Though forging process give generally prior quality product as compared to the other manufacturing processes. There are some defects that are lightly to come a proper care is not taken in forging process design.
Forging Defects can be categorized into two broad categories:
• Geometrical Defects
• Non Geometrical Defects
GEOMETRICAL DEFECTS: The main types of geometrical defects are
1. Laps and folds
2. Underfills
3. Overfills
There are a number of other different geometrical defects that can occur during forging. These include:
• Piping
• Forging shape does not match design
• Die deflection, yielding or wear
• Eccentricity or buckling
A) UNFILLED SECTION: In this some section of the die cavity are not completely filled by the flowing metal. The causes of this defects are improper design of the forging die or using forging techniques.
B) COLD SHUT: This appears as a small cracks at the corners of the forging. This is caused mainly by the improper design of die. Where in the corner and the fillet radii are small as a result of which metal does not flow properly into the corner and the ends up as a cold shut.