Q. Explain the following terms.
(i) Flash in forging.
(ii) Fullering and up setting in forging.
(iii) Trimming of forging components.
Ans.(i) Flash in forging
Flash is internal breaks and ruptures. It is caused due to rapid cooling of the work piece. Flash is disadvantage of the forging operation because during the forging operation a small metal part is break from the forging due to applied force of hammers.
(ii) Fullering and up setting in forging.
Fullering
Reducing the thickness of a work piece is done in fullering operation. In the hand i.e. hole of the anvil, the bottom fuller is held and the heated work piece is placed over it. Then the top fuller is placed over it and the hammering operation is carried out till the piece gets required thickness by moving the job to and fro.
Upsetting or jumping
It is the process in which the cross-section of a bar is increased with a corresponding reduction in its length. In upsetting, the increase in thickness is generally local, like forming the head of a bolt.
(iii) Trimming of forging components
Since the is not fully closed in forging operation, it should properly be called impression die. The die cavity however must be filled without defects of material flow.
When some of the material flows outwards and forms a flash, which is excess metal that is remove by equipments. This process of removal of excess material is known "trimming of forging components".