In which situation is the centrifugal casting process specifically suitable—considering how metal is forced against a mould to form parts that are symmetric about the axis of rotation?

Introduction / Context:

Centrifugal casting uses rotation to generate a high radial head that forces molten metal against the mould wall, producing dense, fine-grained parts. It excels when geometry is symmetric about the rotation axis.

Given Data / Assumptions:

• True (rotational) centrifugal casting, not centrifuging or semi-centrifugal variants.
• Common industrial applications like pipes, liners, and rings.
• Axis of rotation can be horizontal or vertical depending on component.

Concept / Approach:

Articles such as pipes and cylindrical sleeves are typically cast with a horizontal axis of rotation (longitudinal axis aligns with the part), enabling uniform distribution along the length. Vertical axis is also used (e.g., rings), but the most classic and widely referenced case in exams is symmetry about a horizontal axis (e.g., pipes).

Step-by-Step Solution:

Verification / Alternative check:

Reference examples include cast-iron pipes and bushings formed in rotating horizontal moulds, validating the answer.

Why Other Options Are Wrong:

• Symmetrical about vertical axis: also feasible in some setups, but standard textbook association for pipes/liners is the horizontal axis.
• Irregular shape/only thin sheet sections: not suited to centrifugal forming.
• Non-ferrous only: process is used for both ferrous and non-ferrous alloys.

Common Pitfalls:

• Confusing true centrifugal casting (for axisymmetric parts) with centrifuging (for small intricate shapes using radial feed).

Final Answer:

symmetrical shape about horizontal axis