Numerical analysis of the deformation behavior of 2205 duplex stainless steel TIG weld joint based on the microstructure and micro-mechanical properties

The microstructure-based finite element model is developed to investigate the microscale strain and macroscopic deformation response in different regions of the 2205 duplex stainless steel weld joint produced by tungsten inert gas welding. In this model, the microstructure images are obtained from the electron backscattered diffraction measurement. The strain-stress curves of constituent phases are calculated according to the instrumented indentation test. The microscopic strain distributions of weld metal zone, high-temperature heat affected zone, low-temperature heat affected zone and base metal are analyzed respectively with considering the microstructure morphology, phase proportion and stress-strain curves of the constituent phases. The calculated macroscopic stress-strain curve agrees well with the experimental result in the base metal. It is proved that the location and quantity of strain localization bands are mainly determined by the microstructure morphology. The simulated results show that there are a lot of strain localization bands occur in austenite phase especially in LT-HAZ and base metal. It is found that the high-temperature heat affected zone is strengthened obviously, followed by the weld metal zone.