Question

Consider the following statements regarding defects in forgings

1. Flakes are internal breaks or ruptures occurring in some grades of alloy steel.

2. Die shift is caused by misalignment between the top and bottom forging dies.

3. Fins and rags are small projections or loose metal driven into the surface of the forging.

Which of the above statements are correct ? 

1. 1 and 2 only
2. 1 and 3 only
3. 2 and 3 only
4. 1, 2 and 3
5.

Answer 1

Correct Answer - Option 4 : 1, 2 and 3

Explanation:

Defects in forging:

• A mismatch occurs in drop forging when the dies are incorrectly aligned, and results in a lateral displacement between portions of the forging.
• Scale pits are shallow depressions caused by hot removing scale from the dies. The scale is subsequently worked into the surface of the forging.
• An unfilled section is similar to misrun in casting and occurs when metal does not completely fill the die cavity. It is usually caused by using insufficient metal or insufficient heating of metal.
• Defects resulting from improper heating and cooling of the forging such as burnt metal, decarburized steel, and flakes.
• These defects are found in all metals which are heated to the plastic stage and then shaped.
• Defects resulting from the melting practice, such as dirt, slag and blowholes.
• Defects resulting from improper forging such as seams, cracks, laps etc.
• Ingot defects such as pipes, cracks, scabs and segregation.
• Fins and rags are small projections or loose metal driven into the surface of the forging happens due to poor die-design.