The Study Of Online Detection For Weld Seam Of ERW

Before cold-rolled sheet entering tinned unit, forward sheet and subsequent plate are needed to connect, in order to ensure the continuity of tin production process. It is welded by narrow gap resistance welding. The welds often break in the unit, causing the accident. Many reasons lead to fracture of welded joint, however, the quality of the weld itself is the main reason for fracture. So strict control of weld quality is needed to improve production efficiency.For electric resistance welding, this paper presents detection method on line. Surface and internal defects are tested and evaluated by eddy current technology. The principles of eddy current testing technology are studied in the paper. The researching of weld flaw is studied by eddy current testing and metallographic experiment. Tensile test is done to study relationship between eddy current signals and weld quality. The feasibility of the weld quality inspection is verified by simulating eddy current probe detecting weld defects case. Based on simulation results, the best frequency and lift-off is ascertained. In the electric resistance welding quality inspection and evaluation system, we exploit VB6.0software to achieve data collection, processing, storage, evaluation and so on. To determine the evaluation criteria by statistics, curve fitting method and fracture mechanics. Finally, in order to optimize the evaluation criteria and database, a large number of field data is analyzed and equipment operation is investigated.