| 摘要 |
PROBLEM TO BE SOLVED: To provide a butt welding method of reinforcing bars with which probes can approach a welded joint in ultrasonic flaw detection inspection without being affected by a positional relation between the reinforcing bars and a backing material. SOLUTION: Two reinforcing bars 71, 75 having different sizes are butt welded by using the backing material 61 formed by curving a belt-like steel sheet to an approximately U shape. First, the adjustment is so performed that central axes A and B of the reinforcing bars 71, 75 are positioned in parallel and the distance between the grooves of the reinforcing bars 71, 75 becomes the prescribed root gap. Next, the adjustment is so performed that the central axes A and B of the reinforcing bars 71, 75 are positioned nearly on the same line. The backing material 61 is tack welded. The backing material 61 surrounds the space between the grooves of the reinforcing bars 71, 75 and abuts on the side faces of the reinforcing bars 71, 75 in such a manner that its bottom part inclines from the large-sized reinforcing bar 71 toward the small-sized reinforcing bar 75. Then, the grooves of the reinforcing bars 71, 75 are subjected to regular welding and the welded joint 93 is formed between the reinforcing bars 71, 75. COPYRIGHT: (C)2008,JPO&INPIT
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