The low carbon martensitic stainless AWS 410NiMo steel has in its chemical composition 13% chromium, 4% nickel, and 0.4% molybdenum (wt.%) and is used in turbine recovery, rotors, and high-pressure steam pump housings due to its resistance to impact at low temperatures, as well as to corrosion and cavitation. Those applications of the AWS 410NiMo steel frequently demand repair, which is performed by welding or cladding. Arc welding is a well-established technique for joining materials and presents several parameters that influence the mechanical performance of the weld bead. Although numerous welding processes exist, optimizing welding parameters for specific applications and materials is always challenging. The present work deals with a systematic study to verify the correlation between the pulsed fluxed core arc welding (FCAW) parameters, namely pulse current and frequency, welding speed, and contact tip work distance (CTWD), and the bead morphology, microstructure formation, residual stress, and hardness of the martensitic clad. The substrate used was the AISI 1020 steel, and the AWS 410NiMo steel was the filler metal for clad deposition. From the initial nine (9) samples, three (3) were selected for in-depth characterization. Lower heat input resulted in lower dilution, more elevated hardness, and lower compressive residual stresses. Therefore, the results highlight the need for selecting the proper heat input, even when using a pulsed FCAW procedure, to achieve the desired performance of the clad. In the present case, a higher heat input appears to be more advantageous owing to the lower convexity index, smooth hardness transition between fusion and heat-affected zones in addition to more elevated compressive stresses.

Effects of different inoculants on the microstructural characteristics of gray cast iron gg-25, hardness and useful life of tools

In the execution of the welding process, there are a large number of variables to be adjusted by the operator/welder to improve process stability. The quality of a welding process is closely linked to the stability which has been carried out. In this work, the coating welding process in pulsed direct current with Gas-Shielded Flux Cored Arc Welding (FCAW-G) was used, having as base metal SAE 1020 steel and addition metal, martensitic stainless steel 410NiMo with 1.2mm in diameter. Current and voltage data were analyzed to verify, using computational tools and the Vilarinho Regularity Index (IVcc), whether the performed process was. It was observed the effectiveness of the tools, used as a way of detecting the phenomena of voltage signal variation, which serve as indications of drop detachment. Five samples was extracted from the test, where the occurrence of voltage peaks was noted, indicating the occurrence of drop detachment in a stable manner, according to the result observed by the Vilarinho Regularity Index (IVcc).