Class I, Type C, Ni-Cr-GB; Also known as Ni-Hard3

ASTM A352 Class I, Type C, Ni-Cr-GB (Ni-Hard 3)

Nickel-High Chrome Carbon cast iron is the wear and abrasion resistance group of materials sometimes called Ni-Hard 3. These alloys have high hardness and castability.  Relatively high carbon, chromium and Nickel content increases volume fraction of carbides and improves wear and spalling resistance in this alloy. This group is a martensitic iron Ni-Hard cast iron. The Ni-Hard 3 alloys are designed to be largely martensitic as-cast; the only heat treatment commonly applied is tempering. The high hardness result comes from the formation of martensite versus pearlite in the as-cast condition. Martensitic white irons have largely displaced pearlitic white irons for making many types of abrasion-resistant castings.

The predominant characteristics of Ni-Hard 3 irons are that their high strength and toughness can be achieved when heat-treated at relatively low temperatures. 

The Class I Type C alloy (Ni-Hard 3) is specially designed for the production of grinding balls. Microstructure of as-cast Ni-Cr-GB consists of the primary dendrite and the eutectics carbides in martensite.

Chemical Composition (ASTM A532-IC)

Mechanical and Physical Properties

Wear and Abrasion Resistant Properties:

Wear and Abrasion Resistant properties:

Ni-Hard 3 alloys are suitable for high impact, and high sliding abrasion for both wet and dry applications. ASTM A532 Class 1 Type C has high toughness with good wear resistance particularly for ball mill applications.

Typical applications of this group are in ball mill components, balls, liner plates, crusher concaves, pulverizing pegs. They are also suitable for parts subjected to more impact like clinker crushers and those with less wear.


Ni-Hard 3 produced in as-cast, Stress Relieved (SR) and heat-treated condition.

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