Heat Treatment of ASTM B443 N06625 Nickel Alloy Plate

ASTM B443 N06625, widely recognized as Inconel 625, is a nickel-based alloy plate valued for its superior corrosion resistance and high-temperature performance. According to the ASTM B443 standard, this alloy is supplied in two distinct heat-treated conditions—Grade 1 (annealed) and Grade 2 (solution-annealed)—each tailored for specific service environments.

Grade 1 (Annealed): This condition involves annealing at approximately 871°C (1600°F) or higher, followed by rapid cooling. It provides excellent ductility and formability, making it suitable for applications up to 593°C (1100°F). Grade 1 offers a minimum tensile strength of 930 MPa and yield strength of 430 MPa, with high toughness even at low temperatures. It is ideal for marine and chemical processing environments where corrosion resistance and ease of fabrication are critical.

Grade 2 (Solution-Annealed): Achieved by heating to around 1093°C (2000°F) followed by rapid quenching, this treatment enhances creep and rupture strength for service above 593°C. It is designed for high-temperature applications, such as aerospace turbine components and exhaust systems, where prolonged exposure to elevated temperatures is common. The solution-annealed condition maintains the alloy’s corrosion resistance while improving its performance under thermal stress.

Both heat treatments ensure Inconel 625’s versatility, with no need for precipitation hardening. The choice between Grade 1 and Grade 2 depends on the operating temperature and mechanical demands of the application. Suppliers provide these plates in various thicknesses, certified to ASTM B443 standards, ensuring reliability in critical industries.