In metalworking, which of the following would NOT typically be used as a means of inspection?

The correct choice is attributed to the nature of inspection methods used in metalworking. Applying heat treatment techniques is fundamentally a process aimed at altering the material properties of metal, such as increasing hardness or ductility, rather than evaluating the quality or integrity of a finished product.

In contrast, visual inspection for defects is a straightforward and commonly used method to identify surface issues such as scratches, dents, or improper finishes. Ultrasonic testing employs sound waves to detect internal flaws or inconsistencies in metal, which is crucial for assessing the integrity of critical components. Rivet gauge measurement is a specific technique used to ensure rivets meet dimensional standards for strength and fit.

Therefore, while visual inspection, ultrasonic testing, and rivet gauge measurement are all established methods for assessing various aspects of metalwork quality, applying heat treatment techniques does not fit this category as it is not an inspection method.