Effects of High Frequency Mechanical Impact on Fatigue Life of Semi-Automated Gas Metal Arc Welding (GTAW) of HSLA Butt Weld

Abstract

This paper deals with a comprehensive investigation of fatigue life enhancement on semiautomated Gas Metal Arc Welding (GTAW) butt weld joint which is found almost everywhere in Malaysia welding structure steel sectors. The selected material in this study was high strength low alloy steel S460G2+M commonly used extremely in steel structure due to its outstanding mechanical properties. In this investigation, the method for joining the butt weld was conducted by unprofessional welder using semi-automated GMAW. At first, suitable welding parameters were identified and formulated into welding procedure specification (WPS) qualification conforming to AWS D1.1 standard. The test specimens were prepared and tested to ensure the welding quality. Further, the HFMI using Pneumatic Impact Treatment (PIT) technique were applied at the weld toe of the butt weld as tool for fatigue life enhancement. To investigate the influence of HFMI/PIT on the fatigue strength, the specimens were undergone fatigue test using universal fatigue machine using a constant amplitude loading. Finally, the comparison of the fatigue strength of as welded and treated specimens to indicate the beneficial influence of the treatment. Yes, the conduction by unprofessional welder using semi-automatic GMAW, the findings showed the improvement of fatigue strength and slope of S-N curves. In addition, the fracture location of test specimen shows physically affected by shifting from critical weld transition to base metal. The tensile test and hardness value also showed a slight difference as compared to untreated specimens.

Corrosion surface morphology‐based methodology for fatigue assessment of offshore welded structures

“…The fatigue capacity of structural steels in offshore applications is affected by various parameters, each of which can influence the quality and the mechanical properties. Although there are many reports on fatigue testing on structural steels, this review covers a representative number of studies 18–47 focusing on S355 butt‐welded structural steels. These structural steels have been tested using a variety of test setups, loading conditions, welding types, and other postprocessing variables.…”

“…In addition to the reviewed literature, 18–47 S‐N data from the design code standards BS7606, 50 DNVGL‐RP‐C203, 51 BS‐EN1993‐1‐9, 52 and IIW recommendations 53 were also considered. The codes provided S‐N curve values in both air and corrosive conditions in artificial seawater (ASW) and salt spray chambers (SSC).…”