1.Minimum Tensile Strength of Inconel 625 at Room Temperature
The minimum tensile strength of Inconel 625 at ambient temperature (20–25℃) is specified as 860 MPa (125,000 psi) in accordance with international standards such as ASTM B446/B446M and ASME SB446. This high tensile strength is attributed to the alloy's unique chemical composition, including nickel-chromium matrix with molybdenum and niobium additions, which form stable intermetallic phases and prevent grain boundary sliding under tensile loads. It should be noted that this value applies to the standard solution-annealed delivery condition, and the tensile strength may vary slightly with different product forms (e.g., bars, plates, wires).
2.Elongation of Solution-Annealed Inconel 625
For Inconel 625 in the solution-annealed condition (heat treatment process: heating to 1010–1120℃, holding for a sufficient time to ensure uniform dissolution of precipitates, followed by rapid cooling), the minimum elongation is 30% based on a 50 mm (2 in) gauge length, as defined by ASTM B446/B446M. The high elongation reflects the alloy's excellent ductility, which allows it to undergo significant plastic deformation before fracture. This property is critical for manufacturing processes requiring forming operations, such as bending, forging, and welding. In practical tests, the elongation of solution-annealed Inconel 625 often exceeds the minimum requirement, typically ranging from 35% to 45% depending on the product thickness and heat treatment uniformity.
3.Hardness Range of Inconel 625 in Standard Delivery Condition
The standard delivery condition of Inconel 625 is solution-annealed, and its hardness range is specified by both Rockwell B (HRB) and Brinell (HBW) scales:
Rockwell B hardness: 95–135 HRB
Brinell hardness (3000 kgf load, 10 mm ball): 200–250 HBW
This hardness range is consistent with standards like ASTM E18 (Rockwell hardness testing) and ASTM E10 (Brinell hardness testing). The relatively low hardness in the solution-annealed state ensures good machinability and formability, while the underlying alloying elements still maintain sufficient strength for industrial applications. It is important to note that post-delivery heat treatment (e.g., aging) can increase the hardness of Inconel 625, but such treatments are not part of the standard delivery specification.
