Experimental Research of Welding Residual Stress of Butt Welded Joint of Thick Steel Plate

Abstract

The thickness of steel plates used in the structure has gradually increased to meet the load-bearing capacity requirements of long-span steel bridges. Thick steel plate welded by arc welding process will result in considerable welding residual stress with complex distribution. Large welding residual stress will significantly impact the performance of steel bridges. At present; residual welding stress of thick steel plates is not considered enough in bridge engineering; which could lead to potential dangers in safety. In this paper; a butt welded joint with a thickness of 80 mm was designed; the residual welding stress was measured by X-ray diffraction method; and the distribution of residual stress in the direction perpendicular to the weld seam and along the direction of the weld seam is analyzed; and the distribution pattern of welding residual stress in thick steel plate is systematically studied. It is found that in the area near the weld; the stress in the direction along the weld seam is more significant than that in the perpendicular direction; the peak stress in the direction perpendicular to the weld seam usually appears in the weld seam and the heat-affected zone; and the maximum value tends to appear close to the last weld bead on the surface; on the path perpendicular to the weld seam; the stress in the direction perpendicular to the weld seam is distributed in a “Π” shape; the stress in the direction along the weld seam is distributed in an “M” shape; and the stresses in the direction along and perpendicular to the weld seam are symmetrically distributed; however the axis of symmetry may appear anywhere in and around the weld seam. The results could serve as a reference for welding residual stress analysis and guide optimization design of steel bridges made of thick steel plates.