A comparative study on microstructure and properties of Inconel 52M overlays deposited by laser beam and GTA cladding

Abstract

The current study investigates the overlays deposited by laser beam (LB) and gas tungsten arc (GTA) cladding with Inconel 52M filler wire in nuclear power plants. The effects of the deposition methods on the cross section profile, microstructures, and mechanical properties of both overlays are studied using optical microscope, scanning electron microscope (SEM), tensile and impact test and microhardness measurements. Experimental results show that LB cladding with higher wire feed rate improves the deposition efficiency as compared with GTA cladding. The microstructure of the LB clads consists of cellular and columnar dendrites, and Nbrich spherical particles are precipitated in the interdendritic regions, while the equiaxed dendrites are dominant in the GTA clads. The microhardness of the GTA clads is 20-30 HV higher than that of the LB clads. Furthermore, the tensile strength, toughness, and elongation of the LB clads decrease in comparison to the GTA clads. The deep penetration of the LB clads resulting in a wave shape of each pass and high dilution does not benefit the mechanical properties as compared with the GTA clads.

The Effect of Heat Treatment on Fracture Behavior in ENiCrFe-7 Weld Overlay Cladding Materials

“…3 shows SEM image of the as-weld Alloy ENiCrFe-7 and the heat treatment one after 615℃/48h, it is found that Alloy ENiCrFe-7 consists of dendrite(No.1), interdendrite(No.2), spherical precipitates(No.3) in the dendrites and irregular precipitates(No.4) in the interdendrites. It is revealed from Table .3 that Nb content of interdendrites is higher than that of dendrite, it is caused by constitutional supercooling and the equilibrium partition coe cient K of Nb is less than 1 [21] , it is also found that the precipitates are (Al,Ti,O)-rich in the dendrite and (Nb,C)-rich in the interdendritic region simultaneously. There are not precipitates at the grain boundary of the as-weld alloy ENiCrFe-7, while heat treatment one after 48h have continuous precipitates along the grain boundary.…”

The Comparison of Cracking Susceptibility of IN52M and IN52MSS Overlay Welds

“…An alternative to applying a weld overlay onto the damaged components is performed instead of replacement [5]. IN52, 52M, and 152 alloys are widely used as the filler metals for the overlay-welding of different components to alleviate SCC damage in those dissimilar welds [6,7]. Induced compressive residual stress in the inner surface of the pipes is helpful to lower the SCC sensitivity after overlay-welding [8,9].…”