the welding method of the present invention, it is possible to improve the welding work efficiency by achieving penetration welding in butt welding by GMA welding.

  In the above welding method, in the step of welding the first base material and the second base material, the feeding speed of the welding wire may be 30 m / min or more. By doing so, it becomes easy to maintain the buried arc state. In addition, when the feeding speed of the welding wire exceeds 60 m / min, the transition state of the lysing may be a rotation transition. As a result, the penetration becomes shallow, and it may be difficult to achieve penetration welding. Therefore, the feeding speed of the welding wire may be set to 60 m / min or less. From the viewpoint of more reliably avoiding shallow penetration, the feed speed of the welding wire may be set to 50 m / min or less.

  In the above welding method, in the step of preparing the first base material and the second base material, the first base material and the second base material having a thickness of 10 mm or more and 30 mm or less may be prepared. Achieving penetration welding by GMA welding is particularly effective for a base material having a thickness of 10 mm or more from the viewpoint of improving work efficiency. On the other hand, if the thickness of the base material exceeds 30 mm, it may be difficult to achieve penetration welding. Therefore, the thickness of the first base material and the second base material may be 10 mm or more and 30 mm or less.

  In the above welding method, in the step of welding the first base material and the second base material, the first base material and the second base material having no groove may be welded.

  According to the welding method of the present invention, it is possible to weld a base material having no groove. When a groove is formed, it is necessary to fill an area where the groove is formed during welding. Therefore, there is a possibility that the distortion of the base material may increase due to, for example, an increase in the amount of the filler material supplied to the welded portion. By welding the base material having no groove formed by the welding method of the present invention, the occurrence of such a problem can be suppressed.

  In the above welding method, in the step of welding the first base material and the second base material, the first base material and the second base material are welded in a state where a voltage drop with respect to a current increase of 100 A is 10 V or more and 40 V or less. Is also good.

  By setting the external characteristics (output characteristics) of the power supply during welding in this way, it is easy to maintain the buried arc state. This is considered to be due to the following reasons. When the voltage drop is less than 10 V, the fluctuation in voltage is small with respect to the fluctuation in arc length due to a disturbance factor, and the current largely fluctuates. As a result, the molten region swings greatly, and it becomes difficult to maintain the state of the buried arc. By setting the voltage drop to 10 V or more, the swing of the melting region is suppressed, and the buried arc state can be easily maintained.

  When the arc length is shortened due to a disturbance factor, the current value increases, the melting speed of the welding wire increases, and the arc length increases. On the other hand, when the arc length increases due to a disturbance factor, the current value decreases, the melting speed of the welding wire decreases, and the arc length shortens (self-control action of the arc length). When the voltage drop exceeds 40 V, the current fluctuation is small with respect to the fluctuation of the arc length due to a disturbance factor, so that the self-control of the arc length is reduced. As a result, it is difficult to maintain the state of the buried arc. By setting the voltage drop to 40 V or less, the self-control of the arc length is maintained, and the buried arc state can be easily maintained.

  In the above welding method, the voltage drop may be 15 V or more. By doing so, the swing of the molten region is further suppressed, and it becomes easier to maintain the buried arc state.

  In the above welding method, the voltage drop may be 25 V or less. By doing so, the self-control of the arc length is more reliably maintained, and it is easier to maintain the buried arc state.

  In the above welding method, the welding wire may be a solid wire. In the welding method of the present invention, it is preferable to use a solid wire.

  In the above welding method, the diameter of the welding wire may be not less than 1.2 mm and not more than 1.6 mm. This makes it easier to maintain the buried arc state during welding.

  As is clear from the above description, according to the welding method of the present invention, it is possible to provide a welding method that can improve the work efficiency of welding by achieving penetration welding in butt welding by GMA welding.

It is a flowchart which shows the outline of a welding procedure. FIG. 3 is a schematic diagram for explaining a welding method according to the first embodiment. FIG. 3 is a schematic diagram for explaining a welding method according to the first embodiment. FIG. 9 is a schematic diagram for explaining a welding method according to the second embodiment. FIG. 9 is a schematic diagram for explaining a welding method according to the second embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding portions have the same reference characters allotted, and description thereof will not be repeated.

(Embodiment 1)
First, a welding method according to the first embodiment will be described. Referring to FIG. 1, in the welding method according to the first embodiment, first, a base material preparing step is performed as a step (S10). In this step (S10), a pair of base materials to be joined by welding are prepared. Specifically, referring to FIG. 2, first base material 50 and second base material 60 are prepared. The first base material 50 and the second base material 60 are steel plates made of steel such as mild steel, carbon steel for machine structure, and alloy steel for machine structure. The thickness of the steel plate is, for example, 10 mm or more and 30 mm or less.

  Next, a base material arrangement step is performed as a step (S20). In this step (S20), referring to FIG. 2, first base material 50 and second base material 60 prepared in step (S10) are set in welding apparatus 100. The welding device 100 includes a torch 19, a power supply 30, and a wire feeding device 29. The torch 19 includes a contact tip 17 and a nozzle 18 having a hollow cylindrical shape surrounding the contact tip 17. The contact chip 17 is made of a conductive material (metal) such as a copper alloy. The contact tip 17 guides the welding wire 15 while contacting the welding wire 15 as a filler material. That is, the welding wire 15 and the contact tip 17 are electrically connected. The welding wire 15 functions as a consumable electrode. In the present embodiment, the welding wire 15 is a solid wire. The diameter of welding wire 15 is, for example, not less than 1.2 mm and not more than 1.6 mm.

  The nozzle 18 forms a flow path for flowing a shielding gas between the nozzle 18 and the contact tip 17. The welding wire 15 is located in a region including the central axis of the nozzle 18. The wire feeding device 29 feeds the welding wire 15 into the nozzle 18. The power supply 30 is electrically connected to the contact chip 17 via the wiring 34. Power supply 30 is electrically connected to second base material 60 via wiring 64.

  First base material 50 has one main surface 52, the other main surface 53, and first end surface 51. Second base material 60 has one main surface 62, the other main surface 63, and second end surface 61. First base material 50 and second base material 60 are arranged such that first end face 51 and second end face 61 face each other. First base material 50 and second base material 60 are arranged such that first end surface 51 and second end surface 61 are in contact with each other. No groove is formed in the first base material 50 and the second base material 60. That is, the first end face 51 and the second end face 61 are parallel over the entire area in the thickness direction.

  Next, a welding step is performed as a step (S30). In this step (S30), the first base material 50 and the second base material 60 arranged in the step (S20) are welded by GMA welding. Specifically, referring to FIG. 3, while the welding wire 15 is fed by the wire feeding device 29, a voltage is applied between the first base material 50 and the second base material 60 and the welding wire 15 by the power source 30. Is applied, an arc 11 is formed between the welding wire 15 and the first base material 50 and the second base material 60. At this time, for example, a shielding gas such as carbon dioxide is supplied into the nozzle 18 and flows through the space between the contact tip 17 and the inner peripheral surface of the nozzle 18. Then, the shield gas is discharged from the outlet of the nozzle 18 along the arrow G, and the arc 11 and the outside air are shut off. The heat of the arc 11 thus formed forms a molten region 12 in the first base material and the second base material.

  At this time, the arc 11 is formed in a state where the welding wire 15 has penetrated into the region surrounded by the melting region 12 (buried arc state), so that the melting region 12 forms the first base material 50 and the second base material 60. It is formed so as to penetrate in the thickness direction. That is, in a state where the tip 15A of the welding wire 15 that has entered from the side of the one main surface 52 of the first base material 50 and the one main surface 62 of the second base material 60 is located in the region surrounded by the melting region 12. , An arc 11 is formed. The molten region 12 is exposed on the other main surface 53 of the first base material 50 and the other main surface 63 of the second base material 60.

  The relative movement of the torch 19 with respect to the first base material 50 and the second base material 60 moves the region where the melted region 12 is formed. The previously formed molten region 12 solidifies as the temperature decreases. The molten region 12 is sequentially formed along the extending direction of the region to be welded (the region where the first end surface 51 and the second end surface 61 face each other), and the formed molten region 12 is solidified, so that the present embodiment is performed. The welding of the first base material 50 and the second base material 60 in the embodiment is completed.

  In the welding method according to the present embodiment, in step (S30), arc 11 is formed in a state where welding wire 15 has penetrated into a region surrounded by melting region 12, so that melting region 12 becomes first base material 50. And it is formed so as to penetrate the second base material 60 in the thickness direction. Therefore, according to the welding method of the present embodiment, it is possible to improve the welding work efficiency by achieving penetration welding in butt welding by GMA welding.

  In the above step (S30), the feeding speed of the welding wire is preferably set to 30 m / min or more. This makes it easier to maintain the buried arc state.

  In the above step (S30), it is preferable that the first base material 50 and the second base material 60 are welded in a state where a voltage drop with respect to a current increase of 100 A is 10 V or more and 40 V or less. By setting the external characteristics (output characteristics) of the power supply 30 in this manner, it is easy to maintain the buried arc state. The voltage drop is preferably 15 V or more. Further, it is preferable that the voltage drop is 25 V or less.

(Embodiment 2)
Next, a welding method according to Embodiment 2 which is another embodiment of the present invention will be described. The welding method according to the second embodiment is basically performed in the same manner as in the first embodiment, and has the same effect. However, the welding method of the second embodiment is different from that of the first embodiment in the shape of the end face of the base material.

  Referring to FIG. 4, in the welding method according to the second embodiment, in step (S10), first base material 50 and second base material 60 on which groove 70 is formed are prepared. The groove 70 is formed on one of the main surfaces 52 and 62 of the first base material 50 and the second base material 60. The groove 70 includes a corner of the first base material 50 where the first end face 51 and one main surface 52 are connected, and a second base material 60 where the second end face 61 and one main surface 62 are connected. Is formed so as to remove the corners. Therefore, in the step (S20), when first base material 50 and second base material 60 are arranged such that first end face 51 and second end face 61 face each other, in the region corresponding to groove 70, The distance between the first base material 50 and the second base material 60 increases as approaching the main surfaces 52, 62.

  Then, in step (S30), with reference to FIG. 5, first base material 50 and second base material 60 are welded in a state where groove 70 is formed. At this time, the area corresponding to the groove 70 is filled by welding. That is, the amount of the welding wire 15 as the filler material supplied to the melting region 12 is larger than in the case of Embodiment 1 in which the groove 70 is not formed.

  By forming the groove 70 in this manner, it is easy to achieve the penetration welding in the step (S30). Therefore, when the first base material 50 and the second base material 60 having a large thickness are welded, the welding method of the present embodiment is suitable.

  An experiment was conducted to confirm that the welding method of the present invention can achieve penetration welding in butt welding by GMA welding. The specific experimental method is as follows.

  First, a plurality of steel plates having different thicknesses were prepared as a base material. Next, referring to FIG. 2, as in the case of the first embodiment, steel plates having the same thickness are welded by welding device 100 so that the end faces of the two steel plates contact each other without forming a groove. Set to Then, under a condition of a constant welding speed, the feeding speed of the welding wire was changed while maintaining the buried arc state, and the thickness of the steel sheet capable of performing the penetration welding (the thickness capable of the penetration welding) was investigated. The current value, the voltage value, and the wire protrusion length were adjusted to values suitable for maintaining a buried arc state at each wire feeding speed. Further, the voltage drop with respect to the current increase of 100 A, which is an external characteristic of the power supply 30, was set to 10 to 20V or 20V. As the welding wire 15, a solid wire having a diameter of 1.2 mm was employed. Table 1 shows the conditions and results of the experiment.

表１には、種々のワイヤ送給速度において埋もれアーク状態を維持することで貫通溶接可能であることが確認された鋼板の厚みが示されている。なお、表１において外部特性値が負の値となっているのは、１００Ａの電流増加に対して電圧が低下する状態であることを意味する。たとえば、外部特性値が−２０Ｖである状態とは、１００Ａの溶接電流の増加に対して電圧が２０Ｖ低下することを意味する。

Table 1 shows the thickness of the steel sheet confirmed to be capable of penetration welding by maintaining the buried arc state at various wire feeding speeds. It should be noted that the negative external characteristic value in Table 1 means that the voltage decreases in response to a current increase of 100 A. For example, a state where the external characteristic value is −20 V means that the voltage decreases by 20 V with respect to an increase in the welding current of 100 A.

  Referring to Table 1, it is confirmed that by adjusting the current value and the voltage value according to the wire feeding speed, the buried arc state is maintained, and penetration welding can be achieved. Further, by increasing the wire feeding speed, the plate thickness (thickness of the base material) that can be penetrated increases. In order to achieve penetration welding in a steel plate having a thickness of 10 mm or more, it can be said that the wire feeding speed is preferably 30 m / min or more.

  It should be understood that the embodiments and examples disclosed this time are exemplifications in all respects and are not restrictive in any aspect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The welding method of the present invention can be particularly advantageously applied to welding in which improvement in working efficiency is required.

  11 arc, 12 melting area, 15 welding wire, 15A tip, 17 contact tip, 18 nozzle, 19 torch, 29 wire feeder, 30 power supply, 34 wiring, 50 first base material, 51 first end face, 52, 53 Main surface, 60 second base material, 61 second end surface, 62, 63 main surface, 63 wiring, 70 groove, 100 welding equipment.

Claims (7)

Providing a first preform and a second preform;
Arranging the first base material and the second base material such that a first end surface of the first base material and a second end surface of the second base material face each other;
Welding the first base material and the second base material by GMA welding so that the first end surface and the second end surface are joined,
In the step of welding the first base material and the second base material, an arc is formed between the welding wire and the first base material and the second base material, and the first base material is heated by the heat of the arc. The first base material and the second base material are welded by forming a molten region in the material and the second base material,
In the step of welding the first base material and the second base material, the arc is formed in a state in which the welding wire has penetrated to a region surrounded by the melting region, so that the melting region is formed in the second region. The first base material and the second base material are formed so as to penetrate in the thickness direction ,
In the step of welding the said second base member and the first base member, feeding speed of the welding wire Ru der least 30 m / min, a welding method. The welding method according to claim 1, wherein in the step of welding the first base material and the second base material, the first base material and the second base material having no groove are welded. . Providing a first preform and a second preform;
Arranging the first base material and the second base material such that a first end surface of the first base material and a second end surface of the second base material face each other;
Welding the first base material and the second base material by GMA welding so that the first end surface and the second end surface are joined,
In the step of welding the first base material and the second base material, an arc is formed between a welding wire and the first base material and the second base material, and the first base material is heated by the arc. The first base material and the second base material are welded by forming a molten region in the material and the second base material,
In the step of welding the first base material and the second base material, the arc is formed in a state where the welding wire has penetrated to a region surrounded by the melting region, so that the melting region is formed in the second region. The first base material and the second base material are formed so as to penetrate in the thickness direction,
The welding method, wherein in the step of welding the first base material and the second base material, the first base material and the second base material having no groove are welded. In the first base material and the step of preparing the second base member, a thickness of said 10mm or 30mm or less than the first base member and said second base member is prepared, any one of claims 1 to 3 The welding method according to the above.   In the step of welding the first base material and the second base material, the first base material and the second base material are welded in a state where a voltage drop with respect to a current increase of 100 A is 10 V or more and 40 V or less. The welding method according to claim 1.   The welding method according to claim 5, wherein the voltage drop is 15 V or more.   The welding method according to claim 5, wherein the voltage drop is 25 V or less.

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