| In order to ensure the continuity of production process of cold rolling steel plate, the forward sheet and subsequent sheet are needed to connect. Because of welding parameters is not accurate, the welding process is faulty or substrate sheet is flawed, weld seam may exist flaw. The welds often break occurs in the unit, affect the production efficiency and causing the accident. So a kind of method to test and evaluate the weld quality is needed to improve production efficiency.For resistance welding seam of sheet steel, this paper presents a kind of method to test and evaluate the weld quality. Base on this, it could test and evaluate the internal defect and surface defect of weld seam by eddy-current testing. The author has built a set of equipment base on the theory of eddy-current testing to test the eddy current signal and mechanics performance of the weld sample. The experimental results have proved there exist a correspondence relationship between the weld defects and eddy current inspection signal, and have obtained the best frequency and lift-off.And then, based on the united simulation of COMSOL Multiphysics and MATLAB, the author has established the model that consistent with the actual production, and tested by experiments. According to the results of batch computing and analysis, the author has summed up the relationship between the weld defects and eddy current inspection signal. The evaluation criterion of eddy-current testing has been formulated based on working conditions and the results of experimental and simulate.Finally, the author design the data processing flow, build equipment of eddy current testing evaluation system, written the operation software based on VB for realize on-line detection. Detection qualified rate of this equipment meet the production requirements, and it reduced the rate of broken. |
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