Investigation of the mechanical, microstructure and post weld heat treatment (PWHT) properties of the AISI 410S ferritic stainless steel joined using robotic laser beam and plasma arc welding methods

Although stainless steels were not called stainless steel, it was first noticed by French metallurgist Pierre Berthier in 1821. But, it was not possible to pass to practical production as the heat treatment was not enough. The main beginning of stainless steels was coincidentally discovered by British metallurgist Harry Brearly in 1913 as a result of his investigations to develop the rifle gun barrels. In the following years, stainless steels, which were introduced to the market, gained an important place in industry and today. In the following years, stainless steels were developed according to their types and qualities. In this thesis study, AISI 410S ferritic stainless steel sheets were joined with robotic laser beam and plasma arc welding method. Argon was used as shielding gas in the joints. The welding was performed without using filler metal on butt weld joint configuration at horizontal position in the ambient temperature. The jointing was carried out by using two different power and four different speeds with the robotic laser beam welding method. In addition, the jointing was carried out by using three different streams and two different speeds with plasma arc welding method. The mechanical properties of laser welded joints without heat treatment and after welding are determined by tensile, three point bending test and hardness measurements. The metallographic investigation was evaluated by an Optical microscope, Stereo- macroscope, Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Diffraction (XRD).