Alloy Grade UNS: HPNb – Contains Niobium

  • Overview

    HPNb is a high-temperature stainless steel alloy that incorporates niobium to enhance its performance in demanding environments. The addition of niobium significantly improves its stress rupture strength, enabling it to withstand high stresses at elevated temperatures without deforming or fracturing. Furthermore, niobium enhances its carburization resistance, protecting it from the absorption of carbon and subsequent embrittlement in carbon-rich atmospheres. While the niobium addition slightly reduces ductility, HPNb still maintains good tensile strength and overall mechanical properties. With a service limit of 2010 degrees Fahrenheit (1100 degrees Celsius), HPNb offers reliable performance in high-temperature applications where strength, creep resistance, and carburization resistance are critical.

  • Typical Uses

    Petrochemical furnaces, equally well suited for reformer and ethylene furnace applications.

  • MetalTek Grade

    MTEK 25-35Nb

  • Poured At:

    Carondelet Division, Sandusky International Division, Wisconsin Centrifugal Division, Wisconsin Investcast Division

Similar Specifications

Cast ASTM: A297 MOD.

Typical Chemical Composition (% by wt.)

Aluminum: n/a

Carbon: 0.35-0.55

Chromium: 23-27

Manganese: 1.5

Iron: BAL

Copper: n/a

Nickel: 32-37

Lead: n/a

Tin: n/a

Silicon: 2

Zinc: n/a

Other: Mo 0.50; Nb 0.60-1.00

Minimum Mechanical Properties

Tensile, ksi

0

Tensile, MPa

0

Calculated PREn (Minimum)

0

Yield, ksi

0

Yield, MPa

0

Elongation

0%

Heat Treatment: Not Heat Treated

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