Closed die forging

The shaping of hot metal completely within the walls or cavities of two diesThe metal blocks into which forging impressions are machined and from which forgings are produced. that come together to enclose the workpiece on all sides. The impressionA cavity, or series of cavities (multiple), machined into a forging die to produce a desired configuration in the workpiece during forging. for the forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. can be entirely in either dieThe machined recess in a die that gives the forging its shape. or divided between the top and bottom diesThe metal blocks into which forging impressions are machined and from which forgings are produced.. Impression-die forging, often used interchangeably with the term closed-die forging, refers to a closed-die operation in which the dies contain a provision for controlling the flow of excess material, or flashMetal in excess of that required to fill completely the blocking or finishing forging impression of a set of dies. Flash extends out from the body of the forging as a thin plate at the line where the dies meet and is subsequently removed by trimming. Because it cools faster than the body of the component during forging, flash can serve to restrict metal flow at the line where dies meet, thus ensuring complete filling of the impression. See also Closed-Die Forging.... More, that is generated. By contrast, in flashless forging"True" closed die forging in which metal deformed in a die cavity permits virtually no excess metal to escape., the material is deformed in a cavityThe machined recess in a die that gives the forging its shape. that allows little or no escape of excess material. See Impression Die ForgingA forging that is formed to the required shape and size by machined impressions in specially prepared dies that exert three-dimensional control on the workpiece..