Day 7 Evening – Manufacturing Technology → Forging

Why this topic is important for ECET:
Forging is a fundamental manufacturing process frequently asked in ECET Mechanical and ECE-related questions. Understanding forging concepts helps in solving questions on metal forming, strength of materials, and production techniques. A strong grasp ensures faster problem-solving and helps tackle both numerical and conceptual questions in exams.

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📘 Concept Notes

1. Introduction to Forging
Forging is a metal shaping process in which metal is deformed plastically using compressive forces, usually with hammers or presses. It improves mechanical properties like strength, toughness, and fatigue resistance.

Key Types of Forging:

• Hot Forging: Metal is heated above recrystallization temperature. Advantages: easier shaping, reduced fracture.
• Cold Forging: Metal is deformed at or near room temperature. Advantages: higher strength due to strain hardening, better surface finish.
• Warm Forging: Temperature is between hot and cold forging, combining benefits of both.

2. Forging Operations

• Upsetting: Increases diameter by shortening length.
• Drawing Out: Reduces cross-section to increase length.
• Bending: Metal is bent into required shape.
• Fullering: Localized reduction using convex/concave dies.
• Edging: Concentrates metal in specific areas.
• Swaging: Reduces diameter using dies.

3. Forging Equipment

• Hammer Forging: Repeated hammer blows (mechanical or pneumatic hammers).
• Press Forging: Continuous compressive force using hydraulic/mechanical presses.
• Drop Forging: Controlled free-fall hammer impacts the workpiece.

4. Forging Defects

• Cracks: Caused by excessive stress or improper heating.
• Laps: Folding of metal surface.
• Scale Formation: Oxidation at high temperatures.
• Uneven Grain Flow: Leads to weak zones.

5. Advantages of Forging

• Improved mechanical properties
• Uniform grain structure
• Can produce complex shapes
• Reduces porosity in metals

6. Applications

• Automotive: crankshafts, connecting rods
• Aerospace: turbine discs, landing gear
• Tools: hammers, spanners, dies

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⚙️ Formulas

1. Forging Load (Approximate):

Where:

• = forging load
• = load factor (1.1–3 for different operations)
• = yield strength of material
• = instantaneous cross-sectional area

2. Reduction in Area:

Where:

• = initial area
• = final area

3. Power Required in Hot Forging:

Where:

• = velocity of ram
• = efficiency of the forging machine

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🔟 10 MCQs

1. Forging primarily improves:
   A) Electrical conductivity
   B) Mechanical properties
   C) Thermal conductivity
   D) Magnetic properties
2. Hot forging is done above:
   A) Room temperature
   B) Recrystallization temperature
   C) Melting point
   D) 0°C
3. Upsetting operation is mainly used to:
   A) Increase length
   B) Reduce diameter
   C) Increase diameter
   D) Bend the metal
4. The forging load depends on:
   A) Velocity only
   B) Die shape only
   C) Material yield strength and cross-section
   D) Temperature only
5. Which defect is caused by folding of metal?
   A) Crack
   B) Lap
   C) Scale
   D) Grain flow defect
6. Cold forging increases:
   A) Ductility
   B) Strength due to strain hardening
   C) Corrosion resistance
   D) Thermal conductivity
7. For a metal with initial area 50 mm² reduced to 30 mm², the reduction in area is:
   A) 20%
   B) 40%
   C) 60%
   D) 30%
8. Swaging operation is mainly used to:
   A) Bend metals
   B) Reduce diameter
   C) Increase length
   D) Upset metals
9. Press forging is preferred over hammer forging for:
   A) Small jobs
   B) Continuous deformation
   C) Decorative items
   D) None of the above
10. Which of the following is an example of hot forging application?
    A) Spanner
    B) Crankshaft
    C) Screw
    D) Bolt

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✅ Answer Key

Q.No	Answer
1	B
2	B
3	C
4	C
5	B
6	B
7	B
8	B
9	B
10	B

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🧠 Explanations

1. B: Forging enhances mechanical properties like strength and toughness; others are irrelevant.
2. B: Hot forging is done above recrystallization temperature to avoid strain hardening.
3. C: Upsetting increases diameter by shortening length.
4. C: Load depends on yield strength and instantaneous area; die shape or velocity alone is insufficient.
5. B: Lap occurs due to metal folding; cracks are different defects.
6. B: Cold forging strengthens metal via strain hardening.
7. B: Reduction in area = (50−30)/50 = 0.4 = 40%.
8. B: Swaging reduces diameter using dies.
9. B: Press forging provides continuous deformation unlike hammer forging.
10. B: Crankshaft is a common hot forging application.

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🎯 Motivation / Why Practice Matters
Mastering forging concepts helps ECET 2026 aspirants save time during the exam, avoid mistakes in numerical questions, and answer conceptual questions confidently. Practicing these topics boosts both speed and accuracy, giving you a competitive edge.

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