Study on cracking characteristics on aging of super duplex stainless steel weld metal

Abstract

In the present study, we carried out a flux cored arc welding using a super duplex stainless steel as a filler metal and analysed the cause of cracking that occurred at the aging treatment for 30 min at 850°C. The stress concentration effect by the notch of the welding bead affected the hot cracking susceptibility, and the impact value of weldment was remarkably decreased due to the precipitation of secondary phases. In addition, the precipitation of σ of the adjacent area to the crack was measured to be higher by ∼12 wt-% than the non-adjacent area to the crack. As a result of analysis of fracture plane, it was embrittled by segregation of impurities or inclusions, which acted as a starting point of the crack, and the crack grew according to the widely distributed σ phase.

Keywords:

• Welding
• Precipitation
• Electron backscattering diffraction (EBSD)
• Super duplex stainless steel

Acknowledgement

The present research was financially supported by the Ministry of Education, Science Technology (MEST) and National Research Foundation of Korea (NRF) through the Human Resource Training Project for Regional Innovation.