Centrifugal Casting

Centrifugal casting forms dense, sound cylindrical parts by spinning molten metal in a rotating mold, concentrating impurities inward and refining grain structure.

Overview

Centrifugal casting produces pipes, tubes, rings, and sleeves by pouring molten metal into a rotating mold so centrifugal force drives metal outward against the mold wall. The process yields high density, low porosity, and good mechanical properties, with impurities and shrinkage tending to segregate toward the inside diameter for later machining removal.

Choose it for axisymmetric parts with a continuous wall—especially when you need pressure-tightness, wear resistance, or high integrity in thick sections. It scales well from prototype to production and can make long lengths or large diameters without complex cores.

Tradeoffs: geometry is limited to rotationally symmetric forms, and you should expect machining on ID/OD faces to hit final tolerances and remove the “ID skin.” Setup for tooling/fixtures and balancing matters, and wall thickness control depends on process tuning and pour control rather than hard mold constraints.

Common Materials

  • Ductile iron
  • Gray iron
  • Carbon steel
  • Stainless steel 316
  • Bronze C932
  • Nickel alloy 625

Tolerances

±0.010" to ±0.030" as-cast; ±0.002" to ±0.005" after machining

Applications

  • Pressure pipe and cylinder liners
  • Wear sleeves and bushings
  • Bearing races and rings
  • Valve bodies and valve seats (ring forms)
  • Heat exchanger tube shells
  • Pulley and flywheel rims

When to Choose Centrifugal Casting

Pick centrifugal casting for tubular or ring-shaped parts where high integrity, low porosity, and consistent properties through the wall matter. It fits medium to high volumes and also works for prototypes when machining stock from a sound casting is cheaper than forging or billet. It’s strongest when the part can be finished by turning/boring and the ID can be machined to remove segregated material.

vs Sand Casting

Choose centrifugal casting when the part is a tube/ring and you need higher density, better pressure tightness, and fewer internal defects than typical sand castings. It also avoids complex cores and core-related scrap on hollow cylindrical geometries.

vs Die Casting

Choose centrifugal casting when you need ferrous alloys or higher-melting materials, thicker walls, or large diameters that aren’t practical in die casting. It’s also a better fit when integrity and machinable stock quality matter more than near-net-shape details.

vs Investment Casting

Choose centrifugal casting for simple axisymmetric parts where soundness and cost per pound matter more than fine external detail. It’s typically more economical for long tubes and large rings, with finishing done by standard turning/boring.

vs Permanent Mold Casting

Choose centrifugal casting when the geometry is primarily tubular and you want improved feeding/solidification behavior without gates/risers driving yield loss. It’s often better for long lengths and thick sections where permanent molds struggle with shrink control.

vs Shell Mold Casting

Choose centrifugal casting when you need a dense, pressure-retaining tube or ring and can tolerate machining to final dimensions. Shell molds can hold good detail, but centrifugal casting tends to deliver cleaner, more uniform wall integrity on cylindrical parts.

Design Considerations

  • Keep the design rotationally symmetric and avoid features that require cores or non-axisymmetric cavities
  • Leave machining stock on ID and OD; plan to remove the ID layer to meet quality and property requirements
  • Specify minimum/maximum wall thickness and allowable taper; wall control is process-driven and benefits from clear limits
  • Call out critical surfaces for post-machining (seal bores, bearing seats) rather than demanding tight as-cast tolerances
  • Avoid sharp internal corners; use radii/chamfers to reduce hot spots and simplify boring/turning
  • Provide a clear datum scheme and finish requirements so the foundry can plan how the casting will be fixtured for machining