Bulk deformation processes — what is rotary swaging used for? Rotary swaging (also called rotary forging or radial forging) is a hammering process using rapidly opening-and-closing dies around a rotating work. Which of the following best describes its typical application?
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Ais extensively used for making bolts and rivets
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Bis used for reducing the diameters of round bars and tubes by rotating dies which open and close rapidly on the work
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Cis used to improve fatigue resistance of the metal by setting up compressive stresses in its surface
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Dconsists of pressing the metal inside a chamber to force it out by high pressure through an orifice which is shaped to provide the desired form of the finished part
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Eis a finishing process to remove scale after hot rolling
Answer
Correct Answer: is used for reducing the diameters of round bars and tubes by rotating dies which open and close rapidly on the work
Explanation
Introduction / Context:Rotary swaging is a high-speed, incremental deformation process that reduces diameter, forms tapers, and compacts material, particularly for rods and tubes. It creates surface work hardening and improved dimensional control without continuous dies.
Given Data / Assumptions:
- Process involves segmented dies that open/close rapidly.
- Workpiece is typically round bar or tube.
- Cold or warm operation is common, depending on alloy and reduction.
Concept / Approach:In swaging, hammers driven mechanically or pneumatically strike the dies to shrink the work in small steps as it rotates/feeds axially. The method is well suited to forming tapered shafts, reducing tube ends for fittings, and consolidating powder metal preforms. It is not the same as cold heading (bolt making), shot peening (surface compressive stresses), or extrusion (forcing metal through a die orifice under high hydrostatic pressure).
Step-by-Step Solution:
Match the described die action (opening/closing) to rotary swaging machines.Identify the typical product geometry: round bars and tubes.Select the option that states diameter reduction using oscillating dies.Verification / Alternative check:Process capability charts list swaging for reductions of up to moderate percentages per pass, with good surface finish and minimal material loss.
Why Other Options Are Wrong:
- Bolt and rivet manufacture: primarily cold heading.
- Improving fatigue by surface compression: that is shot peening.
- Pressing metal through an orifice: that is extrusion.
- Scale removal: that is descaling or pickling, not swaging.
Common Pitfalls:Confusing swaging with drawing or extrusion; overlooking that swaging can process tubes with internal mandrels to control wall thickness.
Final Answer:
is used for reducing the diameters of round bars and tubes by rotating dies which open and close rapidly on the work