Analytical Studies on Shrinkage Stress Distribution In GMA And Pulse Current GMA Welds Of Thick Wall Stainless Steel Pipe Having Narrow And V-Groove Design

Abstract

Analytical studies on mode, magnitude and distribution of shrinkage stress in eight quadrants of a thick wall stainless steel pipe weld have been carried out. The studies have been conducted on GMA and pulse current GMA welds prepared by using conventional-V and narrow weld groove designs at different welding parameters. The effects of ail such variables on the said aspects of transverse shrinkage stress have been analysed. During welding, different quadrants of pipe are found to experience shrinkage stresses of non uniform mode and magnitude and they further varies as a function of welding process, procedure and parameter. Use of P-GMAW comparatively lowers and results better uniformity in transverse shrinkage stress distribution at different quadrants of the pipe weld than that observed in case of using GMAW. Keeping higher heat input and the pulse parameter giving larger value of their summarised influence defined a well known factor 0 results higher shrinkage stress. The dimensionless factor is defined as.  ϕ = [(I_I, / I_I,) f. t_h]. At a given heat input the narrow groove weld joint gives comparatively less transverse shrinkage stress. X-ray radiography of defect analysis reveals that the quadrants having compressive mode of stress gives rise to more lack of fusion at groove wall.