Casting of pipes — selecting the correct process Cast iron and steel pipes of uniform cylindrical shape are commonly produced by which casting method?

Introduction / Context:
Choosing the right casting route depends on geometry, alloy, and required properties. Pipes require sound tubular shapes with good mechanical integrity along the circumference. Centrifugal casting excels at such axisymmetric hollows.

Given Data / Assumptions:

• Geometry: long cylindrical hollows (pipes).
• Materials: cast iron or steel.
• Objective: dense sound metal at the outer surface and controlled bore.

Concept / Approach:
In true centrifugal casting, molten metal is poured into a spinning mould. Centrifugal force drives the metal outward, forming a dense outer layer while lighter inclusions and gases migrate inward, often machined away. This process is ideal for pipes, liners, and bushings. Slush casting produces thin skins; investment casting is for intricate shapes; die casting is mainly for non-ferrous low-melting alloys; squeeze casting targets near-forged quality but not typically long pipes.

Step-by-Step Solution:
Match geometry (axisymmetric hollow) with process (rotating mould).Note property benefit: high density and fine structure at the periphery.Conclude that true centrifugal casting is preferred.

Verification / Alternative check:
Industrial pipe plants widely use horizontal centrifugal machines for iron and steel pipes; inner bore is sized and finished by machining or controlled solidification.

Why Other Options Are Wrong:
Slush casting produces thin shells without cores but lacks structural soundness for pipes.

Investment casting is uneconomical for long simple cylinders.

Pressure die casting suits zinc/aluminium alloys and complex thin walls, not heavy ferrous pipes.

Squeeze casting is for dense near-net shapes, not long tubulars.

Common Pitfalls:
Confusing semi-centrifugal (for wheels) with true centrifugal (for pipes); neglecting mould coating and speed selection which control bore quality.

Final Answer:
True centrifugal casting (mould rotates about its axis)