This paper shows results for the evaluation of ASTM A36 carbon steel welded joints by Magnetic Barkhausen Noise (MBN). V-groove shape welded samples were made in a 6 mm thickness plates, with one-pass and two-pass. Microstructural and microhardness characterization were made on a transversal section of welds. In the surface was made measurement of MBN. The signal of MBN were analyzed with the maximum value, threshold of 80% above of maximum, the root mean square (rms), the root mean square of the profile, and these parameters were plotted in function of the distance to center bead. Surface maps were obtained, too. The microstructural characterization identified different heat affected zone (HAZ) sizes for one-pass and two-pass. In addition, changes on microhardness showed which higger hardness was happened in the fusion boundary whereas lower microhardness happened in the HAZ end. With MBN monitoring were verified that the lower value happened in the fusion boundary, whereas the MBN higher value happened in the HAZ end. The study showed that changes in the microstructure influence all analyzed parameters. The welded joint are best represented by the root mean square (rms), the root mean square of the profile.
Magnetic Barkhausen Noise (MBN); Carbon Steel Welding; Magnetic Non-destructive Testing
