JP5064840B2 - Ultrasonic flaw detection inspection method for welded joints - Google Patents

Description

  The present invention relates to a method for welding reinforcing bars used in reinforced concrete structures and the like, and more particularly, to a method for butt welding two reinforcing bars having different sizes so that an ultrasonic flaw detection inspection can be suitably performed on a welded joint.

  Previously, the applicant previously applied a welding joint method for reinforcing bars using the metal backing material (joint sleeve) (101) shown in FIG. 13 and an ultrasonic wave applied to a welded joint formed using the construction method. A flaw detection inspection method was proposed (Patent Document 1). Furthermore, the applicant has also proposed an ultrasonic flaw detection inspection method suitably used for such a welded joint (Patent Document 2). The welded joint method disclosed in Patent Document 1 is called the New NT Method (Trademark Registration No. 4235603) and has been implemented by the applicant. Further, the ultrasonic flaw detection inspection methods disclosed in Patent Document 1 and Patent Document 2 are also implemented by the applicant for welded joints manufactured using the construction method.

  The backing material (101) shown in FIG. 13 has a belt-like U-shaped portion (103) and a pair of receiving portions (105a) (105b) extending in opposite directions from the bottom of the U-shaped portion. Yes. The construction method disclosed in Patent Document 1 uses such a backing material (101) to make the probe used for ultrasonic flaw inspection of a welded joint accessible to the welded joint. As a result, This realizes ultrasonic flaw detection inspection with a wide flaw detection area.

JP 2002-45967 A JP 2005-121497 A

  In the ultrasonic flaw detection described above, a probe is disposed on a rib extending in the axial direction of the reinforcing bar. Therefore, in the above construction method, in order to make the probe accessible to the groove of the weld joint and the weld metal portion, on the receiving portion (105a) (105b) of the backing material (101) or their It is required to position the backing material (101) and the two reinforcing bars so that no reinforcing bar ribs are arranged in the vicinity (FIGS. 5A and 5B and paragraph [0022] of Patent Document 1). ] To [0025]).

  Even when two reinforcing bars of different sizes are butt welded using the backing material (101), it is required to position the reinforcing bars in this way. However, in actual construction, there may be a situation where it is impossible to position the reinforcing bars in this way. FIG. 14 shows a state in which two reinforcing bars having different sizes are butt-welded using the backing material (101) shown in FIG. The first rebar (107) having a large size and the second rebar (109) having a small size are arranged so as to contact the receiving portions (105a) and (105b), respectively, and the central axis B ′ of the second rebar (109) is arranged. Is substantially parallel to the central axis A ′ of the first reinforcing bar (107), but is shifted toward the receiving portion (105b).

  FIG. 14 shows a state in which the rib (111) of the first reinforcing bar (107) and the rib (113) of the second reinforcing bar (109) are arranged on the receiving portions (105a) and (105b), respectively. Yes. Such a positional relationship is not preferable for ultrasonic flaw detection inspection of the welded joint (125), but the other ends of the first rebar (107) and the second rebar (109) (not shown) are already welded. Or when it is embed | buried in concrete, the positional relationship of a 1st reinforcing bar (107) and a 2nd reinforcing bar (109) is restrict | limited, and cannot be adjusted freely. Depending on the work position of the operator with respect to these reinforcing bars (107) and (109), the situation in which the first reinforcing bar (107) and the second reinforcing bar (109) must be butt welded as shown in FIG. It often happens.

  In the state shown in FIG. 14, when the ultrasonic flaw detection described above is performed, for example, the transmitting probe (121) is arranged so as to contact the lower rib (113) of the second rebar (109). The receiving side probe (123) is arranged so as to contact the upper rib (115). With respect to the probe (121) on the transmission side, a plurality of fixed positions are set on the lower rib (113). During the inspection, the transmitting probe (121) is maintained in one of these positions, and the receiving probe (123) moves on the rib (115) toward the weld joint (125). . The ultrasonic wave transmitted from the transmitting probe (121) at a refraction angle θ of approximately 70 degrees is reflected by a defect in the weld joint, and the receiving probe (123) receives the defect echo. Thus, the defect is detected. By changing the fixed position of the probe (121) on the transmission side, a flaw detection inspection is performed on different regions of the welded joint (125). A similar flaw detection test is also performed from the first reinforcing bar (107) side.

  As shown in FIG. 14, the lower rib (113) of the second reinforcing bar (109) is placed on the receiving part (105b), and the lower side of the first reinforcing bar (107) is placed on the receiving part (105a). When the rib (111) is placed, the transmitter probe (121) is welded to the groove of the welded joint (125) and welded by the length of the receiving part (105a) (105b) compared to the preferred arrangement. The metal part (127) cannot be approached. As a result, for example, in a preferable reinforcing bar arrangement, it is impossible to apply ultrasonic waves to the detectable defect C ′, and the defect C ′ cannot be detected. Therefore, when such a situation occurs, an ultrasonic flaw inspection is performed after the receiving portions (105a) and (105b) are cut and removed from the welded joint (125).

  Further, as shown in FIG. 14, when the first reinforcing bar (107) and the second reinforcing bar (109) having different sizes are butt welded, the size difference between these reinforcing bars (107) and (109), that is, the diameter difference is large. In this case, the step between the first reinforcing bar (107) and the second reinforcing bar (109) becomes larger on the upper side of the backing material (101). In order to avoid stress concentration on the welded joint (125), the weld metal part (127) of the welded joint (125) must be formed so as to be smoothly connected from the reinforcing bar (107) to the reinforcing bar (109), that is, cured. However, if the steps of the reinforcing bars (107) and (109) become large, it becomes difficult to adjust the shape of the molten metal on the upper side of the backing material (101), and the burden on the operator increases.

  The present invention solves the above problems, and is not affected by the positional relationship between reinforcing bars of different sizes and the backing material, and in ultrasonic flaw detection, the groove of the weld joint and the weld metal part Provided is a butt welding method for reinforcing bars in which a probe can be brought close to the reinforcing bar and a weld metal portion of a welded joint can be easily formed so as to be smoothly connected to the reinforcing bars even when the size difference between the reinforcing bars is large. Furthermore, the present invention provides an ultrasonic flaw detection inspection method suitable for inspecting a defect of a welded joint formed using the method.

  In the butt welding method of the present invention, two linear ribs are formed on each other so as to face each other across the central axis, and two reinforcing bars of different sizes are bent into a substantially U shape. A butt-welding method using a belt-shaped backing material made of steel, wherein the central axes of the two reinforcing bars are positioned substantially in parallel, and the distance between the grooves of the two reinforcing bars is a predetermined route interval A first step of arranging the two reinforcing bars so as to be, a second step of aligning the central axes of the two reinforcing bars so that the central axes of the two reinforcing bars are located substantially on the same line, and The backing material surrounds the space between the gaps of the two reinforcing bars, and the backing material is arranged so that the bottom of the backing material is inclined from the large size reinforcing bar to the small size reinforcing bar. Temporarily attaching the backing material to one of the two reinforcing bars in contact with the side of the reinforcing bars A third step of welding, and the weld between open destination of the two reinforcing bars, comprising a fourth step of forming a welded joint between the two reinforcing bars.

  In the butt welding method of the present invention, two linear ribs are formed on each other so as to face each other across the central axis, and two reinforcing bars of different sizes are bent into a substantially U shape. A butt-welding method using a belt-shaped backing material made of steel, wherein the central axes of the two reinforcing bars are positioned substantially in parallel, and the distance between the grooves of the two reinforcing bars is a predetermined route interval A first step of arranging the two reinforcing bars so as to be, a second step of aligning the central axes of the two reinforcing bars so that the central axes of the two reinforcing bars are located substantially on the same line, and The backing material surrounds the space between the grooves of the two reinforcing bars, the lateral width direction of the backing material is substantially perpendicular to the central axis of the two reinforcing bars, and the band width direction of the backing material is The backing material is brought into contact with the side surfaces of the two reinforcing bars so as to be inclined with respect to the central axis of the two reinforcing bars. A third step of tack welding the backing material to one of the two reinforcing bars and a main welding between the grooves of the two reinforcing bars to form a welded joint between the two reinforcing bars. Including the fourth step.

  In the ultrasonic flaw detection inspection method of the present invention, two linear ribs are respectively formed so as to face each other across the central axis, and a welded joint formed between two reinforcing bars having different sizes is provided. A method for flaw detection inspection using ultrasonic waves, wherein the central axes of the two reinforcing bars are arranged substantially on the same line, and the two reinforcing bars are made of a metal strip curved in a substantially U-shape. The backing material encloses the space between the two reinforcing bars, and the bottom of the backing material has a small size from a large size reinforcing bar. The side surface of the two reinforcing bars is in contact with the two reinforcing bars so as to incline toward the reinforcing bars, and the transmitting probe is arranged on one rib of either reinforcing bar, and the receiving probe is placed on the other rib. A transducer is placed and supersonic waves are directed from the transmitting probe toward the weld joint at a predetermined refraction angle. To send.

  In the ultrasonic flaw detection inspection method of the present invention, two linear ribs are respectively formed so as to face each other across the central axis, and a welded joint formed between two reinforcing bars having different sizes is provided. An ultrasonic flaw detection inspection method for a welded joint for flaw detection inspection using ultrasonic waves, wherein the central axes of the two reinforcing bars are arranged on substantially the same line, and the two reinforcing bars are strip-shaped steel plates Are butt welded using a backing material curved in a substantially U shape, and the backing material surrounds the space between the grooves of the two reinforcing bars, and the lateral width direction of the backing material is Is substantially perpendicular to the central axis of the two reinforcing bars, and is in contact with the side surfaces of the two reinforcing bars so that the width direction of the backing material is inclined with respect to the central axis of the two reinforcing bars, A transmitter probe is placed on one of the two ribs of any reinforcing bar, and the receiver probe is placed on the other rib. By placing the probe, from the probe of the transmitter-side, for transmitting ultrasonic waves toward the weld joint at a predetermined angle of refraction.

  In the combination of the reinforcing bar and the welded joint according to the present invention, two linear ribs are formed on each other so as to face each other across the central axis, and the two reinforcing bars having different sizes are curved in a substantially U shape. It is a combination with a welded joint formed between the two rebars using a metal belt-like backing material, and the central axes of the two rebars are arranged substantially on the same line, The backing material surrounds the space between the gaps of the two reinforcing bars, and the bottom of the backing material is inclined from the large size reinforcing bar toward the small size reinforcing bar. The weld joint is in contact with a side surface, and is composed of a weld metal portion filled between the grooves of the two reinforcing bars and the backing material.

  In the combination of the reinforcing bar and the welded joint according to the present invention, two linear ribs are formed on each other so as to face each other across the central axis, and the two reinforcing bars having different sizes are curved in a substantially U shape. It is a combination with a welded joint formed between the two rebars using a metal belt-like backing material, and the central axes of the two rebars are arranged substantially on the same line, The backing material surrounds the space between the grooves of the two reinforcing bars, the width direction of the backing material is substantially perpendicular to the central axis of the two reinforcing bars, and the width direction of the backing material Is in contact with the side surfaces of the two reinforcing bars such that the welded metal part is filled between the grooves of the two reinforcing bars. And the backing material.

  According to the butt welding method of the reinforcing bar of the present invention, regardless of the positional relationship between the ribs of two reinforcing bars of different sizes and the backing material, the contact used for the ultrasonic flaw detection test is used for the groove of the weld joint and the welding. These two rebars can be butt welded so that they are sufficiently accessible to the metal part. In addition, since the worker does not need to consider the positional relationship between the reinforcing bar ribs and the backing material, the burden on the worker is reduced. Furthermore, according to the butt welding method of the reinforcing bar of the present invention, even when the size of these reinforcing bars is relatively large, the step between the reinforcing bars is reduced on the upper side of the backing material as compared with the conventional method. The weld metal portion of the weld joint can be easily formed so as to be connected smoothly.

  According to the ultrasonic inspection method for welded joints, regardless of the positional relationship between the ribs and backing material of two reinforcing bars of different sizes, the contact used for the ultrasonic inspection test is used for the groove of the welded joint and It is possible to get close enough to the weld metal part. Further, the combination of the reinforcing bar and the welded joint of the present invention has the same effects as the butt welding method of the present invention and the ultrasonic flaw detection inspection method of the welded joint. In the present invention, the backing material is preferably in contact with the side surfaces of the two reinforcing bars in the vicinity of the groove of the two reinforcing bars.

  Hereinafter, an embodiment of the present invention will be described. The reinforcing bars to be butt welded in this embodiment are deformed reinforcing bars (deformed bar) generally used for reinforced concrete structures, for example, deformed reinforcing bars defined in JIS G 3112 (reinforcing steel bars for reinforced concrete). is there. On the side surface of the deformed reinforcing bar (hereinafter referred to as the reinforcing bar), two linear ribs extending in parallel to the central axis of the reinforcing bar and symmetrically arranged with respect to the central axis, and predetermined in the direction of the central axis A plurality of semicircular (or annular) nodes (or spiral nodes) arranged at intervals of. The sizes of such reinforcing bars are distinguished using the notation indicating the maximum diameter in JIS G 3112. For example, D13 (nominal diameter 12.7 mm), D16 (nominal diameter 15.9 mm), D19 (nominal diameter 19 .1 mm), D22, D25, D29, D32, D35, D38, D41, etc. In the present invention, two reinforcing bars of different sizes, such as D13 and D16, D19 and D22, D19 and D25, are butt welded. The reinforcing bars are made of steel types such as SD295A, SD345, and SD390, for example.

  FIG. 1 is a perspective view of a reinforcing bar support (1) used in this embodiment. FIG. 2 is a cross-sectional view of the reinforcing bar support (1) cut along a vertical plane including the line II in FIG. The reinforcing bar support (1) includes a cylindrical casing (3), a first holding part (5) and a second holding part (7) for holding the reinforcing bar, respectively, and the first holding part (5 ) Is fixed to one end side of the housing (3) via a connecting member (9) extending outward from the side surface of the housing (3). The second holding portion (7) is movably provided on the other end side of the housing (3). The first holding portion (5) is formed with a first extending portion (11) and a second extending portion (13) extending outward, and the first extending portion (11) A reinforcing bar holding surface (15) with which the reinforcing bars shown in phantom lines in FIG. 1 abut is formed. The reinforcing bar holding surface (15) is composed of two plane portions arranged in parallel to the central axis F of the casing (3), and these plane portions intersect so as to form an obtuse angle. The length of the reinforcing bar holding surface (15) along the central axis F of the housing (3) is preferably at least several times the interval between the reinforcing bar nodes.

  The second extension part (13) of the first holding part (5) is arranged so as to face the first extension part (11), and the reinforcing bar holding screw (17) is connected to the second extension part (13). ) And screwed into the threaded hole formed in the first extending portion (11) so as to approach and separate from the reinforcing bar holding surface (15). The user arranges the reinforcing bar on the reinforcing bar holding surface (15) so as to protrude from the first holding part (5) toward the second holding part (7), and then rotates the reinforcing bar holding screw (17). The reinforcing bar is fixed to the first holding part (5) by being sandwiched between the tip of the reinforcing bar holding screw (17) and the reinforcing bar holding surface (15). The central axis of the reinforcing bar held by the first holding part (5) is parallel to the central axis F of the housing (3).

  The second holding part (7) comprises a first extending part (19), a second extending part (21) and a reinforcing bar holding screw (23) having the same shape as that of the first holding part (5). The rebar is held in the same manner as the first holding portion (5). A cylindrical member (25) disposed in parallel with the casing (3) is joined to the side surface of the second holding section (7) on the casing (3) side. A cylindrical first sliding member (27) that slides along the inner surface of the casing (3) is provided inside the casing (3), and the cylinder on the side wall of the casing (3) is provided. An opening (29) along the central axis F of the housing (3) is opened in the region on the member (25) side. A thick plate-like fitting member (31) extending toward the housing (3) is joined to the side surface of the cylindrical member (25) on the housing (3) side, and the first sliding member (27) The end of the side fitting member (31) is fitted in a groove (33) formed in the first sliding member (27). The fitting member (31) is slidable in the direction perpendicular to the central axis F of the housing (3) along the wall surface of the groove (33). Does not move relative to the first sliding member (27).

  A route interval adjustment knob (35) is rotatably provided at the end of the casing (3) on the second holding part (7) side. The route interval adjustment knob (35) is coupled to a shaft body (37) disposed inside the housing (3) along the central axis F of the housing (3). The shaft body (37) is rotatably supported inside the casing (3) so that the center axis thereof coincides with the center axis F of the casing (3), and the cylindrical first slide It penetrates the hole of the member (27). A thread portion is formed on the outer surface of the shaft body (37), and the shaft body (37) and the first sliding member (27) are screwed together.

  A thick plate-like screw support member (39) is joined to the side surface of the housing (3) so as to extend toward the cylindrical member (25). The screw support member (39) has a hole perpendicular to the thickness direction, and an axial position adjusting screw (41) is inserted into the hole. A flange is formed on the body portion of the shaft position adjusting screw (41), and the flange and the head of the shaft position adjusting screw (41) are arranged so as to sandwich the screw support member (39). The cylindrical member (25) has an opening (43) along the central axis of the cylindrical member (25) (central axis F of the casing (3)) on the side of the shaft position adjusting screw (41). Inside the cylindrical member (25), a columnar second sliding member (45) that can slide along the inner surface is disposed. The second sliding member (45) is provided with a screw hole (47) along the radial direction thereof, and the shaft position adjusting screw (41) passes through the opening (43) and passes through the second sliding member. It is screwed into the screw hole (47) of (45).

  Since the reinforcing bar support (1) has the above configuration, the gap between the reinforcing bar held by the first holding part (5) and the reinforcing bar held by the second holding part (7) And the center axis of these reinforcing bars, that is, the central axes of these reinforcing bars can be arranged on substantially the same line. When the route interval adjustment knob (35) is rotated in a predetermined direction, the shaft body (37) connected thereto rotates, and the first sliding member (27) screwed with the shaft body (37) is provided in the housing. It moves along the central axis F in (3). Accordingly, the fitting member (31), the cylindrical member (25), and the second holding portion (7) also move toward the first holding portion (5) along the central axis F of the housing (3). At this time, the rotation of the first sliding member (27) and the like with respect to the shaft body (37) is restricted by the second sliding member (45). When the route interval adjustment knob (35) is rotated in the reverse direction, the second holding part (7) moves away from the first holding part (5).

  For example, as shown in FIGS. 1 and 2, the second holding portion (7) is in a position where the first holding portion (5) is translated along the central axis F of the housing (3). The two flat portions of the reinforcing bar holding surface of the second holding portion (7) are arranged on the same plane as the two flat portions of the reinforcing bar holding surface (15) of the first holding portion (5). When the shaft position adjusting screw (41) is rotated in a predetermined direction, the shaft position adjusting screw (41) enters through the screw hole (47) of the second sliding member (45), so that the second sliding member (45) Approaches the screw support member (39). Along with this, the cylindrical member (25) and the second holding portion (7) connected thereto move upward. At this time, the first sliding member (27) rotates around the shaft body (37), and the fitting member (31) moves away from the first sliding member (27). When the shaft position adjusting screw (41) is rotated in the reverse direction, the second holding portion (7) moves downward.

  The reinforcing bar support (1) described above is an example of a reinforcing bar support used in the reinforcing bar butt welding method of the present invention, and has a groove root interval adjusting function and a reinforcing bar center axis adjusting function. Any support can be used in the present invention without any particular limitation. For example, a reinforcing bar support that can move the second holding portion (7) in two directions orthogonal to the central axis F of the housing (3) may be used. Further, in the above-mentioned reinforcing bar support (1), the fitting member (31) is completely fixed to the first sliding member (27), and the inner surfaces of the second sliding member (45) and the cylindrical member (25). A slight gap may be provided between the two. In this case, the second holding portion (7) moves around the central axis F of the housing (3) with the rotation of the route interval adjustment knob (35), but thereafter, the central axes of the reinforcing bars are aligned. So there is no problem.

FIG. 3A is a perspective view of a metal backing material 61 used in this embodiment, and FIG. 3B is a backing material viewed from the direction along the band width W1 ( It is a front view of 61). The backing material (61) has a substantially U-shape, a curved portion (63) curved in a semicircular arc shape, and a flat plate portion (65a) (65a) extending from both ends of the curved portion (63). 65b). The backing material (61) is produced, for example, by bending a strip-shaped steel plate having a width W1 using a steel material such as SS400 shown in JIS G 3101 "General structural rolled steel material".

  The size or shape of the backing material (61) is determined in accordance with the rebar having a larger size among the two rebars to be butt welded (different sizes). For example, when D16 to D41 are used as large size reinforcing bars, the curvature radius r of the inner surface of the curved portion (63) is 10 to 23 mm, and the height H of the backing material (61) is 17 to 38 mm. The band width W1 of the backing material (61) is 15 to 19 mm. Further, the thickness t of the backing material (61) is set to 4.5 to 6.0 mm. The value obtained by adding twice the thickness t to twice the radius of curvature r of the curved portion (63) is the lateral width W2 of the backing material (61). Note that. The route interval between the grooves is set to about 5 to 9 mm in accordance with the large size reinforcing bar (the route interval is basically increased when the reinforcing bar size increases), and the set route interval is A backing material (61) having a band width W1 value of about 6 mm to 12 mm is used (basically, the band width W1 is increased when the route interval is increased). It should be noted here that the band width W1 of the backing material (61) used in the present embodiment is considerably smaller than the width of the U-shaped backing material used conventionally. is there. The above numerical values are merely examples, and can be changed as long as the effects of the present invention are obtained.

  Next, the butt welding method of the reinforcing bar which is an Example of this invention is demonstrated in order of a process using figures. First, as shown in FIG. 4, one rebar (71) to be butt welded is fixed to the first holding portion (5) of the rebar supporter (1) as described above. The reinforcing bar (71) is fixed so that a portion on the groove side protrudes from the first holding part (5) toward the second holding part (7) of the reinforcing bar support (1). Next, as shown in FIG. 5, the other reinforcing bar (75) to be butt welded is fixed to the second holding portion (7) of the reinforcing bar support (1). The reinforcing bar (75) is fixed so that the groove side portion protrudes from the second holding part (7) toward the first holding part (5) side. The interval between the grooves of the two reinforcing bars (71) and (75) is made larger than the route interval to be set at this point. In addition, when the reinforcing bar support (1) has the above-described configuration, the central axes A and B of the two reinforcing bars (71) and (75) are shifted in parallel but parallel. However, it is not necessary for the butt welding of the reinforcing bars (71) and (75) that the central axes A and B of the two reinforcing bars (71) and (75) are strictly parallel, and the two reinforcing bars ( 71) It is sufficient that the central axes A and B of (75) are arranged substantially in parallel.

  In FIG. 5 and the drawings to be referred to hereinafter, a large size reinforcing bar (71) is fixed to the first holding part (5), and a small size reinforcing bar (75) is fixed to the second holding part (7). The state in which the ribs (73a), (73b), (77a), and (77b) are arranged vertically is shown. However, a small-sized reinforcing bar (75) may be fixed to the first holding part (5), and a large-sized reinforcing bar (71) may be fixed to the second holding part (7), and these holding parts (5) ( The positions of the reinforcing bars (71) and (75) fixed to 7) around the central axis are not limited (the illustrated reinforcing bars (71) and (75) are rotated around their central axes A and B by an arbitrary angle). May be) In FIG. 5, as shown in FIGS. 1 and 2, the second holding portion (7) is a position where the first holding portion (5) is translated along the central axis F of the housing (3). However, in the implementation of the present invention, the upper and lower positions (positions around the central axis F of the housing (3)) of the second holding portion (7) when the reinforcing bar (75) is fixed are not particularly limited.

  Next, the root cage (81) is inserted between the grooves of the two reinforcing bars (71) and (75) so that the second holding part (7) approaches the first holding part (5), that is, The route interval adjustment knob (35) of the reinforcing bar support (1) is rotated so that the groove of the reinforcing bar (75) approaches the groove of the reinforcing bar (71). The root cage (81) is a plate material having a thickness corresponding to the root interval to be set, and as shown in FIG. 6, the groove of the reinforcing bar (71) abuts on one surface of the root cage (81), The route interval adjusting knob (35) is rotated until the groove of the reinforcing bar (75) comes into contact with the other surface of the root cage (81) and the second holding portion (7) cannot be further moved. Thereby, the route interval between the grooves is set to a desired value. Thereafter, the root cage (81) is extracted from between the grooves.

  Next, as shown in FIG. 7, a step of aligning the central axes A and B of the two reinforcing bars (71) and (75) is performed. In this process, by rotating the shaft position adjusting screw (41) shown in FIGS. 1 and 2, the rebar (75) of the second holding part (7) is moved, and the rebar (71) (75) The central axes A and B are arranged on a substantially straight line. For example, a ruler (83) is used to align the central axes of the two reinforcing bars (71) and (75). The operator adjusts the position of the reinforcing bar (75) so that the central axes A and B of the reinforcing bars (71) and (75) are arranged on the same straight line within a predetermined error range.

  For example, when the reinforcing bars 71 and 75 are different in size by one size such that the reinforcing bars 71 and 75 to be welded are a combination of D13 and D16 or a combination of D35 and D38, these central axes A The center axes are aligned so that B and B match within an error range of about 1 mm. When the reinforcing bars (71) and (75) are different in two sizes, such as the combination of D19 and D25 and the combination of D35 and D41, the central axes A and B are matched within an error range of about 2 mm. Center axis alignment is performed. For example, in a state where the reinforcing bars (71), (75) are arranged as shown in FIG. 6, the groove of the reinforcing bars (71) is shown in FIG. 7 so that a predetermined scale is entered toward the central axis A side. Apply ruler (83) to. Thereafter, when the reinforcing bar (75) is moved until the side surface of the reinforcing bar (75) comes into contact with the end of the ruler (83), the center axis alignment of the reinforcing bars (71) and (75) is completed. Further, instead of the ruler (83), a gauge (85) as shown in the upper left of FIG. 7 may be used. The end of this cage (85) is formed in a stepped shape, the side of the small-sized reinforcing bar (75) abuts on the protruding part (85a), and the large-sized reinforcing bar (71) in the notched part (85b) By aligning the reinforcing bars (71) and (75) so that the side surfaces of the reinforcing bars are in contact with each other, the central axes A and B of the reinforcing bars (71) and (75) are arranged on the same line within a desired error range. The

  Next, as shown in FIG. 8, the substantially U-shaped backing material (61) shown in FIGS. 3 (a) and 3 (b) is tack welded to one of the reinforcing bars (71) and (75). . FIG. 9 is a plan view of the periphery of the groove from above in FIG. 8, and the tack welded portion (91) is indicated by a hatched area. In FIG. 9, the side surface of the large-sized reinforcing bar (71) and the inner surface of the backing material (61) are partially welded. The backing material (61) is disposed so as to surround the space between the grooves of the two reinforcing bars (71) and (75). The backing material (61) is in contact with the side surfaces of the two reinforcing bars (71) and (75) so that the bottom part is inclined from the large-sized reinforcing bar (71) toward the small-sized reinforcing bar (75). Yes. Further, as shown in FIG. 9, the width direction W2 of the backing material (61) is substantially perpendicular to the central axes A and B of the two reinforcing bars, and as shown in FIG. The backing material (61) is arranged so that the band width direction W1 of the backing material (61) is inclined with respect to the central axes A and B.

  In the present embodiment, for example, tack welding of the backing material (61) and main welding described later are performed using a semi-automatic carbon dioxide arc welding method. FIG. 8 shows a welding torch (87), a welding wire (89), and the like. The semi-automatic carbon dioxide arc welding method is well known and will not be described in detail. A welding method other than the semi-automatic carbon dioxide arc welding method may be used in the present invention.

  When the tack welding of the backing material (61) is completed, the main welding is performed, and a weld joint (93) is formed between the reinforcing bars (71) and (75) as shown in FIG. Here, the weld joint (93) means a joint structure constituted by a weld metal portion (95) filled between the grooves and the backing material (61). In this welding, the molten metal in which the welding wire (89) is melted is divided into several passes, and the space between the bottom of the backing material (61) and the groove, and the reinforcing bars (71) (75) The space between the materials (61) is filled. By cooling the filled molten metal, a weld metal portion (95) is formed, and the weld joint (93) is completed.

  In the present invention, the reinforcing bars (71) and (75) having different sizes are butt-welded so that their central axes A and B are arranged on substantially the same line. The steps of (71) and (75) become smaller on the upper side of the backing material (61). Therefore, on the upper side of the backing material (61), the weld metal portion (95) can be easily formed, that is, cured so as to be smoothly connected to the outer surfaces of the reinforcing bars (71) and (75). Further, as described above, in the present invention, a backing material (61) having a smaller width than that of the conventional method is used, and the backing material (61) is a groove of the reinforcing bars (71) (75). In the vicinity, they are in contact with the side surfaces of the reinforcing bars (71) and (75). This reduces the gap between the backing material (61) and the reinforcing bars (71), (75), and the weld metal part (95) filled between the backing material (61) and the reinforcing bars (71), (75). ) And the occurrence of defects at the interface between the backing material (61) and the reinforcing bars (71) and (75) is also suppressed.

  Next, an embodiment of the ultrasonic flaw detection inspection method of the present invention will be described. FIG. 11 shows a state in which an ultrasonic flaw detection inspection is performed on a welded joint (93) formed based on the above-described butt welding method for reinforcing bars. The transmitter probe (97) is placed on the lower rib (77a) of the small reinforcing bar (75), and the receiver probe (99) is placed on the upper rib (77b). ing. In the ultrasonic flaw detection method of this embodiment, oblique flaw detection is performed, and the probe (97) on the transmission side is inclined in a direction inclined by a predetermined angle (refractive angle) θ with respect to the radial direction of the reinforcing bar (75). Send ultrasound. The refraction angle θ is set to 70 degrees, for example. When hitting a defect existing in the welded joint (93), the ultrasonic wave is reflected and an echo (defect echo) is generated. As the probes (97) and (99), for example, the one described in Appendix 3 of JIS Z 3062, which is 5Z5 × 5A70, is used.

  The probe (97) on the transmission side is arranged on any one of a plurality of fixed positions set at a predetermined interval (for example, 10 mm) on the lower rib (77a). The probe (99) on the receiving side is a welded joint from a predetermined distance (for example, 2.5D to 3D (D is the size of the rebar (75))) from the groove of the rebar (75). It slides on the upper rib (77b) toward (93). The defect echo received by the probe (99) on the receiving side is converted into an electric signal, and the electric signal is amplified and attenuated by a receiving unit (not shown) and then displayed on a display (not shown). , Displayed as a waveform. When the receiving side probe (99) moves to the end of the reinforcing bar (75), the transmitting side probe (97) is moved to another fixed position, and the inspection is performed in the same manner. It is preferable to swing the probe (97) (99) during the flaw detection inspection, and in particular, to swing the probe (97) (99) as described in Patent Document 2. Is preferred. Even if the probes (97) and (99) are arranged on the rebar (71) of a large size, the ultrasonic flaw detection is performed in this way. The receiving side probe (99) may be arranged on the lower rib (77a), and the transmitting side probe (97) may be arranged on the upper rib (77b).

  FIG. 12 shows a state in which ultrasonic flaw inspection is performed when the reinforcing bars (71) and (75) shown in FIG. 11 are butt welded at positions rotated 90 degrees around the central axes A and B. . As can be understood by comparing FIG. 11 and FIG. 12 with FIG. 14, in the ultrasonic inspection method of the present invention, the receiving portions (105a) and (105b) such as the backing material (101) shown in FIG. The backer material (61) is not used, so it depends on the positional relationship between the backer material (61) and the ribs (73a) (73b) (77a) (77b) of the reinforcing bars (71) (75). Without connecting the transmitter probe (97) and the receiver probe (99) near the groove of the reinforcing bar (71) (75) and the welded metal part (95) of the welded joint (93). Can be placed. As a result, depending on the positional relationship between the backing material (61) and the ribs (73a), (73b), (77a), and (77b) of the reinforcing bars (71) and (75), for example, the defect C shown in FIG. In the present invention, a situation in which a defect near the edge of the groove surface is not detected and the ultrasonic flaw detection range is narrowed does not occur.

  The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. Moreover, each part structure of this invention is not restricted to the said Example, Of course, a various deformation | transformation is possible within the technical scope as described in a claim.

It is a perspective view which shows the reinforcing bar support used in the Example of the butt welding method of the reinforcing bar of this invention. FIG. 2 is a cross-sectional view of the reinforcing bar support broken along a vertical plane including the line I-I shown in FIG. 1. FIG. 3A is a perspective view of the backing material used in the embodiment of the present invention, and FIG. 3B is the same as seen from the direction along the band width w1 shown in FIG. It is a front view of a backing material. It is a front view explaining the process of the butt welding method of the reinforcing bar which is an Example of this invention. It is a front view explaining the process of the butt welding method of the reinforcing bar which is an Example of this invention. It is a front view explaining the process of the butt welding method of the reinforcing bar which is an Example of this invention. It is a front view explaining the process of the butt welding method of the reinforcing bar which is an Example of this invention. It is a front view explaining the process of the butt welding method of the reinforcing bar which is an Example of this invention. FIG. 9 is a plan view of the vicinity of the groove and the backing material of the reinforcing bar shown in FIG. 8. It is a front view explaining the process of the butt welding method of the reinforcing bar which is an Example of this invention. It is a front view which shows a mode that the ultrasonic flaw inspection method of this invention is performed in the state in which two rebars from which size differs were butt-welded using the butt welding method of the reinforcing bar which is an Example of this invention. . It is a front view which shows a mode that the ultrasonic flaw inspection method of this invention is performed in the state in which two rebars from which size differs were butt-welded using the butt welding method of the reinforcing bar which is an Example of this invention. . It is a perspective view which shows the backing material used for the conventional butt welding method. It is a front view which shows a mode that the ultrasonic flaw detection test method is performed in the state by which two rebars from which size differs were butt-welded using the backing material shown in FIG.

Explanation of symbols

(1) Rebar support
(61) Backing material
(71) Large size rebar
(73a) Ribs
(73b) Ribs
(75) Small size rebar
(77a) Ribs
(77b) Ribs
(93) Welded joint
(95) Weld metal part
(97) Probe
(99) Probe

Claims (8)

A method for flaw detection using ultrasonic waves of a welded joint formed between two rebars each having two linear ribs formed so as to face each other across the central axis Because
The central axes of the two reinforcing bars are arranged substantially on the same line,
The two rebars are butt welded using a metal belt-like backing material curved in a substantially U-shape,
The backing material surrounds the space between the grooves of the two reinforcing bars and the two reinforcing bars so that the bottom of the backing material is inclined from the large size reinforcing bar to the small size reinforcing bar. Is in contact with the side of
A transmitting probe is arranged on one rib of any one of the reinforcing bars, and a receiving probe is arranged on the other rib so that the transmitting probe has a predetermined refraction angle. A method of transmitting ultrasonic waves toward the weld joint.    The method according to claim 1, wherein the backing material is in contact with a side surface of the two reinforcing bars in the vicinity of a groove of the two reinforcing bars. Two linear ribs are formed on each other so as to face each other across the central axis, and two reinforcing bars of different sizes are used using a metal belt-like backing material curved in a substantially U shape A method of performing a flaw detection inspection using ultrasonic waves on a welded joint formed between the two rebars by butt welding,
A first step of arranging the two reinforcing bars so that the central axes of the two reinforcing bars are positioned substantially parallel and the distance between the grooves of the two reinforcing bars is a predetermined route interval;
A second step of aligning the central axes of the two reinforcing bars so that the central axes of the two reinforcing bars are located substantially on the same line;
The backing material surrounds the space between the two reinforcing bars, and the bottom of the backing material is inclined from the large size reinforcing bar toward the small size reinforcing bar. A third step in which the backing material is tack welded to either of the two reinforcing bars,
A fourth step of performing main welding between the grooves of the two reinforcing bars and forming the welded joint between the two reinforcing bars;
A transmitting probe is arranged on one rib of any one of the reinforcing bars, and a receiving probe is arranged on the other rib so that the transmitting probe has a predetermined refraction angle. And a fifth step of transmitting ultrasonic waves toward the weld joint .   The method according to claim 3, wherein, in the third step, the backing material is tack welded so as to abut the side surfaces of the two reinforcing bars in the vicinity of the groove of the two reinforcing bars. A method for flaw detection using ultrasonic waves of a welded joint formed between two rebars each having two linear ribs formed so as to face each other across the central axis Because
The central axes of the two reinforcing bars are arranged substantially on the same line,
The two reinforcing bars are butt welded using a backing material obtained by curving a strip-shaped steel plate into a substantially U shape,
The backing material encloses a space between the grooves of the two reinforcing bars, the lateral width direction of the backing material is substantially perpendicular to the central axis of the two reinforcing bars, and the width of the backing material Abuts against the side of the two reinforcing bars so that the direction is inclined with respect to the central axis of the two reinforcing bars;
A transmitting probe is arranged on one rib of any one of the reinforcing bars, and a receiving probe is arranged on the other rib so that the transmitting probe has a predetermined refraction angle. A method of transmitting ultrasonic waves toward the weld joint.   The method according to claim 5, wherein the backing material is in contact with a side surface of the two reinforcing bars in the vicinity of a groove of the two reinforcing bars. Two linear ribs are formed on each other so as to face each other across the central axis, and two reinforcing bars of different sizes are used using a metal belt-like backing material curved in a substantially U shape A method of performing a flaw detection inspection using ultrasonic waves on a welded joint formed between the two rebars by butt welding,
A first step of arranging the two reinforcing bars so that the central axes of the two reinforcing bars are positioned substantially parallel and the distance between the grooves of the two reinforcing bars is a predetermined route interval;
A second step of aligning the central axes of the two reinforcing bars so that the central axes of the two reinforcing bars are located substantially on the same line;
The backing material surrounds the space between the two reinforcing bars, and the lateral width direction of the backing material is substantially perpendicular to the central axis of the two reinforcing bars, and the width direction of the backing material The backing material is temporarily attached to one of the two reinforcing bars by bringing the backing material into contact with a side surface of the two reinforcing bars so that is inclined with respect to the central axis of the two reinforcing bars. A third step of welding;
A fourth step of performing main welding between the grooves of the two reinforcing bars and forming the welded joint between the two reinforcing bars;
A transmitting probe is arranged on one rib of any one of the reinforcing bars, and a receiving probe is arranged on the other rib so that the transmitting probe has a predetermined refraction angle. And a fifth step of transmitting ultrasonic waves toward the weld joint .   The method according to claim 7, wherein, in the third step, the backing material is tack welded so as to come into contact with a side surface of the two reinforcing bars in the vicinity of a groove of the two reinforcing bars.

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