Inclusions (Slag)

Technical Support

Struggling with a specific casting defect or just need general technical support?

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  • Missing areas (a mix of round, irregular or angular shaped craters or cavities) of metal in the casting or black, crusty particles sitting on the metal surface

  • Indicates a presence of liquid and solid slag inclusions; which are being carried into the shell by the metal

Causes of this defect are evident in the metal and other portions of the process; to cure, R&R recommends taking the following actions:


Poor deslagging.

Use a filter to remove slag from metal during pouring.

Poor deoxidation and/or poor deslagging practice.

When molten metal is exposed to air, it begins to oxidize, forming slag. Improve deoxidation and/or deslagging technique and limit metal exposure to oxygen during pouring.

Metal overheat.

Determine proper temperature and control. Cast at lowest possible temperature.


Poor condition of refractory liners in ladles and furnaces (moisture).

Check on firing of new refractory linings.

Improper deoxidation.

Improve deoxidation.

Contamination from casting ladle or turbulent casting.

Inspect ladles and avoid turbulence.

Poor deslagging practice.

Use proper deslagging practices.