Residual Stress Assessment of PWMT Butt Joint with 10mm HSLA S460G2+M Steel using HFMI/PIT FEA and XRD

Abstract

This research involves the assessment of the residual stress of HSLA S460G2+M steel on butt joints which were welded using manual GMAW and further treated with HFMI/PIT process. The assessment began by manually welding 3-pass butt joint specimens using GMAW with ER80S-N1 as filler wire and mixed shielding gas (80%Ar-20%CO2). The weld toe of the specimens was then treated using HFMI/PIT operating at a peening frequency of 90Hz and a pneumatic pressure of 6 bar. The residual stress on the surface of treated and untreated specimens were measured using the X-ray diffraction method. Following the measurements, a simulation was conducted using non-linear solver FEA software MSC Marc/Mentat. The HFMI/PIT treatment process was simulated using a quasi-dynamic model approach for the force of the hammering pin. A customized spring function applying a consistent force onto the surface of the weld joint was modelled with this method. The material behavior model used for the specimen was based on a simplified Hensel-Spittel model obtained from the material database software MatILDa. It is observed that the HFMI/PIT-treated specimens induces compressive residual stress on the weld toe that is beneficial for fatigue life and the simulation demonstrated good agreement with the actual process.