Overview
Grade HP15Nb is a high-performance austenitic stainless steel casting alloy specified by ASTM A297/A297M, developed for demanding high-temperature applications where enhanced creep strength and oxidation resistance are critical. It contains approximately 25% chromium and 35% nickel, with the addition of niobium to improve carbide stability and resistance to thermal degradation under long-term exposure. HP15Nb is commonly used in reformer tubes, radiant coils, and furnace components operating in petrochemical and thermal processing environments. The niobium addition enhances its creep resistance and structural integrity, making it a preferred material for components subject to prolonged service at elevated temperatures.
Chemical Composition
Carbon
Manganese
0.50 - 1.60%
Silicon
0.50 - 1.50%
Phosphorus
0.030% Max
Sulfur
0.030% Max
Chromium
24 - 27%
Nickel
34.0 - 38.0%
Molybdenum
0.50% Max
Physical Properties
Yield Strength
25 ksi Min
Tensile Strength
63 ksi Min
Elongation at 2 in
20% Min
Resources
ASTM Standard
