Question 28

The Correct Answer is A. **Why option A ("swaging") is correct:** Swaging is a specific metalworking process used primarily in refrigeration, HVAC, and plumbing where the end of a tube is expanded or reformed so that a tube of the same size (diameter) can be inserted snugly into it. This process creates a strong mechanical joint, often used when joining copper tubing without requiring a coupling fitting, thereby reducing material costs and the number of soldered joints. The description provided—"Enlarging one tube end so the end of another tube of the same size will fit inside"—is the precise definition and purpose of swaging. **Why the other options are incorrect:** * **B) stretching:** While swaging involves localized stretching of the material, "stretching" is a generic term that describes the elongation of material under tension. It is not the specific industrial term used for preparing a tube end for insertion. * **C) flaring:** Flaring is the process of expanding the end of a tube outward into a cone shape. This shape is designed to seal against a mating flared fitting (like a nut and seat) to create a leak-proof connection, not to fit another tube inside. * **D) belling:** Belling is sometimes used synonymously with swaging, particularly in older contexts or specific industries, but it is a less common and less precise term for this specific tube-joining preparation. However, in technical metalworking and HVAC contexts, the standard and most precise term for this tube-expanding process is **swaging**.