Q1: What are the main differences between Inconel 800, Incoloy 800HT, and Inconel 825 sheets?
A1: Inconel 800 is designed for high-temperature strength and oxidation resistance. Incoloy 800HT is a modified version with controlled carbon and aluminum-titanium content for improved creep and rupture strength at elevated temperatures. Inconel 825, on the other hand, emphasizes corrosion resistance, particularly against sulfuric and phosphoric acids, while still maintaining good strength.
Q2: What industries commonly use these nickel alloy sheets?
A2: They are widely used in petrochemical plants, chemical processing, power generation, nuclear reactors, marine environments, and heat-treating equipment where both corrosion resistance and high-temperature performance are required.
Q3: What are the typical operating temperature ranges of these alloys?
A3: Inconel 800 and 800HT are suitable for service up to about 1100°C (2000°F), particularly in high-temperature structural applications. Inconel 825 performs best in medium-high temperature environments, typically up to 540°C (1000°F), with a focus on resisting aggressive corrosive media.
Q4: What is the general chemical composition of these alloys?
A4: All three alloys are nickel-iron-chromium based. Inconel 800/800HT typically contains around 30–35% Nickel, 19–23% Chromium, and the balance Iron. Inconel 825 contains about 38–46% Nickel, 19–23.5% Chromium, 2.5–3.5% Molybdenum, and 1.5–3% Copper for enhanced corrosion resistance.
Q5: Which standards and testing methods apply to these nickel alloy sheets?
A5: They are usually produced under ASTM B409 (for Alloy 800/800HT) and ASTM B424 (for Alloy 825). Testing includes tensile strength tests, hardness tests, chemical composition verification, intergranular corrosion testing, and non-destructive testing to ensure product quality.
