Fig. 3 Map of microhardness distribution along the transverse cross-section of BM and welding joint.
The tensile properties of BM, AS-HAZ and WNZ were tested and shown in Fig. 4, the results were consistent with hardness arrangement. BM showed the maximum yield strength (YS: 515 MPa), ultimate tensile strength (UTS: 593 MPa), while the YS and UTS in the softening position of AS-HAZ were the lowest, decreasing to 262 MPa, 415 MPa respectively. In contrast, WNZ processed the best elongation to failure and the strength was lower than BM but much higher than AS-HAZ.