| 摘要 |
PURPOSE:To improve the detection precision of a flaw by using such carrying rolls that a magnetic powder is not scraped off from an object to be examined when the object is carried from a magnetizing position to a flaw detecting position. CONSTITUTION:An object 5 to be examined of a square steel material fed by a carrying device is held with both sides stabilized by standard rolls 4a arranged in the incoming side and the outgoing side of a line. The object 5 to be examined is carried by a right-opened roll 4c after a magnetic powder 6R is coated on right upper and lower faces of the object to be examined in the first magnetizing zone. Since the magnetic powder 6R is not brought into contact with the roll 4c, the magnetic powder 6R is not scraped off. The object to be examined is supported by a double-opened roll 4b after a magnetic powder 6L is coated on opposite faces of the object 5 to be examined, and magnetic powders 6R and 6L are not scraped off therefore. The object to be examined is supported by a left-opened roll 4d after flaw discrimination of the right of the object 5 to be examined is completed in the first flaw detecting position, and the object 5 to be examined is so carried that only the magnetic powder 6L in the left is not scraped off, and flaw discrimination of the left is performed in the second flaw detecting position. Thus, the flaw detection precision is improved. |
