Residual Stress Simulations of Girth Welding in Subsea Pipelines

Abstract

Abstract-This research focuses on simulation of the dissimilar materials' welding, stainless steel and mild steel, using finite element and experiment to enhance the method and better understand the transient temperature profiles and the stress distribution in a cladded pipe. The microstructural come as fenestrated and the computer results show that the temperature distribution in the modelled pipe is a function of the thermal conductivity of each weld metal as well as the distance away from the heat source.Index Terms-Transient temperature response, dissimilar material joint, girth weld, microstructure I. INTRODUCTIONT is known that the welding of cylindrical objects is complex and poses a source of concern in manufacturing processes. There are several benefits of welding as a joining technology which includes cost effectiveness, flexibility in design, enhanced structural integrity, and composite weight reduction. However, thermal stresses are usually initiated on the weld and the base metal [1][2][3][4][5]. Poorly welded joints result in leakages, pipe failures and bursts, which lead to possible environmental hazards, loss of lives and properties. Welding of dissimilar materials is carried out in-house using Gas Metal Arc Weld (GMAW), and a finite element analysis (FEA) on pipe models having different clad thicknesses of 2mm and 12mm, respectively, and the temperature versus distance profile obtained. The 12mm cladded pipe results are discussed in this paper.The process of carrying out welding using an arc weld entails melting down the base metal and, in this research, it also involves melting down the clad metal. In the course of carrying out the welding, filler metals are also melted such that the solution formed by heating up all these materials and holding them at that range of temperature long enough permits the diffusion of constituents into the molten solution; this is followed by cooling down rapidly in order to maintain these constituents within the solution. The result of this procedure generates a metallurgical structure positioning insitu the material which supplies superior tensile strength. The bulk of the material immediately after the fusion zone (FZ), which has its characteristics altered by the weld, is termed Heat Affected Zone (HAZ). The volume of material within the HAZ undergoes considerable change which could be Manuscript

Experimental and Numerical Simulation of Girth Welded Joints of Dissimilar Metals in Clad Pipes

“…The Gaussian transformation principle states that a Gaussian flat surface has a Gaussian curvature at each and every point of the magnitude of zero (Kogo et al, 2017a). In other words, provided the dimensions are consistent, a plate can be transformed into a pipe and vice-versa.…”