Improving welded valve quality by vibratory weld conditioning

The aim of this study was to investigate the application of vibration during submerged arc multi-pass welding to improve the quality of full welded valve. Cylinders of different thickness were used. The residual deformation and stress due to each pass of welding have been reduced significantly in vibratory weld conditioning (VWC). Variations in tensile, side bend and Charpy V-notch impact properties have been documented. Though the bend property was improved obviously by adoption of vibration, the yield strength and tensile strength of the welded joint did not changed distinctively in VWC when compared with normal welding. The results indicate that effects of vibration on impact property mechanics is complex. The enhancement of the impact property was observed in the weld metal (WM), but not in the heat-affected zone (HAZ). The results were evaluated in terms of the weld microstructure variation. The possible solidification behaviour in VWC is discussed. (C) 2007 Elsevier B.V. All rights reserved.