TYPES OF FORGING PRESSES

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TYPES OF FORGING PRESSES
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FRICTION HILL IN FORGING
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FRICTION HILL IN FORGING
Note the strong dependence on the ratio a/h.
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FRICTION HILL FOR FINITE SIZES
Note that more lateral strain occurs for the
thinner width, and is largely a result of smaller
frictional restraint.
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FORGING WITH STICTION
Sticking friction (stiction) occurs when m.p
becomes larger than the yield strength in shear
Y/2 or Y'/2Y/(sqrt(3). Under this condition,
the friction stress becomes constant at Y'/2..
Pressure profile, p Y' 1(a-x)/h
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FORGING OF CYLINDRICAL WORKPIECE WITH FRICTION
Pressure profile, p Y' exp2m(r-x)/h
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IMPRESSION DIE FORGING
Gaps
Flash
Flash has a high a/h ratio, and is therefore
difficult to deform. Hence, much of the
deformation is confined to the interior of the
cavity, thereby removing any internal gaps. The
loads are high in impression and closed die
forging. The force is approximately given by F
K.Y'.A, where K (3-8) for simple flashes,
and (8-12) for more complex shapes
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CLOSED DIE FORGING
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FINITE ELEMENT METOD FOR CALCULATION DEFORMATION,
STRESSES, AND STRAINS IN A FORGING
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HEADING, USED FOR FORGING FATENER HEADS
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DEFECTS IN FORGING
Buckling of webs. Die design must take into
account material flow sequence.
Cold shut and internal cracks