Civil Engineering Reference
In-Depth Information
Top Platen
Insulation
Top Die
Specimen
Bottom Die
Insulation
Electric
Cable
Bottom
Platen
Fig. 9.31
Test setup for EAF tribological evaluation [
13
,
14
]. This test setup included insulated
top and bottom dies that compressed ring compression samples, while thermal and mechanical
data were collected
Initial specimen
Deformed specimen -Low friction
Deformed specimen -High friction
Fig. 9.32
Effect of friction on the deformation pattern [
13
,
14
]. If there is low friction, the inside
diameter of the ring compression specimen will increase throughout the test. Conversely, if there
is high friction, the inside diameter will decrease over the duration of the test
The purpose of the ring compression test is to establish a correlation between
the friction conditions at the workpiece/die interfaces and the ratio of the reduction
of the inner diameter, and use it to quantify the existing friction conditions. The
internal diameter of the ring is very sensitive to the friction conditions. If the fric-
tion is low, than the internal diameter increases, but if the friction is high, the inner
diameter reduces (Fig.
9.32
). The shear friction for the lubricant can be estimated
when the inner diameter reduction corresponding to a certain height reduction is
measured. This value is superimposed on friction calibration curves determined
using finite element analysis (FEA) [
18
,
19
].
