Cast irons—identifying properties of white cast iron White cast iron is not which of the following?

Introduction / Context:
Cast irons are classified by microstructure and resulting properties. White cast iron is characterized by a hard, brittle phase due to carbon existing mainly as iron carbide rather than as graphite. Understanding which mechanical attributes do or do not apply is essential for material selection in wear and abrasion environments versus ductility applications.

Given Data / Assumptions:

• White cast iron microstructure: cementite and pearlite with minimal free graphite.
• Mechanical requirements: consider hardness, brittleness, and ductility.
• Color descriptor refers to the fractured surface appearance.

Concept / Approach:
In white cast iron, rapid cooling or specific chemistry promotes carbide formation. Cementite confers high hardness and excellent abrasion resistance but at the cost of ductility. The fracture surface appears bright or whitish because of the carbide network, in contrast to the dull grey appearance of graphite in grey cast iron. Malleability refers to the ability to deform plastically without fracture, a property white iron does not possess until it is heat treated to become malleable iron (through prolonged annealing that transforms carbides).

Step-by-Step Solution:

Verification / Alternative check:
Materials handbooks list white cast iron with high hardness, low impact resistance, and brittle fracture. Applications include wear plates and grinding balls, consistent with non-malleable behavior.

Why Other Options Are Wrong:

• Whitish in color: correct descriptor of fracture surface, so not the answer.
• Brittle: accurately describes white cast iron.
• Strong and hard: hardness is indeed high; compressive strength can be high though tensile ductility is poor.

Common Pitfalls:
Confusing malleable iron (a heat-treated product made from white iron) with as-cast white iron. The as-cast state is brittle; malleability is developed only after controlled annealing that decomposes carbides.

Final Answer:
malleable