APPARATUS AND METHOD FOR ON-LINE DETECTING WELDING PART OF STRIP SHEET

摘要

An apparatus and a method for an on-line detecting welding part of a strip sheet are provided to detect a laser-welded portion without making a hole and to stabilize the location tracking of the welded portion of a production line by maximizing the detected rate of the laser-welded portion. An apparatus and a method for an on-line detecting welding part of a strip sheet comprises: a plurality of unit detection devices(10) arranged in a row in a width direction of a steel sheet(1) which is being transferred; and a signal processing device(11) calculating the correlation between the detected signal waveforms. The unit detection device irradiates minute linear laser beam of fixed length on the surface of each steel sheet and detects the signal waveform to the laser beam reflected on the surface of the steel sheet. The signal processing device detects a welded part(2) of the steel sheet in case the calculated correlation value is over threshold level which is set up in advance. The unit detection device irradiates the minute linear laser line spot on the steel sheet. The minute linear laser line spot is smaller than the width of the strip welding part.