Alloy Grade UNS: HH TYPE I – Sensitive to Composition Balance

  • Overview

    HH Type I is a high-temperature alloy that requires precise compositional control to achieve its desired properties. This alloy is carefully balanced to contain sufficient chromium for excellent scaling resistance at elevated temperatures, making it suitable for applications where oxidation resistance is critical. Its sensitivity to composition ensures that the alloy maintains its structural integrity and resists degradation even under prolonged exposure to high temperatures. With a service limit of 980 degrees Celsius (1800 degrees Fahrenheit), HH Type I offers reliable performance in demanding environments where precise control of its composition is essential for optimal performance.

  • Typical Uses

    Convection furnace components, grate bars, rabble arms, radiant tubes, refractory support hardware.

  • MetalTek Designation

    MTEK 25-12 TYPE I

  • Poured At:

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

Similar Specifications

Cast UNS: J93303

Cast Grade: HH TYPE I

Cast ASTM: A447

Typical Chemical Composition (% by wt.)

Aluminum: n/a

Carbon: 0.20-0.45

Chromium: 23-28

Manganese: 2.5

Iron: n/a

Copper: n/a

Nickel: 10.0-14.0

Lead: n/a

Tin: n/a

Silicon: 1.75

Zinc: n/a

Other: N 0.20 MAX

Minimum Mechanical Properties

Tensile, ksi

0

Tensile, MPa

0

Calculated PREn (Minimum)

0

Elongation

0%

Heat Treatment: Not Heat Treated

Frequently Asked Questions

Heat resistant stainless steel refers to alloys designed to maintain mechanical properties and resist oxidation at elevated temperatures.

Applications include furnace parts, heat exchangers, and components in petrochemical plants.

Heat resistant stainless steels can withstand temperatures up to 1,150°C (2,100°F), depending on the grade and exposure time.

High chromium and nickel contents stabilize the austenitic structure and form a protective oxide layer, resisting scale and oxidation.

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Non-ferrous alloys are, literally, materials that are not iron-based. While others may provide non-ferrous materials of other materials, the MetalTek family of non-ferrous alloys are copper-based. In general, these materials deliver high strength, and excellent wear and corrosion resistance. They are often found in marine applications and also bushing, bearing, and gear environments.
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Stainless steels owe their ability to resist corrosion primarily to the presence of a passive film on their surface. Chromium is chiefly responsible for formation of the passive film. Iron ceases to rust at approximately 12% chromium content and resistance to oxidizing corrosives increases rapidly with chromium content up to approximately 20%.
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Specialty Alloys comprise a broad group of materials that deliver properties for more demanding applications, use more exotic or expensive materials, or require special processes to manufacture. Where standard materials may not offer desired performance, specialty alloys (including those that are modified further) may be a sensible selection.