Inconel Alloy 625 Grade 1 VS Grade 2
What is the ASME specification for Inconel 625 alloy?
Inconel 625 alloy, numbered UNS N06625, has a nominal composition of 60Ni-22Cr-9Mo-3.5Cb.
What is the difference between Inconel Alloy 625 Grade 1 and Grade 2?
Inconel Alloy 625 Grade 2 material is supplied in the solution annealed condition. The primary difference between Grade 2 and Grade 1 is the annealing temperature. The minimum annealing temperature for Grade 1 is 1600°F (871°C), while the minimum annealing temperature for Grade 2 is 2000°F (1093°C).
Is UNS N06625 alloy difficult to machine?
Machining Inconel 625 alloy is a challenging task because of its low thermal conductivity, rapid work hardening, and ability to maintain strength even at high temperatures. This high-temperature alloy is widely used in the aerospace, oil and gas industries due to its excellent corrosion and heat resistance.
Is Inconel 625 alloy magnetic?
Inconel 625 alloy is a non-magnetic, corrosion-resistant and oxidation-resistant nickel-chromium alloy. The high strength of Inconel 625 alloy comes from its strengthening combination of molybdenum and niobium added to the nickel-chromium matrix.
What is the difference between Inconel Alloy 625 Grade 1 and Grade 2?
Understand the Difference Between 625 Alloy Grade 1 and Grade 2
625 Alloy Grade 1 is solution annealed to provide excellent resistance to oxidation and corrosion in a wide range of environments. It is widely used in applications that require flexibility, strength, and corrosion resistance at elevated temperatures up to 1100°F (approximately 577°C).
In contrast, 625 Alloy Grade 2 is solution annealed at elevated temperatures to enhance creep and stress rupture resistance, making it suitable for high pressure and high stress applications where durability is critical. The main differences between the two steel grades are as follows:
Heat Treatment:
Grade 1 steel is typically annealed at temperatures between 1600°F and 1800°F (approximately 871°C and 982°C) to provide good ductility and corrosion resistance while maintaining higher strength than Grade 2 steel.
Grade 2 steel is heat treated above 2000°F (about 1093°C) to enhance creep and stress rupture resistance while maintaining corrosion resistance.
Mechanical Properties:Per ASTM B444, ASME SB444, AMS 5581
| Condition | Tensile Strength | Yield Strength | Elongation |
| minimum, ksi | minimum, ksi | minimum, % | |
| Grade 1 | 120 | 60 | 30 |
| Grade 2 | 100 | 40 | 30 |
Applications:
Grade 1 is typically used in marine, oil and gas, aerospace, and chemical processing applications.
Grade 2 is suitable for hydrogen production and hydrogen dissociation catalyst tubes where high temperature performance and corrosion resistance are critical.
Conclusion
625 Grade 2 alloy is a high-performance material used in a wide range of industries with stringent requirements for high-temperature strength, corrosion resistance, and durability. Its ability to withstand extreme temperatures, resist hydrogen embrittlement, and operate reliably in corrosive environments makes it a top choice for applications such as hydrogen dissociator catalyst tubes, power generation, and chemical processing. With these properties, 625 Grade 2 alloy will continue to play a key role in technological advancements in high-demand industries.
