Evaluating mechanical properties of duplex stainless steel with flux core arc welding: a comparison of welding modes

ABSTRACT

This study investigates the mechanical properties of Flux Core Arc Welded (FCAW) Duplex Stainless Steel (DSS) under various welding modes: Constant Current (CC), Pulsed Current (PC), and Surface Tension Transfer (STT). Results indicate that the STT mode of FCAW delivers optimal mechanical properties, with yield strengths ranging from 711 MPa to 743 MPa and ultimate strengths from 758 MPa to 842 MPa. In comparison, CC mode yielded slightly lower results with yield strengths of 766 MPa to 781 MPa and ultimate strengths of 890 MPa to 901 MPa, while PC mode showed intermediate values. Impact strength analysis across CC, PC, and STT modes reveals that STT welds absorb the highest energy, ranging from 47 J to 48 J in the weld metal and 50 J to 74 J in the HAZ, compared to CC (20 J to 28 J) and PC (24 J to 38 J) modes. Fractographic analysis using Scanning Electron Microscopy (SEM) confirms uniform surface properties and minimal defects in STT mode welds, indicating improved weld integrity. Vickers hardness testing demonstrates higher values in the Heat Affected Zone (HAZ) near the weldment for STT mode (up to 300.27 HV), suggesting superior strength characteristics.

Keywords:
Flux Core Arc Welding; Duplex Stainless Steels; Welding Modes; Mechanical Characterization