Casting defect 

Process of fabrication

Process of heat treatment

Weathering of non-ferrous materials

Radiography 

Visual inspection

Damping test

Dye penetration test

Which occur due to some sand shearing from the cope surface

Which take the form of internal voids or surface depression due to excessive gaseous material not able to escape

Which occur due to discontinuity in metal casting resulting from hindered contraction

Caused by two streams of metals that are too cold to fuse properly 

Surface defect 

Internal defect

Crack

Notch

high moisture content of the sand

low permeability of sand

excessive fine grains and gas producing ingredients

any of the above