A297 HP15Nb

ASTM

A297 HP15Nb

ASME

SA297 HP15Nb

Type

25Cr-35Ni

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

0.05 - 0.25%

0.05 - 0.25%

0.05 - 0.25%

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

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© Alloy Casting Industries Ltd 2025

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© Alloy Casting Industries Ltd 2025

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© Alloy Casting Industries Ltd 2025