Casting methods — rotating moulds Identify the casting method in which molten metal is poured and allowed to solidify while the mould is revolving to develop centrifugal forces.

Introduction / Context:
Casting processes exploit gravity, pressure, or centrifugal action to fill moulds. Knowing which process uses rotation helps select tooling for pipes, bushings, and rings where directional solidification and low-inclusion levels are beneficial.

Given Data / Assumptions:

• Mould rotates about an axis during pouring and solidification.
• No expendable cores are needed for true centrifugal pipes (bore created by centrifugal action).
• Objective: dense, fine-grained outer surfaces.

Concept / Approach:
In centrifugal casting, rotation forces the molten metal to the mould wall, driving lighter inclusions and gases toward the inner diameter. Variants include true centrifugal (tubes), semi-centrifugal (wheels), and centrifugal investment casting. This differs from die casting (pressure-injected into a rigid die), slush casting (hollow thin shells by partially solidifying then pouring out excess), and non-rotating permanent mould casting.

Step-by-Step Solution:
Identify the rotating mould condition → centrifugal process.Match to products: pipes, sleeves, rings benefit from centrifugal action.Select “Centrifugal casting method”.

Verification / Alternative check:
Process produces characteristic inner shrinkage defects that are machined away; macrostructure shows radial segregation consistent with centrifugal solidification.

Why Other Options Are Wrong:
Die casting uses plunger-injection, not rotation; slush casting creates thin shells without rotation; permanent mould refers to reusable moulds but typically static during fill.

Common Pitfalls:
Insufficient rotational speed causing misruns; inadequate gating into the spinning mould yielding turbulence.

Final Answer:
Centrifugal casting method