A peak into the most important metal forming operations

1. CHAPTER III: FORGING
VIBHAS PURUSHOTHAMAN
ASSISTANT PROFESSOR
MECHANICAL ENGINEERING
DBIT-BANGALORE

2. INTRODUCTION
“the working of metal, mostly in hot condition,
under direct compressive forces, such as by
loading under impact(hammering) or
pressure(pressing) or both, to obtain a useful
shape and improve its mechanical properties.”

3. INTRODUCTION
• Hammer forging:
– forces are imparted to the surface of the metal.
– Pressure intensity is max at surface and hence
deformation is max at surface.
• Press forging:
– slow speed compressive forces.
– Pressure increases as the metal is being deformed,
and reaches max just before pressure is released.

4. FORGEABILITY
• Ease with which given metal can be forged to
reqd shape.
• Depends on lattice structure. FCC then BCC
and then HCP.
• High temp improves forgeability.

5. METALS & ALLOYS SUITABLE FOR
FORGING
• Non ferrous alloys: wrought Al-alloys, Mg-based
alloys, Cu- based alloys, cupro nickel and pure
Cu. Used in aircraft and aerospace.
• Ferrous alloys: plain carbon steels

6. FORGING TEMPERATURES
• Temp always above recrystallisation temp.
• For low carbon steels: 1300 to 850 deg
• For high carbon steels: 1150 to 850 deg
• Heating much above leads to oxidation of
metals and finishing at a lower temp leads to
strain hardening and cracks.
• Hence heating should be optimum and uniform.

7. ADVANTAGES & DISADVANTAGES OF
FORGING
• Better grain flow, so
better directional
properties.
• Improved mech
properties.
• Can be shaped easily to
reqd dimensions.
• Heavy parts can be
formed easily
• Initial equipment is high.
• Maintenance is high.
• Intricate shapes not
possible.
• Size limitations when
compared to casting.
• Cost more than cast
product.

8. CLASSIFICATIONS OF FORGING
OPERATIONS

10. CLASSIFICATIONS OF FORGING
OPERATIONS

11. CLASSIFICATIONS OF FORGING
OPERATIONS