Objectives of Mechanical Working of Metals Metalworking operations subject the metal to plastic deformation primarily to achieve which of the following outcomes?

Introduction / Context:
Mechanical working (rolling, forging, drawing, extrusion) modifies a metal’s shape and microstructure. Appreciating its multiple objectives helps engineers choose processes and parameters for performance and cost.

Given Data / Assumptions:

• Processes considered: hot/cold rolling, open/closed-die forging, extrusion, drawing.
• Materials: common industrial alloys.
• Evaluation criteria: shape, properties, and microstructural control.

Concept / Approach:
Plastic deformation breaks up cast dendrites, closes internal voids, and can refine grain size after subsequent recrystallisation. It also converts stock into usable shapes and aligns flow lines to improve directional properties like fatigue and impact resistance. Thus, mechanical working serves not one but many purposes simultaneously.

Step-by-Step Solution:
Assess Option A: deformation and controlled thermal cycles refine grain size.Assess Option B: bulk shape change is the most apparent outcome.Assess Option C: fibre flow alignment enhances mechanical properties.Conclude that all listed objectives are valid.

Verification / Alternative check:
Forged crankshafts show oriented flow lines following stress paths, improving fatigue life.

Why Other Options Are Wrong:
Choosing any single objective omits the other equally important benefits.“None of these” contradicts well-established metallurgical practice.

Common Pitfalls:
Focusing only on shape change and ignoring microstructural advantages of working.

Final Answer:
all of these