JP6382593B2 - Welding method - Google Patents

Description

Embodiments of the present invention relates to a welding how.

  Conventionally, welding, which is one of the joining processes, has been applied as an indispensable basic technology for manufacturing large structures such as the construction industry, the automobile industry, shipbuilding, bridges, and power generation equipment. In particular, in the welding of thick steel plates used in the large structures described above, applying a deep penetration welding method leads to a reduction in manufacturing man-hours.

  Here, various methods have been developed as welding methods capable of obtaining deep penetration. For example, the first welding method enables double-sided welding by applying a melting accelerator to the front or back surface of a joint portion made of stainless steel or low-carbon steel and using non-consumable electrode arc welding. As a result, the first welding method performs complete penetration welding with no joint shortage while maintaining a so-called I-type joint or T-type joint that is not subjected to groove processing.

  Further, the second welding method is, for example, that a flux-cored wire filled with a flux material that promotes penetration depth is arc-welded to a T-shaped joint made of stainless steel by non-consumable electrode arc welding. It is possible to perform through-welding while feeding the wire. Thereby, a 2nd welding method performs complete penetration welding without joining shortage with the T type joint which does not give a groove processing.

JP 2007-196266 A Japanese Patent No. 5153368

  However, as described above, since the first welding method needs to apply the penetration accelerator to the joint portion, the material cost for purchasing the penetration accelerator increases and the man-hour required for the application work increases. . In addition, there is a high risk that the penetration depth varies depending on the amount of the penetration accelerator applied and the variation in the application range. Furthermore, since the first welding method uses arc welding of a non-consumable electrode method having a shallow penetration depth compared to mag welding, which is a consumable electrode method, the thickness of the steel material applicable to this welding is generally 6 mm. It becomes as follows.

  On the other hand, since the second welding method also uses non-consumable electrode type arc welding, the thickness of the steel material applicable to welding is similarly 6 mm or less. Furthermore, the second welding method requires a flux-cored wire filled with a flux material having a penetration promoting property, which necessitates an increase in manufacturing cost.

An object of the present invention is to provide is to provide welded how the that deep penetration at relatively low heat input is obtained.

The welding method according to the embodiment includes an arrangement process and a welding process. In the placement step, the first base material and the second base material to be welded are placed as a T-shaped joint with a gap therebetween. In the welding process, the first and second base metals arranged are completely penetration welded using a mag welding method in a state of a buried arc with a heat input of 25 kJ / cm or less. The thickness of the first base material is in the range of 6 mm or more and 20 mm or less. Furthermore, the thickness of the second base material is in the range of 4 mm or more and 24 mm or less. In the welding process, one pass each from the first surface side of the first base material arranged together with the second base material as the T-shaped joint and the second surface side located on the back side thereof. Perform the welding operation. Further, the penetration depth obtained by the welding operation for each pass from the first and second surface sides is at least 0.5 times and not more than 0.9 times the thickness of the first base material. It is in the range. Further, the beads formed by the penetration from the first and second surface sides overlap each other. The gap is in a range of 0.1 to 0.2 times the thickness of the first base material.

Sectional drawing for demonstrating the arrangement | positioning process of the welding method which concerns on 1st Embodiment. Sectional drawing for demonstrating the welding process from the 1st surface side of the 1st and 2nd preform | base_material in the welding method shown to FIG. 1A. Sectional drawing for demonstrating the welding process from the 2nd surface side of the 1st and 2nd preform | base_material in the welding method shown to FIG. 1A. Sectional drawing for demonstrating the welding method of the comparative example 1. FIG. Sectional drawing for demonstrating the arrangement | positioning process of the welding method which concerns on 2nd Embodiment. Sectional drawing for demonstrating the welding process in the welding method of FIG. 3A. Sectional drawing for demonstrating the arrangement | positioning process of the welding method which concerns on 3rd Embodiment. Sectional drawing for demonstrating the welding process from the 1st surface side of a 1st preform | base_material in the welding method shown to FIG. 4A. Sectional drawing for demonstrating the welding process from the 2nd surface side of a 1st preform | base_material in the welding method shown to FIG. 4A. Sectional drawing for demonstrating the welding method of the comparative example 2. FIG. Sectional drawing for demonstrating the arrangement | positioning process of the welding method which concerns on 4th Embodiment. Sectional drawing for demonstrating the welding process in the welding method of FIG. 6A. The front view for demonstrating the T-type coupling containing a projection part as a welding method of other embodiment from which a structure differs from the 1st-4th embodiment. The arrow view which looked at the T type joint shown in Drawing 7A from the A direction. The side view of the T-shaped coupling which concerns on other embodiment from which the structure of a projection part differs from the T-shaped coupling shown in FIG. 7B. The front view for demonstrating the I-type coupling containing a projection part as a welding method of other embodiment from which composition is different from the embodiment shown in the 1st-the 4th embodiment and Drawing 7A and Drawing 8. FIG. 9B is an arrow view of the I-shaped joint illustrated in FIG. 9A as viewed from the B direction. FIG. 9B is a side view of an I-shaped joint according to another embodiment in which the structure of the protrusion is different from that of the I-shaped joint illustrated in FIG. 9B. The macro photograph of the cross section in the I-type joint of Example 1. The macro photograph of the section in the I type joint of comparative example 3. The macro photograph of the section in the I type joint of comparative example 4. 5 is a macro photograph of a cross section of a T-shaped joint of Example 3. FIG. The macro photograph of the section in the T type joint of Example 4.

  Hereinafter, embodiments will be described with reference to the drawings. The welding method of the 1st-4th embodiment mentioned later has the arrangement | positioning process and welding process which satisfy | fill the following conditions, respectively. In the placement step, the first base material and the second base material to be welded are placed with a gap (gap) therebetween. In the welding process, the first and second base metals arranged are buried in a state of an arc with a heat input of 25 kJ / cm or less, and a mag welding method (among the consumable electrode type arc welding technology, shield gas). Complete penetration welding using a welding technique that uses a mixture of inert gas and carbon dioxide gas.

  The first and second base materials are, for example, alloy steels such as stainless steel and steel materials such as carbon steel. In the welding process, the welding posture is a downward posture or a horizontal posture. Other welding postures include a vertical posture, an upward posture, and the like, which are not preferable because a bead may hang down during welding and a sound penetration depth may not be obtained.

  The thicknesses of the first and second base materials described above are in the range of 4 mm or more and 24 mm or less. The gap is in the range of 0.05 to 0.4 times the thickness of the first and second base materials. The state of the buried arc is a state in which the welding wire is thrust into a molten pool dug by the arc (a molten metal pool formed by heat of the arc or the like).

  Here, if the thickness (plate thickness) of the first and second base materials is less than 4 mm, it is difficult to stop the penetration depth at a predetermined depth, and the molten metal may melt from the back side of the gap. This is not preferable. On the other hand, if the thickness of the first and second base materials is greater than 24 mm, it is not preferable because complete penetration welding may not be obtained due to insufficient penetration depth.

  In addition, by setting the gap between the base materials to an appropriate value according to the thickness of the base material, it is possible to obtain a sound complete penetration welding. When this gap is less than 0.05 times the thickness of the base material, it becomes difficult for the arc during welding to enter the gap, and the penetration depth decreases. On the other hand, if the gap is larger than 0.4 times the thickness of the base metal, the amount of metal required for welding will increase, and multiple passes may be required for the welding operation from one side. In addition, there is a possibility that the molten metal melts from the back side of the gap.

<First Embodiment>
In the welding method of the first embodiment, in addition to satisfying the above-described conditions when performing the placement step and the welding step, respectively, in the placement step, as shown in FIG. 1A, a base material (first base material) ) 1 and the base material (second base material) 2 are arranged as an I-type joint (butt joint) 8. Here, when welding the I-type joint 8 as in the present embodiment, the thicknesses of the base materials 1 and 2 (thickness between the first surfaces 1a and 2a and the second surfaces 1b and 2b). ) T1 is more preferably in the range of 6 mm or more and 24 mm or less (6 mm ≦ T1 ≦ 24 mm). Furthermore, when welding the I-type joint 8 as in the present embodiment, the gap G1 is 0.05 times or more and 0.1 times or less (0.05 × T1 mm) of the thickness T1 of the base materials 1 and 2. ≦ G1 ≦ 0.1 × T1 mm) is more preferable.

  Further, in the welding process, as described above, in the state of a buried arc by heat input of 25 kJ / cm or less, as shown in FIG. 1B and FIG. The welding operation is performed for each pass from the second surfaces 1b and 2b located on the back side. That is, as shown in FIG. 1B, first, from the first surface 1a, 2a side of the I-type joint 8 to the penetration depth H1 by one pass, the bead (melt solidification made by one pass) is performed. Weld metal) 3 is formed.

  Further, as shown in FIG. 1C, the bead 4 is formed by mag welding from the second surfaces 1b and 2b side of the I-type joint 8 to the penetration depth H2 in one pass. More specifically, as shown in FIG. 1C, the penetration depths H1 and H2 respectively obtained by welding operations for each pass from the first surfaces 1a and 2a and the second surfaces 1b and 2b of the I-type joint 8. Is in the range of 0.5 to 0.9 times the thickness T1 of the base materials 1 and 2. Further, the bead 3 and the bead 4 formed by melting from the first surface 1a, 2a side and the second surface 1b, 2b side of the I-type joint 8 are the central portions of the base materials 1 and 2 in the thickness direction. Or in the vicinity, they overlap each other. As a result, a welded structure 10 (welded I-type joint 8) that is completely penetration welded is obtained.

  When the penetration depth H1 and the penetration depth H2 described above are less than 0.5 times the thickness T1 of the base materials 1 and 2, from the respective sides of the first and second surfaces of the base materials 1 and 2. Even if the welding operation is performed one pass at a time, the material is not melted to the center in the thickness direction of the base materials 1 and 2, which may cause insufficient welding. On the other hand, if the penetration depths H1 and H2 are larger than 0.9 times the thickness T1, the molten metal may be melted down to the back side of the gap (the side opposite to the passing surface). Absent.

  Further, when welding the I-type joint 8 as in this embodiment, if the thicknesses T1 of the base materials 1 and 2 are thinner than 6 mm, it is difficult to stop the penetration depth to a predetermined depth, and the molten metal has gaps. There is a possibility of melting from the back side. On the other hand, if the thickness T1 is thicker than 24 mm, there is a possibility that complete penetration welding cannot be obtained due to lack of penetration depth.

  Furthermore, if the gap G1 is less than 0.05 times the thickness T1, as described above, it becomes difficult for the arc during welding to enter the gap, and the penetration depth decreases. Further, in the case of the I-type joint 8 as in this embodiment, when the gap G1 is larger than 0.1 times the thickness T1, the amount of metal required for welding increases, and the first surface 1a, Multiple passes may be required for each welding operation from the 2a side and the second surface 1b, 2b side, and the molten metal may melt from the back side of the gap.

  Here, the welding method of the comparative example 1 is demonstrated based on FIG. As shown in FIG. 2, the welding method of the comparative example 1 has illustrated the case where the base materials 1c and 2c whose thickness T1a is 20 mm are butt-welded using MAG welding, for example. When such base materials 1c and 2c are butt welded, for example, a grooving groove having a groove angle of about 45 °, a V-shaped groove, an X-shaped groove, etc. are provided, and then mag welding is performed. There is a need to. Furthermore, in order to completely melt and weld these grooves, as shown in FIG. 2, for example, about 10 passes of welding (forming the beat 3a many times) are required. For this reason, the welding method of Comparative Example 1 results in a long welding operation time.

  In general, there is a correlation between the heat input during welding and the penetration depth, and it is known that the penetration depth increases by increasing the heat input. Therefore, in order to increase the heat input, it is necessary to prepare a welding power source with a large rated output current. In addition, it is commercially available in the case of semi-automatic MAG welding where the welding wire is automatically fed and the welding current exceeds 400A. In general-purpose welding power sources, it is difficult to induce a weld defect and obtain a sound weld. Further, in such a semi-automatic MAG welding in which the current during welding exceeds 400 A, the bead build-up increases with the increase in the amount of welded molten metal, but the penetration depth does not increase. It is extremely difficult to completely melt and weld a base material having a thickness of a certain degree with a small number of passes.

  In consideration of such a situation, the welding method of the present embodiment appropriately sets the thickness T1 and the gap G1 of the base materials 1 and 2 to be the I-type joint 8, as shown in FIGS. 1A to 1C. In addition, with a relatively low heat input of 25 kJ / cm or less, in the state of a buried arc, the magnet of one pass on each side of the first surface 1a, 2a side and the second surface 1b, 2b side of the I-type joint 8 By welding, complete penetration welding is realized. That is, in the welding method of the present embodiment, groove processing is not necessary and the number of passes can be reduced, so that the welding time can be shortened. In addition, when implementing mag welding in the state of a buried arc, it is preferable to use a mag welding power source with good responsiveness to changes in current with respect to variations in arc length.

  As described above, according to the first embodiment, for example, a commercially available general-purpose welding material (base material) is applied, and welding with which a deep penetration can be obtained with a relatively low heat input of 25 kJ / cm or less. A method and a welded structure 10 welded using this welding method can be provided.

<Second Embodiment>
Next, a second embodiment will be described with reference to FIGS. 3A and 3B. In the welding method of the second embodiment, in addition to satisfying the above-mentioned conditions common to the first to fourth embodiments when performing the placement step and the welding step, respectively, the placement step is shown in FIG. 3A. As described above, the base material (first base material) 21 and the base material (second base material) 22 are arranged as the I-type joint 28 together with the backing metal 25.

  Here, when welding the I-type joint 28 as in the present embodiment, the thicknesses of the base materials 21 and 22 (thickness between the first surfaces 21a and 22a and the second surfaces 21b and 22b). ) T2 is more preferably in the range of 4 mm or more and 12 mm or less (4 mm ≦ T2 ≦ 12 mm). Furthermore, when welding the I-type joint 28 as in the present embodiment, the gap G2 is 0.2 times or more and 0.4 times or less (0.2 × T2 mm) of the thickness T2 of the base materials 21 and 22. ≦ G2 ≦ 0.4 × T2 mm) is more preferable.

  Further, in the welding process, as shown in FIG. 3B, a second metal is applied to a backing metal 25 for the base materials 21 and 22 arranged as an I-type joint 28 in a state of a buried arc with a heat input of 25 kJ / cm or less. Surface (the contacted surface of the backing metal 25) 21b, from the first surface 21a, 22a side located on the back side of 22b, by a one-pass welding operation, the base material 21 and the base material 22 A bead 23 for welding the backing metal 25 to each other is formed. As a result, a welded structure 20 (welded I-type joint 28) that has been completely melt-welded is obtained.

  Here, when welding the I-type joint 28 as in the present embodiment, when the thickness T2 of the base materials 21 and 22 is thinner than 4 mm, for example, by TIG welding, which is one of consumable electrode type arc welding, The I-type joint 28 can be welded. Further, in the case of the welding method as in the present embodiment in which the I-type joint 28 is welded in one pass, if the thickness T2 is greater than 12 mm, there is a possibility that complete penetration welding cannot be obtained due to insufficient penetration depth. .

  Further, in the case of the I-type joint 28 as in the present embodiment, if the gap G2 is less than 0.2 times the thickness T2 of the base materials 21 and 22, it becomes difficult for the arc during welding to enter the gap. , The penetration depth may decrease. Furthermore, in the case of the I-type joint 28 as in the present embodiment, when the gap G2 is larger than 0.4 times the thickness T2, the amount of metal required for welding increases, and further, the first surface 21a, The welding operation from the 22a side may be required many times.

  That is, according to the welding method of the present embodiment, as shown in FIGS. 3A and 3B, the thickness T2 and the gap G2 of the base materials 21 and 22 that become the I-type joint 28 are appropriately set, and a comparison of 25 kJ / cm or less is further performed. Due to the relatively low heat input, complete penetration welding is realized by one-pass mag welding from the first surface 21a, 22a side of the I-type joint 28 in the state of a buried arc. Therefore, also in the welding method according to the second embodiment, deep penetration can be obtained with relatively low heat input.

<Third Embodiment>
Next, a third embodiment will be described based on FIGS. 4A to 4C. In addition to satisfying the above-described conditions common to the first to fourth embodiments, the welding method of the third embodiment is shown in FIG. In this way, the base material (first base material) 31 and the base material (second base material) 32 are arranged as a T-shaped joint 38.

  Here, when welding the T-shaped joint 38 as in the present embodiment, at least the thickness of the base material 31 (the thickness between the first surface 31a and the second surface 31b) T3 is 6 mm. As mentioned above, it is more preferable that it exists in the range of 20 mm or less (6 mm <= T3 <= 20mm). Furthermore, when welding the T-shaped joint 38 as in this embodiment, the gap G3 is not less than 0.1 times and not more than 0.2 times the thickness T3 of the base material 31 (0.1 × T3 mm ≦ G3). ≦ 0.2 × T3 mm) is more preferable. In the present embodiment, the thickness of the base material 31 and the thickness of the base material 32 are the same.

  In the welding process, as shown in FIGS. 4B and 4C, the first surface of the base material 31 arranged together with the base material 32 as a T-shaped joint 38 in a state of a buried arc with a heat input of 25 kJ / cm or less. A welding operation is performed for each pass from the 31a side and the second surface 31b side located on the back side. That is, as shown in FIG. 4B, first, the first surface of the base material 31 is subjected to mag welding from the first surface 31a side of the base material 31 in the T-shaped joint 38 to the penetration depth H31 in one pass. A bead 33 is formed at a boundary portion between 31 a and the base material 32.

  Further, as shown in FIG. 4C, the bead 34 is formed by mag welding from the second surface 31b side of the base material 31 to the penetration depth H32 in one pass. More specifically, as shown in FIGS. 4B and 4C, the penetration depths H31 obtained by welding operations for each pass from the first surface 31a and the second surface 31b side of the T-shaped joint 38, H32 is in the range of 0.5 to 0.9 times the thickness T3 of the base materials 31 and 32. Further, the bead 33 and the bead 34 formed by the melting from the first surface 31a side and the second surface 31b side of the T-shaped joint 38 are mutually in the central portion in the thickness direction of the base material 31 or in the vicinity thereof. They are overlapping. As a result, a welded structure 30 (welded T-type joint 38) that is completely melt-welded is obtained.

  When the penetration depth H31 and the penetration depth H32 are less than 0.5 times the thickness T3, for example, the welding operation is performed one pass at a time from each side of the first and second surfaces of the base material 31. Even so, the material has not melted to the center of the base material 31 in the thickness direction, and there is a concern about insufficient welding. On the other hand, if the penetration depths H31 and H32 are larger than 0.9 times the thickness T3, the molten metal may be melted down to the back side of the gap (the surface opposite to the passing surface). Absent.

  Further, when welding the T-shaped joint 38 as in this embodiment, if the thickness T3 of the base material 31 is less than 6 mm, it is difficult to stop the penetration depth at a predetermined depth, and the molten metal is behind the gap ( It may melt away from the surface opposite to the passing surface. Furthermore, when welding the T-shaped joint 38 as in the present embodiment, if the thickness T3 is greater than 20 mm, there is a possibility that complete penetration welding cannot be obtained due to lack of penetration depth.

  Further, in the case of the T-shaped joint 38 as in this embodiment, if the gap G3 is less than 0.1 times the thickness T3, it becomes difficult for the arc during welding to enter the gap, and the penetration depth is reduced. There is a case. Furthermore, in the case of the T-shaped joint 38 as in the present embodiment, when the gap G3 is larger than 0.2 times the thickness T3, the amount of metal required for welding increases, and the first surface 31a side. In addition, a plurality of passes may be required for each welding operation from the second surface 31b side, and the molten metal may melt from the back side of the gap.

  Here, the welding method of the comparative example 2 is demonstrated based on FIG. As shown in FIG. 5, the welding method of the comparative example 2 illustrates the case where the base materials 31c and 32c whose thickness T3a is 20 mm are welded as T-shaped joints using mag welding, for example. In order to obtain a desired strength by fillet welding these base materials 31c and 32c, generally a leg length of about 0.7 times the thickness T3a of the base materials 31c and 32c (in this case, a leg length of about 14 mm) H3a It is necessary to provide. That is, for example, in order to form a leg length H3a of 14 mm, a total of 12 passes of welding operations (for example, 12 passes in total for 6 passes on the first surface 31e side and the second surface 31f side of the base material 31c). 33a and 34a) is required. For this reason, the welding method of the comparative example 2 is a result which requires much welding construction time.

  On the other hand, in the welding method of the present embodiment, as shown in FIGS. 4A to 4C, the thickness T3 of the base material 31 that becomes the T-shaped joint 38 together with the base material 32 and the gap G3 are set as appropriate. Further, with a relatively low heat input of 25 kJ / cm or less, in the state of a buried arc, complete welding is performed by one-pass mag welding from the first surface 31a side and the second surface 31b side of the base material 31. It achieves penetration welding. That is, in the welding method of the present embodiment, the welding operation time can be shortened by reducing the number of passes, and further, welding with deep penetration can be obtained with low heat input.

<Fourth embodiment>
Next, a fourth embodiment will be described with reference to FIGS. 6A and 6B. In the welding method of the fourth embodiment, when performing the placement step and the welding step, in addition to satisfying the above-described conditions common to the first to fourth embodiments, the placement step is shown in FIG. 6A. As described above, the base material (first base material) 41 and the base material (second base material) 42 are arranged as a T-shaped joint 48.

  Here, when welding the T-shaped joint 48 as in the present embodiment, at least the thickness of the base material 41 (thickness between the first surface 41a and the second surface 41b) T4 is 4 mm. As mentioned above, it is more preferable that it exists in the range of 12 mm or less (4 mm <= T4 <= 12mm). Furthermore, when welding the T-shaped joint 48 as in the present embodiment, the gap G4 is not less than 0.2 times and not more than 0.3 times the thickness T4 of the base material 41 (0.2 × T4 mm ≦ G4). ≦ 0.3 × T4 mm) is more preferable.

  In the welding process, as shown in FIGS. 6A and 6B, the second surface of the base material 41 arranged together with the base material 42 as a T-shaped joint 48 in a state of a buried arc with a heat input of 25 kJ / cm or less. One-pass welding operation is performed from the first surface 41a side located on the back side of 41b. That is, as shown in FIG. 6B, a bead 43 is welded to the boundary portion between the entire end surface of the base material 41 to be welded and the base material 42 by performing one-pass mag welding from the first surface 41 a side of the base material 41. Form. As a result, a welded structure 40 (welded T-type joint 48) that has been completely melt-welded is obtained.

  Here, when welding the T-shaped joint 48 as in this embodiment, if the thickness T4 of the base material 41 is less than 4 mm, it is difficult to stop the penetration depth at a predetermined depth, and the molten metal is behind the gap. There is a possibility that it will melt away from the second surface 41b side opposite to the passing first surface 41a. Further, in the case of the welding method as in the present embodiment in which the T-shaped joint 48 is welded in one pass, if the thickness T4 is thicker than 12 mm, there is a possibility that complete penetration welding cannot be obtained due to lack of penetration depth. .

  Further, in the case of the T-shaped joint 48 as in the present embodiment, if the gap G4 is less than 0.2 times the thickness T4, it becomes difficult for the arc during welding to enter the gap and the penetration depth is reduced. There is a case. Furthermore, in the case of the T-shaped joint 48 as in the present embodiment, when the gap G4 is larger than 0.3 times the thickness T4, the amount of metal required for welding increases, and further, the first base material 41 has a first amount. There is a possibility that many passes from the surface 41a side are required.

  In the welding method of the present embodiment, as shown in FIGS. 6A and 6B, the thickness T4 of the base material 41 arranged as the T-shaped joint 48 together with the base material 42 and the gap G4 are appropriately set, and further 25 kJ / With a relatively low heat input of cm or less, complete penetration welding is realized by one-pass mag welding from the first surface 41a side of the T-shaped joint 48 in the state of a buried arc. Therefore, also in the welding method according to the fourth embodiment, deep penetration can be obtained with relatively low heat input.

  For example, the gaps G1 to G4 applied to the welding methods of the first to fourth embodiments are at least one of a pair of base materials that are components of the I-type joints 8 and 28 and the T-type joints 38 and 48, respectively. You may comprise by the projection part provided in. That is, as shown in FIGS. 7A and 7B, for example, a base material (first base material) 51 disposed as a T-shaped joint 58 together with a base material (second base material) 52 has an end portion (bottom portion). ) Is provided with a plurality of protrusions 57.

  As shown in FIG. 7B, each of the plurality of protrusions 57 is configured in a rectangular parallelepiped shape, and has a width W1 of, for example, 5 mm. Further, the plurality of protrusions 57 are arranged at a predetermined interval (pitch P1) along the width direction of the base material 51 configured with a width L5 (for example, 300 mm). The front end surface (bottom surface) of each protrusion 57 in the base material 51 is disposed at a position in contact with the flat portion (upper surface) of the base material 52. Therefore, the protrusion amount of each protrusion 57 is an amount of a gap secured between the base material 51 and the base material 52. With such a configuration, a gap G <b> 5 is formed in the T-shaped joint 58.

  Moreover, as shown in FIG. 8, you may comprise the T-shaped coupling 68 provided with the some projection part 67. As shown in FIG. In the T-shaped joint 68, the plurality of protrusions 67 are provided at the end (bottom) of the base material (first base material) 61 that comes into contact with the flat surface (upper surface) of the base material (second base material) 62. It has been. Each protrusion 67 has an angle of, for example, 90 ° from the base end side to the tip end side when viewed from the thickness direction of the base material 61, and the tip end portion is sharp. The plurality of protrusions 67 are arranged at a predetermined interval (pitch P1) along the width direction of the base material 61 having a width L6 (for example, 300 mm). With such a configuration, a gap G <b> 6 is formed in the T-shaped joint 68.

  Furthermore, as shown in FIGS. 9A and 9B, an I-type joint 78 including a plurality of protrusions 77 may be configured. In the I-shaped joint 78, the plurality of protrusions 77 are provided at the end portion of the base material (first base material) 71 that contacts the end portion of the base material (second base material) 72. As shown in FIG. 9B, each of the plurality of protrusions 77 is formed in a rectangular parallelepiped shape, and has a width W1 of, for example, 5 mm. The plurality of protrusions 77 are arranged at a predetermined interval (pitch P1) along the width direction of the base material 71 having a width L7 (for example, 300 mm). With such a configuration, a gap G7 is formed in the I-type joint 78.

  Moreover, as shown in FIG. 10, you may comprise the T-type coupling 88 provided with the some projection part 87. As shown in FIG. In the T-shaped joint 88, the plurality of protrusions 87 are provided at the end portion of the base material (first base material) 81 that contacts the end portion of the base material (second base material) 82. Each protrusion 87 has an angle of 90 ° from the base end side to the tip end side when viewed from the thickness direction of the base material 81, and the tip end portion is sharp. The plurality of protrusions 87 are arranged at a predetermined interval (pitch P1) along the width direction of the base material 81 having a width L8 (for example, 300 mm). With such a configuration, a gap G8 is formed in the I-type joint 88.

  For example, when the base material itself is cut into a welding material, as shown in FIGS. 7A, 7B, 8, 9A, 9B, and 10, projections are formed on at least one base material. By doing so, a predetermined amount of gap can be easily secured even for a relatively large welded joint.

Next, examples will be described.
<Example 1>
In Example 1, the welding method for the I-type joint 8 according to the first embodiment shown in FIGS. 1A to 1C was applied, and the following detailed conditions were added to perform the placement step and the welding step.

<< Welding conditions of Example 1 >>
・ Welding method: Semi-automatic mag welding, 1-pass welding on both sides ・ Base materials 1, 2: Carbon steel (JIS G3101 SS400, length 300mm x width 300mm x thickness 20mm)
・ Welding wire: AWS A5.18 ER70S-G, diameter 1.2mm
・ Welding current: 300A
・ Welding voltage: 27V
-Welding speed: 300 mm / min
-Heat input: 16.2 kJ / cm
・ Thickness T1: 20mm of base materials 1 and 2
・ Gap G1: 1.5mm

  FIG. 11 shows the welding result of the I-type joint 8 according to the first embodiment. As shown in FIGS. 1C and 11, the depth (melting depth H1) of the beads 3 formed from the first surfaces 1a and 2a side of the base materials 1 and 2 was 12 to 13 mm. On the other hand, the depth (melting depth H2) of the beads 4 formed from the second surfaces 1b and 2b of the base materials 1 and 2 was 12 to 13 mm. That is, in Example 1, as shown in FIG. 11, the bead on one side and the bead on the other side overlap each other, and complete penetration welding is achieved. In addition, complete penetration welding is possible also to a base material whose thickness T1 is 24 mm, for example, by changing the above-mentioned 16.2 kJ / cm heat input appropriately within a range of 25 kJ / cm or less.

  On the other hand, FIGS. 12 and 13 show the welding results of the I-type joints of Comparative Examples 3 and 4. FIG. As shown in FIGS. 12 and 13, Comparative Examples 3 and 4 apply a base material having a thickness of 25 mm that is outside the range of the conditions of the first embodiment (Example 1). The I-type joint is welded. In Comparative Example 3, the welding conditions other than the thickness of the base material are the same as those in Example 1. Moreover, the comparative example 4 differs from Example 1 in the thickness of a base material mentioned above among welding conditions, a welding voltage, and heat input. In Comparative Example 4, the welding voltage is 32 V and the heat input is 19.2 kJ / cm. Other welding conditions of Comparative Example 4 are the same as those of Example 1. Here, as shown in FIGS. 12 and 13, in Comparative Examples 3 and 4, the bead on one side does not overlap the bead on the other side, and it is possible to confirm the lack of welding.

<Example 2>
In Example 2, the welding method of the I-type joint 28 according to the second embodiment shown in FIGS. 2A and 2B was applied, and further, the following detailed conditions were added to perform the placement process and the welding process.

<< Welding conditions of Example 2 >>
・ Welding method: Semi-automatic mag welding, one-pass welding on one side ・ Base materials 21, 22: Carbon steel (JIS G3101 SS400, length 300mm × width 300mm × thickness 10mm)
・ Welding wire: AWS A5.18 ER70S-G, diameter 1.2mm
・ Welding current: 300A
・ Welding voltage: 27V
-Welding speed: 300 mm / min
-Heat input: 16.2 kJ / cm
-Thickness T2 of base materials 21 and 22: 10 mm
・ Gap G2: 2.5mm

  The second embodiment is opposite to the second surfaces 21b and 22b to which the backing metal 25 of the base materials 21 and 22 is applied, as shown in FIG. 3B, in a state of a buried arc with a heat input of 16.2 kJ / cm. By performing mag welding in one pass from the first surfaces 21a and 22a side, complete penetration welding was realized through the bead 23 that welds the base material 21, the base material 22, and the backing metal 25 to each other. Note that, by appropriately changing the above-described 16.2 kJ / cm heat input within a range of 25 kJ / cm or less, complete penetration welding is possible even for a base material having a thickness T2 of 12 mm, for example.

<Example 3>
In Example 3, the welding method for the T-shaped joint 38 according to the third embodiment shown in FIGS. 4A to 4C was applied, and further, the following detailed conditions were added to perform the placement process and the welding process.

<< Welding conditions of Example 3 >>
・ Welding method: Semi-automatic mag welding, 1-pass welding on both sides ・ Base materials 31 and 32: Carbon steel (JIS G3101 SS400, length 300mm x width 300mm x thickness 16mm)
・ Welding wire: AWS A5.18 ER70S-G, diameter 1.2mm
・ Welding current: 320A
・ Welding voltage: 29V
-Welding speed: 300 mm / min
・ Heat input: 18.56kJ / cm
-Base material 31 (and base material 32) thickness T3: 16 mm
・ Gap G3: 2.5mm

  FIG. 14 shows the welding result of the T-shaped joint 38 according to the third embodiment. As shown in FIGS. 4C and 14, the depth of the beads 33 formed from the first surfaces 31 a and 32 a side of the base materials 31 and 32 (penetration depth H31) was 9 to 10 mm. On the other hand, the depth of the beads 34 (melting depth H32) formed from the second surfaces 31b and 32b of the base materials 31 and 32 was 9 to 10 mm. That is, as shown in FIG. 14, in Example 3, the bead on one side and the bead on the other side overlap each other, and complete penetration welding is achieved. In addition, complete penetration welding can be performed even for a base material having a thickness T3 of, for example, 20 mm by appropriately changing the above-described heat input of 18.56 kJ / cm within a range of 25 kJ / cm or less.

<Example 4>
In Example 4, the welding method for the T-shaped joint 48 according to the fourth embodiment shown in FIGS. 6A to 6B was applied, and the following detailed conditions were added to perform the placement process and the welding process.

<< Welding conditions of Example 4 >>
・ Welding method: Semi-automatic mag welding, one-pass welding on one side ・ Base materials 41 and 42: Carbon steel (JIS G3101 SS400, length 300mm × width 300mm × thickness 10mm)
・ Welding wire: AWS A5.18 ER70S-G, diameter 1.2mm
・ Welding current: 320A
・ Welding voltage: 29V
-Welding speed: 300 mm / min
・ Heat input: 18.56kJ / cm
-Base material 41 (and base material 42) thickness T4: 10 mm
・ Gap G4: 2.5mm

  FIG. 15 shows the welding result of the T-shaped joint 48 according to the fourth embodiment. As shown in FIGS. 6B and 15, a bead (bead 43) was formed over the entire region (the entire end surface of the base material 41) in the thickness direction of the base material 41 (the penetration depth direction). That is, as shown in FIG. 15, in Example 4, it was confirmed that complete penetration welding was achieved. In addition, complete penetration welding can be performed even for a base material having a thickness T4 of, for example, 12 mm by appropriately changing the above-described heat input of 18.56 kJ / cm within a range of 25 kJ / cm or less.

  According to at least one embodiment described above, deep penetration can be obtained with relatively low heat input.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  1, 21, 31, 41, 51, 61, 71, 81 ... base material (first base material), 2, 22, 32, 42, 52, 62, 72, 82 ... base material (second base material) ) 1a, 2a, 21a, 22a, 31a, 32a, 41a, 42a ... first surface, 1b, 21b, 31b, 41b, 2b, 22b, 32b, 42b ... second surface, 3, 4, 23, 33, 34, 43 ... beads, 8, 28, 78, 88 ... I type joints, 10, 20, 30, 40 ... welded structures, 25 ... backing metal, 38, 48, 58, 68 ... T type joints, 57, 67, 77, 87 ... protrusion, T1, T2, T3, T4 ... thickness of base material, G1, G2, G3, G4, G5, G6, G7, G8 ... gap, H1, H2, H31, H32 ... depth of penetration.

Claims (7)

An arrangement step of arranging a first base material and a second base material to be welded as a T-shaped joint with a gap;
A welding step in which the first and second base metals arranged are filled by heat input of 25 kJ / cm or less and are fully arc welded using a mag welding method in a state of an arc.
The thickness of the first base material is in the range of 6 mm or more and 20 mm or less,
The thickness of the second base material is in the range of 4 mm or more and 24 mm or less,
In the welding process, one pass each from the first surface side of the first base material arranged together with the second base material as the T-shaped joint and the second surface side located on the back side thereof. Welding operation,
The penetration depth obtained by the welding operation for each pass from the first and second surface sides is at least 0.5 times and 0.9 times or less the thickness of the first base material. In
Each bead formed by melting from the first and second surface sides overlaps each other,
The welding method, wherein the gap is in a range of 0.1 to 0.2 times the thickness of the first base material. An arrangement step of arranging a first base material and a second base material to be welded as a T-shaped joint with a gap;
A welding step in which the first and second base metals arranged are filled by heat input of 25 kJ / cm or less and are fully arc welded using a mag welding method in a state of an arc.
The thickness of the first base material is in the range of 4 mm or more and 12 mm or less,
The thickness of the second base material is in the range of 4 mm or more and 24 mm or less,
In the welding step, a one-pass welding operation is performed from the first surface side located on the back side of the second surface of the first base material arranged together with the second base material as the T-shaped joint. Done
The welding method, wherein the gap is in a range of 0.2 times to 0.3 times the thickness of the first base material. An arrangement step of arranging the first base material and the second base material to be welded as an I-shaped joint with a gap;
A welding step in which the first and second base metals arranged are filled by heat input of 25 kJ / cm or less and are fully arc welded using a mag welding method in a state of an arc.
The thicknesses of the first and second base materials are in the range of 6 mm or more and 24 mm or less,
In the welding step, a welding operation is performed for each pass from the first surface side of the first and second base materials arranged as the I-type joint and the second surface side positioned on the back surface side. ,
The penetration depth obtained by the welding operation for each pass from the first and second surface sides is at least 0.5 times and 0.9 times or less the thickness of the first base material. In
Each bead formed by melting from the first and second surface sides overlaps each other,
The welding method, wherein the gap is in a range of 0.05 to 0.1 times the thickness of the first and second base materials. An arrangement step of arranging a first base material and a second base material to be welded as an I-type joint together with a backing metal with a gap;
A welding step in which the first and second base metals arranged are filled by heat input of 25 kJ / cm or less and are fully arc welded using a mag welding method in a state of an arc.
In the welding step, one pass is made from the first surface side located on the back side of the second surface to which the backing metal for the first and second base materials arranged as the I-type joint is applied. Welding operation,
The thickness of the first and second base materials is in the range of 4 mm or more and 12 mm or less,
The welding method, wherein the gap is in a range of 0.2 to 0.4 times the thickness of the first and second base materials. The welding method according to any one of claims 1 to 4 , wherein in the welding step, the welding posture is a downward posture or a horizontal posture. Said gap, said first and constituted by projections provided on at least one of the second base member, the welding method according to any one of claims 1 to 5. The welding method according to any one of claims 1 to 6 , wherein the first and second base materials are carbon steel or stainless steel.

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