Study on the microstructure influence in ultrasonic test in duplex forged components

Abstract

Ultrasonic tests are fundamental to grant the integrity of the metal products, especially after forging
operations. Due to the high attenuation of duplex stainless steel (DSS), the efficiency of ultrasonic test (UT)
performed on DSS components could decrease and make the inspection difficult.
The interaction between the ultrasonic acoustic radiation and the microstructure of 2205 duplex stainless
steel was studied. The specimens were treated at 780 °C for different soacking times to promote the
precipitation of intermetallic phases. The UT response of each specimen was measured and associated to the
corresponding microstructural features.
Electron Back Scatter Diffraction (EBSD) was performed to analyze the grains orientation and to relate the
revealed crystallographic texture with the acoustic signal attenuation.
Tensile test were performed to determine the variation of the main mechanical parameters (yield strength,
ultimate tensile strength, elongation and Young modulus) induced by the presence of the secondary phases.
The variation of ultrasound velocity can be associated to the modification of the volume fraction of the
precipitated intermetallic phases (sigma (s) and chi (?) phases) and to the morphology of the structural
constituents observed within the material.