CASTING DEFECTS AND INSPECTION

The defects in a casting may be due to pattern and moulding box equipment, moulding sand, cores,gating system or molten metal. Some of the defects are : Mould shift It results in a mismatching of the top and the bottom parts of the casting, usually at the parting line.

Swell It is an enlargement of the mould cavity by molten metal pressure resulting in localized or general enlargement of the casting.

Fins and Flash These are thin projections of the metal not intended as a part of casting. These usually occurs at the parting line of the mould.

Sand Wash It usually occurs near the in the gates as rough lumps on the surface of a casting.

Shrinkage It is a crack or breakage in the casting on the surface of the work piece, which results from un equal contraction of the metal during solidification.

Hot Tear It is an internal or external ragged discontinuously in the metal casting resulting just after the metal has solidified.

Sand Blow or Blow Hole It is smooth depression on the outer surface of the casting work piece.

Honeycombing or Slag holes These are smooth depression on the upper surface of the casting. They usually occur near the ingates.

Scabs These are patches of sand on the upper surface of the casting component.

Cold Shut and Misruns These happens when the mould cavity is not completely filled by the molten and insufficient material or metal.

Run-outs and Bust-outs These permit drainage of the metal from the cavity and result in incomplete casting.