Effect of Carbon Content and Other Variables on Yield Strength, Ductility and Creep Properties of Alloy 625

Abstract

Strength and ductility have been evaluated on various alloy 625 compositions, including carbon contents between 0.009 and 0.045 wt. % and iron contents between 1.1 and 4.2 wt. %. Grain size was between ASTM No 3 and 7. Aging treatments at 600, 700 and 800°C up to 1000 hrs duration cause an increase of yield strength, being accelerated when aging is carried out at 700°C but with highest tensile elongation after aging at 600°C. Accordingly accompanying loss of IS0 V-notch impact strength is least pronounced after aging at 600°C but more severe when the iron content is at 4.2 wt. % compared to lower iron alloyed material. The influence of carbon content on creep strength is the more pronounced the higher the temperature. If 10,000 and 30,000 hrs creep-rupture stress is considered, the influence of carbon is small at 650°C and more distinct at 850°C. In changing ASTM grain size No from 6 to 3 the 30,000 hrs creep-rupture stress is increasing by about 4 % at 650°C and by about 43 % at 850°C. If creep stress for 1 % strain at 750 and 850°C is considered, the influence of carbon is very strong at carbon contents up to about 0,025 wt. %, improving 30,000 hrs creep stress for 1 % strain at 850°C by about 700 % when carbon content is increased from 0.015 to 0.025 wt. %. Creep deformation may be supposed to improve with decreasing carbon content.

Temperature- and Time-Dependent Mechanical Behavior of Post-Treated IN625 Alloy Processed by Laser Powder Bed Fusion

“…In this study, for example, concentrations of Fe and C in the LPBF alloy were lower than in the wrought alloy. Note that according to the data of Heubner [42], elevated contents of Fe and C in IN625 negatively affect the creep behavior, especially at high temperatures.…”

Effect of Fe and C Contents on the Microstructure and High-Temperature Mechanical Properties of IN625 Alloy Processed by Laser Powder Bed Fusion

“…A significant number of fine carbide particles in Alloy 2 disrupted the accommodation mechanisms restricting the mobility of extrinsic dislocations along the grain boundaries [ 62 ]. As shown in [ 63 ], the negative impact of C on the high-temperature properties of IN625 can be avoided by lowering the carbon content to the 0.015–0.025 wt.% C range.…”

Optimization of the Mechanical and Corrosion Resistance of Alloy 625 through Aging Treatments

“…Its precipitation kinetics have not been investigated in depth in the literature [18,19]. The formation of intergranular carbides and intermetallic phases determines sensitization and the reduction in ductility and deformability [4,20,21]. In fact, intergranular chromium-and molybdenum-rich carbides deplete such alloying elements from their surroundings, resulting in a local reduction in the resistance to intergranular corrosion [1,2,3,4,9,15,20,21,22].…”