Application of Barkhausen noise to biaxial residual stress measurements in welded steel tubes

Abstract

The relationship between Barkhausen noise and biaxial stress was studied in mild steel specimens in as received and annealed conditions. In the as received condition the saturation stress of the Barkhausen noise was higher but the stress sensitivity was lower than in the annealed condition. In the as received condition the Barkhausen noise response was different in the rolling and transverse directions. In the annealed condition no difference was observed. The stress sensitivity was found to be independent of stress perpendicular to the magnetising direction in the annealed condition. In the as received condition the stress sensitivity depended on the perpendicular stress. The biaxially calibrated Barkhausen noise method was applied to residual stress measurements of welded steel tubes. The results were compared with X-ray diffraction and hole drilling results. In the axial direction of the tube all methods produced consistent results. In the hoop direction of the tube Barkhausen noise and X-ray diffraction provided similar results. They were different from those obtained with the hole drilling method.