Press forging
Press forging dies are similar to drop forging dies as also the process. In press forging the metal is shaped not by means of a series of blows as in drop forging, but by means of a single continuous squeezing action. This squizing is obtained by means of hydraulic presses. Because of continuous action of the hydraulic presses, the material gets uniformly deformed throughout the entire depth. More hammer force is likely to be transmitted to the machine frame in drop forging where in press forging it is absorbed fully by stock. The impression obtained in press forging is clean compared to that of jarred impression which is like in drop forged component. The draft angle in press forging is less than in drop forging. But the press capacity required for deforming is higher and as a result the smaller sized component only are press forged in closed impression dies.
The processes have capacities ranging from 5MN to 50 MN for normal application For special heavy duty application, higher capacity press of order 150 MN are required. To provide the necessary alignment the two halves, die post are attached to the bottom die so that the top die would slide only on the post and thus register the correct alignment. This ensures better tolerance for press forged components.
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