Many operations in manufacturing, particularly processes such as forging, rolling,
and extrusion (Part III), are performed with the workpiece subjected to compressive
stresses. The compression test, in which the specimen is subjected to a compressive
load, gives information that is useful for estimating forces and power requirements
in these processes. This test is usually carried out by compressing a solid cylindrical
specimen between two well-lubricated flat dies (platens). Because of friction between
the specimen and the platens, the specimen’s cylindrical surface bulges, an effect is
called barreling (see Fig. 14.3). Note that slender specimens can buckle during this
test; thus, the height-to-diameter ratio of the solid cylindrical specimen is typically
less than 3:1