JP3997447B2 - Welding backing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a welding backing provided on the back side of a groove portion when welding plate materials to be welded to perform welding from both front and back surfaces.
[0002]
[Prior art]
As is well known, when welding the thick plate materials to be welded and performing welding from both the front and back sides, first, the opposing end surfaces of the plate materials are grooved into a predetermined angle and shape to form a groove portion, The plate members are fixed so as to be substantially flush with each other at a predetermined groove root interval. Then, the backing material is sandwiched from the back side of the groove portion and placed in close contact with the groove surface, and this backing material is used as the backing for the first layer welding of the multi-layer welding, and the opposite surface side The first layer is welded. The conventional backing material to be temporarily installed will be described with reference to FIGS.
[0003]
As shown in FIG. 5, the end faces of the thick plate members 1 and 1 adjacent to each other in the vertical direction and the welded groove portion 3 are abutted and held at a predetermined interval, and the gate is formed so as to straddle the groove portion 3 at a right angle. The shaped members 5, 5... Are fixed to the plate materials 1 and 1 to be welded. The shape of the groove portion 3 in the illustrated example shows a case where the groove portion 3 is formed in an X-shaped groove having a substantially X-shaped cross section. A conventional block-shaped backing material 4 as shown in the figure is sandwiched from the back surface side of the groove portion 3, and a strip-shaped square arrow receiving plate 6 is placed on the upper portion of the backing material 4 as necessary. The wedge-shaped square arrow 7 is driven into the space between the square arrow receiving plate 6 and the gate-shaped member 5, and the backing material 4 is installed in close contact with the groove portion 3 with a pressing force. The backing material 4 is used as a backing on the back surface side of the first layer welding, and the first layer welding is performed by the welding torch 8 from the opposite surface side. After the first layer welding, the backing material 4 and the square arrow receiving plate 6 are removed, the first layer welding back surface is polished and cleaned, and the first layer welding portion or the back side welding portion is over. The welding was completed by laminating single-layer or multi-layer welding.
[0004]
The use situation of the above-described conventional general backing material 4 will be described in more detail based on a partially enlarged view of the groove portion 3 shown in FIG. The end face of the plate materials 1 and 1 to be butt welded and the groove portion 3 are shown as being formed on the groove surfaces 2 and 2 having a substantially X-shaped cross section. The distance between 9 and the route interval L are maintained at predetermined dimensions. The backing material is made to correspond to the shape and dimensions of the groove portion 3 formed in this way, and so that the upper end surface 10 of the backing material 4 reaches and contacts the route edges 9a, 9a in the vicinity of the root portions 9, 9. 4 is manufactured using a metal member such as a copper material. The backing material 4 having a conventional general shape illustrated in the solid line cross section of FIG. 6 shows a case where it is formed in a substantially trapezoidal cross-section with a narrow tip portion so as to correspond to the X-shaped groove. That is, the backing material 4 has a substantially horizontal upper end surface 10 formed at a width approximately the same size as the root interval L of the X-shaped groove portion 3, and the groove surface 2 continuously on both lower sides thereof. , 2 is formed into a long block shape having a substantially trapezoidal cross section from both side surfaces 11, 11 formed to be inclined at a slightly acute angle from the inclination angle of 2, and overhang portions 12, 12 extending in a flat plate shape on the outer side of the lower part thereof. This shows the case. The backing material 4 formed in this way has the width of the upper end surface 10 of the backing material 4 set as the root interval of the groove when sandwiched on the back surface side of the groove portion 3 as shown by a one-dot chain line in FIG. Since L is substantially matched, both ends of the upper end surface 10 are in close contact with the root edges 9a and 9a of the root portions 9 and 9 of the plate members 1 and 1, and both side surfaces 11 and 11 are groove surfaces 2 respectively. , 2, the overhanging portions 12, 12 are installed in a state of being substantially in contact with or slightly separated from the surfaces of the plate materials 1, 1.
[0005]
The backing material 4 has a relatively large thickness such as welding of the side plate of the cylindrical tank, welding of the knuckle portion connecting the side plate of the cylindrical cryogenic tank and the roof portion in an arc shape, welding of the spherical shell plate of the spherical tank, etc. Used when welding thick plate materials from both front and back sides, the back of the first layer of welding is exposed to the atmosphere, resulting in pores and cracks in the welded part, poor external appearance shape, or melting of the weld metal. Therefore, a good back wave (back side portion of the first layer welding) free from welding defects is obtained. In addition to the X shape described above, there are various groove shapes such as a K shape, an H shape, and a double-sided J shape. The backing material 4 having a shape similar to the substantially trapezoidal cross section as illustrated above is used.
[0006]
[Problems to be solved by the invention]
7 (a), 7 (b) and 8 (a), 8 (b) show examples of the state in which the backing material 4 of the conventional example is not properly installed in the groove portion 3. The problem of the conventional backing material 4 will be described in detail based on the illustrated example. In addition, the name and code | symbol of each part are the same as the name and code | symbol shown in FIG.
[0007]
FIG. 7A shows the front end of the backing material 4 because the route interval L between the root portions 9 and 9 of the groove portion 3 is wide or the width of the upper end surface 10 of the backing material 4 is narrow. The case where the part upper end surface 10 protrudes upward away from the route edges 9a and 9a of the route parts 9 and 9, and the level difference part 13 is generated is shown. On the other hand, FIG. 7 (b) shows that the back distance L between the root portions 9 and 9 of the groove portion 3 is narrow or the width of the upper end surface 10 of the backing material 4 is wide. The case where the top end surface 10 of the tip portion of the material 4 is recessed downward from the root edges 9a and 9a of the root portions 9 and 9 to form the stepped portion 13 is shown. In the step portion 13 as shown in FIGS. 7A and 7B, when the distance L between the route portions 9 and 9 slightly changes, the manufacturing dimensional accuracy of the backing material 4 is not sufficient, and the upper end surface 10 This may also occur when the width of the is different. If there are such uneven step portions 13, welding defects such as poor fusion and shape failure may occur when welding the first layer, and a good back welded portion may not be obtained on the back surface. It was.
[0008]
FIG. 8A shows a case where the backing material 4 is lifted from the groove portion 3 and a separating portion 14 is formed between the upper end surface 10 and the left and right groove surfaces 2 and 2. Such a separation portion 14 due to lifting is likely to occur when the curved plate members 1 and 1 are welded, when the surfaces of the plate members 1 and 1 are uneven, and when the groove portions 3 are uneven. For example, in the case of the curved plate members 1 and 1 as shown in FIG. 5, it tends to occur when the gap between the gate-shaped members 5 and 5 is wide. Although closely in contact with the groove portion 3, as shown by the left arrow in FIG. 5, the backing material 4 is easily lifted partially from the groove portion 3 at a location away from the gate-shaped member 5. Further, as shown in FIG. 8B, when the plate surfaces of the plate materials 1 and 1 are shifted and a misplacement M is generated, a separating portion 14 may be generated on one side thereof. In order to bring the backing material 4 into close contact with each other so that the separating portion 14 does not occur, the backing material 4 is installed obliquely as shown by the broken line in the figure, or the backing material 4 is bent or twisted. There must be. However, the backing material 4 having a substantially trapezoidal cross section is difficult to hold in an oblique direction, and is difficult to bend and twist because it is block-like and has high rigidity, and its installation and fixing work is quite difficult. In addition, as shown in FIGS. 8A and 8B, when the backing material 4 cannot be adhered to the groove surfaces 2 and 2, the backing function is insufficient, so In some cases, the weld of the layer did not go well and a good back welded part could not be obtained.
[0009]
As described above, when the processing accuracy of the upper end surface 10 of the backing material 4 is not sufficient, or when the accuracy of the bending processing of the backing material 4 with respect to the curvature of the plate materials 1 and 1 is not sufficient, the route interval L of the groove portion 3. Is not constant, the machining accuracy of the groove surfaces 2 and 2 is not sufficient, or the curvature accuracy of the plate materials 1 and 1 slightly changes, etc., the closeness between the groove portion 3 and the backing material 4 is obtained. The backing material 4 could not be properly installed. Thus, in the state where the backing material 4 of the conventional example is not properly installed in the groove portion 3, the back surface of the first layer of the welded portion is raised or recessed and has a smooth and good appearance. May not be obtained, and the welds near the tips of the groove portions 2 and 2 and the root portions 9 and 9 may be insufficiently welded, resulting in weld defects such as poor shape of welds and occurrence of cracks. .
[0010]
And when the backing material 4 is removed and welding is performed from the back side in this direction, the back wave welded portion of the first layer having the poor shape is ground to prepare a smooth shape, or the welding defect is removed. In order to remove the work, large-scale and labor-intensive operations such as hanging and grinding of the deep back by arc air gouging and grinder are required. And when this back is insufficiently hanged or the like, a weld defect may occur in the welded portion from the back side, and an appropriate welded portion may not be obtained.
[0011]
The present invention has been made in view of the above-mentioned problems of the prior art, and follows the change in the shape of the welded groove part and adapts to the change in the interval of the groove part. This provides a welding backing that is in close contact with the vicinity of the root portion of the steel plate and that provides a good back wave during the first layer welding from the opposite surface side.
[0012]
[Means for Solving the Problems]
  In order to solve the above-mentioned problems, the welding backing of the present invention has a substantially circular cross section that abuts against the root edge of the groove when the welding backing provided on the groove when the welded plate materials are butted on both sides is welded. Formed of a shape contact material and a pressing material that presses the contact material against the groove.The contact material is a contact material that is formed of a member that is softer than the plate member to be welded, and deforms by conforming to the groove surface of the groove portion when pressed against the groove portion by the pressing material..
[0014]
In the welding backing of the present invention, an engagement groove for fixing the contact material is provided on the contact surface of the pressing material that contacts the contact material.
[0015]
  Further, the welding backing of the present invention is the above contact material.Inside, or inside of pressing material, or contact material and pressing material, respectivelyIs provided with a hollow portion through which the refrigerant passes.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
A welding backing according to the present invention will be described on the basis of the embodiment shown in FIGS. The welding backing according to the present invention is excellent in suppressing dripping of the molten metal on the back side of the first layer welding during the first layer welding when welding the thick plate materials to be welded and performing welding from both the front and back sides. In order to obtain a deep back welded portion, it is provided on the groove back side of this first layer welding.
[0017]
As shown in FIG. 1 and a partially enlarged view thereof, the welding backing of the present invention abuts against the root edges 9a and 9a of the root portions 9 and 9 of the groove portion 3 of the welded plate materials 1 and 1 which are butted together. A contact member 15 having a substantially circular cross section and a pressing member 16 having a substantially trapezoidal cross section and pressing the contact member 15 are formed. As shown in FIG. 1, this welding backing is pressed so as to be sandwiched between a gate-shaped member 5, a square arrow 7, and a square arrow receiving plate 6 that are fixed to the welded plate materials 1, 1 across the groove portion 3. Install with pressure. The contact material 15 and the pressing material 16 are used as the backing for the first layer welding, and the first layer welding is performed by the welding torch 8 from the opposite side.
[0018]
In the partially enlarged view illustrated in FIG. 2, the groove portion 3 of the X-shaped groove is formed so that the end groove surfaces 2, 2 of the welded plate materials 1, 1 which are butted together have a substantially X-shaped cross section. In this case, a root interval L is provided between the root portions 9 and 9 at the groove tip, and the lower back surface is used as a backing when the first layer is welded from the upper surface side of the groove portion 3. An abutting member 15 having a substantially circular cross section is provided to abut against the root edges 9a, 9a of the side root portions 9, 9 to prevent the weld metal from being melted and to obtain a good back wave. And the state which installs the press material 16 (a part is abbreviate | omitted illustration) with a substantially trapezoidal cross section which absorbs welding heat from the contact material 15 is shown.
[0019]
In this way, the welding backing is pressed against the portion of the contact material 15 that contacts the root edges 9a, 9a of the groove portion 3, and the portion that absorbs and dissipates the welding heat by pressing it against the groove portion 3 side. Since it is formed in a structure separated from the material 16, the abutment material 15 at the portion that abuts against the root edges 9a, 9a has a rigidity smaller than that of the conventional welding backing. The contact work to 9a becomes easy. Since the contact material 15 has a substantially circular cross section with a point-symmetric cross section, it is easy to bend in any direction and the contact work is easy. Further, the pressing member 16 can be easily and easily manufactured without requiring a certain degree of accuracy, and the cross-sectional area can be reduced. Therefore, the pressing member 16 can be easily pressed even on a curved surface and can be easily attached. Further, even if the backing is damaged by welding heat, it is economical because only the contact material 15 that is easily damaged needs to be replaced. Furthermore, since the separated backing can be lengthened to reduce the length of the connecting portion in the longitudinal direction, the attachment work is easy, and in addition, the contacting material 15 is connected to the connecting portion in the longitudinal direction. It is also possible to suppress the occurrence of defects that are likely to occur.
[0020]
The contact member 15 has a substantially circular cross section such as a perfect circle, an ellipse, or a polygon close to a circle, and both shoulder portions (both diagonally upper contact portions) thereof are the root edges 9a of the groove portion 3 as described above. It is formed to a size that abuts on 9a. The contact member 15 illustrated in an enlarged manner in FIG. 2 shows a case where the contact member 15 is formed of a round bar member 25 having a true circular cross section as shown by a solid line cross section in the drawing. The diameter D of the round bar 25 is slightly larger than the root interval L of the groove portion 3 and preferably has a dimension that contacts the lower end root edges 9a, 9a of the root portions 9, 9. Although this dimension also depends on the shape of the groove portion 3, for example, when the root interval L is 5 millimeters, a round bar 25 having a diameter D of about 8 millimeters is used. In addition, the length of the round bar 25 can be appropriately used as long as several tens of centimeters or several meters. If the diameter D of this round bar 25 is too smaller than the route interval L, it will enter the route 9, 9 and will slip out, or it will bite in too much, making it difficult to remove it. . On the other hand, if the diameter D of the round bar 25 is much larger than the route interval L, the route edges 9a, 9a and the vicinity of the route edges 9a, 9a are not filled and an interval is generated. Therefore, the contact member 15 is formed to have a size adapted to the shape of the groove portion 3.
[0021]
2 shows the welding backing of the second invention in the case where the abutting material 15 is formed of a member softer than the plate materials 1 and 1 to be welded. As shown by the one-dot chain line in the figure, the contact member 15 has a diameter D that is somewhat larger than the root interval L of the groove portion 3, that is, a cross-sectional true diameter that is slightly larger than the diameter D of the round bar 25 in the solid line cross section in the figure. It is formed with a circular round bar 35. As shown by the one-dot chain line in the figure, when the pressing member 16 having a substantially trapezoidal cross section is pressed from below the round bar 35 and brought into contact with the groove surfaces 2 and 2 in the vicinity of the root portions 9 and 9 and further pressed. Since the round bar 35 is a softer member than the plate, as shown by the broken line in the figure, the shoulders that are in contact with each other are concavely deformed so as to come into contact with each other from the linear contact to form the groove surfaces 2 and 2. Familiarly, the root portions 9 and 9 are in close contact with the vicinity of the lower portions of the root edges 9a and 9a with a wide contact surface. The installation work of the round bar 35 can be easily performed while adjusting it by tapping the upper surface of the pressing member 16.
[0022]
As described above, the round bar material 35 formed of a member softer than the plate materials 1 and 1 is bent by the pressing force, and is easily deformed by conforming to the shape of the groove surfaces 2 and 2, and has high heat resistance and heat conductivity. When the metal material, for example, the plate materials 1 and 1 are steel materials, copper, a copper alloy, or the like is preferable. The round bar 35 formed of such a material easily follows the curvature and deformation along the weld line direction of the groove portion and bends closely, and the groove angle, groove shape, and route interval. Since it abuts with a wide contact area so as to be easily deformed and fill in the gap, the contact performance is improved and a suitable welding backing is obtained. Even if the round bar member 35 is used once and is deformed with both shoulders having a circular cross section recessed, the round bar member 35 originally has a point-symmetric cross-sectional shape. , 2 can be combined and brought into close contact and reused for economic efficiency.
[0023]
The welding backing, that is, the welding backing in which the contact material 15 is formed of a member softer than the plate materials 1 and 1 can easily bring the contact material 15 into close contact even if the groove shape is uneven. , Knuckle part of arc-shaped cross-section plate connecting the cylindrical side plate of a flat bottom cylindrical cryogenic tank and a spherical shell-like roof part (curvature changes in a large and complex manner in two directions, the cylindrical circumferential direction and the cylindrical axis direction) It can be used as a more suitable backing for the groove part 3 of the plate material or the groove part 3 of the spherical shell plate of the spherical tank. Moreover, the groove part 3 where it is difficult to align the plate materials 1 and 1 having different plate thicknesses, the groove part 3 where the center lines of the plate materials 1 and 1 do not match each other, or the groove part 3 that tends to cause a misunderstanding, a cylindrical shape It can also be used as a more suitable backing for the groove portion 3 of the peripheral joint of the side plate.
[0024]
The pressing material 16 for the welding backing of the present invention is formed in a band plate shape having a substantially trapezoidal cross section, for example, so as to hold the contact material 15 inside the groove portion 3 with a space from the groove surfaces 2 and 2. In addition, it is formed of a member having high heat conductivity, such as copper or copper alloy, which easily absorbs and dissipates heat during welding from the contact material 15. By thus absorbing the welding heat through the pressing member 16 and dissipating the heat to the outside, the contact member 15 can be prevented from being thermally deformed and melted, and further welded to the groove surfaces 2 and 2. . Moreover, since the front-end | tip part and right-and-left inclined surface of the press material 16 may have a space | interval inside the groove part 3 without making it closely_contact | adhere to the groove surfaces 2 and 2, a moderate precision is not required. Therefore, it can be easily manufactured by bending a strip having a substantially trapezoidal cross section to a shape along the weld line direction, for example, the curvature of the groove portion 3, and the cross-sectional area is also reduced, so that it is easy to bend. Installation work is also easy.
[0025]
As described above, when the first layer is welded using the welding backing made of the contact material 15 and the pressing material 16 of the present invention, the groove portions 2 and 2 are connected to the root portions 9 and 9. Because of the good closeness, when performing gas shielded arc welding using an inert gas, the gas shielding performance is also maintained in good condition, and the welded steel material melts well and has no unevenness at the welding site. Since it is carried out sufficiently and has good heat absorption and dissipating properties, there is no occurrence of welding defects, and a back-like shape with a good appearance with no irregularities on the back surface of the weld is obtained.
[0026]
The boundary surface from which the contact member 15 having a substantially circular cross section is removed has a U-shaped cross section, and the boundary portions on both sides thereof are smoothly raised in an arc shape and are continuously removed. It is easy to do, and since there is no discontinuity at the boundary between the left and right groove surfaces 2 and 2 and the weld metal, it is completely melted. It is not necessary to perform cleaning by simple and easy surface grinding or polishing. When performing the welding from the opposite back side, the boundary surface is smooth with a U-shaped cross section as described above. Therefore, welding on the upper surface is smooth and easy to laminate on average, and a high-quality thick welded part is formed. Obtainable.
[0027]
An embodiment of the welding backing of the third invention will be described based on a partially enlarged view shown in FIG. This welding backing is provided with an engagement groove 17 for fixing the contact material 15 so as not to move at the substantially central portion of the contact surface of the pressing material 16 that contacts the contact material 15. By providing the engagement groove 17, the movement of the contact member 15 is restrained so that it can be easily pressed, the pressing member 16 is also stable without being displaced, and the attachment work can be performed efficiently. The engagement groove 17 may be a groove shape having a depth and width sufficient to stably fix the contact member 15. For example, the engagement groove 17 is an elongated groove shape such as a U-shaped cross section, a concave shape, or a V shape, and has a very high accuracy. Can be easily and easily manufactured by cutting or the like. By inserting and fixing the lower part of the contact material 15 in the engagement groove 17 formed in this way, the contact portion between both increases, the heat transfer area increases, the heat transfer performance of the welding heat improves, and the welding heat increases. Since the function of absorbing and radiating the heat increases, the function of preventing the thermal welding and the thermal deformation of the contact material 15 by the welding heat can be further increased.
[0028]
An embodiment of the welding backing of the fourth invention will be described based on a partially enlarged view shown in FIG. This welding backing is provided with a hollow portion 18 inside the contact member 15, inside the pressing member 16, or inside each of the contact member 15 and the pressing member 16. The illustrated example of FIG. 4 shows a case where the hollow portion 18 is provided inside the abutting member 15 to form a circular tube. When the hollow portion 18 is provided in the interior of the backing in this manner, the weight of the backing is improved, so that the workability of carrying and mounting is improved, and the material is saved, so that the economy is improved. A refrigerant such as air or water is passed through the hollow portion 18 so as to absorb and cool the heat at the time of welding. When the coolant is passed through the hollow portion 18 in this way, the backing is cooled, so that the contact material 15 does not reach a high temperature, thereby further increasing the function of preventing melting, thermal welding, and thermal deformation. Can do. In addition, it absorbs and cools excessive welding heat and enables cooling control of the welded part, so it can also be prevented when adverse effects such as high temperature alteration of the deposited metal and the crystal particles of the heat affected zone are considered, It also has a function of modifying the weld metal.
[0029]
As described above, the welding backings of the first to fourth inventions according to the present invention are used for the welding back surface of the first layer when performing multi-layer welding from the front and back both sides, and have good close contact performance. In addition, there is no occurrence of weld defects on the back surface of the welded portion, and a back surface shape with a good appearance can be obtained. Further, the present invention is not limited to the X-shaped groove shape described in detail above, and can be applied to any groove shape such as a K-shaped groove, an H-shaped groove, a double-sided J-shaped groove, or the like. Furthermore, it is easy and easy to manufacture and can follow the curvature and deformation, so installation work can be done easily. Moreover, it can use suitably for any welding methods, such as an inert gas arc welding and a carbon dioxide gas arc welding, not a manual type, a semi-automatic type, or an automatic type. In particular, high-quality thick plate welding of 9% nickel steel performed by automatic TIG welding provides a more suitable welding backing, and enables higher-quality welding and highly efficient welding work.
[0030]
【The invention's effect】
  As stated,The contact material is formed of a member softer than the plate material to be welded, and is a contact material that is deformed by conforming to the groove surface of the groove portion when pressed against the groove portion by the pressing material. Both shoulders are recessed and deformed so as to change from line contact to surface contact, and conform to the shape, and are in close contact with a wide contact surface near the lower portion of the root edge. Therefore, the contact material formed of such a soft member bends and closely follows the curvature and deformation along the weld line direction of the groove part, and the groove angle and groove shape, Corresponding to changes such as unevenness in the route interval, the contact is made with a large contact area so as to be deformed and fill the interval, so that the close contact performance is further improved and a more suitable backing for welding is provided. Even if the abutment material is used once and both shoulders are recessed and deformed, it originally has a point-symmetric cross-sectional shape. It is economical because it can be reused.
[0031]
  The contact material is formed of a member softer than the plate material to be welded, and is a contact material that is deformed by conforming to the groove surface of the groove portion when pressed against the groove portion by the pressing material. The welding backing can connect the cylindrical side plate of the flat bottom cylindrical cryogenic tank and the spherical shell-shaped roof portion in particular because the contact material can be easily brought into close contact even with irregular groove shapes. At the groove part of the knuckle part of the arc-shaped cross section (plate material whose curvature changes complicatedly in two directions of the cylindrical circumferential direction and the cylindrical axis direction) and the groove part of the spherical shell plate of the spherical tank, It can be used as a more suitable backing. In addition, the groove part where the plate thickness is different and the plate alignment is not successful, the groove part when the center lines of the plate materials do not match, the groove part where the misalignment occurs, the groove part of the side plate circumferential joint, etc. Can be used as a suitable backing.
[0032]
  The welding backing of the present invention formed from a contact material having a substantially circular cross section and a pressing material that presses the contact material against the groove portion is a curved shape or deformation in the weld line direction of the groove portion of the contact material. Since the groove angle, groove shape, and root interval easily follow the deformation, it is easy to contact the root edge of the groove part, and the close contact state is improved, so that the molten metal hangs down from the back of the welded part. A uniform, stable and good first-layer welding can be performed without generating irregularities without generating irregularities, and a smooth and smooth appearance of the back surface without welding defects can be obtained on the back surface of the weld. Further, since heat due to welding is also absorbed and dissipated from the contact material via the pressing material, a good weld surface can be obtained without the contact material being deformed or welded by heat.
[0033]
  In addition, this welding backing has a structure that is separated into a contact material at a portion that contacts the root edge of the groove portion and a pressing material that absorbs and dissipates the welding heat by holding it. Since the rigidity of the contact material of the portion that contacts the edge is smaller than that of the conventional welding backing, the contact operation to the root edge is facilitated. The contact material having a substantially circular cross section with a point-symmetric cross section is easy to bend in any direction, and the contact work is easy. Further, the pressing material can be easily and easily manufactured without requiring a certain degree of accuracy, and the cross-sectional area can be reduced, so that the mounting work is also easy. Moreover, even if the backing is damaged by welding heat, it is economical because only the contact material that is easily damaged can be replaced. Furthermore, since the separated backing can be lengthened by one to reduce the number of longitudinal connecting portions, it is easy to install and also suppresses the occurrence of defects that are likely to occur in the connecting portions. It becomes possible.
[0034]
  In addition, since the contact material having a substantially circular cross section is formed with a U-shaped groove at the time of back surface welding after being removed, it is possible to remove welding defects and make the shape smooth and uniform as in the past. The time-consuming back side does not require a lifting operation, and cleaning such as surface grinding and polishing is easy and easy, and welding from the back side is easy to perform, so a high-quality thick welded portion can be obtained.
[0035]
In addition, the welding backing of the third aspect of the present invention, in which the contact groove for fixing the contact material is provided on the contact surface of the pressing material that contacts the contact material, makes it easy to press the contact material against the weld groove. Also, the pressing material is stable without shifting, the abutting material can be stably fixed, and the efficiency of the mounting work can be improved. In addition, since the contact area between the abutting material and the pressing material is increased, the welding heat transmitted to the abutting material is well transmitted to the pressing material and the function of radiating heat is increased. The deformation prevention function can be increased.
[0036]
Further, for welding according to the fourth aspect of the present invention, a hollow portion through which a coolant passes is provided in the inside of the welding backing, that is, in the inside of the abutting material, in the pressing material, or in each of the abutting material and the pressing material. Since the backing can cool the welding heat with the refrigerant, the function of preventing the contact material from being melted, welded and thermally deformed by the welding heat can be further increased. Furthermore, the workability is improved by reducing the weight of the material, and the economy is improved because the material is saved.
[0037]
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a perspective explanatory view in which a part of an embodiment of a welding backing according to the present invention is partly omitted and made into a cross section.
FIG. 2 is an explanatory cross-sectional view showing a part of an embodiment of a welding backing according to the first and second inventions in an enlarged manner with a part removed.
FIG. 3 is an explanatory cross-sectional view showing a part of an embodiment of a welding backing according to a third aspect of the present invention by removing a part thereof and enlarging it.
FIG. 4 is an explanatory cross-sectional view showing a part of an embodiment of a welding backing according to a fourth aspect of the present invention by removing a part thereof and enlarging it.
FIG. 5 is an explanatory perspective view of a cross-section with a part removed showing a case where a plate material is welded using a conventional backing material.
FIG. 6 is an explanatory cross-sectional view showing a conventional backing material with a part removed and enlarged.
FIGS. 7A and 7B are cross-sectional explanatory views showing a conventional backing material partly omitted and enlarged. FIG.
FIGS. 8A and 8B are cross-sectional explanatory views showing a conventional backing material with a part thereof removed and enlarged. FIG.
[Explanation of symbols]
1,1 Plate material 2,2 Groove surface
3 groove part 4 backing material
5 Portal member 6 Square arrow receiving plate
7 Square arrows 8 Welding torch
9,9 root part 9a, 9a root edge
10 Top surface 11, 11 Both sides
12 Overhang part 13 Step part
14 Isolation part 15 Contact material
16 Pressing material 17 Engaging groove
18 Hollow part
25, 35 Round bar

Claims (3)

  The welding backing provided on the groove portion when the welded plate materials are butted on both sides is a substantially circular cross-sectional contact material that contacts the root edge of the groove portion, and presses the contact material against the groove portion. The contact material is formed of a member softer than the plate material to be welded, and when pressed against the groove portion by the pressure material, the contact material is deformed by conforming to the groove surface of the groove portion. Backing for welding characterized by being an adhesive material.   The welding backing according to claim 1, wherein an engagement groove for fixing the contact material is provided on a contact surface of the pressing material that contacts the contact material. The welding backing according to claim 1 or 2, wherein a hollow portion through which a coolant passes is provided in the abutting material, in the pressing material, or in each of the abutting material and the pressing material .

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