Laser welding of dissimilar materials

Abstract

Abstract This study addresses to the laser welding with active flux (SiO2 + Poly (vinyl alcohol)) for improving the geometrical profile and microstructure of the dissimilar carbon steel – stainless steel joints. The experimental tests were carried out using a TRUMPH 556 pulsed laser and a Precitec YW50 welding head manipulated by a robotic arm. AISI 321 and S235 plates with the dimensions of 50X100X0.5 mm were used as welding specimens. Several fusion lines were made in order to determine the optimal SiO2 / Poly mixing ratio and to highlight the influence of the SiO2 flux on the microstructure. Addition of the active flux results in a more stable welding process and with less plasma plume and a narrower weld bead profile. The samples have been analyzed by optical and electron microscopy showing that SiO2 addition lead to formation of mixed morphology of lathy and skeletal ferrite in the weld zone.