Mechanical analysis under stress of GTAW-P robotic welded joints of Cr-Ni alloy steel

Abstract

The parameters of welding current (A), welding voltage (V), preheating (oC), frequency (Hz) and feed speed (mm/min) were evaluated on GTAW-P robotic welded joints in Cr-Ni alloy steel. experimental, which were characterized with uniaxial stress tests. The results showed that the best mechanical performance was observed with the combination of parameters of 200 A, preheating of 25 ° C, voltage of 12.7 V, frequency of 20 Hz, welding speed of 180 mm / min and average input heat of 0.523 kJ / mm, resulting in maximum tensile strength (Su) of 1283 MPa and resistance to fracture (Sf) of 1223 MPa and rupture in the base metal. While the critical junction of low performance was obtained with the combination of 200 A, 13.1V, 25 ° C, 20 Hz, 480 mm/min high and low Qnet of 0.202 kJ / mm, which resulted in Su of 191 MPa and Sf of 166 MPa was associated with the welding speed and the heat input, which led to the fracture of the weld bead.