Corrosion resistance of thermal-pulsed Inconel 625 MIG/MAG weld overlays

Abstract

The deposition of Inconel 625 can be performed by MIG/MAG (Metal Inert Gas/Metal Active Gas) welding process. Despite resulting in larger dilution than other welding methods, MIG/MAG has the advantage of a high production capacity. The present work aimed to study the use of a variant of the MIG/MAG process known as MIG/MAG Double Pulse (MIG/MAG-DP), where the variation of the welding current in the form of pulses can alter the microstructure of the deposits. The effects on corrosion resistance of the macrogeometry and microstrucure of Inconel 625 weld overlays onto low carbon steel substrates were evaluated via cyclic potentiodynamic polarization corrosion tests under two test temperatures (25 °C and 60 °C). The results showed that the MIG/MAG-DP process produced weld overlays with higher dilution (almost twice of that observed for conventional MIG/ MAG). Moreover, MIG/MAG-DP resulted in more refined microstructure; the spacing between the dendritic secondary arms was around 49% smaller than for conventional MIG/MAG. This had a negative impact on the corrosion resistance of the deposits at both temperatures and increased the susceptibility of the deposits to crevice corrosion. Therefore, the use of MIG/MAG-DP, although often a positive strategy in welding operations, is not a good route for depositing high corrosion resistance deposits.

WITHDRAWN: A Contribution to the Analysis of the Effects of Pulsed Current in GTAW Welding

“…The successful achievement of a microstructure with a grain growth break can only be obtained if the welding procedure variables result in a thermal cycle in the workpiece that effectively allows for cooling of the pool during the base current phase [12,13]. If there is no compatibility between the process variables and cooling conditions, the microstructure resulting from pulsed current may not be distinct from that obtained in constant current.…”

A Contribution to the Analysis of the Effects of Pulsed Current in GTAW Welding of 1-mm-Thick AISI 304 Sheets

“…This result indicates that the application of pulsed current is tending to worsen the geometric shape Thus, it is verified that the desired effect of thermal pulsation in GTAW welding is not always achieved. The successful achievement of a microstructure with a grain growth break can only be obtained if the welding procedure variables result in a thermal cycle in the workpiece that effectively allows for cooling of the pool during the base current phase [30,31]. If there is no compatibility between the process variables and cooling conditions, the microstructure resulting from pulsed current may not be distinct from that obtained in constant current.…”

Brazilian Tribology: origin, status quo and future perspectives

“…Activities related to tribology and surface engineering at the Federal University of Rio Grande -FURG started in 2016 when Prof. Henara Costa moved from LTM/ UFU to FURG, culminating with the creation of the Laboratory of Surface Engineering (LabSurf) in 2019. The works span from surface engineering techniques such as surface modifications [113,280,[320][321][322][323][324][325][326][327][328][329][330][331][332] and different coating technologies [112,113,[333][334][335] to their effects on surface topography [102,103,121,326,[336][337][338], surface hardness [339][340][341], machinability [2], formability [337,342,343], corrosion [335,[344][345][346], tribological performance [13, 50-52, 113,280,320,322,333,337,347,348] and tribo...…”

“…Different coating technologies, including electrodeposited coatings [13], plasma spray and hardfacings [334,335,345,346,349], have been developed at Lab-Surf/FURG. Surface modification technologies have mainly focused on changing microstructure [340,341] and surface topography [90-93, 95, 110, 113, 320, 322-324, 326] to achieve surface functionality.…”