Manufacturing Processes II - Forming Technology

Study Notes

Forming Definition: A mechanical deformation process that reshapes metals without adding or removing material.
Forming Mechanism: Uses plastic deformation to change the shape of workpieces, maintaining their mass.

Volume/Bulk Deformation: Involves shape changes through plastic deformation using applied forces.
Material Forms: Typically starts with cylindrical bars, billets, or rectangular slabs.
Temperature Classification: Includes cold forming, warm forming, and hot forming.

Low-Carbon Steel: Contains <0.3% carbon; noted for being cost-effective, easily weldable, and machinable.
Medium-Carbon Steel: Contains 0.3%-0.6% carbon; balances workability, cost, and durability; commonly used in automotive applications.
High-Carbon Steel: Contains 0.6%-2% carbon; very hard, used for tools and blades; more brittle and challenging to machine.

Rolling: Thickness reduction through compressive forces from opposing rolls.
Forging: Squeezing and shaping material between dies.
Extrusion: Material is pushed through a die to take its shape.
Wire and Bar Drawing: Diameter reduction by pulling material through dies.

Definition: Reduces thickness using compressive forces from rolls.
Mill Configurations: Various designs for different rolling needs, including flat rolling and shape rolling.
Types of Rolling:
- Flat Rolling: Reduces thickness of rectangular sections.
- Shape Rolling: Forms complex shapes (e.g., I-beams).
- Hot Rolling: Common for significant deformation; increases ductility.
- Cold Rolling: Produces finished sheets with improved surface finish.

Process: Forms threads on cylindrical parts using dies; favorable for mass production of bolts and screws.
Advantages: Higher production rates, material savings, strong threads due to work hardening, and improved fatigue resistance.

Process: Thick-walled rings are transformed into thinner, larger diameter rings, used in bearings and pressure vessels.
Advantages: Material savings, ideal grain orientation, and strengthened properties through cold working.

Process: Gradually forms materials into contoured cross sections like I-beams and channels.

Similar to Thread Rolling: Uses multiple gears to form gear profiles on metal.

Desirable Material Properties for Forming: Low yield strength and high ductility, both influenced by temperature during the process.
Work Hardening: Metal becomes stronger and more resistant to deformation with increased strain hardening.