FABRICATION OF SURFACE FLAW MAP OF ROUND STEEL BAR

摘要

PURPOSE:To fabricate the surface flaw map of a round steel bar with high accuracy by eliminating positional shift, by a method wherein an origin mark is scribed on the round steel bar and the origin is read at every rotation to perform the zero clearing of a rotary signal and combined with the position signal in the longitudinal direction. CONSTITUTION:A round steel bar 1 is rotated by a turing roller 3 and the origin mark applied to the end part of the round steel bar 1 is read by a detector 11. The signal of a pulse generator 15 is subjected to the clearing of a zero point at every one rotation by a rotary origin signal 16 to be inputted to a map fabrication signal apparatus 21 as a round steel bar rotary signal. The position signal in the longitudinal direction is inputted to a flaw detection probe 5 to detect a flaw and the position of the flaw in the longitudinal direction is detected by a position detector 19 while the signals of the flaw and the position are inputted to the apparatus 21 to fabricate a map. Because the origin mark is scribed on the round steel bar and the rotation signal is subjected to zero clearing at every rotation, the surface flaw is detected in a sectioned region with good accuracy and the map can be fabricted with high accuracy.