Determination of welding residual stress distribution in API X65 pipeline using a modified magnetic Barkhausen noise method

A modified magnetic Barkhausen noise (MBN) method was applied to obtain the residual stress distribution in an API X65 pipeline weldment. Different weldment microstructures affected the magnetic response and yielded different MBN values. In order to reflect the microstructural variations in the heat-affected zone (HAZ), calibration samples were extracted from four different regions: weld metal, coarse-grained HAZ (CGHAZ), fine-grained HAZ (FGHAZ), and base metal. This approach yielded that compressive residual stresses existed in the CGHAZ contrary to the tensile results using the base-metal-based calibration method. Compared with the results from the mechanical saw-cutting method, it can be concluded that the data obtained with the HAZ-based calibration method were more reliable. (C) 2003 Elsevier Ltd. All rights reserved.