Closed-Die Forging in Hammers and Presses

Abstract This article provides an overview of the capabilities of closed-die forging. One of the most important aspects of closed-die forging is proper design of preforming operations and of blocker dies to achieve adequate metal distribution. The article describes the effects of friction and lubrication in forging. It discusses the types of closed-die forgings, namely, blocker-type, conventional, and close-tolerance. The article illustrates the classification of forging shapes and explains how to predict the forging pressure and the control of die temperature during closed-die forging. It explains the use of heating equipment for closed-die forging and tabulates the maximum safe forging temperatures for carbon and alloy steels. The article concludes with a discussion on a trimming method used for closed-die forgings.