Cold working of metals — effect on size and structure Evaluate the statement: “Cold working distorts the grain structure and does not provide an appreciable reduction in size.”

Introduction / Context:
Cold working (deformation below the recrystallisation temperature) is central to sheet, bar, and wire production. It affects mechanical properties and geometry. This prompt asks whether cold working fails to reduce size appreciably.

Given Data / Assumptions:

• Processes include cold rolling, cold drawing, swaging, and pressing.
• Materials are ductile metals at room temperature.
• No intermediate annealing unless specified.

Concept / Approach:
Cold working does two prominent things: it significantly reduces cross-section/changes thickness and it introduces strain hardening with elongated, distorted grains. Many industrial operations rely precisely on its ability to achieve large percentage reductions in thickness or area with good surface finish.

Step-by-Step Solution:
Consider cold rolling of sheet: thickness reductions of 30–70% (or staged with anneals) are common.Wire drawing can reduce diameter from, say, 10 mm to 2 mm through multiple draws.These are undeniably appreciable size reductions. Thus, the statement claiming 'no appreciable reduction' is incorrect.

Verification / Alternative check:
Engineering data sheets report percent cold work as the reduction of area or thickness; mechanical property changes (yield strength up, ductility down) correlate with these significant size reductions.

Why Other Options Are Wrong:
Any option endorsing the statement ignores commonplace reductions; limiting correctness to certain alloys is misleading because both ferrous and nonferrous metals undergo substantial reduction during cold work.

Common Pitfalls:
Confusing cold working with surface burnishing; assuming springback prevents thickness reduction; overlooking intermediate anneals that allow even larger cumulative reductions.

Final Answer:
Incorrect