1. What is ASTM B165, and why is it relevant to these alloy pipes?
Answer:
ASTM B165 is the standard specification for nickel and nickel-alloy seamless pipes. It defines chemical composition, mechanical properties, manufacturing process, and testing requirements. Compliance ensures that the seamless pipes made from Inconel, Incoloy, or other nickel alloys meet high-temperature and corrosion-resistant performance for industrial applications.
2. What are the main differences between Inconel 600, 625, 718, C22, C276, Incoloy 825, and 800HT?
Answer:
| Alloy | Key Feature | Typical Use | Temperature Resistance |
|---|---|---|---|
| Inconel 600 | High corrosion & oxidation resistance | Chemical, food, heat exchangers | Up to 1200°F (649°C) |
| Inconel 625 | High strength + excellent corrosion resistance | Marine, chemical, aerospace | Up to 1800°F (982°C) |
| Inconel 718 | Precipitation-hardenable, very high strength | Gas turbines, nuclear | Up to 1300°F (704°C) |
| Hastelloy C22 | Outstanding resistance to oxidizing & reducing acids | Chemical, pharmaceuticals | Up to 1500°F (816°C) |
| Hastelloy C276 | Excellent resistance to pitting & stress corrosion | Chemical, petrochemical | Up to 1600°F (871°C) |
| Incoloy 825 | Resistance to sulfuric & hydrochloric acids | Chemical, petrochemical | Up to 1000°F (538°C) |
| Inconel 800HT | High-temperature strength & oxidation resistance | Furnace components, heat exchangers | Up to 1200°F (649°C) |
3. What are the mechanical properties of DN100 Sch80S seamless pipes for these alloys?
Answer:
Tensile Strength (MPa): 450–1250 (depends on alloy and heat treatment)
Yield Strength (MPa): 200–1100
Elongation (%): 25–50
Hardness: HRB 70–95 or HRC 20–35 depending on alloy
These pipes are designed to maintain strength and ductility under high temperature and pressure conditions.
4. What corrosion resistance can be expected from these alloys?
Answer:
Inconel 600/625/718: Excellent resistance to oxidation and high-temperature corrosion; good resistance to alkalis and mild acids.
Hastelloy C22/C276: Exceptional resistance to oxidizing and reducing acids, chlorides, and seawater.
Incoloy 825: Resistant to sulfuric, hydrochloric, and phosphoric acids, as well as chloride-induced stress corrosion.
Inconel 800HT: Resistant to oxidation and carburization at elevated temperatures.
5. What are the typical industrial applications for these seamless alloy pipes?
Answer:
Chemical & Petrochemical Plants: Handling acids, chlorides, and corrosive fluids
Power Generation & Heat Exchangers: High-temperature service
Marine & Offshore: Seawater piping, saltwater handling
Aerospace & Gas Turbines: High-strength, high-temperature structural components
Pharmaceutical & Food Processing: Corrosion-resistant piping systems
