| 摘要 |
PROBLEM TO BE SOLVED: To detect flaws in a wide range by arranging bar steel ribs that nodes with a specified height are protruded at an angle crossing with the ribs, in four or more even number of ribs scattered at a certain angle from the sectional center of the bar steel and arranging them in symmetrical positions. SOLUTION: Four or more even number of ribs 2 are arranged and disposed in scattered symmetrical positions at an equal angle from the sectional center of a bar steel 1. Four ribs 2 are used for instance and disposed at symmetrical positions of 90 degrees from the sectional center of the bar steel 1. Or six ribs 2 are used for instance and disposed at symmetrical positions of 60 degrees from tune sectional center or the bar steer 1. When the ribs 2 are four, a flaw detector for transmission and a flaw detector for receiving are arranged in a pair of ribs 2 arranged at the symmetrical positions and scanned to obtain two pairs of detection results of flaws. Accordingly, the flow-detectable range is widened and further, if the extended lines of both side ribs 2 of the bar steel do not coincide with each other when it is welded with pressure, the flow-detectable range is widened from bar steels of both sides pressure-welded. In this way, flaws near the central part imparting an influence to the strength of the pressure-welding joint can be securely detected and hence, the reliability of the pressure-welding joint can be increased. |
