SHIELDING GAS AND HEAT INPUT EFFECTS ON THE MECHANICAL AND METALLURGICAL CHARACTERIZATION OF GAS METAL ARC WELDING OF SUPER MARTENSITIC STAINLESS STEEL (12Cr5Ni2Mo) JOINTS

摘要

This paper deals with the effects of shielding gas mixtures (100% CO2, 100% Ar and 80 % Ar + 20% CO2) and heat input (3.00, 3.65 and 4.33 kJ/mm) on the mechanical and metallurgical characteristics of AISI 410 S (American Iron and Steel Institute) super martensitic stainless steel (SMSS) by gas metal arc welding (GMAW) process. AISI 410 S SMSS with 1.2mm diameter of a 410 filler wire was used in this study. A detailed microstructural analysis of the weld region as well as the mechanical properties (impact, microhardness and tensile tests at room temperature and 800 degrees C) was carried out. The tensile and impact fracture surfaces were further analyzed through scanning electron microscope (SEM). 100% Ar shielded welds have a higher amount of delta ferrite content and due to this fact the tensile strength of the joints is superior to the other two shielded welds.