Question

Which of the following metal working operation is a direct compression process?

• A. Extrusion
• B. Forging
• C. Wire drawing
• D. Stretch forming

Hint:

- Direct Compression: Forging, Rolling.
- Indirect Compression: Extrusion.
- Indirect Tension: Wire Drawing.
- Pure Tension: Stretch Forming.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks to identify which of the listed metal forming (working) processes is categorized as a "direct compression process".

Step 2: Detailed Explanation:

• Metal forming operations are classified based on the primary state of stress acting on the metal workpiece:

• Direct Compression Processes:
The external forces are applied directly to the surface of the workpiece, squeezing it to deform.
The metal is subjected to compressive stresses in all directions.
Forging is a classic direct compression process where the metal is compressed between flat or shaped dies using hammer blows or press forces.

• Indirect Compression Processes:
The primary applied force is tensile or compressive, but the geometry of the die converts this into high compressive stresses within the metal.
Extrusion is an indirect compression process because the compression is induced by pushing the metal through a die opening, which creates compressive reactions from the container walls.

• Tension-Compression (Indirect Tension):
Wire drawing involves pulling the wire (tensile force) through a die, creating indirect compression within the die.

• Pure Tension:
Stretch forming involves wrapping and stretching a sheet metal over a tool primarily under tensile stresses.

Step 3: Final Answer:
Forging is a direct compression metal working operation.