Eddy Current Inspection And Defect Classification Of Welded Joints Of A5083 Aluminum Alloys

The base metal and joints of A5083 aluminum alloys have a wide range of applications in industries. Multi-pass metal-inertia-gas welding was used for realizing the joints of base metal, and the defects were inevitable. The laws of defect signal were researched via multi-frequency eddy current inspection. In order to quantify quality level of joints, the standard BS 7910-2005 was utilized to acquire the process of evaluating. Data base obtained through the former manner might benefit for design of welding joints.Multi-frequency eddy current inspection was employed for detecting the defect having various orientation and depth in welding joints with different types, surfaces condition in the article. Then more attention was paid for exploring the morphological characteristics and the laws of amplitude of defect signals in detail. In addition, the welding joints with cracks or pores were manufactured by means of reasonable approach. Then the quality level of joints was assessed.The surface defect signals had conspicuous impeller, but not obvious near surface. The latter defect signals containing significant irregularity were recognized for the machining accuracy of embedded flaws for joints with different types or various surface condition.Local defect signals tangled in the weld of lapping or angle joint, and the phenomenon did not occur in butt joints. Amplitude of long direction defect signals concentrated and a large difference in transverse direction except in sectional material of butt joints. The amplitude of signals was increasing with the increasing depth. The amplitude of embedded defect signals was larger than the surface defect signals in transverse direction. The amplitude of signals was largest in butt joints besides embedded defect in transverse directions for various types of joints. Obvious discrepancy existed between the butt joints and the lapping or angle joints.Having different surface condition, the amplitude of defect signals with polishing was greater than the original condition in transverse direction, and the opposite laws in long direction. The quality level of weld of standard plate, plate containing cracks, and plate containing pores were Q2, Q2, Q3, respectively.