Microstructural effects on the fretting wear of Inconel 690 steam generator tube

Structure, Microsegregation, and Precipitates of an Alloy 690 ESR Ingot in Industrial Scale

“…[1][2][3] Alloy 690 exhibits austenitic matrix with carbides and nitrides or carbon nitrides. [3][4][5] The microstructure, especially the carbides of the Alloy 690 in various heat treatment conditions, have drawn much attention and been extensively studied. Carbon tends to segregate to the grain boundaries [3] and the precipitation of carbides is attributed to the carbon super-saturation.…”

“…[4] It has also been reported that titanium nitrides are the preferential sites for pit initiation, [10,11] and Dutta et al attributed this to the large degree of misfit between nitrides and the austenitic matrix. [12] Besides, the corrosion behavior, [13][14][15][16][17][18] mechanical properties, [5,10,[19][20][21][22][23][24] and workability [25,26] of deformed Alloy 690 have also been investigated.…”

Effect of carbide size and spacing on the fretting wear behavior of Inconel 690 SG tube mated with SUS 409

“…However, at the operation temperature as low as 320°C, carbide coarsening could possibly occur due to long operation times ranging from years to tens of years. These changes in carbide size and spacing could affect fretting wear resistance [5] as well as stress corrosion cracking (SCC) [4,6].…”

“…Inconel 690 has good resistance to SCC because of its proper carbide size and spacing, which promote crack tip blunting and decrease the stress concentration at the crack tip [4][5][6], as well as its high concentration of Cr. However, despite the appropriate carbide size and spacing of Inconel 690, further coarsening of carbide decreases its resistance to SCC, because closely distributed small carbide is more beneficial for crack tip blunting [4].…”

“…Wear resistance of Inconel 690 increases with increasing carbide volume fraction [5]. However, the effect of size and spacing of intergranular carbide on the wear behavior of Inconel 690 has not yet been studied.…”