Heat generation zones in metal cutting: The region where heat is produced by friction between the moving chip and the tool face is known as the…

Introduction / Context:
In metal cutting, three principal regions are associated with energy conversion to heat: the primary shear zone, the chip–tool interface (friction zone), and the secondary deformation within the chip/tool contact. Correctly identifying these regions helps in choosing coatings, rake angles, and cutting parameters to manage temperature and tool wear.

Given Data / Assumptions:

• Orthogonal or oblique cutting with a sharp tool.
• Continuous or discontinuous chips depending on material.
• Focus on the interface between chip underside and tool face.

Concept / Approach:
The shear zone (primary) is where the work material plastically deforms into chip, generating heat due to plastic work. The friction zone (chip–tool interface) is where the newly formed chip slides over the rake face, producing heat by sliding friction and secondary deformation. Distinguishing these zones clarifies why rake face coatings (e.g., TiAlN) and cutting fluids that reach the interface can lower temperature and reduce crater wear.

Step-by-Step Solution:

Verification / Alternative check:
Temperature maps and tool wear patterns (crater wear) peak along the rake face contact, confirming the frictional and secondary deformation source of heat there.

Why Other Options Are Wrong:
“Work–tool contact zone” is a generic description, but the standard technical term is friction zone; “shear zone” is primary deformation; bulk heat in workpiece is a result, not the specific interface region.

Common Pitfalls:
Assuming all heat comes from shear only; neglecting coolant/coating roles at the interface; misattributing crater wear to only chemical diffusion rather than also frictional heating.

Final Answer:
friction zone