Die Casting Defects - Causes and Solutions
textbook for die casting engineers. Provides
basic procedures for reducing scrap and
controlling defects; identifies 22 types of die
casting defects with photomicrographs of each;
provides technical details of causes and
formation mechanisms of each; suggests solutions
to correct each type of defect.
Item #E-515, 161
TABLE OF CONTENTS
A review of some of the major operational practices
required to reduce or eliminate defects. Just
knowing the cause of the defect and asking for a correction
won't fix the problem.
Surface Defects -- Those defects commonly called cold
flow or non-fills.
Laminations -- Defects from layers of metal forming
during the process.
Gas Porosity -- Internal porosity from trapped gas of
Blisters -- Surface manifestation of trapped gas.
Flow Porosity --Surface or internal porosity from poor
Shrink Porosity -- Porosity from the volume change as
the metal changes state.
Sinks -- Surface depressions from shrinkage porosity
Leakers -- Porous sections of the casting.
Cracks -- Visible and not-so-very visible cracks in
Inclusions -- Foreign material that may cause machining
Solder -- Buildup of the cast material on the die, and
damage to the surface condition of the casting.
Carbon -- Deposits other than the cast material on the
die causing damage to the surface condition of the casting.
Erosion, Cavitation -- Removal of die steel and subsequent
deformation of the casting.
Outgassing -- Gas escaping from the casting during a
painting or finishing operation that causes defective
Bending, Warping -- Deformation of the casting sometime
after it is formed in the die cavity.
Flash -- Excessive material extending from a parting
line, often accompanied by dimensional deviation.
Stained Castings -- Discolored castings.
Waves and Lakes -- Decorative castings with small imperfections
visible only under reflected light.
Drags -- Surface area of the casting is broken by metal
stuck to the die.
Deformation From Ejector Pins (Pushed Pins) -- Casting
is deformed by ejector pins.
Cold Flakes -- Leakers and break in at the gate.
Excessive Flux -- Corrosion or porosity from excessive