What are the composition and mechanical properties of INCONEL 625?

Certainly! Here's a comprehensive breakdown of the composition and mechanical properties of INCONEL 625 from six different aspects:

Composition:

1. Nickel (Ni): INCONEL 625 is a nickel-based alloy with a significant proportion of nickel, typically comprising around 58% to 71% of the alloy by weight. Nickel is the primary element providing the alloy with its outstanding corrosion resistance and high-temperature properties.

2. Chromium (Cr): Chromium content in INCONEL 625 typically ranges from 20% to 23%. Chromium enhances the alloy's resistance to oxidation and corrosion, especially in high-temperature environments, by forming a protective oxide layer on the surface.

3. Molybdenum (Mo): Molybdenum is present in INCONEL 625 at levels between 8% and 10%. Molybdenum contributes to the alloy's strength, particularly at elevated temperatures, and enhances its resistance to pitting and crevice corrosion.

4. Niobium (Nb) and Columbium (Cb): Niobium or columbium content in INCONEL 625 is typically around 3.15% to 4.15%. These elements contribute to the alloy's high-temperature strength, stability, and weldability.

5. Iron (Fe): Iron is present in INCONEL 625 at levels ranging from 5% to 9%. Iron acts as a strengthening element and helps control the alloy's phase stability and mechanical properties.

6. Other Elements: INCONEL 625 may contain smaller amounts of other alloying elements such as titanium (Ti), aluminum (Al), manganese (Mn), silicon (Si), sulfur (S), and carbon (C), which contribute to specific properties and characteristics of the alloy.

Mechanical Properties:

1. Tensile Strength: INCONEL 625 exhibits high tensile strength, typically ranging from 760 MPa to 930 MPa (110,000 psi to 135,000 psi), depending on the heat treatment condition and manufacturing process.

2. Yield Strength: The yield strength of INCONEL 625 is typically between 340 MPa and 760 MPa (49,000 psi to 110,000 psi), depending on factors such as temperature, strain rate, and processing history.

3. Elongation: INCONEL 625 offers good elongation properties, with elongation percentages typically ranging from 15% to 30% in the annealed condition.

4. Hardness: The hardness of INCONEL 625 varies depending on the heat treatment condition and manufacturing process. In the annealed condition, it typically exhibits a hardness of around 150 to 200 HB (Brinell hardness).

5. Fatigue Resistance: INCONEL 625 demonstrates excellent fatigue resistance, allowing it to withstand cyclic loading and repeated stress without experiencing premature failure or fatigue crack propagation.

6. Impact Resistance: INCONEL 625 exhibits good impact resistance, making it suitable for applications subject to sudden or dynamic loading conditions.

Understanding the composition and mechanical properties of INCONEL 625 is crucial for selecting the appropriate material for various high-performance applications, where corrosion resistance, high-temperature strength, and mechanical reliability are essential requirements.