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Defects in Forgings

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Defects in forging Mahander Pratap Singh (071577) Munish kumar (071425) video1.swf
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Page 1: Defects in Forgings

Defects in forging

Mahander Pratap Singh(071577)Munish kumar(071425)

video1.swf

Page 2: Defects in Forgings

What is forgingForging can be defined as the controlled plastic deformation of metals at elevated temperatures in to a predetermined size or shape using compressive forces exerted, through some type of die, by a hammer, a press or upsetting machine.

Forging enhances the mechanical properties of metals and improves the grain flow, which in turn increases the strength and toughness of the forged components. 

Page 3: Defects in Forgings

Types of forging• Open die forging• Closed die forging

Page 4: Defects in Forgings

Forging Temperatures

Sr.No. Metal / Alloy

Forging Temperature oC

Starting Finishing

01Mild steel

1300 800

02Wrought iron

1275 900

03Medium carbon steel

1250 750

04High carbon steel

1150 825

05Copper, brass and bronze

950 600

06

Aluminium and magnesium

alloys500 350

Page 5: Defects in Forgings

DEFECTS IN FORGING

• Defective structure of metal; Reason – defective original metal.

• Presence of cold shuts or cracks at corners; Reason – improper forging and faulty die design.

• Incomplete component; Reason – less metal used, faulty die design and inadequate metal flow.

• Mismatched forging; Reason – die halves not properly aligned.

• Burnt and overheated metal; Reason – improper heating.• Fiber flow lines or grain flow lines disconnected; Reason –

very rapid plastic flow of metal.• Scale pits; Reason – formed by squeezing of scale into metal

during forging.• Oversize components; Reason – worn out dies, incorrect dies.

Page 6: Defects in Forgings

Types of defects (Samrat forging)

• Unfill • Mismatch• Cracks• Double strokes• Overheating• Lapping• Undersize

Page 7: Defects in Forgings

Quality measurements of products.

Page 8: Defects in Forgings

CRACKS• Causes: Surface cracking can occur as a result of excessive working of the s/c at too low

tempr.

Can be due to hot shortness.

• Remedial measures:

Page 9: Defects in Forgings

LAPPING• Causes: When metal flows past part of the die cavity that has already been filled or that is

only partly filled becoz the metal failed to fill in due to ssharp corner Due to excessicve chilling Due to high friction. Too small die radius .

• Remedial measures:

Page 10: Defects in Forgings

UNFILL• Causes:

• Remedial measures:

Page 11: Defects in Forgings

Cracking at flash• Causes: When the flash is thin.

• Remedial measures: Increase the flash thickness of the metal By relocating the flash to a less critical region of the forging.

Page 12: Defects in Forgings

PITTING• Causes:

• Remedial measures:

Page 13: Defects in Forgings

Out comes of the project

• Understand the whole process of forging.• Comes to understand various defects related to

forging process.• Tried to find the possible causes of defects at

samrat forging.• Tried to find out the possible remidial measures.


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