1. Metal Forging
Chapter 3.13

2. Forging Metal is shaped to a desired form through plastic deformation
Types: open die, impression die, ring rolling, rotary swaging, cold heading
Terms: upset forging, draft, parting line, flash, gutter, rib, web

4. Typical Characteristics
Controlled grain structure is primary benefit
High strength (high strength to weight ratio)
Seldom have internal blemishes
Size is limited by facilities
Machining operation required in most cases

5. Bralla
ASM Metals Handbook Vol.9

6. Economics
Economically viable in large quantities for impression die parts or small quantities for open dies parts (but lots of skilled labor)
Tooling cost – may be high for impression die
Labor cost – may be high for open die
Finishing costs can be moderate

7. Design Recommendations
Parting line choice is critical
Ideal – in one plane perpendicular to die motion (pg )
Economical – one flat die, one w/ impression (Fig )
Minimize side thrust forces – keep parting line < 75 degrees from principal plane (pg )
No undercuts (pg )
Use parting line to control grain (Fig )
Flow horizontally if possible (Fig )

8. Design Recommendations
Draft angle per material (Table )
Avoid ribs and bosses that are high and narrow, webs that are thin w/ variable thickness (Fig )
Fillets and rounds (Table )
Consider machining allowances (pg )
Tolerances: length and width, die wear, die closure, match, straightness, draft, radii (pg )