1. Question: What is the chemical composition of Inconel 825?
Answer: Inconel 825 is a nickel-iron-chromium alloy with additional elements to enhance corrosion resistance. Its typical composition includes:
Ni: 38–46%
Fe: 38% maximum
Cr: 19.5–23.5%
Mo: 2.5–3.5%
Cu: 1.5–3%
Minor amounts of C, Mn, Si, Ti, and Al
This combination provides exceptional resistance to oxidation, acids, and seawater corrosion.
2. Question: What are the main applications of Alloy 825 plates and sheets?
Answer: Alloy 825 is widely used in industries requiring high corrosion resistance, such as:
Chemical processing equipment (reactors, heat exchangers, tanks)
Acidic environments, including sulfuric, hydrochloric, and phosphoric acids
Oil and gas pipelines, particularly in offshore environments
Marine engineering and desalination plants
Flue gas desulfurization units
3. Question: How does Inconel 825 perform in corrosive environments?
Answer: Inconel 825 has excellent resistance to:
Pitting and crevice corrosion in chloride-containing solutions
Stress corrosion cracking
Oxidation and sulfidation at high temperatures
It is suitable for both oxidizing and reducing chemical environments, making it superior to standard stainless steels in aggressive media.
4. Question: What are the mechanical properties of Alloy 825 sheets and plates?
Answer: Alloy 825 maintains good strength and ductility over a wide temperature range:
Tensile strength: 515–827 MPa
Yield strength: 205–380 MPa
Elongation: 30–50%
Hardness (Brinell): 150–200 HB
These properties ensure reliable performance in high-stress and high-temperature applications.
5. Question: Can Alloy 825 be welded and fabricated easily?
Answer: Yes, Alloy 825 is easily fabricated and welded using conventional methods:
TIG, MIG, and arc welding with Alloy 825 filler rods are recommended
Preheating is typically not required
Machining is straightforward with proper tools, although the alloy's toughness may require slower cutting speeds
Post-weld annealing is generally not necessary for maintaining corrosion resistance
