Joining of duplex stainless steel (DSS) and low carbon steel (LCS) was performed using gas tungsten arc welding (GTAW) with aid of argon as a shielding gas. Sample was welded using ER308L weld wire to produce joined material. Physical and mechanical properties of the heat effect zone and the welded joint were investigated using optical microscope (OP), scanning electron microscope (SEM), Electron dispersive spectroscopy (EDS), hardness test and ultimate tensile test (UTS). SEM at the both sides of HAZ revealed difference in morphological changes at DSS HAZ and LCS HAZ with a precipitation of martensitic phase and chromium carbide respectively which are suspected to be responsible variation in mechanical properties at this region. UTS conducted also shows a plastic deformation mode of failure at the DSS HAZ while failure occurred at the HAZ of LCS indicating brittle property at this point. Redistribution and migration of manganese from DSS to LCS during welding from EDS is also suspected to be the reason for brittle property of HAZ of LCS. © 2018 Author(s).